Leptin Gene (T117C) Polymorphism and Its Association with Milk Yield Performance in Crossbred Anglo-Nubian Goats

Abstract

This study was performed to determine polymorphism in the leptin gene (T117C) and investigate the association between genotypes and milk yield in 101 crossbred Anglo-Nubian dairy goats from Awang, Opol, Misamis Oriental and Talay, Dumaguete City, Negros Oriental in the Philippines. Milk yield performance data were standardized to 90 and 140 d milking periods. The goat’s hair follicles were collected to extract genomic DNA. Polymerase chain reaction– restriction fragment length polymorphism (PCR-RFLP) was the method used in genotyping with NmuCI as the restriction enzyme. Statistical analysis was performed following the two-way factorial (2 x 4) in a randomized complete block design (RCBD), where leptin genotypes and parity were used as main factors and farm as the blocking factor. Two genotypes (TT and TC) were obtained. Genotypic frequencies between TT (0.50) and TC (0.50) were evenly distributed, while allele T (0.75) occurred more frequently than allele C (0.25) in the total population studied. Observed heterozygosity is higher than the expected heterozygosity and the genetic variation observed in the overall population was in Hardy-Weinberg equilibrium (p > 0.05). Milk yield traits at 140 d milking period in crossbred Anglo-Nubian dairy goats were significantly influenced by polymorphisms in leptin (T117C). Goats having TT genotype had superior milk yield performance (140dADMY: 0.90L ± 0.058L, 140dTMP: 124.65L ± 8.51L) than those with TC genotype (140dADMY: 0.78L ± 0.051L, 140dTMP: 107.90L ± 7.21L). Further studies should be conducted in other goat breeds to validate associations of leptin polymorphism with milk production and in other economically important traits.