Effect of polymorphisms in the FASN, OLR1, PPARGC1A, PRL and STAT5A genes on bovine milk-fat composition

P>The aim of our study was to estimate effects of polymorphisms in the ATP-binding cassette G2 (ABCG2), fatty acid synthase (FASN), oxidized low-density lipoprotein receptor 1 (OLR1), peroxysome proliferator-activated receptor-gamma coactivator-1 alpha (PPARGC1A), prolactin (PRL) and signal transducer and activator of transcription 5A (STAT5A) genes on milk production traits and detailed milk-fat composition. Milk-fat composition phenotypes were available for 1905 Dutch Holstein-Friesian cows. First, the presence of each SNP in the Dutch Holstein-Friesian population was evaluated by direct sequencing of the PCR product surrounding the SNP in 22 proven Dutch Holstein-Friesian bulls. The ABCG2 SNP did not segregate in the bull population. Second, we genotyped the cows for the FASN(g.16024G > A), FASN(g.17924A > G), OLR1(g.8232C > A), PPARGC1A(c.1790+514G > A), PPARGC1A(c.1892+19G > A), PRLg.8398G > A and STAT5A(g.9501G > A) polymorphisms, and estimated genotype effects on milk production traits and milk-fat composition. FASN(g.17924A > G) and OLRg.8232C > A had a significant effect (P < 0.05) on milk-fat percentage. However, we were not able to confirm results reported in the literature that showed effects of all evaluated polymorphisms on milk-fat percentage or milk-fat yield. All polymorphisms showed significant effects (P < 0.05) on milk-fat composition. The polymorphisms in FASN and STAT5A, which had an effect on C14:0 and were located on chromosome 19, could not fully explain the quantitative trait locus for C14:0 that was previously detected on chromosome 19 in a genome-wide scan using linkage analysis.