The Impact of Plant Additives on the Quality and Safety of Ostrich Meat Sausages.

Ostrich meat is an interesting alternative to poultry or beef due to its nutritional value. The addition of three plant species (hot peppers, acerola, Schisandra chinesis) was suggested as a method to improve the quality, safety, and consumer acceptance of sausages prepared from ostrich meat. A series of microbiological and chemical analyses (including, inter alia, content of biogenic amines, heavy metals, and bioactive compounds) of the products as well as their sensory evaluation was performed to verify this claim. The microflora of all sausages was dominated by lactic acid bacteria. The biggest threat to consumers' health could be connected to the presence of biogenic amines formed through the enzymatic activity of lactic acid bacteria. The sausages with plant additives had better antioxidative and anti-inflammatory properties and lower fat oxidation-these features were correlated with the presence of vitamin C. Sausages with plant additives had a higher acceptability in terms of taste and smell.

Different narcotic gases and concentrations for immobilization of ostrich embryos for in-ovo imaging.

In-ovo imaging using avian eggs has been described as a potential alternative to animal testing using rodents. However, imaging studies are hampered by embryonal motion producing artifacts. This study aims at systematically comparing isoflurane, desflurane and sevoflurane in three different concentrations in ostrich embryos. Biomagnetic signals of ostrich embryos were recorded analyzing cardiac action and motion. Ten groups comprising eight ostrich embryos each were investigated: Control, isoflurane (2%, 4%, and 6%), desflurane (6%, 12%, and 18%) and sevoflurane (3%, 5%, and 8%). Each ostrich egg was exposed to the same narcotic gas and concentration on development day (DD) 31 and 34. Narcotic gas exposure was upheld for 90 min and embryos were monitored for additional 75 min. Toxicity was evaluated by verifying embryo viability 24 h after the experiments. Initial heart rate of mean 148 beats/min (DD 31) and 136 beats/min (DD 34) decreased over time by 44-48 beats/minute. No significant differences were observed between groups. All narcotic gases led to distinct movement reduction after mean 8 min. Embryos exposed to desflurane 6% showed residual movements. Isoflurane 6% and sevoflurane 8% produced motion-free time intervals of mean 70 min after discontinuation of narcotic gas exposure. Only one embryo death occurred after narcotic gas exposure with desflurane 6%. This study shows that isoflurane, desflurane and sevoflurane are suitable for ostrich embryo immobilization, which is a prerequisite for motion-artifact free imaging. Application of isoflurane 6% and sevoflurane 8% is a) safe as no embryonal deaths occurred after exposure and b) effective as immobilization was observed for approx. 70 min after the end of narcotic gas exposure. These results should be interpreted with caution regarding transferability to other avian species as differences in embryo size and incubation duration exist.

Adaptive foraging behaviours in the Horn of Africa during Toba supereruption.

Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago1. Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements2. Here we report an archaeological site-Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago-that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow. The diet included a wide range of terrestrial and aquatic animals. Stable oxygen isotopes from fossil mammal teeth and ostrich eggshell show that the site was occupied during a period of high seasonal aridity. The unusual abundance of fish suggests that capture occurred in the ever smaller and shallower waterholes of a seasonal river during a long dry season, revealing flexible adaptations to challenging climatic conditions during the Middle Stone Age. Adaptive foraging along dry-season waterholes would have transformed seasonal rivers into 'blue highway' corridors, potentially facilitating an out-of-Africa dispersal and suggesting that the event was not restricted to times of humid climates. The behavioural flexibility required to survive seasonally arid conditions in general, and the apparent short-term effects of the Toba supereruption in particular were probably key to the most recent dispersal and subsequent worldwide expansion of modern humans.

Development and Evaluation of a Stable Oil-in-Water Emulsion with High Ostrich Oil Concentration for Skincare Applications.

This study investigates the development of an oil-in-water (O/W) emulsion enriched with a high concentration of ostrich oil, recognized for its abundant content of oleic acid (34.60 ± 0.01%), tailored for skincare applications. Using Span and Tween emulsifiers, we formulated an optimized emulsion with 20% w/w ostrich oil and a 15% w/w blend of Span 20 and Tween 80. This formulation, achieved via homogenization at 3800 rpm for 5 min, yielded the smallest droplet size (5.01 ± 0.43 µm) alongside an appropriate zeta potential (-32.22 mV). Our investigation into the influence of Span and Tween concentrations, types, and ratios on the stability of 20% w/w ostrich oil emulsions, maintaining a hydrophile-lipophile balance (HLB) of 5.5, consistently demonstrated the superior stability of the optimized emulsion across various formulations. Cytotoxicity assessments on human dermal fibroblasts affirmed the safety of the emulsion. Notably, the emulsion exhibited a 52.20 ± 2.01% inhibition of linoleic acid oxidation, surpassing the 44.70 ± 1.94% inhibition observed for ostrich oil alone. Moreover, it demonstrated a superior inhibitory zone against Staphylococcus aureus (12.32 ± 0.19 mm), compared to the 6.12 ± 0.15 mm observed for ostrich oil alone, highlighting its enhanced antioxidant and antibacterial properties and strengthening its potential for skincare applications. The optimized emulsion also demonstrates the release of 78.16 ± 1.22% of oleic acid across the cellulose acetate membrane after 180 min of study time. This successful release of oleic acid further enhances the overall efficacy and versatility of the optimized emulsion. Stability assessments, conducted over 6 months at different temperatures (4 °C, 25 °C, 45 °C), confirmed the emulsion's sustained physicochemical and microbial stability, supporting its promise for topical applications. Despite minor fluctuations in acid values (AV) and peroxide values (PV), the results remained within the acceptable limits. This research elucidates the crucial role of emulsification in optimizing the efficacy and stability of ostrich oil in skincare formulations, providing valuable insights for practical applications where stability is paramount.

Apparent absence of hypothalamic cholinergic neurons in the common ostrich and emu: Implications for global brain states during sleep.

We examined the presence/absence and parcellation of cholinergic neurons in the hypothalami of five birds: a Congo grey parrot (Psittacus erithacus), a Timneh grey parrot (P. timneh), a pied crow (Corvus albus), a common ostrich (Struthio camelus), and an emu (Dromaius novaehollandiae). Using immunohistochemistry to an antibody raised against the enzyme choline acetyltransferase, hypothalamic cholinergic neurons were observed in six distinct clusters in the medial, lateral, and ventral hypothalamus in the parrots and crow, similar to prior observations made in the pigeon. The expression of cholinergic nuclei was most prominent in the Congo grey parrot, both in the medial and lateral hypothalamus. In contrast, no evidence of cholinergic neurons in the hypothalami of either the ostrich or emu was found. It is known that the expression of sleep states in the ostrich is unusual and resembles that observed in the monotremes that also lack hypothalamic cholinergic neurons. It has been proposed that the cholinergic system acts globally to produce and maintain brain states, such as those of arousal and rapid-eye-movement sleep. The hiatus in the cholinergic system of the ostrich, due to the lack of hypothalamic cholinergic neurons, may explain, in part, the unusual expression of sleep states in this species. These comparative anatomical and sleep studies provide supportive evidence for global cholinergic actions and may provide an important framework for our understanding of one broad function of the cholinergic system and possible dysfunctions associated with global cholinergic neural activity.

Development of an ostrich-derived single-chain variable fragment (scFv) against PTPRN extracellular domain.

In type 1 diabetes, the immune system destroys pancreatic beta cells in an autoimmune condition. To overcome this disease, a specific monoclonal antibody that binds to pancreatic beta cells could be used for targeted immunotherapy. Protein tyrosine phosphatase receptor N (PTPRN) is one of the important surface antigen candidates. Due to its high sequence homology among mammals, so far, no single-chain monoclonal antibody has been produced against this receptor. In this study, we developed a novel single-chain variable fragment (scFv) against the PTPRN extracellular domain. To this aim, ostrich species was used as a host is far phylogenetically birds from mammals to construct a phage display library for the first time. An ostrich-derived scfv phage display library was prepared and biopanning steps were done to enrich and screen for isolating the best anti-PTPRN binders. An scFv with appropriate affinity and specificity to the PTPRN extracellular domain was selected and characterized by ELISA, western blotting, and flow cytometry. The anti-PTPRN scFv developed in this study could be introduced as an effective tool that can pave the way for the creation of antibody-based targeting systems in cooperation with the detection and therapy of type I diabetes.

Spillover of an endemic avian Influenza H6N2 chicken lineage to ostriches and reassortment with clade 2.3.4.4b H5N1 high pathogenicity viruses in chickens.

Prior to 2017, chicken production in South Africa had only ever been affected by an endemic strain of H6N2 low pathogenic avian influenza (LPAI), but since 2017, an outbreak of Goose/Guangdong clade 2.3.4.4b H5N8 high pathogenicity avian influenza (HPAI) introduced by wild birds, followed by clade 2.3.4.4b H5N1 HPAI (2021-present), affected the country. In the present study, the viruses from seven cases of H6N2 LPAI from commercial poultry between October 2019 and August 2020 were genome-sequenced along with an H5N2 HPAI virus, and phylogenetic analysis was performed. The H5N2 HPAI virus caused localized outbreaks in a small-scale chicken farm and a large commercial layer farm in the KwaZulu-Natal province between late October and early December 2022. The phylogenetic results confirmed the first incidence of the chicken-adapted H6N2 lineage in commercial ostriches in the Western Cape province, with a likely epidemiological origin in chickens from the KwaZulu Natal province. The results also showed that the H5N2 HPAI virus was a novel reassortant of PB2, PB1, PA, NP and NA genome segments derived from a parental H6N2 virus that circulated in region, whereas the HA, M and NS genome segments were derived from sub-genotype SA10 H5N1 HPAI parental virus that had circulated in the local wild bird reservoir since July 2021.

Ostrich (Struthio camelus) syrinx morphology and vocal repertoire across postnatal ontogeny and sex: Implications for understanding vocal evolution in birds.

Vocal production in birds has been the target of considerable research that mostly has focused on phylogenetically well-nested songbirds. Anatomical descriptions and recordings of many non-songbirds have often only focused on a single ontogenetic stage or sex. While basic morphology of the vocal organ (syrinx) of ostrich (Palaeognathae, Struthio camelus) has been known since the 1800s, descriptions of its vocal repertoire and syrinx anatomy since then have been incomplete or inconsistent. New toolkits now enable detailed qualitative description of internal anatomy and meristic data and allow it to be compared to vocal production. Here we describe the anatomy of the syrinx in Struthio camelus for three post-hatching ontogenetic stages and both an adult male and female utilizing dissection and contrast enhanced X-ray computed tomography (diceCT). We find changes in ring geometry and spacing through ontogeny as well as lateral labia thickness. We document a small unpaired, midline, cartilaginous structure, a "pessuliform process" at the tracheobronchial juncture present throughout ontogeny and in both males and females. Investigation of the vocal repertoire of ostriches across ontogeny using a new dataset of 77 recordings led to identification of four vocalizations not previously reported in the literature, including the simultaneous production of a hiss and tonal. We find syrinx morphology largely consistent across ontogeny and in male and female adults. Both are capable of producing long duration tonal calls, but these may be more frequent in male birds. Closed-mouth boom calls remain unique to males. A detailed understanding of diversity in parts of early diverging clades is pivotal in attempting to estimate features of the ancestral syrinx in birds and how avian vocalization evolved.

Histochemical analysis, smooth muscle immunolocalization and volumetric density of the elastic system fibres of the ostrich (Struthio camelus) phallus.

There are few scientific reports on the histology of the phallus of ratite birds. The aim of this study was to conduct a histochemical analysis to determine the distribution of smooth muscle cells and the volumetric density (Vv) of the fibres of the elastic system in the ostrich phallus. Adult ostriches, 14 months old, were used. The phalluses were fixed in Bouin's solution and then transferred to a buffered formalin solution. They were then processed using standard histological stains for paraffin and slices were obtained. The following techniques were performed: HE, Picrosirius red, Alcian Blue at pH 1.0 and 2.5. The Periodic acid-Schiff reagent and Weigert's Resorcin-Fuchsin with previous oxidation were performed. The M42 test system was used to quantify the elastic system fibres. For immunohistochemical analysis, an anti alpha smooth muscle actin monoclonal antibody was used. The surface of the phallus is covered by a non-keratinized stratified squamous epithelium, which becomes stratified cylindrical in the region of the spermatic sulcus. No glands associated with the connective tissue were observed. The Vv of the elastic system fibres was 4.75%. Smooth muscle cells were visualized only in the walls of blood vessels through immunostaining, with an absence in the lymphatic sinuses. Despite similarities with other birds, such as the presence of a fibrous external axis, a lymphatic core, and a spermatic groove, the ostrich phallus shows marked differences, including the absence of an elastic core, a non-keratinized lining epithelium, and the absence of glands throughout its extension.

Comparative digital reconstruction of Pica pica and Struthio camelus and their cranial suture ontogenies.

To date, several studies describe post-hatching ontogenetic variation in birds; however, none of these studies document and compare ontogenetic variation of the entire skull in multiple avian species. Therefore, we studied ontogenetic skull variation of two bird species with very different ecologies, Pica pica, and Struthio camelus, using µCT based 3D reconstructions. For each specimen, we performed bone-by-bone segmentation in order to visualize and describe the morphological variation of each bone during ontogeny and estimated the average sutural closure of the skulls to identify different ontogenetic stages. Although bone fusion of P. pica occurs more rapidly than that of S. camelus the general sequence of bone fusion follows a similar trend from posterior to anterior, but a more detailed analysis reveals some interspecific variation in the fusion patterns. Although growth persists over a longer period in S. camelus than in P. pica and adults of the former species are significantly larger, the skull of the most mature S. camelus is still less fused than that of P. pica. Different growth and fusion patterns of the two species indicate that the interspecific ontogenetic variation could be related to heterochronic developments. Nevertheless, this hypothesis needs to be tested in a broader phylogenetic framework in order to detect the evolutionary direction of the potential heterochronic transformations.

Construction of Chicken and Ostrich Antibody Libraries.

Recombinant antibody libraries based on chicken immunoglobulin genes are potentially valuable sources of phage-displayed scFvs for use in veterinary diagnostics and research. To add diversity to the scFv repertoire, we expanded the library to include genes from the ostrich, indigenous to southern Africa. The libraries described in this chapter are based on the chicken and ostrich variable heavy and light chain immunoglobulin genes joined by a short flexible linker cloned in the phagemid vector pHEN1. The resulting phagemids produce either scFvs displayed on the surface of the fusion phage subsequent to co-infection with helper phage or soluble scFvs following IPTG induction. This chapter provides detailed and proven methods for the construction of such libraries.

Partial Amputation of a Nonreducing Prolapsed Phallus in an Ostrich (Struthio camelus).

A 19-year-old male ostrich (Struthio camelus) was referred to a veterinary teaching hospital (São Paulo State University, Botucatu, Brazil) due to a 6-month history of recurrent prolapse of the phallus. On physical examination, 2 ulcerative wounds were present on the phallus, as well as caseous plaques and myiasis. Conservative treatment resulted in improvement but prolapse of the phallus remained. Thus, a decision was made to perform a partial phallectomy. The surgery was successful and no postoperative complications occurred. When the ostrich was reexamined 6 months postsurgery, the ostrich was alert, in good health, and the surgical site completely healed. The owner verbally reported no recurrence of the phallus prolapse 1 year after surgery.

Morphometric studies on the appendicular bony skeleton of the ostriches (Struthio Camelus).

BACKGROUND: Morphometric study of the bony elements of the appendicular skeleton in the ostrich was fully described and identified. The appendicular skeleton included the bones of the pectoral girdle, the wing, the pelvic girdle and the pelvic limb. RESULTS: The shoulder girdle of the ostrich included the scapula and coracoid bones. The scapula appeared as a flattened spoon-like structure. The coracoid bone appeared quadrilateral in outline. The mean length of the scapula and coracoid (sternal wing) were 15.00 ± 0.23 and 10.00 ± 0.17 cm, respectively. The wing included the humerus, ulna, radius, radial carpal bone, ulnar carpal bone, carpometacarpus and phalanges of three digits. The mean length of the humerus, radius, and ulna were 33.00 ± 0.46, 10.50 ± 0.40 and 11.50 ± 0.29 cm respectively. The carpometacarpus was formed by the fusion of the distal row of carpal bones and three metacarpal bones. Digits of the wing were three in number; the alular, major and minor digits. Os coxae comprised the ilium, ischium and pubis. Their mean lengths were 36.00 ± 0.82 cm, 32.00 ± 0.20 and 55.00 ± 0.2.9 cm, respectively. The femur was a stout short bone, that appeared shorter than the tibiotarsus. The mean length of the femur, tibiotarsus, and tarsometatarsus were 30.00 ± 0.23, 52.00 ± 0.50 and 46.00 ± 0.28 cm. Tibiotarsus was the longest bone in the pelvic limb. The fibula was a long bone (44.00 ± 0.41 cm) lying along the lateral surface of the tibiotarsus. The tarsometatarsus was a strong long bone formed by the fusion of the metatarsal (II, III, IV) and the distal row of tarsal bones. It was worth mentioning that metatarsal II was externally absent in adults. CONCLUSIONS: In the appendicular skeleton of ostrich, there were special characteristic features that were detected in our study; the clavicle was absent, the coracoid bone was composed of a sternal wing and scapular wing, the ulna was slightly longer in length than the radius. The coupled patellae i.e., the proximal and distal patella were observed; and the ostrich pedal digits were only two; viz., the third (III) and fourth (IV) digits.

Soft tissues influence nasal airflow in diapsids: Implications for dinosaurs.

The nasal passage performs multiple functions in amniotes, including olfaction and thermoregulation. These functions would have been present in extinct animals as well. However, fossils preserve only low-resolution versions of the nasal passage due to loss of soft-tissue structures after death. To test the effects of these lower resolution models on interpretations of nasal physiology, we performed a broadly comparative analysis of the nasal passages in extant diapsid representatives, e.g., alligator, turkey, ostrich, iguana, and a monitor lizard. Using computational fluid dynamics, we simulated airflow through 3D reconstructed models of the different nasal passages and compared these soft-tissue-bounded results to similar analyses of the same airways under the lower-resolution limits imposed by fossilization. Airflow patterns in these bony-bounded airways were more homogeneous and slower flowing than those of their soft-tissue counterparts. These data indicate that bony-bounded airway reconstructions of extinct animal nasal passages are far too conservative and place overly restrictive physiological limitations on extinct species. In spite of the diverse array of nasal passage shapes, distinct similarities in airflow were observed, including consistent areas of nasal passage constriction such as the junction of the olfactory region and main airway. These nasal constrictions can reasonably be inferred to have been present in extinct taxa such as dinosaurs.

Effect of storage periods and conditions on embryonic mortalities and hatchability of artificially incubated ostrich eggs.

1. Despite substantial research, the hatching failure of ostrich eggs remains a key concern for many commercial breeding farms.2. This source of reproductive failure needs to be addressed for ostrich farming to become more profitable.3. Information from 2212 eggs were obtained from the ostrich resource flock at the Oudtshoorn Research Farm (2013-2014). Egg data were divided on a daily basis into two groups: Group 1 included eggs stored from 1 to 13 d in cold storage (CS) at a controlled temperature of 17°C and a relative humidity (RH) of 90%. Group 2 was stored for the same time interval as Group 1, but in a cool room (CR) at ambient temperature to simulate the uncontrolled storage conditions prevalent on most breeding farms.4. Overall embryonic mortalities (OEM) were significantly higher for eggs stored for 1 d (0.38 ± 0.04) and for 8 d or more (between 0.31 ± 0.04 and 0.43 ± 0.04) compared to eggs stored for between 2 and 7 d (between 0.20 ± 0.03 and 0.26 ± 0.04).5. The moisture loss during storage (ML) for eggs stored for 13 d in CS during spring was on average slightly higher (1.28%) than that during summer (0.95%). In contrast, the ML of eggs stored in the CR for 13 d was significantly higher, at 1.59% in spring and 2.08% in summer.6. A general reduction in chick weight occurred for all the seasons (winter, spring and summer) as the number of storage days increased. Ostrich eggs should be stored for between 2 and 8 d under controlled storage conditions for improved hatchability.

Methods of In Ovo and Ex Ovo Ostrich Embryo Culture with Observations on the Development and Maturation of the Chorioallantoic Membrane.

Culture of shell-free and windowed eggs for drug testing and other experiments has been perfected for smaller eggs such as those of chickens, where the developing blood vessels of the chorioallantoic membrane (CAM) become accessible for manipulative studies. However, due to the thickness and hardness of the ostrich egg shell, such techniques are not applicable. Using a tork craft mini rotary and a drill bit, we established windowed egg, in-shell-membrane windowed egg, and in-shell-membrane shell-free methods in the ostrich egg, depending on whether the shell membranes were retained or not. Concomitant study of the developing CAM revealed that at embryonic day 16 (E16), the three layers of the CAM were clearly delineated and at E25, the chorionic capillaries had fused with the epithelium while the CAM at E37 had reached maturity and the chorion and the allantois were both 3-4 times thicker and villous cavity (VC) and capillary-covering cells were well delineated. Both intussusceptive and sprouting angiogenesis were found to be the predominant modes of vascular growth in the ostrich CAM. Development and maturation of the ostrich CAM are similar to those of the well-studied chicken egg, albeit its incubation time being twice in duration.

Description of natal down of the ostrich (Struthio camelus) and comparison with common quail (Coturnix coturnix): Developmental and evolutionary implications.

Natal down is a feather stage that differs in both form and function from the definitive feathers of adult birds. It has a simpler structure that has been speculated to be similar to the body coverings of non-avian dinosaurs. However, inference of the evolution of natal down has been limited by our understanding of its structural variation in extant birds. Most descriptive work has focused on neognathous birds, limiting our knowledge of the full diversity of feathers in extant taxa. Here, we describe the natal down of a post-hatch ostrich (Struthio camelus) and compare it to that of a post-hatch quail (Coturnix coturnix). We confirm the presence of featherless spaces (apteria) in S. camelus and the lack of barbules on the tips of natal down in both species. We also find differences between dorsal and ventral natal down structures, such as barbule density in S. camelus and the extent of the bare portion of the barb in both species. Surprisingly, we do not find that the neoptiles of either species follow the ideal morphologies for increasing insulation. Finally, we hypothesize that the different barb types present in S. camelus natal down result from a large addition of new barb ridges during development, which is not known except in feathers with a rachis. These results have implications for our understanding of how structure informs function and development in understudied feather types, such as those shared by non-avian dinosaurs.

The evolutionary maintenance of ancient recombining sex chromosomes in the ostrich.

Sex chromosomes have evolved repeatedly across the tree of life and often exhibit extreme size dimorphism due to genetic degeneration of the sex-limited chromosome (e.g. the W chromosome of some birds and Y chromosome of mammals). However, in some lineages, ancient sex-limited chromosomes have escaped degeneration. Here, we study the evolutionary maintenance of sex chromosomes in the ostrich (Struthio camelus), where the W remains 65% the size of the Z chromosome, despite being more than 100 million years old. Using genome-wide resequencing data, we show that the population scaled recombination rate of the pseudoautosomal region (PAR) is higher than similar sized autosomes and is correlated with pedigree-based recombination rate in the heterogametic females, but not homogametic males. Genetic variation within the sex-linked region (SLR) (π = 0.001) was significantly lower than in the PAR, consistent with recombination cessation. Conversely, genetic variation across the PAR (π = 0.0016) was similar to that of autosomes and dependent on local recombination rates, GC content and to a lesser extent, gene density. In particular, the region close to the SLR was as genetically diverse as autosomes, likely due to high recombination rates around the PAR boundary restricting genetic linkage with the SLR to only ~50Kb. The potential for alleles with antagonistic fitness effects in males and females to drive chromosome degeneration is therefore limited. While some regions of the PAR had divergent male-female allele frequencies, suggestive of sexually antagonistic alleles, coalescent simulations showed this was broadly consistent with neutral genetic processes. Our results indicate that the degeneration of the large and ancient sex chromosomes of the ostrich may have been slowed by high recombination in the female PAR, reducing the scope for the accumulation of sexually antagonistic variation to generate selection for recombination cessation.

Assessment of the microbiological status of two Hungarian ostrich farms.

The aim of this study was to estimate the occurrence of bacterial infection and contamination in two ostrich-producing farms. Compared to other poultry species, the hatchability of ostrich eggs is especially low. In a quest to identify factors that may affect hatchability, we collected faecal samples from adult birds, as well as eggs with dead-in-shell embryos, dead chicks and swab samples from the surface of the eggs and from the environment. The samples were screened for the presence of bacteria by routine bacteriological culture methods. The most prevalent bacteria, detected in the samples, were Escherichia coli, Bacillus spp. and coliform bacteria, whereas Pseudomonas spp. were less frequently found. The intensity and species compositon of the bacterial contamination was comparable in the two farms. Our results revealed that the bacteria, present in the environment, may likely be transmitted to the surface of the eggs. If they are able to penetrate the shell then the embryos and chicks become infected easily. These findings draw the attention to the special importance of enforcing efficient decontamination and disinfection measures to keep the environment and egg surface free from germs. Besides the appropriate egg treatment procedure, the incubation and hatching technology should also be kept under control.

The feeding apparatus of Rhea americana (Aves, Palaeognathae): Jaw myology and ontogenetic allometry.

In birds, the jaw musculature is a crucial adaptive feature involved in feeding. The morphological traits and postnatal growth patterns of jaw muscles constitute a useful proxy to interpret feeding function and ecology. This study aims to describe the jaw muscles of Rhea americana and explore their postnatal growth pattern. A total of 20 specimens of R. americana representing four ontogenetic stages were studied. Jaw muscles were described, weighed and their proportions with respect to body mass were calculated. Linear regression analysis was used to characterize ontogenetic scaling patterns. The morphological patterns of jaw muscles were characterized by their simplicity: bellies with few or no subdivisions and similar to those described for other flightless paleognathous birds. In all stages, the muscles pterygoideus lateralis, depressor mandibulae, and pseudotemporalis had the greatest mass values. The proportion of total jaw muscle mass decreased with age from 0.22% in 1-month-old chicks to 0.05% in adults. Linear regression analysis showed that all muscles scaled with negative allometry with respect to body mass. The progressive decrease of jaw muscle mass relative to body mass in adults could be related to the generation of less force, which is in accordance with the herbivorous diet of adults. In contrast, the diet of rhea chicks includes a large proportion of insects thus, this greater muscle proportion could be associated with the ability to generate more force, thus providing better abilities to grasp and hold more mobile prey.