O PERFIL DE EXPRESSÃO DO GENE KCNJ11 AFETA CARACTERÍSTICAS RELACIONADAS COM EFICIÊNCIA ALIMENTAR EM BOVINOS

Genes involved in metabolic pathways associated to feed efficiency traits are sought for better understanding the underlying molecular and regulatory mechanisms related to them. The KCNJ11 gene ispotentially a functional candidate for these traits since it is involved in pathways regulating energy metabolism and insulin secretion in cattle and regulation of glycogen storage and body fat in mice. Thus, this study aimed to determine whether the transcriptional profile ofKCNJ11 gene is associated with feed efficiency-related traits. Steers totaling 593 Nellore were evaluated for the feed efficiency traits, of which 79 were used to analyze the expression profile of KCNJ11 gene in muscle. Quantitative cycle values (Cq)were corrected using BLUP estimates predicted by a model that considered fixed and random effects originated from the experimental design and other variables. After adjusting the Cq values, a mixed model which includes effects of slaughter, birth location, kinship and age was applied to assess the association between the level of KCNJ11 expression and the target traits. The expression levels of KCNJ11 gene were associated with daily weight gain calculated by regression (kg/day), Dry matter intake (kg/day), total digestible nutrients (kg/day) and relative growth rate (%/day), however, no significant association was found for feed efficiency (Kg/kg) and efficiency of weight gain (kg/Mcal). These results contribute to the understanding of the molecular mechanisms that affect feed efficiency. Keywords:qPCR, Nelore, residual feed intake, feed conversion