The Effects of Slaughter Age and Sex on Carcass Traits, Meat Quality, and Leg Bone Characteristics of Farmed Common Pheasants (Phasianus colchicus L.)

The aim of this study was to determine the effects of slaughter age and sex on the carcass characteristics, meat quality parameters, and leg bone dimensions of common pheasants. The study material consisted of 40 common pheasants, including 10 males and 10 females at 12 weeks of age and 10 males and 10 females at 15 weeks of age. The birds were kept on a farm in a semi-intensive system. The slaughter age had significant effects on the eviscerated carcass weight; the percentage of skin with subcutaneous fat; the wings percentage; electrical conductivity (EC24); the work required to cut the samples (cutting work); redness (a*); the intramuscular fat content in the breast meat; and the protein, intramuscular fat, water, and collagen contents in the leg meat. The sex of the pheasants had significant effects on the eviscerated carcass weight; the contents of leg muscles, skin with subcutaneous fat, and wings in the carcasses; and the electrical conductivity, thermal loss, lightness (L*), and redness (a*) of the breast muscles. It also significantly affected the protein and water contents of the pectoral and leg muscles, the intramuscular fat contents of the leg muscles, the texture traits of the pectoralis major muscle, and all femur and tibia bone dimensions. The results indicate a greater influence of sex compared to slaughter age on the pheasant traits studied. We confirmed the occurrence of a clearly marked sexual dimorphism in birds of this species. Both factors (slaughter age and gender) have significant effects on the nutritional and technological value of pheasant meat. The few studies on meat texture and the dimensions of pheasant leg bones indicate a need for continued research in this area in the future.

Transmission dynamics and pathogenesis differ between pheasants and partridges infected with clade 2.3.4.4b H5N8 and H5N1 high-pathogenicity avian influenza viruses

During the UK 2020-2021 epizootic of H5Nx clade 2.3.4.4b high-pathogenicity avian influenza viruses (HPAIVs), high mortality occurred during incursions in commercially farmed common pheasants (Phasianus colchicus). Two pheasant farms, affected separately by H5N8 and H5N1 subtypes, included adjacently housed red-legged partridges (Alectoris rufa), which appeared to be unaffected. Despite extensive ongoing epizootics, H5Nx HPAIV partridge outbreaks were not reported during 2020-2021 and 2021-2022 in the UK, so it is postulated that partridges are more resistant to HPAIV infection than other gamebirds. To assess this, pathogenesis and both intra- and inter-species transmission of UK pheasant-origin H5N8-2021 and H5N1-2021 HPAIVs were investigated. Onward transmission to chickens was also assessed to better understand the risk of spread from gamebirds to other commercial poultry sectors. A lower infectious dose was required to infect pheasants with H5N8-2021 compared to H5N1-2021. However, HPAIV systemic dissemination to multiple organs within pheasants was more rapid following infection with H5N1-2021 than H5N8-2021, with the former attaining generally higher viral RNA levels in tissues. Intraspecies transmission to contact pheasants was successful for both viruses and associated with viral environmental contamination, while interspecies transmission to a first chicken-contact group was also efficient. However, further onward transmission to additional chicken contacts was only achieved with H5N1-2021. Intra-partridge transmission was only successful when high-dose H5N1-2021 was administered, while partridges inoculated with H5N8-2021 failed to shed and transmit, although extensive tissue tropism was observed for both viruses. Mortalities among infected partridges featured a longer incubation period compared to that in pheasants, for both viruses. Therefore, the susceptibility of different gamebird species and pathogenicity outcomes to the ongoing H5Nx clade 2.3.4.4b HPAIVs varies, but pheasants represent a greater likelihood of H5Nx HPAIV introduction into galliforme poultry settings. Consequently, viral maintenance within gamebird populations and risks to poultry species warrant enhanced investigation.

Safety for the environment of a feed additive consisting of diclazuril (Coxiril®) for chickens reared for laying and pheasants (Huvepharma NV)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety for the environment of diclazuril (Coxiril®) as a coccidiostat feed additive for chickens reared for laying and pheasants. In its previous assessments, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) could not reach a final conclusion on the risk resulting from the use of diclazuril in acid soil from Coxiril®. On the basis of the new data provided, the FEEDAP Panel updates the previous conclusions as follows: no risk is expected for the terrestrial compartment and for sediment when diclazuril is used in chickens reared for laying and to pheasants at the proposed condition of use (in both acidic and non-acidic soils). No concern for groundwater is expected for both acidic and non-acidic soils. Due to the lack of data, no conclusions can be drawn for the aquatic compartment. Diclazuril does not have the potential for bioaccumulation; therefore, a risk of secondary poisoning is unlikely.

A novel Chaphamaparvovirus is the etiological agent of hepatitis outbreaks in pheasants (Phasianus colchicus) characterized by high mortality

In the present study, we report the occurrence of several outbreaks of hepatitis in flocks of young pheasants in France, between 2017 and 2021. The disease was characterized by prostration, apathy and a median cumulative mortality of 12%, with the birds presenting multifocal to coalescing necrotizing hepatitis on necropsy. Severe extensive areas of degeneration and necrosis were observed in the liver, with degenerative hepatocytes presenting large amphophilic to acidophilic intranuclear inclusion bodies. Transmission electron microscopy examination of liver samples showed the presence of parvovirus-like virions of 21-24 nm, a finding already reported decades ago. Further investigations by Next Generation Sequencing and PCR revealed the complete genome of a novel species of parvovirus, here designated Phasianus chaphamaparvovirus 1 (PhChPV-1), that belongs to the new genus Chaphamaparvovirus in the Hamaparvovirinae subfamily. In situ hybridization and real-time PCR confirmed the etiology of the outbreaks, demonstrating the viral genome in the lesions. The findings establish the etiology of a pathology first described in pheasants 50 years ago and pave the way for a targeted protection strategy.

Common Diseases of Michigan Gamebirds: A Retrospective Study

Michigan has abundant resources for outdoor activity including upland gamebird hunting in the wild and on licensed hunting preserves. Due to the popularity of hunting, Michigan had a thriving gamebird industry before the economic downturn of 2008/2009. After the economic downturn, the number of gamebird preserves decreased. To understand the health issues faced by captive gamebird raisers while the industry was thriving, a 25-year retrospective study of gamebird submissions to the Michigan State University Veterinary Diagnostic Laboratory from 1983 through 2008 was undertaken. Although pheasants, quail, partridges, grouse, and mallard ducks were raised, pheasants greatly outnumbered all other gamebird species, both in numbers and submissions, and quail were the next most predominant species. Causes for submission included parasitic, bacterial, viral, and miscellaneous causes. Parasitic diseases were predominant, with coccidiosis being the leading diagnosis in pheasants and partridges and Capillaria spp. infestation of the crop prevailing in quail. Bacterial diseases were the next most predominant affliction, with clostridial enteritis, both necrotic and ulcerative, in quail, and a variety of bacterial diseases were found in pheasants and partridges. Rotaviral enteritis and adenovirus were the most prevalent viral diseases in pheasants, with adenovirus being the predominant viral disease in quail and paramyxovirus the most prevalent in partridges. From these findings, we conclude that gamebird submissions should be closely screened for parasitic diseases and the diagnosis confirmed at necropsy through scraping and examination of affected tissues.

Nutritional Composition and Heavy Metal Content in Breast and Thigh Muscles of Wild and Intensively Reared Common Pheasants (Phasianus Colchicus)

Introduction

Differing conditions in captive breeding and in the wild have impact on the mineral profile of the pheasant carcass and its heavy metal contents. This may be an indicator of environmental contamination. The study evaluated the nutritional composition and selected macro- and trace element contents (heavy metals in particular) in usable sections of pheasant breast and thigh muscles originating from captive breeding and wild birds.

Material and Methods

The tests were performed on the breast and thigh muscles of 20 wild and 20 farm bred birds from around Lublin, Poland, with equal sex representation. The nutrient and lead, cadmium, chromium, and nickel contents were determined using inductively-coupled plasma atomic emission spectroscopy.

Results

The farmed pheasants had a higher proportion of breast muscle. The thigh muscles of all birds had a higher fat content than the breast muscles (5.1 g vs. 3.4 g per kg of natural weight). The macroelement level depended on the muscle type and bird origin. The trace element content also did and gender dependence was also evident. The wild birds contained more cadmium in the breast muscles and lead in both muscles than the farm-raised ones.

Conclusion

The high quality and usefulness of wild and farmed pheasant meat is confirmed. It has advantageous macro- and trace element contents and permissible heavy metal contents except for lead in wild birds. The heavy metal level can be a bioindicator of their environmental occurrence. In wild birds, the lead level may also reflect birdshot remnants.

Mortality-Based Triggers and Premovement Testing Protocols for Detection of Highly Pathogenic Avian Influenza Virus Infection in Commercial Upland Game Birds

Outbreaks involving avian influenza viruses are often devastating to the poultry industry economically and otherwise. Disease surveillance is critically important because it facilitates timely detection and generates confidence that infected birds are not moved during business continuity intended to mitigate associated economic losses. The possibility of using an abnormal increase in daily mortality to levels that exceed predetermined thresholds as a trigger to initiate further diagnostic investigations for highly pathogenic avian influenza (HPAI) virus infection in the flock is explored. The range of optimal mortality thresholds varies by bird species, trigger type, and mortality thresholds, and these should be considered when assessing sector-specific triggers. The study uses purposefully collected data and data from the literature to determine optimal mortality triggers for HPAI detection in commercial upland game bird flocks. Three trigger types were assessed for the ability to detect rapidly both HPAI (on the basis of disease-induced and normal mortality data) and false alarm rate (on the basis of normal mortality data); namely, 1) exceeding a set absolute threshold on one day, 2) exceeding a set absolute threshold on two consecutive days, or 3) exceeding a multiple of a seven-day moving average. The likelihood of disease detection using some of these triggers together with premovement real-time reverse transcription PCR (rRT-PCR) testing was examined. Results indicate that the performance of the two consecutive days trigger had the best metrics (i.e., rapid detection with few false alarms) in the trade-off analysis. The collected normal mortality data was zero on 66% of all days recorded, with an overall mean of 0.6 dead birds per day. In the surveillance scenario analyses, combining the default protocol that relied only on active surveillance (i.e., premovement testing of oropharyngeal swab samples from dead birds by rRT-PCR) together with either of the mortality-based triggers improved detection rates on all days postexposure before scheduled movement. For exposures occurring within 8 days of movement, the protocol that combined the default with single-day triggers had slightly more detections than that with two consecutive days triggers. However, all assessed protocol combinations were able to detect all infections that occurred more than 10 days before scheduled movement. These findings can inform risk-based decisions pertaining to continuity of business in the commercial upland game bird industry.

Pathological Changes in Natural Infection of Pheasants with Highly Pathogenic Avian Influenza A (H5N8) in Bulgaria

Introduction

The study of histopathological changes caused by influenza A (H5N8) viral infection in bird species is essential for the understanding of their role in the spread of this highly infectious virus. However, there are few such studies under natural conditions in minor gallinaceous species. This article describes the pathomorphological findings in Colchis pheasants infected naturally with H5N8 during an epizootic outbreak in Bulgaria.

Material and Methods

Samples of internal organs of 10 carcasses were collected for histopathological and immunohistochemical evaluation, virus isolation and identification, and nucleic acid detection.

Results

Consistent macroscopic findings were lesions affecting the intestine, heart, lung, and pancreas. Congestion and mononuclear infiltrate were common findings in the small intestine, as were necrosis and lymphoid clusters in the lamina propria of the caeca. Congestion with small focal necrosis and gliosis with multifocal nonpurulent encephalitis were observed in the brain. Myocardial interstitial oedema and degenerative necrobiotic processes were also detected. Immunohistological analysis confirmed systemic infection and revealed influenza virus nucleoprotein in all analysed organs.

Conclusion

Variable necrosis was observed in the brain, liver, trachea, heart, small intestine, and caeca. Viral antigen was commonly found in the brain, heart, lung and trachea. Contact with migrating waterfowls was suspected as a reason for the outbreak.

The Influence of the Partial Replacing of Inorganic Salts of Calcium, Zinc, Iron, and Copper with Amino Acid Complexes on Bone Development in Male Pheasants from Aviary Breeding

Simple Summary

A significant problem of birds reared in farms and then reintroduced to natural living environment is their survival, which is usually much lower than that of the free-living ones. Behavioral and physiological deficiencies rather than morphological anatomy decide about failure, nevertheless, the birds’ body condition, including quality and maturity of skeletal system, are also important. In this context, the problem of proper nutrition for growing game birds is a major one. The level and source of microelements, as well as the source of protein are the main factors affecting bone growth in young captive-reared birds. Since calcium, zinc, iron, and copper are critical nutrients in all practical diets, this experiment was undertaken to determine the possibility of the partial inclusion of organic forms of these elements to the diet of pheasants in order to improve their bone development and survival.

Abstract

This study analyzed the effects of partial replacing of Ca, Fe, Zn, and Cu salts with glycine chelates on the measures of bones health in 16-week-old captive-reared male pheasants, allocated to one of the three experimental groups supplemented with Ca, Fe, Zn, and Cu in forms of inorganic salts (the control group) or groups receiving from the ninth week 25% and 50% of supplemented elements as glycine chelates. At the end of rearing birds receiving chelates were heavier (p < 0.001) and their tibia showed an increase of numerous mechanical parameters: yield and ultimate force (p = 0.028, p < 0.001, respectively), stiffness (p = 0.007), Young modulus (p < 0.001), compared to the control animals. The bones of birds receiving chelates in 50% were also heavier (p < 0.001) and longer (p = 0.014), with thinner cortical bone in midshaft (p = 0.027) and thicker proximal trabeculae (p < 0.001) compared to the control. While both doses of chelates increased mineral density in midshaft (p = 0.040), bone content of Cu and Zn decreased (p = 0.025, p < 0.001, respectively). The content of immature collagen in cancellous bone and articular cartilage increased in groups receiving chelates (p < 0.001, p = 0.001, respectively). In conclusion, glycine chelates probably enhanced development of the skeletal system in male pheasants as bones were denser and more resistant to mechanical damage.

Intra-individual variation in performance on novel variants of similar tasks influences single factor explanations of general cognitive processes

Intra-individual variation in performance within and across cognitive domains may confound interpretations of both domain-general and domain-specific abilities. Such variation is rarely considered in animal test batteries. We investigate individual consistency in performance by presenting pheasant chicks (n = 31), raised under standardized conditions, with nine different cognitive tasks. Among these tasks were two replicated novel variants of colour learning and colour reversal problems, tests of positional learning and memory, as well as two different tasks that captured multiple putative measures of inhibitory control and motor-related performance. These task variants were also used to compare subjects' performance on alternative test batteries comprised of different task combinations. Subjects' performance improved with experience, yet we found relatively little consistency in their performance, both within similar tasks using different paradigms and across different tasks. Parallel analysis revealed non-significant factors when all nine tasks were included in a principal axis factor analysis. However, when different combinations of six of the nine tasks were included in principal axis factoring, 14 of 84 combinations revealed significant main factors, explaining between 28 and 35% of the variance in task performance. While comparable findings have been suggested to reflect domain-general intelligence in other species, we found no evidence to suggest that a single factor encompassed a diverse range of cognitive abilities in pheasants. Instead, we reveal how single factor explanations of cognitive processes can be influenced by test battery composition and intra-individual variation in performance across tasks. Our findings highlight the importance of conducting multiple tests within specific domains to ensure robust cognitive measures are obtained.

Safety and efficacy of Coxiril® (diclazuril) for pheasants

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Coxiril^® for pheasants. Coxiril^®, containing 0.5% diclazuril, is intended for the prevention of coccidiosis in pheasants at a dose range of 1.0-1.2 mg/kg of complete feed. Diclazuril from Coxiril^® is considered safe for pheasants at a level of 1.2 mg/kg complete feed. The conclusion was made by extrapolating the results of a tolerance study with turkeys for fattening. The FEEDAP Panel considered that the residues in pheasant tissues and eggs would be of the same magnitude as those measured in the physiologically similar major species chickens and turkeys for fattening. The use of diclazuril at a maximum concentration of 1.2 mg/kg complete fed for pheasants would be safe for the consumer, provided that the maximum residue limits (MRLs) established for poultry would not be exceeded. The conclusions on the safety of the additive for the target species and the consumer are made under the provision that Coxiril^® is not fed to laying birds. Coxiril^® is considered as a non-irritant to eyes and skin. It is not a potential skin sensitiser. User inhalation exposure to Coxiril^®, as a result of normal handling, is unlikely to cause respiratory or systemic toxicity. The use of diclazuril from Coxiril^® in pheasants does not pose a risk to the environment for neutral/alkaline soils (pH ≥ 7). A final conclusion on the risk resulting from the use of the additive in acid soil cannot be done due to the high uncertainties related to potential accumulation of diclazuril over time. The FEEDAP Panel concluded that diclazuril from Coxiril^® at a minimum dose of 1 mg/kg complete feed has the potential to control coccidiosis in pheasants.

Comparative pathomorphological, bacteriological and serological examination of broiler breeders and pheasants experimentally infected with Ornithobacterium rhinotracheale

The aim of the investigations was to determine the influence of Ornithobacterium rhinotracheale (ORT) on the development of pathomorphological lesions in the respiratory organs and on the health status of experimentally infected broiler breeders and pheasants from the rearing stage. There was no evidence of clinical signs in infected broiler breeder hens nor in the group of infected pheasants except for one bird in the latter group which exhibited slower movement and gasping. The frequency and intensity of pathomorphological lesions were higher in pheasants. The gross pathology findings were characterized mainly by redness of the mucosa of the upper respiratory tract and accumulation of mucous content in the nasal cavities, infraorbital sinuses, larynx and trachea. Histopathology confirmed the presence of inflammation of the upper respiratory tract. Lesions in the lungs included hyperaemia, granulomatous and fibrinous pneumonia. ORT was reisolated only from the group of infected pheasants. Reisolation was successful from the respiratory organs (trachea, larynx, infraorbital sinuses, and lungs) of eight out of 10 infected birds. The serological response in both species was characterized by rapid production of specific antibodies that reached a maximum level in the blood in the first week after experimental infection. The antibody titres decreased gradually and were maintained at a stable level until the 12th week after inoculation. Fourteen weeks post-inoculation specific antibodies could not be detected by enzyme-linked immunosorbent assay.

A problem with problem solving: motivational traits, but not cognition, predict success on novel operant foraging tasks

Rates of innovative foraging behaviours and success on problem-solving tasks are often used to assay differences in cognition, both within and across species. Yet the cognitive features of some problem-solving tasks can be unclear. As such, explanations that attribute cognitive mechanisms to individual variation in problem-solving performance have revealed conflicting results. We investigated individual consistency in problem-solving performances in captive-reared pheasant chicks, Phasianus colchicus, and addressed whether success depends on cognitive processes, such as trial-and-error associative learning, or whether performances may be driven solely via noncognitive motivational mechanisms, revealed through subjects' willingness to approach, engage with and persist in their interactions with an apparatus, or via physiological traits such as body condition. While subjects' participation and success were consistent within the same problems and across similar tasks, their performances were inconsistent across different types of task. Moreover, subjects' latencies to approach each test apparatus and their attempts to access the reward were not repeatable across trials. Successful individuals did not improve their performances with experience, nor were they consistent in their techniques in repeated presentations of a task. However, individuals that were highly motivated to enter the experimental chamber were more likely to participate. Successful individuals were also faster to approach each test apparatus and more persistent in their attempts to solve the tasks than unsuccessful individuals. Our findings therefore suggest that individual differences in problem-solving success can arise from inherent motivational differences alone and hence be achieved without inferring more complex cognitive processes.

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Problem-solving performance was assessed in artificially reared pheasant chicks.

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Performance was consistent within same/similar tasks but not across different tasks.

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Successful solvers did not improve performance with trial and error experience.

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Differences between successful and unsuccessful birds were mediated by motivation.

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Success at problem solving may not reveal cognitive differences between individuals.