Harderian Gland in Canadian Ostrich (Struthio camelus): A Morphological and Histochemical Study

Heads of ten healthy adult ostrich obtained from slaughter house were the constituted materials of the study. The Harderian gland (HG) was dissected out, and all of the gross morphometrical parameters including length, width and thickness as well as weight of left and right glands were recorded. Tissue sections were stained, using haematoxylin and eosin, Masson trichrome, periodic acid‐Schiff and Alcian blue (pH 2.5) techniques. In ostrich, HG was an orbital organ located ventromedially around the posterior part of the eyeball. It was an oval flatted shape, light pink colour with irregular outline and was pointed in the dorsal end. Its mean length was 35.30 ± 2.84 mm and 35.55 ± 3.58 mm in left and right sides, respectively, and mean width 15.30 ± 1.20 mm and 15.65 ± 1.18 mm in left and right sides, respectively. There was no significant difference between length, thickness, weight and width of left and right glands. Histological results showed that the glandular epithelium was multilobular and compound tubuloalveolar. The gland was surrounded by a connective tissue capsule, and the epithelium was lined by simple columnar epithelial cells of varying height. The secretion of HG was mucous and the secretion type was apocrine. Mucosubstance analysis revealed that secretory units contained acidic and neutral glycoproteins. The granules within the epithelial cells lining the intralobular and inter‐lobular excretory ducts of the gland were positive for periodic acid‐Schiff and Alcian blue (pH 2.5).     

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.     

Ostrich (Struthio camelus) chick and grower nutrition

The ostrich (Struthio camelus) is an important agricultural animal. The successful raising of ostriches from hatching to grower to breeder bird stage requires high standards of nutrition, and the producer should be knowledgeable about how the ingredient will provide the essential nutrients for growth and development, the utilization capacity of each nutrient and expected performance outcomes. Correct nutrition of chicks is critical, as they are most vulnerable up to the age of 3 months. Correct nutrition in growers (3–12 months) is important for the attainment of healthy breeding birds. Detailed is an analysis of studies on correct balance of essential nutrients, protein/energy inclusions and of fiber.     

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.     

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.     

A preliminary study on the glycosylation of the reproductive tract in the Ostrich (Struthio camelus camelus)

Glycosylation of the reproductive tract of an adult female red-necked ostrich (Struthio camelus camelus) carrying a fully formed calcified egg in her uterus when accidently killed by a blow to the head was examined using lectin histochemistry on samples from the infundibulum, magnum, uterus and vagina. Glycans in the luminal epithelium and underlying glands were described after staining with 23 lectins after neuraminidase pre-treatment in some cases. Ciliated and non-ciliated cells were evident at all levels in the luminal epithelium, the latter full of richly glycosylated secretory granules. The ciliated cells also showed glycosylation and, in the magnum, these cells often stained more intensely than the non-ciliated cells. High mannose and complex N-glycans, α1,6-linked fucosyl and sialic acid residues were present throughout the tract and there was a complete absence of GalNAcα1,3(LFucα1,2)Galß1,3/4GlcNAcß1- and rare terminal GalNAcα1- residues. Fucose in α1,2-linkage as H2 antigen and Le^y was also rare in the luminal epithelium and completely absent in glands. Terminal galactose was present in the luminal epithelium apart from in the infundibulum. Gland epithelium showed similar glycosylation to the luminal epithelium except in the magnum where there were significant differences and here the glands were packed full of large secretory granules, unlike the glands in the rest of the tract. Each section of the tract had its own specific pattern of glycosylation which could be related to the stage of egg formation.     

Limb Deformities of Farmed Ostrich (Struthio camelus) Chicks in Botswana

Limb deformities were detected in 135 out of 885 ostrich chicks, giving a prevalence of 15.3%. Tibiotarsal rotation affected 73% of the chicks with limb deformities, whereas rolled toes accounted for 36%. The right leg was more often affected than the left leg. The incidence of limb deformities was highest in 2- to 3-week-old ostrich chicks. The incidence of limb deformities was highest at the beginning of the breeding season and lowest towards the end, when it was relatively warmer. The mean serum manganese and zinc levels in deformed ostrich chicks were higher than the levels reported for normal chicks.     

Novel reovirus isolation from an Ostrich (Struthio camelus) in Japan

An orthoreovirus was isolated from an Ostrich (Struthio camelus) and rapidly identified as orthoreovirus by the rapid determination of viral RNA sequences (RDV) system and electron microscopy. Phylogenetic analysis of the sigma A protein indicated that the isolate belonged to avian species and was closely related to chicken orthoreovirus strain 138. The results of the present study indicated that an ostrich orthoreovirus is slight different from other chicken orthoreoviruses and provided evidence of diversity among avian orthoreoviruses. To our knowledge, this is the first genetic report of an orthoreovirus isolated from an ostrich.     

The fine structure of the Harderian gland in the ostrich (Struthio camelus)

The Harderian gland of the ostrich (Struthio camelus) is a tubuloalveolar gland containing holocrine secreting epithelial cells. The gland epithelium is composed of two different cell types, which can be classified as type I and type II. These cells contain dense secretory vesicles in their cytoplasm and they are connected laterally with desmosomes. At the basal site of these cells, myoepithelial cells are present. Plasma cells are observed in the subepithelial region of the gland. In the interlobular trabeculae, forming the gland stroma, fibroblasts, blood vessels and nerve fibres are included. Another important finding in the ostrich Harderian gland is the presence of homogeneous material.     

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.     

Regional specialization of the Ganglion cell density in the retina of the Ostrich (Struthio camelus)

In this study, retinal whole-mount specimens were prepared and stained with 0.1% cresyl violet for the ganglion cell study in the Ostrich (Struthio camelus) . The total number, distribution, and size of these cells were determined in different retinal regions. The mean total number of ganglion cells (three retinas) was 1 435 052 with an average density of 652 cells/mm². The temporo – nasal area of the retina with high cell density were identified with the peak of 7525 cells/mm² in the central area. The size of most ganglion cells ranged from 113–403 µm², with smaller cells predominating along the temporo-nasal streak above the optic disc and larger cells comprising more of the peripheral regions. The average thickness of the retina was 196 µm. The central area was the thickest area (268.6 µm), whereas the peripheral area was the thinnest area. Thus, the specialization of ganglion cell densities, their sizes and the thickness of the retina support the notion that the conduction of visual information towards the brain from all regions of the retina is not uniform, and suggests that the temporo – nasal streak is the fine quality area for vision in ostriches.     

Bacterial, fungal and parasitic infections in the ostrich (Struthio camelus var. domesticus)

The ostrich is susceptible to microorganisms of bacterial, fungal and parasitic origin. Anthrax, caused by Bacillus anthracis, is dangerous to other livestock and humans. Salmonella is transmitted from rodents or wild bird reservoirs. Pausterellosis caused by Pasteurella multocida results in air sac infections in ostriches. Colibacillosis is caused by Escherichia coli. Tuberculosis caused by Mycobacterium avium, is very rare in ostriches. Aspergillosis principally afflicts chicks. Zygomycosis, a secondary fungal infection of the upper gastrointestinal tract, is caused by Basidia, Mucor and Rhizopus. Leucocytozoon struthionis and Plasmodium spp. are harmless protozoa transmitted from flying arthropods. The tapeworm, Houttuynia struthionis, is dangerous in young ostriches. The adult ratite fluke (Philophthalmus gralli) is transmitted to ostriches following ingestion of infected freshwater crustaceans. Tick infestations of ostrich skin in Africa include Amblyomma spp., Haemaphysalis punctata, Hyalomma spp., Rhipicephalus turanicus and Argus spp. The ostrich quillmite (Pterolichus bicaudatus) and louse (Struthioliperus struthionus) may lower skin and leather quality via pruritis and/or excessive preening and feather loss. Nemododa infections are rare.     

Effect of diet on the metabolic profile of ostriches (Struthio camelus var. domesticus)

In order to study the metabolic profile of ostriches in relation to diet, 40 animals of both sexes were divided equally into two groups and fed two diets ad libitum consisting, on a dry matter basis, of the same commercial concentrate (60%) for the two groups and of corn silage (group A) or alfalfa hay (group B). In the morning, after about 12 h of fasting, blood was collected from the wing vein. The following haematological parameters were determined with an automatic system (Ektachem 250 analyser, Kodak): glucose, cholesterol, triglycerides, lactate (LAC), total protein (TP), uric acid, total bilirubin (Tbil), creatinine (CREA), calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K), chloride (Cl⁻), iron (Fe), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), cholinesterase (ChE), α-amylase (Amyl), lipase (LIP) and γ-glutamyltrasferase (GGT). Diet significantly affected some parameters of the metabolic profile. Indeed, owing to the presence of alfalfa hay in the diet, group B showed, in comparison to group A, significantly higher values of uric acid (222.5 vs 387.5 mmol/L, p < 0.01), GGT (8.50 vs 11.3 U/L, p < 0.05), Tbil (8.50 vs 10.7 mmol/L, p < 0.05), Ca (2.41 vs 2.83 μmol/L, p < 0.01), Mg (1.01 vs 1.18 μmol/L, p < 0.05) and K (2.71 vs 3.16 μmol/L, p < 0.01). The levels of creatinine (27.3 vs 32.6 mmol/L, p < 0.05) and AST (344.9 vs 461.4 U/l, p < 0.01) were also higher for group B.     

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.     

Embryonic development in the ostrich (Struthio camelus) during the first 7 days of artificial incubation

1. Early development of ostrich embryos was investigated in relation to time of egg collection and genotype.

2. A total of 321 ostrich eggs were collected during the 2008 and 2009 breeding seasons and the development of the embryo for up to the first 168 h of incubation was described and analysed. A sample of the incubated eggs was weighed and opened daily to investigate developmental changes.

3. In fresh eggs, the blastoderm contained a round, translucent dark area pellucida (AP) in the centre, with a surrounding thin white ring, likely to be the beginning of the area opaca (AO). Fresh eggs were considered infertile if the blastoderm was absent and instead numerous white droplets were present surrounded by vacuoles.

4. The average blastoderm area of a fresh fertile egg was 15.8 mm², increasing to 143.3 mm² after 2 d of incubation. By 72 h of incubation the area vasculosa (AV) was discernible in the posterior half of the blastoderm.

5. At 48 h of incubation the blastoderm area in eggs from the South African Black genotype (SAB) × Zimbabwean Blue genotype (ZB) crosses (104.5 ± 18.6 mm²) was lower than the pure SAB (141.0 ± 10.5 mm²), ZB (161.7 ± 13.5 mm²) and ZB × SAB crosses (166.1 ± 14.2 mm²).

6. Embryo length was 5.01 mm after 72 h of incubation and 14.5 mm after 168 h of incubation. At 168 h of incubation AV lengths for both ZB × SAB (53.2 mm) and SAB × ZB crosses (54.1 mm) were longer than in embryos from the pure breeds.

7. Results from this study can be put to practical use when determining whether eggs are infertile or fertile and also in investigating the age of early embryonic mortalities.     

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.     

Morphological features of the luminal surface of the magnum in the sexually immature ostrich (Struthio camelus)

Summary Observations were made, using scanning electron microscopy, of the surface features of the magnum in the immature ostrich during periods of ovarian inactivity, activity and regression. In birds with inactive ovaries the luminal surface of the magnum was lined with non-ciliated cells, which were densely covered by microvilli. In contrast, the magnum in birds with active ovaries was composed of ciliated and non-ciliated cells. The distribution of ciliated cells was not uniform, with clumps of cilia occurring next to non-ciliated areas. Samples collected from birds with regressing ovaries, during periods of decreasing daylength, revealed that the magnum was undergoing involution. The deciliation of ciliated cells and the presence of short microvilli on non-ciliated cells characterized magnal regression. These results suggest that ovarian activity and changes in daylength have a profound effect on the surface features of the magnum in the immature ostrich.     

Macro-microscopic study on the toepad of ostrich (Struthio camelus)

The ostrich foot has four toepads, two on the 3rd digit, one on the 4th digit and one at metatarso-phalangeal joint. Previous studies have not detailed the histo-morphological structure of these toepads. In this study, we have described the macroscopic and microscopic structures of the toepad of ostrich (Struthio camelus). Numerous papillae with different direction, length and thickness have been observed grossly on the ventral surface of each toepad. Histological examinations have revealed that the epidermis of the ostrich toepad, similar to other digitigrades, consists of an outer stratum corneum and an inner stratum germinativum (which is subdivided into basal, intermediate and transitional layers). The stratum corneum has several layers of flattened horny cells. The nuclei of basal cells have several mitotic figures. The cytoplasm of the stratum germinativum cells has multiple lipid droplets and multigranular bodies (in transitional cells only). Scanning electron microscopic examination revealed presence of collagen fibers in mid and deep dermis of each toepad. These fibers run parallel and connect to each other by very thin fibrils which are branched, crossed with each other in an oblique direction. Such arrangement of these collagen fibers, thin fibrils and presence of digital cushion are likely to be responsible for the protection of the underlying soft tissues and absorption of concussion.