A synonymous mutation of uncoupling protein 2 (UCP2) gene is associated with growth performance, carcass characteristics and meat quality in rabbits

Background: Uncoupling proteins 2 (UCP2) plays an important role in energy regulation, previous studies suggested that UCP2 is an excellent candidate gene for human obesity and growth-related traits in cattle and chicks. The current study was designed to detect the genetic variation of UCP2 gene, and to explore the association between polymorphism of UCP2 gene and growth, carcass and meat quality traits in rabbits. Results: A synonymous mutation in exon 1 and four variants in the first intron of the UCP2 gene were identified by using PCR-sequencing. The synonymous mutation c.72G>A was subsequently genotyped by MassArray system (Sequenom iPLEXassay) in 248 samples from three meat rabbit breeds (94 Ira rabbits, 83 Champagne rabbits, and 71 Tianfu black rabbits). Association analysis suggested that the individuals with AA and AG genotypes showed greater 70 d body weight (P < 0.05), 84 d body weight (P < 0.01), ADG from 28 to 84 days of age (P < 0.05), eviscerated weight (P < 0.01), semi-eviscerated weight (P < 0.01) and semi-eviscerated slaughter percentage (P < 0.05), respectively. Additionally, the individuals with AA and AG genotype had a lower pH value of longissimus muscle (P < 0.01) and hind leg muscle (P < 0.05) after slaughter 24 h. Conclusions: These findings indicated that UCP2 could be a candidate gene that associated with growth performance, body composition and meat quality in rabbits, and this would contribute to advancements in meat rabbit breeding practice.