Expressão de genes mitocondriais e de crescimento associados à eficiência alimentar de codornas submetidas a diferentes ambientes térmicos

Abstract

This work was structured as a single experiment involving a factorial arrangement where the gene expression and performance of quails were analyzed. The factors lineage (layer and meat), feed efficiency (high and low-efficiency) and thermal stress exposition (cold and heat) were considered. Thus, the experiment results were analyzed considering the lineages separately, first layer then meat. The gene expression analysis of domestic animals is increasing, due to the need to better understand the molecular and biochemical mechanisms involved on nutrition and ambiance. The analysis of mitochondrial and growth related genes, enabled the confirmation of some expected results, considering the action of such genes; although this data also brought other challenges such as explaining unexpected results, where hypothesis might be drawn. When we analyzed the expression of these genes on layer quails, we could observe that IGF-I mRNA expression was higher in the livers of high feed efficiency (FE) quail than in the livers of low-FE quail under both heat and cold stress conditions. High-FE birds also showed higher GHR mRNA expression independent of temperature. UCP mRNA expression in the liver was lower in high-FE birds and higher under cold stress compared with the other conditions. IGF-I mRNA expression was higher in the muscle of high-FE quail under the three conditions tested, and UCP mRNA expression was higher under cold stress. The ANT mRNA expression was lower in the liver of heat stress animals. In the muscle greater ANT mRNA expression was observed for high FE and for cold stress animals. The greatest COX III mRNA expression in the muscle was observed for high FE animals and that were subjected to cold stress. In the liver there was a much higher expression of COX III mRNA in cold stress animals. The analysis results of gene expression on muscle and liver of meat quails are similar to the ones of layer quails. IGF-I mRNA expression was higher in the livers of high-FE quail than in