Tissue-specific changes in the activities of antioxidant enzymes during the development of the chicken embryo. Br Poult Sci

Abstract 1. Tissue-specific profiles of the expression of the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) and the concentrations of reduced glutathione (GSH) during the development of the chick embryo were investigated. 2. The liver, brain, yolk sac membrane (YSM), kidney, lung, heart and skeletal muscles were collected at the following days of embryo development: 10, 11, 13, 15, 17, 19, 21 and 22 (day-old chicks). 3. The different tissues of the embryo displayed distinct development strategies with regard to the acquisition of antioxidant capacity. In the liver the specific activity of SOD increased between days 10 and 11 of development, then significantly decreased up to day 15 and remained at the same value during the rest of the developmental period. GSH-Px specific activity increased through the time of development. CAT had 2 peaks of specific activity at day 10 of the development and in day-old chicks. 4. The brain was characterised by comparatively high SOD-specific activity especially during the last days of incubation. The specific activities of GSH-Px and CAT were low throughout development. 5. In the YSM maximal GSH-Px and CAT-specific activities were found on day 15 of incubation. In the kidney and heart GSH-Px-specific activity increased at hatching time. CAT-specific activity in the kidney increased just after hatching. 6. It is concluded that each tissue studied expressed a profile of antioxidant defence mechanisms to deal with oxidative stress at hatching time

Modelling effects of phytobiotic administration on coherent responses to Salmonella infection in laying hens

Practice of layer poultry farming and commercial egg production relies on the optimal use and improvement of the welfare and genetically determined functional abilities of laying hens, their efficient intake of feed and its components, adaptation to housing conditions and resistance to infectious diseases including salmonellosis. Previous studies were focussed on relationships of chicken performance and resistance with the expression profiles of individual genes involved in metabolic processes and immune system, or with genetic markers that can be closely associated with these processes in chickens. In this study, mathematical models of coherent changes in laying hens were developed for the expression of eight genes involved in immunity and metabolism, on the one hand, and biochemical and immunological blood parameters, on the other hand, in response to Salmonella infection and administration of a phytobiotic Intebio. The proposed modelling approach can be a further basis for an in-depth research of the relationship between the gene expression, functional state and welfare of poultry, impact of pathogenic microorganisms and use of immunomodulatory drugs

[Mathematical assessment of BAC-based interspecies hybridization data in the process of genomic mapping in the white-throated sparrow as an avian behavioral model] Математическая оценка данных межвидовой БАК-гибридизации в процессе геномного картирования у белошейной зонотрихии как модели поведения птиц

The white-throated sparrow (Zonotrichia albicollis) known for its morphological, behavioral and chromosomal polymorphisms represents a quite new model system to study genomic mechanisms underlying variable behavioral repertoire interwoven with population biology, reproduction and adaptation in this species. It was previously shown that these polymorphisms could be due to chromosomal rearrangements (inversions) on sparrow chromosome 2 (ZAL2) that is characterized by a heterogeneity in two distinct morphs, tan (ZAL2/ZAL2) and white (ZAL2/ZAL2m). To construct a comparative genomic map of ZAL2 and other chromosomes, we used a sparrow genomic BAC library, CHORI-264. Following a cross-species overgo hybridization approach, we screened the library and developed a first-generation BAC-based comparative physical map using the chicken and zebra finch reference genomes. The map includes 640 BAC-gene assignments for 77 loci and serves for further refining the genomic regions and identifying candidate genes that are affected by rearrangements and contribute to the observed behavioral polymorphisms. Mathematical assessment of the BAC-based hybridization data was undertaken to show evolutionary relationships of avian genomes. В настоящей работе представлена математическая оценка межвидовой БАК-гибридизации в процессе геномного картирования у белошейной зонотрихии – вида воробьев, рассматриваемого в качестве удобной модели поведения птиц

Effects of essential oils-based supplement and Salmonella infection on gene expression, blood parameters, cecal microbiome and egg production in laying hens

Simple Summary Salmonellosis is one of the most severe zoonotic diseases transmitted to humans through animal products (especially poultry meat and eggs). Essential oils (EOs)-based feed additives in poultry nutrition are a possible alternative replacement of antimicrobials to fight this infection. In the present study on laying hens, we tested a phytobiotic, Intebio®, and elucidated formation of immune response and changes in cecal microbiocenosis and biochemical/immunological variables in blood caused by Salmonella. Changes in differential gene expression were observed at both one and seven days post-inoculation in the hens’ intestines, revealing similarities with known mammalian/human tissue-specific expression. The results of this study suggest that the challenge of birds with Salmonella had a negative effect, while phytobiotic intake had a positive effect on the status of their gastrointestinal microbiome, their level of metabolism, and their performance. Abstract One of the main roles in poultry resistance to infections caused by Salmonella is attributed to host immunity and intestinal microbiota. We conducted an experiment that involved challenging Lohmann White laying hens with Salmonella Enteritidis (SE), feeding them a diet supplemented with an EOs-based phytobiotic Intebio®. At 1 and 7 days post-inoculation, the expression profiles of eight genes related to immunity, transport of nutrients in the intestine, and metabolism were examined. Cecal microbiome composition and blood biochemical/immunological indices were also explored and egg production traits recorded. As a result, the SE challenge of laying hens and Intebio® administration had either a suppressive or activating effect on the expression level of the studied genes (e.g., IL6 and BPIFB3), the latter echoing mammalian/human tissue-specific expression. There were also effects of the pathogen challenge and phytobiotic intake on the cecal microbiome profiles and blood biochemical/immunological parameters, including those reflecting the activity of the birds’ immune systems (e.g., serum bactericidal activity, β-lysine content, and immunoglobulin levels). Significant differences between control and experimental subgroups in egg performance traits (i.e., egg weight/number/mass) were also found. The phytobiotic administration suggested a positive effect on the welfare and productivity of poultry

The interplay between gonadal steroids and immune defence in affecting a carotenoid-dependent trait

The hypothesis that sexual ornaments are honest signals of quality because their expression is dependent on hormones with immune-depressive effects has received ambiguous support. The hypothesis might be correct for those signals that are carotenoid-dependent because the required carotenoid deposition in the signal, stimulated by testosterone, might lower the carotenoid-dependent immune defence of the organism. Two pathways underlying this androgen-dependent honest signaling have been suggested. Firstly, androgens that are needed for ornament expression may suppress immune defence, a cost that only high-quality animals can afford. Alternatively, immune activation may downregulate the production of androgens in low-quality individuals. Which of these alternatives is correct, and to what extent these effects are mediated by the different metabolites of androgens, remain open questions. To provide answers to these questions, we manipulated the levels of testosterone (T), 5α-dihydrotestosterone (DHT), and 17-β-estradiol (E2) in diamond doves Geopelia cuneata, a species in which both sexes exhibit a carotenoid-dependent, androgen-regulated red–orange periorbital ring of bare skin. On the first day of the experiment (day 0), we inserted steroid-releasing implants into groups of birds and on day 14, we subjected half of the birds to an immunological challenge by immunizing them with sheep red blood cells (SRBC). In females, but not in males, androgen but not estradiol treatments reduced antibody production to SRBC. In addition, the immunological challenge reduced redness and size of the trait as well as androgens levels in both sexes and in all treatments. This indicates that an immunological challenge can lower circulating T at the cost of the trait expression. These findings are in accordance with both pathways postulated in the immunocompetence-handicap hypothesis, but do not entirely support the idea that the immunosuppressive effect of androgens yields honest signaling since both T and DHT were not immunosuppressive in males, for which sexual signaling is supposed to be especially important

Immune Activation Reduces Sperm Quality in the Great Tit

Mounting an immune response against pathogens incurs costs to organisms by its effects on important life-history traits, such as reproductive investment and survival. As shown recently, immune activation produces large amounts of reactive species and is suggested to induce oxidative stress. Sperm are highly susceptible to oxidative stress, which can negatively impact sperm function and ultimately male fertilizing efficiency. Here we address the question as to whether mounting an immune response affects sperm quality through the damaging effects of oxidative stress. It has been demonstrated recently in birds that carotenoid-based ornaments can be reliable signals of a male's ability to protect sperm from oxidative damage. In a full-factorial design, we immune-challenged great tit males while simultaneously increasing their vitamin E availability, and assessed the effect on sperm quality and oxidative damage. We conducted this experiment in a natural population and tested the males' response to the experimental treatment in relation to their carotenoid-based breast coloration, a condition-dependent trait. Immune activation induced a steeper decline in sperm swimming velocity, thus highlighting the potential costs of an induced immune response on sperm competitive ability and fertilizing efficiency. We found sperm oxidative damage to be negatively correlated with sperm swimming velocity. However, blood resistance to a free-radical attack (a measure of somatic antioxidant capacity) as well as plasma and sperm levels of oxidative damage (lipid peroxidation) remained unaffected, thus suggesting that the observed effect did not arise through oxidative stress. Towards the end of their breeding cycle, swimming velocity of sperm of more intensely colored males was higher, which has important implications for the evolution of mate choice and multiple mating in females because females may accrue both direct and indirect benefits by mating with males having better quality sperm