REPRODUCTIVE FUNCTION IN HYBRID POULTRY. II. AN IMPACT OF BREEDING FOR TRAITS OTHER THAN PRODUCTIVITY (review)

Abstract

Herein, the data are summarized on the impact of such selection criteria as poultry cannibalism, ascites resistance, stress responsiveness, and primary immune response to reproductive function in poultry. The selection for one of these signs changes the productivity and other body functions. High-productive meat crosses differ from slow-growing chicks in a susceptibility to ascites (R. Wideman, 2001). Broilers' mortality because of ascites makes 5-10 %, and at the lowered temperature of the environment can reach 50 % calculated from world production (H. Pavlidis et al., 2007). Prerequisites to development of the disorder are formed during embryogenesis (E. Decuypere еt al., 2000). In the embryos who are the descendants of ascite resistant poultry (L ), a relative heart weight is reliable higher, and pipping shells and a hatching occur earlier, than in L + genotype lines for which the hypothyroidism and tachycardia are characteristic (D. Luger et al., 2002). An observed increase in egg incubation period in L + lines can be caused by lower activity of thyroid gland and an increased pCO 2 in egg air camera, and as a result, the embryos suffered from hypoxia. A positive correlation is revealed between the development of lungs and the thyroid gland activity during embryogenesis, i.e. the lungs volume is the larger the higher thyroidal hormone rate, and vice versa (M. Hassanzadeh et al., 2008). In the chickens with better developed lungs, grown up under chronic hypoxia, the mortality from ascites was reliably lower. In L + and L  broilers the mortality was 93.2 and 9.0 %, respectively (S. Druyan, 2009). The heart beating in L + and L  1-day chickens differed, being on average 435 and 404 beats per minute, respectively, but to the day 17 the difference practically leveled (419 and 417 beats per minute, respectively) due to a decreased rate in L + and an increased rate in L . Divergent selection for the feather pecking behavior causes differentiation in reactivity of the neuro-endocrine and immune systems (A. Buitenhuis, 2006). There are the evidences that the optimized incubation protocols for meat hens can prevent broiler chicks from ascites and improve safety of the poultry. Feather pecking reduced in the course of selected is associated with improvements in egg production (number and weight of eggs), but the deterioration in the quality of hatching eggs, the results of incubation, the state of derived chickens and changes of stress responsiveness and(or) immune response. So, the feather pecking rate was reliable lower in L  than in L + poultry, and the number and weight of eggs laid during a month are higher (i.e. 0.38 and 2.01 feather pecking per hour, 1223 and 1132 g, 24.4 and 18.3 eggs, respectively). However, the egg quality in L + hens was better compared to L  , with the Haugh units of 73.0 and 64.9, shell thickness of 38.1 and 37.0 mm, and yolk ration of 30.6 and 29.5 %, respectively (G. Su, 2006). Selection for humoral immune response causes the metabolic changes and influences on the synthesis of prote...

Reproductive Function in Hybrid Poultry. V. The Effect of Egg Storage Prior to Incubation

“…У зародышей в яйцах, подвергавшихся долговременному хранению, в финальный период эмбриогенеза отмечают снижение функции сердечно-сосудистой системы (79), вызванное истощением энергетических резервов организма, о чем свидетельствует активизация глюконеогенеза (47). Эти обстоятельства необходимо принимать во внимание, особенно при размножении высокопродуктивных бройлерных кур, предрасположенных к развитию синдрома асцита из-за присущей им хронической сердечной недостаточности, формирующейся уже в эмбриогенезе (80).…”

REPRODUCTIVE FUNCTION IN HYBRID POULTRY. IV. AN IMPACT OF MATERNAL HORMONES ACCUMULATED IN EGG (review)

“…I nf lue n ce of ma te rn a l g luco co r tico id s. In commercial poultry farming, there is a high probability of stress resulted from some technological factors [17][18][19][20][21][22][23]. The risk of developing a metabolic stress is typical of both the egg crosses showing increased aggression, tending to pecking, plucking feathers (PPF), fatty liver syndromes and the sudden cessation of egg laying, and for broiler chickens predisposed to ascites and a reduced thermotolerance [24,25]. Metabolic stress in birds is realized through the stimulation of sympaticadrenomedullary and hypothalamic-pituitary-corticoadrenal (HPCA) systems as a result of activity of noradrenaline, adrenaline and corticosterone secreted into the blood [26,27].…”

“…In particular, decreased indicators of fertility and shell quality, higher mortality (prior and post hatching), immunodeficiency are developed [37,38]. These processes are accompanied by a depression of the reproductive function caused by genetic breeding for productive and/or unproductive traits, or by parents' aging [24,25,39]. Some authors report that the bird's stress response decreases with age, depends on the genotype, and is higher in hybrids than in specialized lines [40].…”

“…Reproductive function during breeding for identical but different productive and unproductive traits or during divergent selection for the same trait differs [24,25]. The content of maternal glucocorticoids in the deutoplasm of eggs from highly productive poultry of different crosses is different [41][42][43][44][45][46].…”

“…Breeding for increased performance of the latter has negative consequences as well resulting in a decrease in the reproductive function and efficiency of vital systems, including the cardiovascular problems, e.g. ascitic syndrome [24,25,94].…”