Theses and Dissertations (Anatomy and Physiology)

Permanent URI for this collectionhttp://hdl.handle.net/2263/32296

Browse

Now showing 1 - 20 of 31

Mitigating the negative effects of heat stress in broiler chickens using Saccharomyces cerevisiae and ascorbic acid
(University of Pretoria, 2024-04) Chamunorwa, Joseph P.; Naidoo, Vinny; Oosthuizen, Marinda C.; devicpet@gmail.com; Sumanu, Victory Osirimade
The production of broiler chickens is often affected by fluctuating environmental conditions leading to loses economically during the hot summer season globally. This has resulted in calls to evaluate the non-ventilating measures available for alleviating excessive heat stress in broiler chickens. Antistress and/or antioxidant agents are readily available and potent agents that are considered in mitigating the negative effect of heat stress in broiler chickens‘ production. The research focused on mitigating the negative effects of heat stress using Saccharomyces cerevisiae and ascorbic acid in broiler chickens. Fifty-six broiler chicks were divided into 4 groups of 14 each, control, probiotic-administered, ascorbic acid-administered and probiotic + ascorbic acid-administered. Broiler chickens were fed diet fortified with probiotic at a dose of 1 g/kg of feed and ascorbic acid at a dose of 200 mg/kg of feed from day (D) 1 to D35 of the study period. Cloacal temperature (CT), temperature-humidity index, dry-bulb temperature and relative humidity and in the pen were obtained bi-hourly, from 07h00 – 19h00, while body surface temperature (BST) was measured thrice on D21, D28 and D35 of the study period. Feed intake, water intake and body weight were measured on D7, D14, D21, D28 and D35 of the study. Behavioural parameters were measured on D21, D28 and D35 of the study period. Interleukin 10 (IL-10) gene expression; 8-hydroxyl-2-dioxyguanosine (8-OHdG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) activities and concentration, respectively, as well as erythrocyte osmotic fragility (EOF), haematology and small intestinal morphology, were evaluated after sacrificing the chickens at the end of the experiment. Ambient temperature parameters were outside the thermoneutral zone which was indicative of thermal stress during this study. Cloacal temperature and body surface temperature (BST) obtained in the treatment groups were significantly higher (P < 0.0001) than those of the control. Water intake and body weight were significantly higher (P < 0.01) in the treatment groups when compared to the control. Improved tonic immobility and vigilance parameters were obtained in the treatment groups when compared with the control group. The administered antioxidants were efficacious in reducing the expression of oxidative gene damage and enhancing that of interleukin-10. Superoxide dismutase, CAT, GPx, EOF and some haematological parameters were significantly lower (P < 0.0001) in the treatment groups when compared with the control. Small intestinal morphometry and goblet cells count were significantly higher (P < 0.0001) in the treatment groups in comparison with the control group. Interestingly, chickens on probiotic and/or ascorbic acid did not display the detrimental effects of heat stress compared to the control group and this was evident in their performance indices. We therefore conclude that both probiotic and ascorbic acid, anti-stress and antioxidant agents show potential to be effective in mitigating the negative effects of heat stress in broiler chickens, while the best performance was obtained in the Saccharomyces cerevisiae group of broiler chickens. Based on this result, production scale studies are recommended.
Correlation of cloacal gland histomorphology, ultrastructure and androgen receptor expression with testosterone levels during sexual maturation in the Japanese quail (Coturnix coturnix japonica)
(University of Pretoria, 2020) Madekurozwa, Mary-Catherine; Neves, Luís C.B.G.; siyamamkela21@gmail.com; Gunuza, Siyamamkela Zikhona
The cloacal gland of the Japanese quail is an enlarged glandular protuberance, found on the dorsal wall of the cloaca. The gland is unique to the genus Coturnix and is present in both male and female quails, but only sexually active males demonstrate functional development. There is a positive correlation between the size of the gland and circulating testosterone levels. Furthermore, it is known that testicular activity and cloacal gland size are influenced by photoperiod. However, it is unknown whether sexual maturation during a period of decreasing daylength affects the morphology of the cloacal gland. Thus, the aim of the current study was to investigate the correlation of cloacal gland histomorphology and ultrastructure with testosterone levels in the Japanese quail during sexual maturation through a period of decreasing daylength. A total of 7 pre-pubertal, 7 pubertal and 7 adult male Japanese quails were used in this study. The cloacal glands of the birds were investigated using: haematoxylin and eosin staining; periodic acid Schiff and alcian blue histochemistry; terminal deoxynucleotidyl transferase-mediated deoxyuridine 5’-triphosphate nick-end labelling (TUNEL); androgen receptor immunohistochemistry and transmission electron microscopy. In addition, testosterone levels were measured in blood samples collected during euthanasia. Histological examinations revealed that the glandular units of the cloacal glands in pre-pubertal, pubertal and adult birds were lined by columnar secretory cells. The secretory cells showed positive staining for periodic acid Schiff and alcian blue, indicating the presence of both acidic and neutral mucopolysaccharides. The cloacal gland cells in pre-pubertal birds were TUNEL negative, while positive TUNEL staining was observed in nuclei of the secretory cells in pubertal and adult birds. These results suggest that decreasing daylengths caused a decrease in testicular activity which led to a reduction in circulating testosterone levels in the pubertal and adult birds. Due to the fact that the cloacal gland is an androgen-dependent organ, the reduction in testosterone resulted in glandular regression. At an ultrastructural level apoptotic cells were observed in the glandular units of pubertal and adult birds. These ultrastructural findings corroborate the TUNEL results. This study has shown that changes in plasma testosterone concentrations, during sexual maturation, are positively correlated with histomorphological and ultrastructural alterations in the cloacal glands of Japanese quails.
Reproductive physiology of the female African lion (Panthera Leo), and development of artificial insemination protocols
(University of Pretoria, 2019) Ganswindt, Andre; Lüders, Imke; icallealta@gmail.com; Callealta Rodríguez, Isabel
At present, most felid species are listed as Vulnerable or Endangered by the International Union for the Conservation of Nature (IUCN). Assisted reproduction techniques (ART), such as artificial insemination (AI), are extremely important for their conservation. However, ART overall success in non-domestic felids remains <25%. Thus, research on the specific feline reproductive physiology, and development of a model for application of ART into the breeding conservation of these species is needed. With that purpose, the African lion served as a large-felid-model species. Six lionesses were trained by positive reinforcement conditioning (PRCT) to voluntary allow frequent collection of blood samples and vaginal swabs. In parallel, their ovarian cycles were non-invasively monitored by behavioural observation and measurement of faecal steroid metabolite concentrations. This information was used to determine the optimum timing for AI in this species. Routine sampling by PRCT was possible after 20 weeks of training, enabling collection of about 750 vaginal swabs and 650 blood samples over 18 months. Revealed plasma and faecal oestrogen and progestogen profiles allowed identification of and differentiation between pregnancy and pseudopregnancy, but resulted inconclusive for oestrus detection. For the first time, the ovarian cycle of the African lioness was described from a detailed cytological point of view, including the report of Simonsiella spp. during oestrus, and a remarkably high number of neutrophils during proestrus in all females. Lastly, non-surgical AI with fresh semen in lionesses presenting natural heat was possible both, prior to and after ovulation induction with GnRH, resulting in the birth of the first lion cubs ever conceived by AI.
Changes in the testicular capsule and peritubular boundary tissue in pre-pubertal, pubertal and adult Japanese quails (Coturnix Coturnix Japonica)
(University of Pretoria, 2020) Madekurozwa, Mary-Catherine; khumalolindokuhle7@gmail.com; Khumalo, Lindokuhle Innocent
The aim of this study was to investigate age-related changes in the morphology of the peritubular boundary tissue and the testicular capsule of pre-pubertal, pubertal, and adult Japanese quails. The peritubular boundary tissue and testicular capsule are involved in the propulsion of spermatozoa from the seminiferous tubules into the excurrent duct system. In addition, the peritubular boundary tissue is thought to contribute to the formation of the blood-testis barrier. The use of transmission electron microscopy, as well as the immunolocalization of key cytoskeletal proteins revealed that the testicular capsule in the Japanese quail was composed predominantly of smooth muscle cells with relatively few fibroblasts. Furthermore, the use of histochemistry demonstrated the presence of collagen and reticular fibres in the testicular capsule, with a few elastic fibres present only in adult quails. In the current study, the morphology of the peritubular boundary tissue varied with testicular maturation. The results showed a reduction in the number of peritubular cell layers surrounding the seminiferous tubules as the birds matured. In addition, immunohistochemistry revealed age-related changes in the localization of cytoskeletal and basement membrane proteins.
Age related changes in apoptosis of germ cells in normal and dibutyl phthalate-treated testes of Japanese quail (Coturnix coturnix japonica)
(University of Pretoria, 2021-03) McGaw, Lyndy Joy; mzakariah@unimaid.edu.ng; Zakariah, Musa
Excess germ cells in normal and in pathological conditions are removed from testicular tissue by the mechanism of apoptosis. Studies on germ cell apoptosis in avian species are grossly lacking, and there are only a few reports of induced germ cell degenerations in the testicular tissue of birds. This study was designed to evaluate selected pro-apoptotic proteins, their mechanism of action and their involvement in germ cell apoptosis. Seminiferous tubule parameters such as seminiferous tubule diameter, seminiferous tubule epithelial height and seminiferous tubule lumen diameter were also investigated. In addition, the process of apoptosis of germ cells under normal conditions, and in pathological conditions induced by an endocrine disruptor, di-n-butyl phthalate (DBP) in the testes of Japanese quail (Coturnix coturnix japonica) was evaluated. Features of germ cell apoptosis were observed in birds of all age groups, namely pre-pubertal, pubertal, adult and aged under normal conditions. The morphological features of these apoptotic germ cells under normal conditions ranged from irregular nuclear membrane, ruptured nuclear membrane, condensed nuclear material and apoptotic bodies. The treated birds were administered a daily dosage of 10, 50, 200 or 400 mg/kg/body weight of DBP (dissolved in corn oil) for 30 days intra-gastrically by lavage. Apoptosis of germ cells in the quail under normal conditions and those of the DBP treated groups was evaluated using various methods. These included haematoxylin and eosin (H&E) staining, TdT dUTP Nick End Labeling (TUNEL) assay and electron microscopy, and results were similar to those observed in previous studies of germ cells and somatic cells of mammalian species. The observed morphological features of these apoptotic cells under pathological (DBP-treated testis) conditions were also similar to those under normal conditions, which ranged from irregular plasma and nuclear membranes in the early stage of apoptosis to rupture of the nuclear membrane, condensation of nuclear material, as well as fragments of apoptotic bodies, in later stages of apoptosis. These apoptotic germ cell features were similar to those observed in mammalian species, although the DBP doses were higher in reported data on mammalian species. Therefore, it is logical to propose that spermatogenic cells of Japanese quail seem to be more sensitive to DBP-induced germ cell degenerations compared to mammalian species. Therefore, more studies need to be conducted on the effects of DBP exposure on avian spermatogenesis.
Morphology of the Southern Ground-Hornbill (Bucorvus leadbeateri) gastro-intestinal tract
(University of Pretoria, 2020) Crole, Martina R.; Koeppel, Katja Natalie; u13024982@tuks.co.za; Naude, Anel Delene
The Southern Ground-Hornbill (SGH) is the largest bird species that breeds cooperatively and the only entirely carnivorous hornbill. Currently, there are only an estimated 417 breeding groups in South Africa. As the bird is an obligatory carnivore the gastro-intestinal tract (GIT) may display specific adaptations which could be of significance in the husbandry of this endangered species. Factors that contribute to unnatural mortality in SGH’s in South Africa are poisoning, both primary and secondary; electrocution on transformer boxes; shooting; and illegal capture for trade. An undescribed threat is lead contamination of hunting offal from the use of lead-based ammunition as well as object ingestion as the SGH is a non-discriminate eater in the wild as well as in captivity. Carnivorous bird species have important gastrointestinal differences in anatomy, physiology, nutrition, and disease etiologies that greatly affect the success of medical and surgical intervention during gastrointestinal diseases. Nine adult SGH’s, of either sex, which succumbed due to natural causes, unknown causes, attack from other birds, euthanasia for humane reasons or untreatable conditions and management reasons (usually reproductive failure) were used in this study. Deceased birds were from Mabula Ground Hornbill project (Bela-Bela, Limpopo, South-Africa) and were transported to the Faculty of Veterinary Science for post-mortem examination. After the latter, the GIT with the liver, pancreas and spleen, were removed and immersion-fixed in 10% neutral-buffered formalin. In some instances, not all parts of the digestive tract were included in the study due to obvious pathology. The hollow organs were cut longitudinally to reveal and describe the inner surfaces. The topography of the organs was described and captured during postmortem examinations with a Go-pro HERO 7 action camera (American technology) and a Samsung A51 smartphone (Samsung electronics, South Africa). The terminology used in this study is that of Nomina Anatomica Avium (Baumel, 1993). After the gross description, samples for histology from the various sections of the GIT were taken, dehydrated and there after processed through 50:50 ethanol: xylol, 2X xylol and 2X paraffin wax using a Shandon model 2LE Automatic Tissue Processor. Tissue samples were then manually imbedded in paraffin wax in plastic moulds. Sections were cut at 3-5 μm and stained with Haematoxylin and Eosin (H&E), Peroidic Periodic acid–Schiff (PAS) and Masson’s Trichrome. The most notable organ from ventral view was the ventriculus situated between the two liver lobes. The coelom cavity is divided into cavities, cranial to caudal consist of a pericardial cavity (Cavum pericardii), four hepatic peritoneal cavities (Cavitas peritonealis hepatica), and an intestinal peritoneal cavity (Cavitas peritonealis intestinalis). The proventriculus is situated in the left Cavitas peritonealis hepatica dorsalis, the ventriculus is situated in the left Cavitas peritonealis hepatica ventralis, the intestine in the Cavitas peritonealis intestinalis and the liver in the left and right Cavitas peritonealis hepatica ventralis and Cavitas peritonealis hepatica dorsalis. The four Cavitas peritonealis hepatica are bounded caudally by the transversely oriented Septum posthepaticum and separates the Cavitas peritonealis hepatica from the Cavum intestinale peritonei. The proventriculus was small and the ventriculus large. Low longitudinal folds were present on the luminal surface allowing for distention, for large prey to move through. Gll. proventriculares profundae were visible macroscopically in the wall of the proventriculus and formed the main feature on the cut surface. Some of the glands emptied into the cranial aspect of the ventriculus and were more concentrated on the dorsal aspect, the Zona intermedia gastris. The proventriculus was seperated from the ventriculus by the Isthmus gastris. The large ventriculus displayed prominent longitudinal folds on the dorsal surface that ran perpendicular to the ventriculo-duodenal opening on the luminal surface and circumferentially around the Centrum tendineum. The pylorus was on the right lateral aspect of the ventriculus and was represented by the slit-like ventriculo-duodenal opening. The intestine consist of the duodnenum, jejunum, ileum and the large intestine, or the rectum. There is a total of 5 loops comprising the small intestine. The Flexura duodenojejunalis marked the transition from the duodenum to the jejunum. The point where the last branch of the cranial mesenteric artery supplied the small intestine marked the transition from the jejunum to the ileum, no Meckel’s diverticulum was present in order to identify this transition. The rectum was short and straight and slightly larger in diameter than the ileum. Ceacae were not observed. The pancreas was situated in the Ligamentum pancreaticoduodenale, between the descending and ascending duodenum, or the Ansa duodenalis. It was composed of three lobes, the dorsal lobe (Lobus pancreaticus dorsalis), the ventral lobe (Lobus pancreaticus ventralis) and the splenic lobe (Lobus pancreaticus splenalis). The Ductus pancreaticus ventralis, Ductus pancreaticus dorsalis and Ductus pancreaticus accessorius, were identified and drained into the ascending duodenum at the duodenal papilla, at the point where the bile ducts entered the ascending duodenum. The liver was large, with a smaller left lobe (Lobus hepaticus sinister) and a larger right lobe (Lobus hepaticus dexter). The two lobes were separated caudally by a complete deep, median, caudal interlobular incisure (Incisura interlobaris caudalis) and connected by the Pars interlobaris. Various organs made impressions on the liver. Two bile ducts were present, the Ductus hepatoentericus communis and the Ductus cysticoentericus.
A comparative morphological and morphometric study of the Musculi bulbi oculi and Apparatus lacrimalis in the ostrich (Struthio camelus) and emu (Dromaius novaehallandiae)
(University of Pretoria, 2017) Groenewald, Hermanus B.; elly1@mweb.co.za; Kleyn, Ellené
The unique adaptation of the avian eye is reflected in its ocular anatomy. The ostrich and emu are commercially important species and a comparative study of the M. bulbi, lacrimal apparatus and their innervation would provide important ophthalmological data. Both species have large eye globes to which four recti, two oblique and two nictitating membrane muscles insert. Greater similarities in the origins of these muscles are evident between the two species, compared to their respective insertions. Branches of cranial nerves II to VII course within the orbit of both species, with cranial nerves II to VI innervating the eye and M. bulbi. The route of CN VI differs from that of other avian species whereas that of CN V and VII differs between the ostrich and emu. The M. bulbi in both species differ in mass, volume, isometric force and power generation, indicating possible variations in the dynamics of ocular motility. Each eye has an associated Harderian and lacrimal gland which empty at the inner margin of the nictitating membrane and lower eye lid, respectively. Morphological variation is evident, with the ostrich lacrimal apparatus being more robust, distinctly lobulated and pigmented. In both species, the lacrimal apparatus is compound in nature. A single large secretory duct extends into the body of both glands in the ostrich and emu, before branching into two to three smaller ducts into which the simple branched tubular units constituting the glands open. The secretory epithelium is simple columnar in nature. Concentrations of lymphocytes are observed in both glands confirming the general observation that the Harderian gland in particular plays an important role in local ocular immunity. The morphology and innervation of the ostrich and emu M. bulbi and Apparatus lacrimalis follow the general avian pattern. However, the small interspecies variations noted should be considered during diagnostic or surgical procedures on the eye or associated structures.
Identification of biomarkers of tumour blood vessels for therapeutic targeting
(University of Pretoria, 2014) Mabeta, Peaceful Lucy; Skepu, Amanda; phumlanit@mintek.co.za; Tetyana, Phumlani
Cancer is a disease that develops as a result of unregulated cell growth, whereby damaged cells grow and divide uncontrollably forming lumps of tissue called tumours. Tumours can either be benign, wherein the tumour is confined within a single cluster and cannot spread to neighbouring tissues, or malignant wherein the tumour is mixed with normal cells and has the ability to invade and grow in normal tissues at a different site (Plank and Sleeman, 2003). The growth and development of tumours is dependent on a continuous supply of blood to ensure a sufficient stream of nutrients and oxygen to the tumour and also the removal of metabolic waste products (Neal and Berry, 2006; Neufeld and Kessler, 2006; DuBois and Demetri, 2007). This is achieved through a process called angiogenesis, the growth of a new network of blood vessels from pre-existing vessels (Bouis et al., 2006; Bhat and Singh, 2008). The aim of the study was to investigate the expression of biomarkers in vascular tumour endothelial (endothelioma) cells and to correlate the biomarker expression with endothelial cell growth and migration, important processes in angiogenesis and tumour progression. Molecules which interfere with cell function, LY294,002 and PF573,228 were employed in this study. LY294,002 is an inhibitor of Phosphatidylinositol 3-kinase (PI3K) signalling, which is involved in the regulation of cell proliferation, cell growth (size) and survival. PF573,228 is an inhibitor of focal adhesion kinase (FAK). FAK forms a scaffold for the attachment of cells at the extracellular matrix and is an important mediator of cell migration and invasion. The MTT assay was used to determine the viability of the cells after treatment with the drugs. Real time cell analysis was also used to determine the migration and invasion of endothelioma cells in response to basic fibroblast growth factor, a proangiogenic factor. Light and electron microscopy were employed to investigate morphological changes of the cells following treatment, while caspase activity was measured using an enzyme linked immunosorbent assay (ELISA). Array studies were undertaken to investigate the expression of angiogenic markers in control and drug-treated cells. A dose-dependent decrease in cell viability and migration were observed in treated cells, with LY294,002 showing a higher potency compared to PF573,228 in both instances. Further studies were undertaken using LY294,002 due to its potency. Light microscopy studies showed that treated cells displayed signs of apoptosis such as an irregular shape and chromatin condensation attributes which were not observed in non-treated cells. This was confirmed by electron microscopy which further revealed signs of apoptosis such as chromatin condensation and margination as well as membrane blebbing. An increase in caspase activity in treated endothelioma cells also confirmed the apoptotic effects of LY294,002. Alteration of the expression levels of various pro- and anti-angiogenic markers in treated cells was observed. Biomarkers that have been suppressed by LY294,002 in treated cells could offer great insight into cancer progression. Also, these markers can serve as targets for cancer therapy in targeted drug delivery.
A morphological study of the kidney and renal portal system of the Cape griffon vulture (Gyps coprotheres)
(University of Pretoria, 2015) Groenewald, Hermanus B.; Duncan, Neil M.; laurenhavenga@hotmail.com; Havenga, Lauren Nicole
In the 1990 s, diclofenac was responsible for the inadvertent deaths of over ten million vultures on the Asian subcontinent. While the pathology associated with their deaths was clearly evident as visceral and articular gout, the mechanism behind their death remains an enigma. In one of the supposition proposed on a potential mechanism of toxicity, it was postulated that the acute necrosis of the proximal convoluted tubules was caused by ischaemia. More specifically, toxicity was related to the avian renal vascular anatomy, whereby a renal portal blood supply exists viz. venous blood originating from the hind-quarters co-perfuses the kidney with arterial blood from the aorta. A further uniqueness of this system, is the presence of the renal portal valve in the v. iliaca communis, which appears to control the shunting of venous blood from the hind limbs to the vena cava, thereby bypassing the cranial renal lobe in times of stress. In the theory put forward, it was suggested that the valve could be under prostaglandin control and that diclofenac (a potent cyclooxygenase inhibitor) would potentially induce a change in the valve functionality with the net effect being the shunting of blood away from the cranial renal lobe resulting in hypoperfusion, ischaemia and necrosis of this lobe. While the theory appears plausible, the valva renalis portalis has only been described in a small number of other bird species such as the chicken (Gallus domesticus) and ostrich (Struthio camelus), which actually has six valvae renales (de Carvalho, et al. 2007). The aim of this study was to evaluate the renal anatomy and related vasculature of the Cape griffon vulture (Gyps coprotheres) (CGV), which is senstive to the toxic effects of diclofenac. Special attention is also being given to comparisons with the anatomy of the domestic chicken. This study made use of 13 CGVs. Six specimens were freshly perfused with formalin within minutes of being euthansed. In all cases, the birds were euthanised on the recommendation of the treating veterinarian due severe orthopaedic injuries. The birds were otherwise deemed to be healthy. For the histological portion of the study, evaluations were made of both stored samples in the bank at the Section of veterinary pathology of the University of Pretoria, while renal and associated vascular tissue from two of the freshly fixed birds were prepared using standard H&E techniques. The other seven were recovered dead in the field. Of these four were prepared for skeletal evaluation, and the remainder used for vascular casting. The kidneys of the CGV were present within the fossae renales and were well attached to the synsacrum and the ilium, and was trilobular. While this was similar to the chicken, the divisions with their connective tissue capsule in the vulture was much more prominent than in the chicken. The vasculature was also almost identical to the domestic chicken, with the only differences being at the entrance of the v. portalis renalis caudalis and the exit of the v. renalis caudalis into the v. iliaca communis on the right. The valva renalis portalis was also present in same location described in the chicken with a similar appearance viz. the valve was present in the v. iliaca communis between the v. renalis caudalis and the v. renalis cranialis and appeared as conical shaped, with finger-like processes. Histologically, the CGV kidney was similar to that to other avian spp, with reptilian, mammalian and intermediate nephrons being evident. The kidney also had the expected appearance with the cortex consisting of the glomeruli and the medulla being made up of medullary cones. On cross-section the renal portal valve was composed of smooth muscle finger-like projections that protruded into the lumen of the lumen of the v. iliaca communis. The valve was well vascularised and was associated with a nerve plexus. While the plexus could not be conclusively associated with the valve, the renal portal valve is the only intravascular smooth muscle structure that has been described to have sympathetic and parasympathetic innervation. Based on the findings of this study, the proposed mechanism of toxicity of diclofenac is anatomically possible. The similarity of the chicken and vulture in their anatomical structure may also explain previous finding that the chicken could serve as a physiological model of the study of the pathophysiology of diclofenac s toxicity.
Aspects of the morphological radiographic and ultrasonographic anatomy of the red panda (Ailurus fulgens) and ring-tailed lemur (Lemur catta)
(University of Pretoria, 2015) Groenewald, Hermanus B.; Du Plessis, Wencke M.; modesta_makungu@yahoo.com; Makungu, Modesta
The red panda and ring-tailed lemur are species, which are commonly kept in zoological gardens. The red panda and ring-tailed lemur are classified as vulnerable and endangered, respectively, by the International Union for Conservation of Nature and Natural Resources. The aim of this study was to describe the normal radiographic thoracic anatomy, radiographic and ultrasonographic abdominal anatomy as well as the normal morphology of the pelvis, thoracic and hind limb in captive red pandas and ring-tailed lemurs as a reference for clinical use. Radiography and ultrasonography were performed in adult captive red pandas and ring-tailed lemurs during annual health examinations. Bone specimens of adult red pandas and ring-tailed lemurs were used for gross osteological study. The morphology of the pelvis, thoracic and hind limb of the red panda and ring-tailed lemur supported the presence of strong flexor and supinator muscles and flexibility of limb joints, which are important in arboreal quadrupedal locomotion. However, the scapula of the ring-tailed lemur is modified for both arboreal and terrestrial quadrupedal locomotion. Additionally, the morphology of the pelvis and hind limb of the ring-tailed lemur showed locomotor adaptation for jumping. Normal radiographic and ultrasonographic reference ranges for thoracic structures and abdominal organs were established and ratios were calculated. Knowledge of the normal morphology, radiographic and ultrasonographic anatomy of the red panda and ring-tailed lemur should prove useful in the diagnosis of diseases and for routine health examinations.
Computed tomography of the thorax and abdomen of the clinically normal common marmoset (Callithrix jacchus)
(University of Pretoria, 2015) Groenewald, Hermanus B.; Gaschen, L.; wduplessis@rossvet.edu.kn; Du Plessis, Wencke M.
The aim of this study was: 1) to describe the computed tomographic thoracic and abdominal anatomy in the clinically normal common marmoset; 2) to describe the normal reference range of Hounsfield units (HU) of major abdominal and thoracic organs; 3) to refine the computed tomography (CT) protocol; 4) to compare abdominal CT to other imaging modalities such as radiography and ultrasound (US). Eight clinically healthy mature common marmosets ranging from 12 to 48 months and 235 to 365 g bodyweight were anesthetised and pre- and post-contrast CT examinations were performed using different CT settings. In 3/8 common marmosets radiography was performed at the same time. Diagnostic quality images could be obtained in the common marmoset despite its small size and high respiration rate using a dual slice CT scanner. Quantitative and qualitative assessments of major thoracic and abdominal structures were obtained. The HU of major abdominal and thoracic organs differed from small animals. Representative cross-sectional images were selected and relevant anatomy was labeled. None of the thoracic lymph nodes were detected and separation of individual lung lobes besides the accessory was only occasionally seen. Identification and delineation of abdominal organs greatly improved with i.v. contrast. A high frequency algorithm with edge enhancement proved to be particularly beneficial for the evaluation of thoracic and to a lesser degree abdominal CT. Due to their size and species specific anatomy (also reflected in their different normal range of HU of individual organs), standard small animal CT protocols need to be critically assessed and adapted for exotics, such as the common marmosets. Imaging findings differed from described anatomic findings (such as positioning of kidneys in relationship to lumbar vertebrae) and could either be due to different study population, imply more mobility of kidneys similar to cats, or emphasize that CT might be better for certain aspects of anatomic descriptions than actual anatomy studies, since it is done in vivo versus the traditional post-mortem approach. This study established normal reference ranges for the thoracic and abdominal computed tomographic anatomy of clinically healthy common marmosets, including adapted CT protocols. This baseline study should facilitate CT examinations of marmosets in a clinical set-up and it is anticipated that diagnostic proficiency will be facilitated. The decision to perform advanced imaging is multi-factorial and highly dependent on patient factors, user experience with the modality and species, emotional value to the owner, availability and accessibility of equipment will be important decision criteria in developing decision strategies in clinical settings. Under ideal circumstances US is recommended as the screening tool of choice for the abdomen in the common marmoset. Radiography still plays an important role as a baseline imaging modality for the abdomen, particularly as whole body radiography in the common marmoset, providing simultaneous information about the thorax and the skeletal system; however its limitations must be considered. In cases where further work-up would be required or in certain clinical presentations, CT should be recommended and should always be combined with i.v. contrast.
Comparative morphology and functional significance of mechanical and sensory structures in the upper digestive tract of the ostrich (Struthio camelus) and emu (Dromaius novaehollandiae)
(University of Pretoria, 2013) Soley, John Thomson; martina.crole@up.ac.za; Crole, Martina Rachel
This study describes, on a comparative basis, the morphology of mechanical (the linguo-laryngeal apparatus) and sensory (Herbst corpuscles and taste buds) specialisations in the upper digestive tract (bill and oropharynx) of the ostrich and emu, with a view to a better understanding of the functional significance of these structures. The ostrich and emu are commercial entities that constitute important niche industries and are farmed intensively throughout South Africa. A lack of information on the mechanical and sensory specialisations of the upper digestive tract in these two birds hampers a sound understanding of food selection and intake. A total of 48 adult (12-14 months) ostrich heads and 48 adult emu (12-14 months) heads obtained from birds at slaughter at commercial abattoirs and farms, as well as 5 ostrich chick (2-4 weeks) heads and 1 emu chick (8 weeks) head, obtained from previous research projects, were used for this study. Morphological features were described using basic gross anatomical (dissection and stereomicroscopy) and histological techniques (H&E staining), supplemented by differential staining for cartilage and bone, transmission electron microscopy and immunohistochemistry. The findings of the study were compared with the relevant literature and hypotheses for functional significance were formed. The avian glottis channels air from the oropharynx to the trachea and is situated on an elevated structure, the laryngeal mound. It is imperative that the glottis be protected and closed during swallowing, which in mammals is achieved by covering the glottis with the epiglottis, as well as by adduction of the arytenoid cartilages. An epiglottis, however, is reportedly absent in birds. Ratites such as the ostrich and emu possess a very wide glottis in comparison to other birds. The question therefore arises as to how these large birds avoid inhalation of food particles through a wide glottis, with apparently little protection, particularly as their feeding method involves throwing the food over the glottis to land in the proximal esophagus. In the ostrich, when the glottis was closed and the tongue body retracted, the smooth tongue root became highly folded and the rostral portion of the laryngeal mound was encased by the pocket in the base of the ∩-shaped tongue body. In this position the lingual papillae also hooked over the most rostral laryngeal projections. However, in the emu, retraction of the tongue body over the closed glottis resulted in the prominent, triangular tongue root sliding over the rostral portion of the laryngeal mound. In both the ostrich and emu these actions resulted in the rostral portion of the laryngeal mound and weakest point of the adducted glottis being enclosed and stabilised. Only after conducting a comparative study between these two birds using fresh specimens did it become clear how specific morphological peculiarities were perfectly specialised to assist in the closure and protection of the wide glottis. A unique anatomical mechanism in ratites was identified, described and proposed, which may functionally replace an epiglottis; the linguo-laryngeal apparatus. The oropharynx of the ostrich and emu is richly supplied with Herbst corpuscles. This widespread distribution of these mechanoreceptors has not previously been reported in birds. Specific concentrations of Herbst corpuscles within the oropharynx, which differ between the ostrich and emu, assist in the accurate positioning of the tongue and laryngeal mound for cleaning the choana (internal nares). The Herbst corpuscles are strategically located to aid in the handling and transport of food and the median palatine and ventral ridges in the ostrich display a concentration of Herbst corpuscles which denote these structures as sensory organs, namely the palatal and interramal organs. Three specific arrangements of Herbst corpuscles were noted in the oropharynx. The first arrangement consisted of groups of corpuscles located peripherally around a myelinated nerve and was present in the bill tip. The second arrangement, possibly linked to the first, was that of individual or groups of corpuscles without an obvious associated nerve and was present throughout the remaining regions of the oropharynx. The third arrangement was that of corpuscles associated with large, simple branched tubular mucus-secreting glands. The basic structure of Herbst corpuscles in the ostrich and emu, observed by light and transmission electron microscopy, of a capsule (with cellular and acellular lamella), an outer zone (collagen fibrils, fibroblasts and a fluid matrix), an inner core (formed by bilaterally symmetrical specialised Schwann cells) and a receptor axon, is similar to that noted for other avian species. However, unlike in other birds, the capsule of the Herbst corpuscle in the ostrich and emu is formed by myofibroblasts which indicates contractile properties for this component of the corpuscle in ratites. Sensory cilia were noted in the myofibroblasts of the capsule and fibroblasts of the outer zone of the ostrich Herbst corpuscle which may assist in regulating the tension of the capsule. These features have not been reported in other avian species. Although the structure of the palaeognathous palate has been widely studied, relatively little information is available on the morphology of the ratite bill. The kiwi possesses a bill tip organ and the present study confirmed the existence of this somatosensory organ in the ostrich and emu. Examination of the rhamphotheca of these two birds demonstrated numerous specialisations. In the emu, rhamphothecal serrations with intervening keratinised pegs on the rostral mandibular tomia resembled a form of pseudo-teeth. These structures may share a similar embryological origin to teeth; however, they would appear to function by channelling and enhancing vibratory stimuli to Herbst corpuscles in nearby bony pits. In the ostrich, epidermal troughs were present in the regions overlying the bill tip organ and functioned to enhance vibratory stimuli to the underlying Herbst corpuscles. Additionally, in the ostrich only, and not related to the structure or functioning of the bill tip organ, the rostral tomia and maxillary and mandibular nails were composed of typical tubular and inter-tubular horn. This may represent a unique feature in birds. The structure of the mandible and premaxilla was similar to that described previously for these birds. However, the persistence of Meckel’s cartilage through to the adult bird in the ostrich and emu is a novel avian feature not previously reported. The bony bill tips were adorned with numerous sensory (bony) pits which displayed similar distribution patterns in the ostrich and emu and indicated the presence, macroscopically, of a bill tip organ. The total number of pits in the bill tip of the ostrich and emu did not differ significantly, although regional differences did occur. The sub-divisions of the trigeminal nerve (N. opthalmicus R. medialis and N. intramandibularis) innervating the bill tip were well developed in both birds and displayed extensive branching. The emu displayed more myelinated nerve fibres in both nerves than in the ostrich. As myelinated nerve fibres supply Herbst corpuscles, the number of nerve fibres is correlated to the number of corpuscles. No correlation could be made between the number of pits in a particular region and the number of nerve fibres or with the relative percentage of Herbst corpuscles in that region. The bill tip organ in both species was basically similar except for the epidermal specialisations noted above. Two parts of the bill tip organ were recognised; the bony bill tip organ (Herbst corpuscles stacked in bony cavities and pits) and the peripheral bill tip organ (Herbst corpuscles in sheets or chains in the connective tissue between the epithelium and bone). The morphology of the bill tip organ in the ostrich and emu indicates that it is an organ that functions by direct touch. These two ratite species appear to possess the most elaborate bill tip organ of any pecking bird. The existence of a bill tip organ in the ostrich and emu is an enigma and points to the possibility that a bill tip organ is a basal structure in all palaeognathous birds (living and extinct). Furthermore, it is evident by observing the exploratory behaviour of the ostrich and emu, that they use their bill tip organ extensively as a tool for exploring and interpreting their environment as well as for discriminating food. The sense of taste in birds is an important motivator for feeding as well as initial food selection. The existence of this sense in ratites has remained largely speculative. In the present study taste buds were only identified in the emu and were predominantly located in the caudal region of the non-pigmented oropharyngeal roof and sparsely located on the oropharyngeal floor. The taste buds extended the full width of the epithelium in which they were located and were ovoid structures. The taste bud was composed of centrally located, vertically oriented light and dark cells (representing both receptor cells and supporting elements) and peripherally situated follicular cells which were continuous with the surrounding Str. germinativum of the stratified squamous epithelium. Positive IHC labelling for neurofilament demonstrated numerous fine nerve fibres (Neurofibra gustatoria) within the connective tissue immediately surrounding the taste bud. Taste bud morphology in the emu was similar to that described in other birds. However, when sectioned tangentially they were indistinguishable from the surrounding epithelium with H&E staining. By using IHC labelling, concentrations of nerve fibres could be demonstrated beneath apparently nondescript epidermal structures, thus indicating the presence of a taste bud. The distribution of taste buds in the oropharynx could be linked to the particular feeding method of the emu. Based on information from GenBank, it would appear that the relatively few taste buds present in the emu oropharynx would mainly function in distinguishing bitter taste. As bitter-tasting compounds can cause a negative association with a particular food type, it would appear that the sense of taste in the emu would predominantly function for protection and not food selection. This study revealed various unique findings regarding the mechanical and sensory specialisations in the upper digestive tract of the ostrich and emu.  The ostrich and emu possess a combination of structures which functionally replace an epiglottis, namely the linguo-laryngeal apparatus.  Herbst corpuscles are widely distributed in the oropharynx of the ostrich and emu and their distribution is related to the particular feeding habits of these birds.  The capsule of Herbst corpuscles in the ostrich and emu is composed of contractile elements, a feature not reported in other birds.  The ostrich and emu possess a well-developed bill tip organ, which is an unusual feature amongst pecking birds.  Taste buds are present in the emu and no structures resembling taste buds were identified in the ostrich.
Arterial supply and histology of the female reproductive organs of the African lion (Panthera leo)
(University of Pretoria, 2013) Groenewald, Hermanus B.; marthinus.hartman@up.ac.za; Hartman, Marthinus Jacobus
This masters project was undertaken to have a better knowledge of the female lion reproductive tract and to equip the author for future surgical studies on this organ system. The objectives of this study were to describe the arterial supply and histology of the female reproductive organs of the African lion. The reproductive organs of three embalmed cadavers and two fresh carcasses from three-year-old known aged nulliparous lionesses weighing between 120 kg and 140 kg were studied. The project was approved by the Animal Use and Care Committee and Research Committee of the University of Pretoria (protocol number V038-09). The arterial supply of the reproductive organs was studied and described in situ and after removal and histology was subsequently performed. A novel technique in Veterinary anatomy involving the maceration of a silicone cast was used in the two fresh carcasses and all five specimens were incorporated in the comparative and arterial studies. Histology was performed on organs from the three embalmed cadavers. The anatomical information obtained during this study was subsequently applied in a surgical study on sixteen lionesses using laparoscopy to perform laparoscopic ovariectomy and salpingectomy. The availability of these two laparoscopic procedures subsequently led to a wider interest to its application in population control of lions in the smaller national parks of South Africa.
Feeding behaviour, plant species selection and in sacco ruminal digestion in Tswana and Boer goats
(2010) Boomker, E.A.; Chimonyo, M.; lebokac@yahoo.com; Lebopa, Cornelia Kedidimetse
The first experiment of this study was aimed at investigating the factors affecting the feeding behaviour and plant species selection of 3 free ranging Tswana (mean weight ± 37 kg) and 3 Boer (mean weight ± 36 kg) goat does in the False Thornveld of the Eastern Cape Province, South Africa. The feeding behaviour and plant species selection was observed and recorded during winter (cold-dry season) and summer (hot-wet season). Observations included the following categories: browsing, grazing and non-feeding activities. Non-feeding activities (NFA) include separate recordings of walking, standing, lying and drinking. Results showed goats spent 21.9 %, 44.65 % and 33.3 % of their day on browsing, grazing and non-feeding activities. Grass was clearly the preferred feed for goats both in the cold-dry season (54 %) and the hot-wet season (76 %) while browse consumption was higher in the cold-dry season (46 %) and lower in the hot-wet season (24 %). Goats spent more time on NFA in the cold-dry season (68.8 %) than the hot-wet season (31.9 %). Though diurnal variations were observed for both breeds and seasons in terms of browsing and non-feeding activities, no diurnal variations were found between the breeds. Goats selected a wide spectrum of woody-plant species. A total of thirteen woody plant species were encountered and selected by goats in the range. Scutia myrtina was the most frequently consumed (29.9 %) woody plant species in the range followed by Rhus refracta (16.3 %), Grewia occidentalis (14.0 %), Olea africana (10.8 %). These four woody-plant species accounted for 71 % of the woody plant selection by goats. Significant differences (P<0.001) were found in percentage time spent selecting the different woody-plant species by goats. The frequency of woody-plant species selection was higher in the cold-dry season than the hot-wet season. Woodyplant selection was higher in the morning followed by the afternoon and lower during midday. Percentage time spent by goats selecting woody plant species decreased with advancing period of occupation of a grazing/browsing camp. Browse was the preferred feed when feed availability was high, but when feed availability declined, the goats decreased their frequency of woody-plant selection and more grass was eaten. The second experiment was aimed at determining and comparing the nutritive value of forages selected by the same free ranging goats. Three (3) Tswana and 3 Boer goats equipped with remote controlled fistula valves were studied. Fistula valve samples were collected for 15 minutes during the day at 6 different times. All extrusa samples were kept on ice in the field and then stored in a deep freeze prior to drying and milling. Each sample was freeze-dried and hand separated into bush (woody species) and grass components (including forbs). These samples were analysed for nitrogen (N), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). The diets selected by the goats differed in CP (cold-dry season: 5.39 % ± 0.15 and hot-wet season 9.48 % ± 0.15; P=0.001), NDF (cold-dry season 48.09 % ± 1.02 and hot-wet season 53.76 % ± 1.02; P=0.001) and ADF (cold-dry season 34.32 % ± 0.72 and hot-wet season 37.50 % ± 0.72) between the seasons, but the ADF content showed no change (cold-dry season 18.01 % ± 0.52 and hot-wet season 19.49 % ± 0.52 P>0.05). Goats selected diets higher in CP, NDF and ADF during hot-wet season compared to cold-dry season. Generally, there were diurnal variations in the NDF (P=0.04), ADF (P=0.02) and ADL (P=0.01) contents of forages selected by goats. Nutrient content of selected diets decreased in quality with advancing period of occupation of a camp. Knowledge of the nutritive value of the diet as selected by these animals is of primary importance in estimating the productivity of any rangeland. The third experiment was aimed at determining in sacco dry matter (DM) and crude protein degradation of woody plant species incubated in the rumen of Tswana and Boer goats. The ruminal degradability of the three most selected woody plant species by goats during the cold-dry season (G. occodentalis, O. africana and S. myrtina) and the hot-wet season (A. karroo, R. refracta and S. myrtina), were measured in situ, using in sacco digestion techniques. The nylon bag incubation revealed large differences in the rumen degradability of DM of the three woody plant species during both cold-dry season and hot-wet season. Ruminal degradation constants (a, b and a+b and c) varied significantly (P<0.001) between breeds and between goats within a breed. Thus, no breed difference in in sacco degradation of DM and CP was found between Tswana and Boer goats. There was a strong positive correlation between DMD, CPD and time of incubation in the rumen. The crude protein content of the woody plant species positively influenced the rumen digestion of dry matter because when CP increased DMD also increased. Both species preference and degradability of plant species are needed to estimate range suitability for browsing animals. Results from this study will help to develop strategies to optimise range resources for sustainable animal production. In order to improve production, the constraints limiting success should be identified. Tswana goats might be a more favoured breed in semi-arid savannah because of their smaller body size, absolute nutrient requirement and better reproductive performance when compared to Boer goats. However, when forage availability is not a limiting factor, Boer goats might yield better returns for the investment since they are superior in meat production.
Morphological study of the effect of the cytoskeletal disrupting agent carbendazim on the oviduct of the Japanese quail (Coturnix coturnix japonica)
(University of Pretoria, 2012) Madekurozwa, Mary-Catherine; Groenewald, Hermanus B.; upetd@up.ac.za; Kimaro, Wahabu Hamisi
Carbendazim (methyl-2-benzimidazole carbamate), a derivative of N-substituted esters of carbamic acid, is widely used as a fungicide on field crops. Carbendazim is of major concern to human and animal health due to the presence of its metabolites and residues in the environment. Several studies have shown the effect of carbendazim on the reproductive systems of male mammals and birds. Relatively little is known of the effect of carbendazim on the female reproductive tract. Therefore, this study was undertaken to establish the effect of carbendazim on the morphological, histochemical and immunohistochemical features of selected regions of the oviduct in the Japanese quail. The functional implication for each region was also considered. A total of 102 sexually mature Japanese quails were used in this study. The study was divided into two experiments. In Experiment I, different doses of carbendazim, in a sunflower oil base, were administered orally to determine the minimum toxic dose which would cause degenerative lesions in the oviduct. The determined dose was used in the Experiment II to establish the time-course effects of carbendazim on the Japanese quail. In Experiment I, 400 mg/kg bodyweight of carbendazim was the minimum toxic dose which caused both macroscopic and microscopic changes in the oviduct. The effect of carbendazim was dose dependent. In Experiment II, the effect of carbendazim was more pronounced with time lapse post-exposure. Macroscopically, increases in oviductal weight, luminal epithelial height and glandular diameter were observed in the initial stages post-exposure. Atrophy and a reduction in oviductal weight were observed in later stages. Microscopically, carbendazim caused hyperaemia and oedema in all sections of the oviduct examined. Leukocytic infiltrations, pyknotic nuclei and cellular swelling were also observed. The histochemical results showed a reduction in PAS positive granules in the luminal and glandular epithelia of all oviductal sections. There were also decreases in the immunostaining intensities of E-cadherin, laminin and vimentin in all oviductal regions. Scanning electron microscopic results showed a loss of cilia, as well as swollen microvilli. Short ciliary stems and shallow pits were also observed in areas exhibiting a loss of cilia. At the ultrastructural level, luminal and glandular epithelia contained cells with degenerating nuclei and cytoplasmic organelles. The observed degenerative changes included pyknosis, karyorhexis, swollen mitochondria, dilated cisternae of rough endoplasmic reticulum, vacuolation and an increased number of lysosomes. Lipofucsin granules and filamentous aggregation were also observed. Compound cilia and myelin figures were frequently observed in the later stages of degeneration. Invagination and occasional duplication of the basal lamina, underlying both luminal and glandular epithelia, were also observed. The observed degenerative changes suggested oviductal regression in carbendazimtreated birds. Degeneration of epithelial and glandular cells may lower the fertility and productivity of exposed birds.
The morphology and development of normal and abnormal spermatozoa in the emu, Dromaius novaehollandiae
(University of Pretoria, 2012) Soley, John Thomson; Du Plessis, Lizette
The morphological features and development of normal and abnormal sperm were studied in the emu, Dromaius novaehollandiae, using both light and electron microscopy. Detailed descriptions of normal as well as abnormal forms were documented. Where possible, the origin and development of the defects were examined and interpreted. Based on these observations, a system for the morphological classification of ratite sperm abnormalities was proposed. Emu sperm typically revealed the basic filiform morphology which is common in other ratites and non-passerine birds in general. At the ultrastructural level, emu sperm displayed a conical acrosome covering the tip of the nucleus and a long distal centriole running the entire length of the midpiece. Mitochondria of the pars spiralis were more numerous than in other ratites, but no intermitochondrial cement was present in the mitochondrial sheath. Although sharing basic ultrastructural features, a distinct difference between sperm of the emu and other ratites was the complete absence of a perforatorium and endonuclear canal. Another distinctive feature revealed by all forms of microscopy was the presence of a cytoplasmic appendage located at the base of the nucleus and which appeared to represent the point of cytoplasmic release during spermiation. Based on the examination of a total of 15 semen samples collected during the middle of the breeding season from the distal deferent ducts of commercially slaughtered adult emus, a total of 14% morphologically abnormal cells were identified. Head defects were represented by bent, microcephalic, macrocephalic or round heads. Acephalic sperm were also present in all samples. Zones of incomplete chromatin condensation and retained cytoplasmic droplets appeared to be implicated in head bending, while giant heads were often associated with multiple tails. In acephalic sperm the tail was complete, but the head was absent, often being replaced by a small spherical structure. Tail defects were subdivided into defects of the neck/midpiece and those of the principal piece. In the neck/midpiece region two anomalies were noted, namely abaxial tail implantation and disjointed sperm. Abaxial tail implantation involved the eccentric positioning of the centriolar complex relative to the head base while disjointed sperm were characterized by the complete separation of the head and midpiece in the neck region, but within the confines of the plasmalemma. Defects observed in the principal piece were subdivided into short, coiled and multiple tails. Cytoplasmic droplets were classified as a separate defect. A small percentage of sperm displayed multiple abnormalities. Defective alignment and/or migration of the centriolar complex (diplosome) was implicated in a number of the defects observed, including head-base bending, disjointed sperm, acephalic sperm and abaxial sperm. Spermiogenesis in the emu broadly paralleled the development of spermatids reported in other nonpasserine birds. However, a previously undescribed morphological feature of avian sperm development was observed. During the circular manchette stage of spermatid development, a unique transient structure appeared. It was associated with the outer nuclear membrane and formed regular finger-like projections into the cytoplasm. This structure was present during both the circular and longitudinal manchette stages of development and was particularly obvious towards the apical aspect of the nucleus where it abutted the cone-shaped acrosome. There were no obvious connections between the structure and the microtubules of the manchette. During the final stages of spermatid development the structure abruptly disappeared. Despite employing immunogold labelling techniques and electron tomography, the nature and function of this structure remained unresolved. Descriptions of a similar structure in various lizard species and the Caiman crocodile, although restricted in its location to the nuclear membrane immediately beneath the acrosome, would appear to reinforce the phylogenetic link previously identified between birds and crocodiles.
The vasculature of the male reproductive organs of the ostrich (Struthio Camelus)
(University of Pretoria, 2012) Aire, Tom A.; Soley, John Thomson; Elias, M.Z.J. (Mario Zefanias Joao)
The ostrich industry is a small, important section of the economy in the Republic of South Africa. The demand for ostrich products is high in the world, but the ostrich industry faces some production problems, one of which is the low fertility of commercially farmed ostriches. This study aimed to determine the vasculature of the reproductive system in the male ostrich and determine the kind of blood-testis and blood-epididymis barriers, since there is no published information regarding this aspect. Thus 85 pre-pubertal and adult sexually active male ostrich were studied. Arterial supply, venous drainage, microvasculature of the male reproductive system, and blood-testis and blood-epididymal barriers, were determined in this specie, for the first time. Results show that the pattern of the arterial blood supply to the reproductive organs of the male ostrich is similar to that of the domestic fowl and pigeon. However, few highlighted, distinctive, features were noted, the communication between the cranial renal arteries and middle renal arteries via collateral circulation. The pattern of the venous drainage of the reproductive organs of the male ostrich, was similar to that described in the domestic fowl. However, important differences were the fusion between the caudal renal veins and the existence of a unique caudal median vein that had the caudal mesenteric vein as tributary. The epithelial structure in the proximal efferent ducts was consistent with fluid absorption. The fluid absorbed in the efferent ducts is harvested also by capillary lymphatics situated in the interstitium. Both the cranial and caudal segments of Ductus deferens and the Receptaculum ductus deferentis displayed one vascular networks beneath the tubular epithelium and other capillaries, venules, arterioles and collecting veins were in the periphery. Arterioles and collecting veins were also under the serosa. Subepithelial capillaries, in those segments, lacked fenestrations. The spongy structure, in the root of phallus, exhibited several blood vessels in the strands. The capillaries and the venules displayed fenestrations. The erectile tissue in the phallic sulcus had the same features like the spongy in phallus. The spongy is comparable to corpus paracloacal vascular body present in other avian species and it should be called lymphobulbus phalli, it is the main source of lymph for phallus erection in the male ostrich. There are similarities in the microvasculature pattern between ostrich and domestic fowl, but there are some differences in the ostrich: (i) Absence of fenestrations in the capillaries of testis, (ii) Very simple and random distribution of stromal blood capillaries, arterioles and venules in the epididymis, Endothelial fenestrations, only in the blood capillaries close to proximal efferent ducts, (iv) Isolated lymphatic capillaries in the epididymis, occasionally, presented endothelial fenestrations fitted with a membranous diaphragm, (v) Existence of three vascular networks surrounding the tubule of deferent duct and receptaculum, that were determined on the base of the distribution, location and size of the vessels. The blood-testis barrier of the ostrich is positioned: in (i) the capillary endothelium in the interstitium, between adjacent seminiferous tubule, (ii) the boundary tissue, and (iii) between spermatogonia and spermatocytes, and spermatogonia and Sertoli cells, and finally, (iv) between Sertoli cells. The occluding junctional complexes between the various tissue or cellular elements are mainly tight junctions. The blood-epididymal barrier in the ostrich is revealed by participation of the endothelium of the capillaries and venules in the epididymal region, as lanthanum is trapped there, it does not appear beyond that point. The blood-testis and blood-epididymal barriers are similar to those described for the domestic rooster.
Effect of water restriction on aspects of digestion in Boer and Tswana goats offered Eragrostis teff and lucerne hay
(University of Pretoria, 2010-05-25) meshack.qinisa@nwu.ac.za; Qinisa, Meshack Mzwandile; Prof E A Boomker; Prof H B Groenewald
The first part of this study was undertaken to investigate the effect of water restriction on aspects of digestion in Tswana goats offered Eragrostis teff hay. Twelve Tswana goat wethers approximately 15 months old weighing on average 28.67 ± 4.48 kg, were randomly allocated to form three groups of four animals in each. The groups were all exposed to the following treatments: Water ad libitum (This served as control); 50% ad libitum water intake once in the morning, and 25% of ad libitum water intake in the morning and 25% ad libitum water in the afternoon. All the goats were adapted and fed Eragrostis teff. The final body weight of the ad libitum group was higher than that of treatment groups whilst no significant difference was observed between the water restriction treatments. Rectal temperature, heart and respiration rates were not affected by water restriction. Similarly haematocrit, total plasma protein, osmolarity and plasma urea levels were not affected by water restriction. Dry matter intake was reduced by water restriction from 848.69 to 740.16 g/d. Water to dry matter ratio dropped from 1.47 to 0.79. Faecal water was not affected by water restriction. However, urine output was reduced from 321.72 to 245 and 255.17 g/d for the half and quarter ad libitum water intake groups, respectively. Insensible water loss was at 549.7 g/d for the ad libitum water intake group compared to – 0.49 and 20.86 g/d of the half and quarter ad libitum water intake groups respectively. Water use efficiency was higher (p < 0.05) for the water restricted groups compared to the ad lib water group. Digestibility coefficients for DM, ADF, and NDF were all not affected by water restriction but apparent digestibility for nitrogen was reduced from 50.7% to 44%. Specific gravity of urine was higher (p< 0.05) for the water restricted groups while urea output and urea concentration were not significantly different among all the three groups. More of the nitrogen was lost through urine in all the groups leading to a negative nitrogen balance. The negative nitrogen retention was more pronounced in the water restricted groups. It was concluded that water restriction did not affect digestion and nutrient utilization of Tswana goats when offered Eragrostis teff. In part II of this study, the aim was to investigate the effect of water restriction on aspects of digestion in Tswana and Boer goat wethers offered either Eragrostis teff or Medicago sativa. Twentyfour goats (12 Boer and 12 Tswana goat wethers) of 12 – 15 months old weighing 18.3 – 32.8 kg were randomly allocated to form 4 groups of 6 goats. Within each group, there were 3 Boer and 3 Tswana goat wethers. These were used into a 4 X 4 Latin square design with the following treatments : (1) Water and teff ad libitum (2) 50% (Half ) of ad libitum water and teff ad libitum (3) Water and lucerne ad libitum (4) 50% (Half ) of ad libitum water and lucerne ad libitum. All the animals lost weight by the end of the water restriction period when fed either teff or lucerne. This weight was regained after a day of rehydration. Both Boer and Tswana goats lost 10% of their body weight when offered lucerne while water – restricted and then regained 13 – 14% of their dehydrated body weight. For both breeds, when teff or lucerne was offered, haematocrit, total plasma proteins, heart rate and rectal temperature were not affected by water restriction. Respiration rate increased in both breeds during water restriction. Plasma urea and osmolarity rose significantly from day 0 to day 4 but there was no significant difference between day 4 and the last day (day 7) when both breeds were fed either teff or lucerne .Regardless of the breed and treatment, water restricted goats had lower water use efficiency and higher urine specific gravity values compared to ad libitum water groups. On teff, water restriction did not have any significant (p>0.05) influence on dry matter intake but faecal dry matter was reduced (p< 0.05) from 360.15 to 315.16 g/d. The water to dry matter ratio was reduced (p< 0.05) from 1.71 to 0.83. The digestibility coefficients for DM, N, ADF, and NDF were unaffected by water restriction. However, ADF and NDF digestibility coefficients were higher than those of DM and N. On lucerne, dry matter intake was significantly (p < 0.05) reduced from 1022.75 to 756.28 g/d while faecal dry matter output decreased from 384.33 to 292.15 g/d. The water to dry matter ratio dropped significantly (p < 0.05) from 2.32 to 1.29. The digestibility coefficients did not differ between the ad libitum and half ad libitum water groups. However the digestibility coefficients for ADF and NDF were lower than those of DM and N. Water restriction did not improve nitrogen retention when either teff or lucerne was offered in both Tswana and Boer goats. It was concluded that goats are efficient in utilizing water and digesting high fibre feedstuffs when water is limited. However, both breeds did not display evidence for a mechanism of improving nitrogen retention when fed low and high nitrogen feedstuffs (teff and lucerne, respectively) while water intake is restricted.
The effect of dietary energy and protein interaction on the physiological plasticity of the small intestine of the young ostrich
(University of Pretoria, 2011) Boomker, E.A.; Soley, John Thomson; Brand, T.S.; mariaanv@elsenburg.com; Viljoen, Mariaan
The study includes separate papers, which are all linked by their emphasis on the effect of different diets on the impact of the development of the small intestine of the young ostrich. This abstract is intended to provide readers with a broad overview of the outcomes of the study. Part 1: Yolk utilisation and the development of the small intestines Chapter 2 deals with the composition of egg yolk as it is absorbed by starved ostrich Struthio camelus L. ) chicks from one to seven days post-hatching and for ostrich (Struthio camelus L.) chicks from one to sixteen days post-hatching on a pre-starter broiler diet. Chapter 3 provides information on the intestinal enzymes of ostrich (Struthio camelus L. ) chicks from one to sixteen days post-hatching on a pre-starter broiler diet. The effect of growth on enzyme activity immediately post-hatching up to sixteen days of age was studied. Chapter 4 details a histological and morphological study of the gastrointestinal tract of ostrich (Struthio camelus L.) chicks from two to sixteen days post-hatching on a pre-starter broiler diet. The effect of growth on histological and morphological changes in the various parts of the small intestines was examined. Part 2: Influence on various pre-starter diets on growth and the development of the intestinal tract Chapter 5 discussed a growth and digestibility study of ostrich (Struthio camelus L.) chicks on eight different pre-starter diets. The performance, growth and physiological development of the chicks on high and low variations of different nutritional components were examined. Chapter 6 provides information on certain intestinal enzymes of ostrich (Struthio camelus L.) chicks on the eight different pre-starter diets. Chapter 7 dealt with the histological and morphological changes of the gastrointestinal tract of ostrich (Struthio camelus L.) chicks as a result of high and low variations of different nutritional components in prestarter diets. Implications The first part of this study revealed that although it appeared that yolk content was absorbed faster in starved ostrich chicks, intake of external feed had a positive influence on the absorption of fat from the yolk. The changes in the fatty acid composition of the yolk fat content that were observed may indicate that ostrich chicks have the ability to withdraw certain fatty acid components, especially unsaturated fatty acids. The digestive tract of ostrich chicks was compared with that of broiler chicks and differences observed in amylase and lipase activity between the birds in this trial and in poultry could be due to genetic differences between species. It could also be due to the genetic homogeneity of the poultry chicks that were used in the trials, whereas ostrich chicks have not been subjected to the same extent of advanced breeding improvement to date. Results on histological and morphological growth of the small intestines of the ostrich chick indicate increased absorption with an increase in age. The second part of this study revealed that ostrich chicks performed differently on diets formulated with different nutritional components. It appears that a high fat and low sugar content in the diet is advantageous in ostrich pre-starter diets. Although there were a few mortalities during the trials, there is no clear indication as to why the chicks died, as the causes of mortalities were not investigated. Differences in composition of the eight pre-starter diets did not seem to have an influence on the protein content or enzyme activity of the small intestines of ostrich chicks. An anti-nutritional factor within certain feedstuffs may, however, have had an influence on enzyme activity. Similar results were obtained for the histological and morphological parameters which were measured in chicks fed the different diets. There was no single diet that promoted intestine development, although it seemed as if the small intestines of the chicks fed the high protein diet were under higher digestive stress than those of the chicks fed the other diets.
The morphology of the oral cavity, pharynx and oesophagus of the ostrich (Struthio camelus)
(University of Pretoria, 2010-12-17) Soley, John Thomson; Groenewald, Hermanus B.; catarinativane@yahoo.com.bc; Tivane, Catarina
Most descriptions of the ostrich oropharynx and oesophagus are superficial and supply little meaningful morphological data. It was therefore the aim of this study to address this deficiency by means of a macroscopic and histological study of this region. The results were supplemented by data obtained by scanning electron microscopy. Macroscopic observations confirmed that in the ostrich the oral and pharyngeal cavities formed a single structure and could not be separated using visual criteria. The most obvious components observed in the roof of the oropharynx were the palate, the choana, the infundibular cleft and the pharyngeal folds, and on the floor, the interramal region, the tongue and the laryngeal mound. The prominent median longitudinal fold running along the palate and the numerous folds in the interrammal region of the floor contained a concentration of Herbst (Pacinian) corpuscles. The ramphotheca forming the rim of the oral cavity carried a sharp tomium along the rostral aspect of the mouth. which would assist the ostrich in tearing off plant material. It was further observed that both the roof and floor of the oropharynx could be macroscopically divided into two regions based on colour differences in the mucosa. The pale rostral regions were lined by a keratinized stratified squamous epithelium whereas the darker, more caudally positioned regions demonstrated a thicker non-keratinised epithelium and, in the case of the roof, a glandular layer. None of the regions of the upper digestive tract sampled revealed structures resembling taste buds and it would appear as if taste plays no role in the selection of food in the ostrich. The presence of large numbers of Herbst corpuscles in the palate may indicate the importance of texture in the selection of food in this species. In addition to confirming the folded nature of the ostrich tongue, this study revealed that the deep pouch formed by the dorsal tongue fold is further subdivided by a smaller secondary fold into dorsal and ventral recesses. The function of this structural adaptation is unclear but the large increase in surface area produced by the folds, and by virtue of the numerous mucous producing glands found in the mucosa, would presumably enhance mucous production and secretion required for ingesting often dry and difficult to swallow plant material. In addition to the tongue, the entire caudal aspect of the oropharynx was well-equipped with glandular tissue. Other adaptations for swallowing food included the presence of a highly folded mucosa in the interramal region which would indicate that the floor of the oral cavity in the ostrich is capable of a certain degree of distension to accommodate the accumulation of food in the oral cavity prior to swallowing. In similar fashion the longitudinal mucosal folds present throughout the oesophagus, as in other avian species, would also allow for distension of this organ when swallowing bulky food items. The pharyngeal folds that lie caudal to and around the opening of the Eustachian tubes in ratites are often referred to as the “tonsils” although no histological information has been presented to support this observation. This study revealed that the pharyngeal folds are filled with masses of diffuse and nodular lymphatic tissue and that epithelial folds emanating from the infundibular cleft and retropharyngeal recess formed tonsillar crypts surrounded by the lymphatic tissue. It has been well documented that in most species of birds papillae are found throughout the oropharynx. Papillae have also been described in ratites, mainly on the tongue and at the caudal aspect of the larynx. Whether the projections observed on the laryngeal mound of the ostrich in this study can be viewed as pharyngeal papillae remains debatable. Likewise, the lingual papillae seen in the ostrich were poorly developed and rudimentary. Compared to other birds, therefore, it is clear that the oropharynx of the ostrich is poorly equipped with papillae. This study confirmed that the hyobranchial apparatus consists of both central and paired caudo-lateral components, the former represented by the paraglossum and fused basihyale and urohyale, and the latter by the ceratobranchiale and the epibranchiale. The most important finding was that the paraglossum of the ostrich consisted of paired caudo-laterally directed cartilages that were connected rostrally to each other by fibrous connective tissue, and which supported the ventro-lateral aspect of the tongue. This information on the paraglossum has not previously been reported. The horns of the hyobranchial apparatus did not pass close to the skull as previously reported but in fact curved downwards away from the skull. The larynx consisted of the cricoid, procricoid and two arytenoid cartilages as is found in birds in general. It can be concluded that the present study, in addition to confirming the basic features of the oropharynx previously described for the ostrich, clarified the contradictory information presented in the literature and also provided new, unreported morphological data, some of which may be important when studying nutrition in these birds.

Browse

Recent Submissions