Features of protein metabolism in bulls of different ages
Questions of the relation ship of indicators of protein metabolism in the body of bulls with age can serve as accumulative material for the development of reference values of biochemical indicators characterizing the normal course of metabolic processes. The serum samples of the Holstein breeding bulls (n=102), divided into 4 groups by age and contained in the conditions of the "Head Center for the Reproduction of Farm Animals", were investigated. The following parameters were determined in blood serum: concentration of total protein, albumin, urea, creatinine, activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST). As a result of research, it has been established that with age, bulls reliably increase blood levels of total protein. In the 2-4 year old bulls, this indicator increased by 11% (P<0.01), 4-6 years old - by 19.1% (P<0.01), and over 6 years old - by 21.5% (P<0,001) compared with animals under 2 years. This was associated with an increase in the globulin fraction. With increasing age of the bulls, an increase in the concentration of creatinine in the blood was observed, which is associated with an increase in body weight of animals. Noted the increase in urea in the blood of the bulls with age. Thus, in the blood of bulls of 4-6 years of age, this indicator increased by 47.9% (P<0.001) as compared with analogues up to 2 years. An increase in AST activity in bulls with age can be associated with an increased load on the liver and the cardiovascular system due to their production use. The obtained data on the metabolic profile of the bulls of different ages will help in practice to monitor and adjust the condition of the animals and to develop reference values for assessing health and nutrition levels.