The effect of incubation factors modifications on endocrine system and growth factors of broilers. [Doctoral dissertation] | Uticaj promena faktora inkubacije na endokrini sistem i faktore rasta teških hibrida pilića. Doktorska disertacija

During the embryonic development muscle growth and the production of poultry meat can be stimulated in different ways. Methods for achieving these results are based on the application of monochromatic green light and thermal conditioning (increasing incubation temperature during certain critical stage). In this doctoral thesis the examining of both types of treatment, and their combination, has been done and also their comparison with the control group. The effect of all treatments was to increase the growth hormone levels during their application and immediately after that. This suggests that differences in production parameters, that occur later, were the result of locally produced growth factors. During the embryonic period of development and during the first days of postnatal development, all applied treatments had the effect of increasing the levels of T3 and decreasing the levels of T4. The protein expression of IGF-1, in breast muscle, was higher in treated groups during embryonic development, while in the postnatal development this was observed with the simultaneous application of both treatments. The protein expression of ERK, in the breast muscle of treated groups, was higher throughout the entire period of development. The biochemical parameters of blood plasma were affected by the application of treatments. The concentration of total proteins during the embryonic period and immediately after hatching was affected, as a result of increased concentrations of albumins, but without changing in the concentration of globulins in blood plasma. In all treated groups the concentration of glucose in the blood plasma was higher at the end of embryonic development, while the treatments had no significant effect on concentration of lipids. Applied treatments did not cause extensive angiogenetic response of chorioalantoic membrane. All applied treatments had significant effect on increasing the body weight, without affecting mortality and conversion. Applied treatments had significant influence on the increase of dry matter in meat as a result of increasing the percentage of total proteins. In addition, all treatments had a significant effect on reducing the progressive loss of moisture from the meat. Our results indicate that the use of these treatments is justified and that there is a possibility that they can be successfully implemented in commercial broiler production. In particular, the significant potential has the possibility of combination of these treatments in order to achieve the optimum effect.