Effects of growth hormone gene polymorphism on lipogenic gene expression levels in diaphragm tissues of Japanese Black heifers.

摘要

Two SNPs (L127V and T172M) of bovine growth hormone (GH) associated with the presence of GH gene haplotypes A, B and C are known to alter intramuscular fatty acid (FA) composition in Japanese Black (JB) heifers. To determine the impact of these SNP on somatotropic hormone concn. and lipogenesis, this study determined plasma GH, insulin and insulin-like growth factor-1 (IGF-1) concn., together with mRNA levels of fatty acid synthase (FASN), stearoyl-coA desaturase (SCD) and sterol regulatory element binding protein-1 (SREBP-1) and FA composition in diaphragm tissues from the cattle. Heifers with genotype CC had the lowest plasma insulin concn. and FASN and SCD mRNA levels among the tested genotypes. FASN mRNA levels in haplotype A tended to positively correlate with saturated FA (SFA) content and negatively correlate with C18:2 and unsaturated FA (USFA) contents. SCD mRNA levels in haplotype A positively correlated with monounsaturated FA (MUFA) contents and negatively correlated with C18:0 content. They also tended to positively correlate with C16:1, C18:1 and USFA contents and USFA/SFA ratio and negatively correlate with SFA content. Taken together, GH gene polymorphism affects lipogenic gene expression levels and their relationships with fatty acid compositions in diaphragm tissues of JB heifers at 31 months of age.