豬 Myostatin 和 IGF-2 基因多態性與生長、屠體及繁殖性狀相關性之探討

Abstract

Myostatin (MSTN), a member of transforming growth factor-β (TGF-β) superfamily, is a negative regulator of muscle development. Loss-of-function of MSTN protein resulted in double-muscled phenotype in several mammalian species, such as cattle, sheep, human, and dog have been found. However, there was no functional mutation in porcine MSTN gene. Therefore, there was no so-called double-muscled breed of pig. The aim of this study was to investigate the effects of polymorphisms of MSTN and IGF-2 genes on porcine growth performance, carcass, and reproductive traits. DNA from purebred and crossbred pigs were extracted, including 1,743 Duroc, 944 Landrace, and 343 Yorkshire for growth performance analysis; 270 Duroc × Landrace (DL) and 153 Duroc × Yorkshire × Landrace (DYL) for carcass traits analysis; 528 Landrace sows for reproductive performance analysis. Data of average daily gain (ADG), feed efficiency (FE), ultrasound backfat thickness (BF), body weight at 70 days-old (BW70) and 150 days-old (BW150), days to 110 kg of body weight (D110 kg), longissimus muscle area (LMA) at 10th rib, carcass backfat thickness, meat and fat weight in the anterior, middle, and posterior cuts of carcass, total lean weight and percentage, and total number born (TNB) and number of born alive piglets (NBA) of each parity were collected. Two SNPs (g.435G>A and g.447A>G) in the promoter region of MSTN gene and one SNP (g.162C>G) in the intron 7 of IGF-2 gene were genotyped using Taqman SNP Genotyping Assay. The association results indicated that the MSTN g.435GG/447AA individuals had better ADG, heavier BW150, and lower Age110kg (P A/447A>G and the TNB or NBA observations. In conclusion, these two loci are potential genetic markers in porcine selection of growth performance and carcass traits, and they could be used independently. Selection for MSTN g.435G/447A allele is expected to increase body weight and growth rate in Duroc and Yorkshire pigs. Furthermore, selection for IGF-2 intron 7 g.162C allele is expected to increase body weight and decrease fat accumulation in Yorkshire, DL and DYL pigs. However, the genotype of MSTN g.435/447 might not affect the litter size in Landrace sows.