Effects of the thyroid hormone responsive spot 14α gene on chicken growth and fat traits

The thyroid hormone responsive spot 14α (THRSPα) gene plays important roles in chicken growth and fat deposition. The aim of this study was to identify new variations in the gene to determine their effects on growth and fat traits in chicken and to observe the effects of the THRSPα gene on chicken lipid profile and lipoprotein and glucose and triiodothyronine effects on the THRSPα expression in liver and fat cells. Two new variations, namely A197835978G and G197836086A, and a reported 9-bp insertion-deletion (indel) of the THRSPα gene were genotyped by single-stranded conformational polymorphism in a Xinghua × White Recessive Rock F2 full-sib resource population. The results showed that the A197835978G was significantly associated with hatch weight and BW at 28 d of age and breast muscle weight at 90 d of age in chickens (P < 0.05). The G197836086A was significantly associated with cingular fat width (P = 0.0349) and breast muscle crude fat content (P = 0.0349). The indel was significantly associated with abdominal fat weight (P = 0.0445). The above new THRSPα polymorphisms were also significantly associated with the total cholesterol and low-density lipoprotein, in which the THRSPα GA/AG genotype was associated with lipid and lipoprotein and the THRSPα BB indel genotype was significantly associated with liver weight in chicken breeds. The mRNA expression analysis in vivo and in vitro culture studies suggested that the THRSPα gene is more responsive to glucose than triiodothyronine. In conclusion, the 3 variations of the chicken THRSPα gene were associated with both growth and fat traits in this study. Such effects of the THRSPα gene were further supported from the data of observations in association analysis of the gene with phenotypic records and plasma lipid profiles, in the THRSPα gene expression in chicken development, and in vivo and in vitro cell culture observation of liver and abdominal fat tissues.