Influence of Romanov sheep genotype on thyroxine content in the blood serum of descendants

The content of the thyroid hormone thyroxine in blood serum of the descendants of three Romanov sheep was studied. The experiment involved 4-month-old sheep and 9-month-old sheep representing the breed zoned in Kuzbass. Three groups of descendants from different sires were formed (father No.40, father No.74, and father No.418), which were kept and fed in the same conditions from birth until slaughter. The hormone level in the blood serum was determined using enzyme immunoassay on “Multiskan FC” analyzer using commercial Steroid IFA-thyroxine kits (St. Petersburg). Standard methods of descriptive statistics were used to process the obtained data, Microsoft Office Excel 2007 and R-Studio tools were applied. Fisher’s criterion was used for statistical analysis of the results to compare the descendants of three fathers. The obtained results demonstrated that the thyroxine level in the blood serum of descendants depends on the genotype of sheep-producers. A reliable difference in the thyroxine level was found between descendants of different fathers: the thyroxine level in the son s of father No.40 was 18% and 23% higher compared to the descendants of producers No.74 and No.418 (P>0.95). The average concentration of thyroxine in the population of Romanov sheep was 155.3 nmol/l. The influence of the father’s genotype on thyroxine level in the blood serum of descendants was 22.4%. This study emphasizes the importance of genetic factors in the formation of physiological parameters of animals, which can influence further selection programs and increase the efficiency of breeding Romanov sheep.