Variation in the stearoyl-CoA desaturase gene (SCD) and its influence on milk fatty acid composition in late-lactation dairy cattle grazed on pasture.

ABSTRACT: Gene markers have become useful tools for improving animal genetics and breeding since they improve the accuracy of selection for superior breeding stock. In this study, the stearoyl-CoA desaturase ( ? -9-desaturase) gene (SCD) was investigated in New Zealand pasture-grazed Holstein-Friesian? × ?Jersey cows. Three nucleotide substitutions were identified in exon 5 of the gene (c.702A/G, c.762T/C and c.878C/T), and a single nucleotide substitution was identified in intron 5 (c.880 + 105A/G). The c.878C/T substitution would, if expressed, result in the amino acid substitution p.A293V. Four nucleotide substitutions (c.*1783A/G, c.*1883C/T, c.*1984G/A and c.*2066T/C/G) were identified in the 3 ' -untranslated region (3 ' -UTR), and these resulted in three nucleotide sequence variants (named a , b and c) . The sequence that would encode valine (V) at position 293 of SCD was linked to 3 ' -UTR variant a , and the sequence that would encode alanine (A) was linked to variants b and c . The frequency of the genotypes was as follows: VV (equivalent to aa: 15.1?%), VA (equivalent to ab+ac : 50.0?%) and AA (equivalent to bb+cc+bc : 34.9?%). The cows with the V variant produced less C10:1, C12:1 and C14:1 fatty acid (FA) but more C10:0, C11:0, C14:0, C16:1 and C18:2 FA than the A variant cows ( P<0.001 ). Effects of c.*1783A/G and c.*2066T/C/G on milk fat composition were also found for the AA cows. The presence of c was associated with decreased levels of C16:1 ( P<0.001 ), C17:1 ( P=0.001 ), C18:2 cis-9, trans-13 ( P=0.045 ), C18:2 cis-9, trans-12 ( P=0.018 ) FA and C16:1 FA index ( P<0.001 ). The presence of b was associated with increased levels of C13:0 iso FAs ( P<0.001 ), monounsaturated FA (MUFA; P=0.002 ) and C12:1 ( P<0.001 ).

SUBMITTER: Li Y 

PROVIDER: S-EPMC7648274 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature