Involvement of cholesterol, progesterone, cortisol and lipoproteins in metabolic changes during early ontogenesis of broiler chicks of an industrial cross

Morphophysiological changes in body are influenced by environmental factors, what is more, the specific nature of the body reactions depends on the reaction rate and the stage of ontogenesis on which the physiological stimuli act (I. Schmalhausen, 1982). Also it is known that hormones participate in the regulation of metabolism, growth and development, in adaptation processes. We determined the concentration of high-density (HDL) and low density (LDL) lipoproteins directly involved in protein and lipid metabolism, total cholesterol (TCS), progesterone (P4), 17-hydroxyprogesterone (17-OHP), and cortisol in blood plasma of Hubbard F15 broiler chickens at early postnatal ontogenesis using four groups of poultry of the industrial herd of Chebarkulskaya Ptitsa LLC (Chelyabinsk Province, Russian Federation), 10 animals in each, aged 1, 7, 23 and 42 days, respectively. The role and interrelations of these substances in metabolism were assessed using Pearson's correlation analysis and factor analysis by the principal components method with Varimax factor rotation. Thus, in 1-day aged chicks, the integration of factors HDL, LDL, TCS, P4 and cortisol involved in metabolic processes and metabolism regulations was noted with r -Pearson for P4 and Cortisol at r = 0.69, p = 0.027; for P4 and TCS at r = 0.82, p = 0.004; for HDL and LDL at r = 0.83, p = 0.003; and for HDL and TCS at r = -0.67, p = 0.033. On day 7 day, the principal components were progesterone and cortisol ( r -Pearson for P4 and cortisol of r = 0.73, p = 0.016), and a cholesterol donation factor with LDL and TCS as the leading elements ( r = 0.73, p < 0.05). In 23-day-old chicks the components which have become principal were HDL ( r = 0.91, p < 0.05) and 17-OHP ( r = 0.74, p < 0.05), which we attribute to growth, and also P4 ( r = -0.88, p < 0.05) and cortisol ( r = -0.77, p < 0.05) viewed as regulatory ones. On day 42 we revealed cholesterol donation factor ( r -Pearson of r = 0.86, p = 0.002 for LDL and TCS) and an integral factor with the principal components HDL ( r = 0.74, p < 0.05), P4 ( r = 0.76, p < 0.05) and cortisol ( r = 0.84, p < 0.05). Thus, here we described the age-specific features of interaction between lipoproteins and hormones of cholesterol-progesterone-cortisol system involved in broiler metabolism, and found out the change of principal components and functional relationships among the hormones of progesterone group and lipoproteins during early growth, which, according to our thought, makes a physiological basis for chicken performance under commercial poultry production. In further studies, it can be reasonable to assess the role of these hormones and metabolites in the control of reaction norm and adaptive capability of broilers, and the physiological cost of adaptation (i.e. adequate or pathological response) to reproduction at commercial farms.