Mitochondrial gene expression in the liver and muscle of high and low feed efficiency Japanese quail layers subjected to different environmental temperatures.

We evaluated the adenine nucleotide translocator (ANT) and cytochrome oxidase subunit III (COX III) mRNA expressions in the muscle and liver of Japanese quails presenting high and low feed efficiency (FE), and subjected them to three different environmental temperatures: comfort, heat stress (38°C), and cold stress (10°C). ANT mRNA expression was lower in the liver of heat-stressed animals. In the muscle, higher ANT and COX III mRNA expressions were observed in high-FE and cold-stressed animals. In the liver, much higher expression of COX III mRNA was observed in cold-stressed animals. These results suggest a possible correlation between the genes involved in energy production by the mitochondria and FE phenotypes, and that environmental temperature can affect the ANT and COX III mRNA expressions. Japanese quails presenting different FE levels respond differently to environmental stimuli.