Unraveling the associations of osteoprotegerin gene with production traits in a paternal broiler line

Marcelo B Fornari, Ricardo Zanella, Adriana MG Ibelli, Lana T Fernandes, Maurício E Cantão, Vanete Thomaz-Soccol, Mônica C Ledur, Jane O Peixoto

Improvements on growth and carcass traits in the poultry industry have been achieved by intense selection for heavier chickens at early ages. This faster growth has caused serious problems due to insufficient skeletal structure development needed to support the musculature of modern broilers. The osteoprotegerin gene (OPG), located on GGA2, is an important regulator of bone metabolism and reabsorption, being suggestive as a possible functional candidate gene associated with bone integrity in chickens. This study reports associations of a single nucleotide polymorphism (SNP) in the OPG gene with production traits in a parental broiler line. Different phenotypic groups were evaluated: performance, carcass and skeletal traits. SNPs were identified within the OPG gene and the most informative SNP g.9144C > G was chosen for association analyses. Chickens (n = 1230) were genotyped using PCR-RFLP. The association was carried out with QxPaK v4.0 software using a mixed model including sex, hatch and SNP as fixed effects, and the infinitesimal and residual as random effects. The OPG SNP was associated with important traits as body weight at 21 days, weights of tibia and drumstick skin, leg muscle yield, and tibia breaking strength (P < 0.05). Associations were explained by the additive effect of the SNP and the additive effect within sex. This SNP could be considered a potential marker to improve bone resistance in chickens; however, caution should be taken because of its negative effect in other important traits evaluated in this study. Furthermore, these findings suggest a possible involvement of the OPG gene in fat deposition in poultry.