Identification of single nucleotide polymorphisms in avian uncoupling protein gene and their association with growth and body composition traits in broilers

Uncoupling protein (UCP) genes are members of the mitochondrial membrane transporter family. They could increase energy expenditure via diminishing the resulting production of adenosine triphosphate (ATP) and instead yielding dissipative heat. Some studies showed that decrease of the energy expenditure was the main reason causing obesity. We identified two SNPs in avian UCP gene and genotyped them in broiler lines that underwent divergently selection for abdominal fat after six generations using the percentage of abdominal fat as well as very low-density lipoprotein (VLDL) as the selection criterion. Two polymorphisms were found in the 3' untranslated region (UTR) (A1197C) and intron 2 (C1240A) region. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) methods were then developed to genotype the population. The correlation between the UCP SNPs and growth as well as body composition traits were carried out using mixed model analysis. Results showed that the polymorphism of A1197C had an effect on percentage of abdominal fat (AFP), abdominal fat weight (AFW) and liver weight (LW). The C1240A polymorphism had effects on body weight (BW), carcass weight (CW), LW and gizzard weight (GW). There is a significant association between the UCP genotypes and the growth and body composition traits in the broiler lines. Key words: Broiler, uncoupling protein gene, SNPs, growth, body composition