Effect of glycerin supplementation on the expression of antioxidant and mitochondrial genes in broilers.

Crude glycerin has been used as an alternative energy source in animal feeding and can thus change both the animal's performance and the levels of gene expression related to energy production process and the antioxidant system, since the effect of glycerin depends on its degree of purity in the diet. The aim of this study was to evaluate the effect of crude glycerin inclusion (0, 6 and 12%) in the diet has on performance characteristics and mRNA abundance of genes associated with the mitochondrial function (uncoupling protein (UCP), cytochrome C oxidase subunit III (COX III) and adenine nucleotide transporter (ANT)) and those that combat the reactive oxygen species (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) in the liver and muscle of broilers at 42 days of age. Total RNA was extracted from the tissues, and cDNA was amplified using specific primers for the genes under study through real-time reverse transcription polymerase chain reaction; the endogenous gene used was β-actin. There was no difference between glycerin concentrations for weight gain, feed intake or feed conversion. Greater expression of UCP at muscle and higher GPx expression at liver were observed in broilers fed 12% glycerin. In conclusion, the addition of 12% glycerin to broiler diets increased the expression of UCP and GPx , but did not change broiler performance. Therefore, glycerin can be used as an alternative ingredient without losses. Glycerin represents an alternative of reducing costs in broiler production. We evaluate whether glycerin interferes in the performance characteristics and in the expression of mitochondrial and antioxidant genes. Although the expression of UCP and GPx genes has been increased, we conclude that glycerin can be used as an alternative in poultry feed without lost performance. [ABSTRACT FROM AUTHOR]