Nutrition and feed management in the ostrich (Struthio camelus var. domesticus)

The ostrich is an important animal in many livestock industries and in the developing world ostrich production is a valuable source of foreign currency netted from the export of meat and skins. Its successful growth and reproductive performance is dependent upon good nutrition. In Zimbabwe, one of the greatest costs involved in the upkeep of ostrich breeder birds is purchased feed (US$4555.45/10 birds p.a.). In order to cover these costs, the producer needs to ensure an adequate throughput of birds for slaughter. The energy provided by a particular feed source is important for growth and development of the bird. More research is required in ostrich nutrition.     

Localization of Vascular Endothelial Growth Factor and Fibroblast Growth Factor 2 in the Ovary of the Ostrich (Struthio camelus)

Vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF‐2) play a paramount role in the regulation of normal and pathologic angiogenesis in the ovary of mammals. Very little is known on the expression of these two growth factors in the avian ovary. The aim of this study was to determine for the first time the localization of VEGF and FGF‐2 in the ovary of the ostrich using immunohistochemical techniques to investigate the vascularization of the rapidly growing huge ostrich oocyte. At the oocyte periphery, distinct VEGF‐positive granules are visible. In our opinion, the expression of VEGF in the growing oocytes, which does not occur in mammals such as bovines, does not significantly contribute to angiogenesis in the theca interna and externa, where all the original and developing vessels are located, but may contribute to the mitoses and survival of granulosa cells during folliculogenesis. A different immunostaining can be demonstrated for FGF‐2: from late pre‐vitellogenic follicles, FGF‐2 immunopositivity can be observed at the inner perivitelline layer area. In the stroma, the smooth muscle cells of small arteries and the endothelial cells of venules and veins are positively stained for FGF‐2. Another interesting finding of this study is the occurrence of a significant number of VEGF‐ and FGF‐2 positive heterophilic granulocytes within the ovarian stroma, which migrate from the periphery of the ovary towards the growing follicles. We assume that the growth factors of the heterophilic granulocytes contribute significantly to the angiogenesis seen in both theca layers.     

Egg yolk fatty acid profile of avian species – influence on human nutrition

Lipids are an important nutritional component of the avian egg. A review of the literature was completed to determine the fatty acid compositions in egg yolk from some avian species. Additionally, the nutritional influence of lipid and lipoprotein content on the plasma of male participants during 30‐day feeding was discussed. The ostrich eggs had the highest unsaturated fatty acid and the lowest cholesterol content in relation to other avian species. Ostrich had a higher proportion of 18:3n‐3 (p < 0.01) compared with other species. Chicken yolk numerically contained much higher levels of 22:6n‐3 than those found in turkeys, quails and geese, but the amount of 22:6n‐3 in ostrich egg was lower by comparison with other species (p < 0.01). After the storage of eggs at the room temperature, there was a notable loss of vitamin E (vitE) in the yolks of all species and this decrease was marginal (p < 0.01) in ostrich compared with other species. There were significant (p < 0.05) increases in plasma low‐density lipoprotein (LDL) level in all male subjects. Plasma high‐density lipoprotein (HDL) level decreased (p < 0.05) only in men who were fed chicken or ostrich eggs daily. Consumption of different species’ eggs had no influence on the total male plasma cholesterol and triglyceride levels. LDL‐C:HDL‐C ratio increased (p < 0.05) after goose and turkey egg consumption. Consumption of one egg/month by healthy human subjects had no effect on serum total cholesterol and triglyceride. The LDL‐C:HDL‐C ratio (which is a strong predictor of coronary heart disease risk) increased, although non‐significantly, by consuming chicken, quail and ostrich eggs.     

A Simple and Rapid PCR‐Based Method for Ostrich Sexing Using Micro Amounts of DNA

The aim of the present study is to identify ostrich sex by using polymerase chain reaction (PCR) on micro amounts of DNA from blood, bloodstain and feathers. Sixteen male and 18 female ostriches were used as test individuals. Genomic DNA as a template was extracted by the Chelex method. Ostrsex‐P1 and P2 primers were designed to perform PCR amplification on the template. PCR products were checked using agarose gel electrophoresis with ethidium bromide staining and ostrich sex was determined directly by the bands shown on the gel. The results demonstrate that ostrich sex can be determined by the extraction of DNA from as little as 0.0125 μl blood using Chelex, whereby the use of large amounts of organic solvents such as phenol and chloroform are unnecessary. In addition, it is possible to identify ostrich sex using micro amounts of DNA extracted from bloodstains and/or feathers. The use of feathers particularly avoids unwanted sampling problems such as the difficulty of collecting ostrich blood, the stress to the ostrich caused by bleeding, and the demand for a lot of manpower for ostrich restraint.     

Ultrastructural characteristics of ostrich eggshell: outer shell membrane and the calcified layers

The ultrastructure of the eggshell of the domestic hen has been well researched and structural studies of other avian species, such as the ostrich, often base their interpretation of egg shell structure on that of the chicken. In the ostrich, lowered hatchability and hatching trauma may be due to shell ultrastructural abnormalities. In the present study the ultrastructure of the calcified portion, and the outer shell membrane (OSM), of domesticated ostrich eggshells was investigated using standard electron microscopic techniques. Transmission and scanning electron microscopy studies demonstrated intimate contact between cup-shaped structures present on the OSM and the mammillary layer of the calcified portion of the shell. The initial calcium carbonate growth of the calcified shell was of a dendritic nature with nucleation sites on the surface of the cup's contents. The dendritic growth gave way to a more randomly-orientated, smaller crystallite growth structure, which changed in form as it neared the vertical crystal layer (VCL). The VCL is described as being both amorphous and 'crumbly' depending on the plane of fracture. These observations suggest that firstly, initial calcification is contained within the cups and is then directed outwards to form the shell and that secondly, the VCL may contain an evolutionary, calcified cuticular layer. These observations serve as a baseline for studies investigating the effect of shell structure and strength on hatchling trauma and the influence of maternal diet.     

Effect of climate region and stocking density on ostrich (Struthio camelus) productive performances

The effects of three climates (hot and dry, mild and humid and Alpine) and three flock densities (<100, 100–300 and >300 m²) on ostrich reproductive and productive traits were studied. Data were compared with the benchmark target sets by the World Ostrich Association (Ostrich benchmark Performance Targets. Version 2, May, 2008) for reproductive qualifications of ostrich. No significant difference was observed on egg production, weight, fertility, hatchability and day‐old chicks weight among the three climate conditions; however, the Alpine climate had a lower performance trend. Mild and humid climates had a significant effect of age at sexual maturity for both males and females as well as on the duration of egg production season. Stocking density did not show significant difference on egg production, hatchability, age of male and female at sexual maturity and on duration of egg production season, while an area >300 m² showed a reduction in egg weight and day‐old chick weight. Further, an area <100 m² led to a weaker ostrich fertility rate. Results showed that the ostrich would have a better performance under hot and dry and mild and humid climates as compared to Alpine climate with a stocking density of 100–300 m² area per breeder bird. Thus, climatic intervention strategies at Alpine regions may be carried out for maintaining optimal reproductive qualification of ostrich so as to improve the productivity in this sector.     

Growth in the ostrich (Struthio camelus var. domesticus)

The use of the ostrich as a livestock animal necessitates an understanding of its ability to utilize specific nutrient requirements if efficient growth is to be realized. Male ostriches may have to be raised separately as they grow faster; they require higher protein diets and are more efficient feed converters for longer periods than female ostriches. Male ostriches exhibit slightly faster maturation rates than female ostriches. The corresponding age at which maximum growth is attained is 181 days for male ostriches and 199 days for female ostriches. The growth curve of ostriches is sigmoid and asymptotic. Body mass reached in 1 year is approximately 104 kg. The metabolic age of ostriches at hatching is approximately 13.7 days. Feed conversion has an impact on growth. The ostrich chick (aged <2 months) has a high feed conversion to body mass ratio of 2:1, which requires very accurate and careful management of chick nutrition.     

Viral diseases of the Ostrich (Struthio camelus var. domesticus)

The ostrich is an important animal in many livestock industries. A significant threat to this industry is losses from diseases. Newcastle disease is a notifiable, highly contagious viral infection of ostriches. Avian influenza may be transmitted from waterfowl, shorebirds and gulls to ostriches. Borna disease virus is a viral neurotropic infection spread mainly by rodents and felines. Crimean‐Congo hemorrhagic fever is a viral disease transmitted by Hyalomma ticks to humans. Avipoxvirus afflicts ostrich chicks and is transmitted by mosquitoes or by direct contact with a pox lesion. Maintenance of a healthy and profitable enterprise requires the implementation, with assistance from the local veterinary authority, of comprehensive, practical and effective methods of health management and preventative medicine.     

The hatching sequence of Ostrich (Struthio camelus) embryos with notes on development as observed by candling

1. The hatching sequence of the ostrich (Struthio camelus) was determined by observing embryos during candling, those in the process of hatching and in dead‐in‐shell eggs.

2. Candling showed that there was a progressive increase in dark shadowing within the egg but fine details were not easily seen. Nevertheless candling is considered to be an important method of assessing development of ostrich eggs during incubation.

3. The ostrich embryo adopts a hatching position and follows a hatching sequence different from that of the fowl. During internal pipping, the air space is pulled towards the beak in the former but the beak moves to the air space in the latter. The right foot has an important role in breaking the shell during hatching.

4. The hatching process is considered to reflect an adaptation to the egg having a hard, brittle shell.

5. Malpositions in the ostrich may have been misinterpreted in the past because of the unusual hatching position. The commonest malposition described here was head‐in‐the‐small‐end.     

A light microscopic and immunocytochemical study of the gastrointestinal tract of the ostrich (Struthio camelus L.)

Although the histological features and endocrine cells of the gastro-intestinal tract of the chicken have been well studied, little is known about these features of the gut of the ostrich. The present study was undertaken to elucidate the histology and peptide-storing endocrine cells of the ostrich. As a rule the histological features of the gastro-intestinal tract of the ostrich corresponded to that of the fowl. However, certain differences were observed. The superficial proventricular glands were simple, branched tubular glands, while the deep proventricular glands were restricted to a slipper-shaped area and extended into the muscularis mucosae. The gizzard had a variably developed muscularis mucosae, a feature that seems to be unique to the ostrich. The villi of the small intestine were long and branched profusely, forming a labyrinthine surface. No Paneth cells were observed. The mucosa of the ceca and the first part of the rectum was thrown in large circular folds, forming a compressed spiral. Numerous melanocytes were seen in the submucosa and the connective tissue around the bloodvessels of the muscle layers at the tips of the ceca. A well developed subserosa was present throughout the gastro-intestinal tract. Endocrine cells immunoreactive to somatostatin, glucagon, gastrin, bombesin, neurotensin, substance P and pancreatic polypeptide were detected in the gastro-intestinal tract of the ostrich. The topographical distribution of those endocrine cells immunoreactive to glucagon, bombesin, neurotensin and substance P differed from that of the chicken. The results of this investigation inferred that at least one of the gut peptides of the ostrich (secretin) to be structurally different from its counterparts in mammal and chicken. Molecular heterogeneity of somatostatin was observed in endocrine cells situated in the deep ventricular glands of the ostrich.     

鸵鸟养殖产业的现状与发展前景

综述了国内外鸵鸟养殖业的现状 ,提出了发展我国鸵鸟产业的具体意见和措施 ,为鸵鸟养殖产业化、规范化和集约化提出了合理的建议。     

Localization of thrombospondin‐1 and its receptor CD36 in the ovary of the ostrich (Struthio camelus)

Angiogenesis, the formation of new blood vessels from pre‐existing vasculature, plays a decisive role for the rapid growth of avian follicles. Compared to mammals, few data on the angiogenesis in the avian ovary are available. However, whereas several pro‐angiogenic factors in the avian ovary have been recently studied in detail, little information is available on the localization of anti‐angiogenic factors. The aim of this study was to determine the localization and possible function of the anti‐angiogenic factor thrombospondin‐1 (TSP‐1) and its receptor CD36 in the ovary of the ostrich using immunohistochemistry and to correlate the results with ultrastructural data. Whereas the oocytes and granulosa cells of all follicular stages were negative for TSP‐1, myofibroblasts of the theca externa and smooth muscle cells of blood vessels showed distinct reactions. A distinctly different staining pattern was observed for CD36. The oocytes were CD36 negative. No immunostaining for CD36 could be observed neither in the granulosa cells nor in the adjacent theca interna of vitellogenic follicles. In the theca externa, blood vessels protruding towards the oocyte showed CD36‐positive endothelial cells. In conclusion, a fine balance between angiogenic and anti‐angiogenic processes assures that a dense net of blood vessels develops during the rapid growth of a selected follicle. Anti‐angiogenic molecules, such as TSP‐1 and its receptor CD36 may, after the oocyte has reached its final size, inhibit further angiogenesis and limit the transport of yolk material to the mature oocyte. By this mechanism, the growth of the megalecithal oocyte during folliculogenesis may cease.     

The Excurrent Ducts of the Testis of the Emu (Dromaius novaehollandiae) and Ostrich (Struthio camelus): Microstereology of the Epididymis and Immunohistochemistry of its Cytoskeletal Systems

The volumetric proportion of the various ducts of the epididymis of the emu and ostrich and the immunohistochemistry of actin microfilaments, as well as cytokeratin, desmin and vimentin intermediate filaments, were studied in the various ducts of the epididymis of the emu and ostrich. The volumetric proportions of various ducts, which are remarkably different from those of members of the Galloanserae monophyly, are as follows: the rete testis, 5.2 ± 1.4% for the emu and 2.4 ± 1.8% for the ostrich; efferent ducts, 14.2 ± 2.3% (emu) and 11.8 ± 1.8% (ostrich); epididymal duct unit, 25.8 ± 5.8% (emu) and 26.1 ± 4.1% (ostrich) and connective tissue and its content, 54.7 ± 5.8% (emu) and 60.0 ± 4.9% (ostrich). Unlike in mammals and members of the Galloanserae monophyly, only vimentin was immunohistochemically demonstrated in the rete testis epithelium of the emu, and none of the cytoskeletal protein elements in the ostrich rete testis. The epithelium of the efferent ducts of the emu co-expressed actin, cytokeratin and desmin in the non-ciliated type I cells, and vimentin in the ciliated cell component. The ostrich demonstrated only cytokeratin in this epithelium. The ratite epididymal duct unit is different from that of mammals in lacking actin (only weaky expression in the ostrich), desmin and cytokeratin, and a moderate/strong immunoexpression of vimentin in the basal cells and basal parts of the NC type III cell in the epididymal duct unit. Immunoexpression of the microfilaments and intermediate filaments varied between the two ratite birds, as has been demonstrated previously in birds of the Galloanserae monophyly, and in mammals.     

Conjunctival mucinous adenocarcinoma in an ostrich (Struthio camelus)

A 2‐year‐old male ostrich (Struthio camelus) presented with a rapidly growing soft tissue mass protruding from the ventromedial aspect of the right eye (OD). The initial physical examination revealed a soft tissue mass attached to the medial inferior conjunctiva. The mass was excised with cryosurgery, and the conjunctival tissue margins were treated with cryoablation. Histopathological examination diagnosed granulomatous inflammation associated with scattered acid‐fast bacteria. The ostrich recovered uneventfully and appeared healthy until recurrence of a grossly similar mass 2 months later. Gross examination revealed a botryoid mass attached to the inferior palpebral conjunctiva and extending onto the palpebral aspect of the nictitating membrane. Euthanasia was selected, and the histological diagnosis of the second mass was a mixed mucinous adenocarcinoma; however, no acid‐fast bacteria were seen. Granulomatous conjunctival lesions have been previously described in the ostrich, while, to the authors' knowledge, neoplastic conjunctival lesions have not. Neoplasia should be considered as a differential diagnosis for a rapidly recurring, granulomatous conjunctival mass in this species.     

雄性雏鸵鸟生殖器官的形态学研究

为了探明雄性雏鸵鸟生殖器官的形态学特点,采用石蜡切片和HE染色技术,对6羽45日龄雄性非洲雏鸵鸟的生殖器官进行了研究,并与家禽的相关结构进行了比较。在光镜下观察了雄雏鸟生殖器官的形态结构,结果表明:(1)鸵鸟睾丸没有睾丸纵隔和睾丸小叶,曲精小管中精原细胞排列紧密且整齐,睾丸间质较少;(2)附睾由睾丸网、输出小管和附睾管组成;(3)输精管管壁由黏膜、肌层和外膜3层组成;(4)阴茎由2个圆形的纤维性淋巴体、淋巴间隙和微血管共同构成。     

GROWTH RATE OF OSTRICH (STRUTHIO CAMELUS) CHICKS UNDER INTENSIVE MANAGEMENT IN BOTSWANA

Thirty-seven ostrich chicks raised artificially had their weights, lengths of metatarsus and heights measured weekly from hatching to the 16th week. Despite weight loss during the first week due to utilization of egg yolk by the chicks, the chicks showed an exponential growth up to the twelfth week with an overall mean weekly weight gain of 1.3 kg. Female chicks showed a superior mean weekly gain of 1.6 kg compared to 1.2 kg for males. The metatarsal length grew rapidly at a weekly rate of 2.5 cm, but began to decline in the 11th week even though the weights and heights of the chicks were still increasing. The correlation coefficient between body weight and metatarsal length was 0.97. Individual chicks also maintained their respective heavy or light weight hierarchies throughout the study period. Thus isolation of chicks into groups by weight and raising them separately could have a role in the artificial rearing of ostrich chicks. Furthermore, ostrich chick rearing may be improved by regularly weighing chicks as a means of detecting changes in the growth patterns.     

A study of the immunohistochemical localization of the progesterone and oestrogen receptors in the magnum of the immature ostrich,Struthio camelus

The immunolocalization of the progesterone (PR) and oestrogen receptors (OR), in the magnum of the immature ostrich, was investigated during periods of ovarian activity and inactivity. In the immature ostrich, with an active ovary, numerous well-developed tubular glands were present in the lamina propria. Significantly, PR immunostaining was strong in the surface epithelium and tubular glands of these birds. In contrast, weak staining for the PR was observed in the surface epithelium of birds with inactive ovaries. Tubular gland formation, in these birds, was indicated by bud-like invaginations of the surface epithelium. Oestrogen receptor immunoreactivity was negligible in both birds with active and inactive ovaries. These findings suggest that steroid hormones, produced by the active ovary of the immature ostrich, influence the differentiation of the magnum. Furthermore, the action of these steroid hormones appears to be mediated through the PR.     

Sperm Supply and Egg fertilization in the Ostrich (Struthio camelus)

We used egg break‐out and spermatozoa trapped in the perivitelline layer of eggs to test the hypothesis that sperm supply and egg fertilization rate are high in the ostrich. Egg fertilization status was determined at break‐out by the appearance of the germinal disc (GD) and then the perivitelline layer overlying the GD region was collected to count sperm (Sperm_OPVL) under fluorescence following staining with 4′,6′‐diamidino‐2‐phenyindole (DAPI). The study was carried out on commercial ostrich farms over two laying seasons. In the first year, 229 eggs from nine randomly chosen ostrich pens comprising pairs, trios (two females, one male) and larger groups were collected for 1 week of every month of laying. Eggs contained 253 ± 18 Sperm_OPVL/mm² of the GD (mean ± SEM; range 0–1330). Egg fertilization rate averaged 89.4 ± 3.4% and varied from 78.6 to 98.2% between pens. Month had no effect on sperm supply or egg fertilization status. Eggs from paired birds (sex ratio 1 : 1) had less sperm in the GD than the eggs from pens with a higher sex ratio. In the second year, 150 eggs from seven pens, each containing only one male and either one, two or three females, were studied for 2 weeks at the beginning (winter), middle (spring) and end (summer) of laying. Eggs contained 364 ± 45 Sperm_OPVL/mm² of the GD (range 0–2880). Season had no effect on sperm supply or egg fertilization. The number of Sperm_OPVL varied between pens, assumed to be due to variation between individual males. The number of Sperm_OPVL increased as the sex ratio increased only when very high‐ranking males were excluded from the analysis. Egg fertilization rate was 94.4 ± 3.1% but varied from 64.0 to 100% between pens. Egg fertilization was not affected by season or sex ratio. Low fertilization rates were observed in two pens and appeared related to the lack of synchrony between timing of laying and sperm production in the first, and lack of mating in the second pen. We conclude that ostrich flocks generally have high rates of egg fertilization and any infertility is associated with lack of sperm supply.     

Aspergillus fumigatus infection in an ostrich (Struthio camelus)

An 11-month-old female ostrich (Struthio camelus) had become gradually emaciated over a 2-week period and subsequently died. Necropsy revealed white to green mold growth on the walls of caseous thickened air sac membranes and multiple white necrotic foci in the lungs and liver. Histologically, the multiple exudative, necrotic and granulomatous lesions were compatible with mycotic infection in the air sacs and lungs, and hyphae positively reacted with a monoclonal antibody (Mab-WF-AF-1) to Aspergillus fumigatus wall fractions. Multifocal hepatic necrosis was also found, and several spores were observed in the blood vessels. Fungal culture of these lesions yielded pure growth of A. fumigatus. This is an established case of fatal A. fumigatus infection in an ostrich reared in Japan.     

A morphological and immunohistochemical study of healthy and atretic follicles in the ovary of the sexually immature ostrich (Struthio camelus)

The morphology of healthy and atretic follicles in the ovary of the sexually immature ostrich was described in the present study. In addition, the distribution of the intermediate filaments desmin, vimentin and smooth muscle actin, in these ovarian follicles, was demonstrated. Healthy and atretic primordial, pre-vitellogenic and vitellogenic follicles were present in the ovaries of the sexually immature ostrich. Atresia occurred during all stages of follicular development. Atretic primordial and pre-vitellogenic follicles were characterized by the presence of a shrunken oocyte surrounded by a multilayered granulosa cell layer. Two forms of atresia (types 1 and 2) were identified in vitellogenic follicles. In the advanced stages of type 1 atresia the follicle was dominated by a hyalinized mass. In contrast, in type 2 atresia the granulosa and theca interna cells differentiated into interstitial gland cells. Positive immunostaining for desmin was observed in the granulosa cells of only healthy primordial and pre-vitellogenic follicles. Atretic primordial and pre-vitellogenic follicles were immunonegative for desmin. Vimentin immunoreactivity was demonstrated in the granulosa cells of all follicles except the vitellogenic atretic follicles. The results of the present study indicate that ovarian follicles in the sexually immature ostrich undergo a cycle of growth and regression, which is similar to that reported in other avian species. Furthermore, based on the results of the immunohistochemical study, it would appear that the distribution and immunostaining of intermediate filaments changes during follicular development and atresia.