Feeding System Resizes the Effects of DGAT1 Polymorphism on Milk Traits and Fatty Acids Composition in Modicana Cows

Abstract

The interaction between genetic polymorphism and feeding system on milk traits and fatty acid composition was investigated in Modicana cows. Two DGAT1 K232A genotypes (AK and AA) and two feeding regimes, extensive system (EX) with 8 h of grazing without concentrate (EX) and semi-intensive systems (SI) with 2 h of grazing with concentrate, were investigated. DGAT1 genotype did not influence milk yield and composition. The feeding system affected milk composition: protein was significantly higher in SI and lactose in the EX system. A significant genotype × feeding system interaction was observed: the protein and casein levels of AK cows were higher in the SI compared to the EX system. Milk fatty acids profile, total saturated to total unsaturated fatty acids, n-6 to n-3 ratios, and atherogenic index were affected by the feeding system, improving the healthy properties of milk from animals reared in the extensive system. DGAT1 genotype influenced the fatty acid composition: milk from AA cows had a more favorable fatty acid composition due to lower total saturated fatty acids, saturated to unsaturated ratio, atherogenic index, and higher levels of oleic acid and total unsaturated fatty acids. Furthermore, an interaction genotype x feeding system was observed: the AK milk was richer in short-chain FAs (C4:0–C8:0) and C10:0 only in the EX but not in the SI system. Our data suggest that a high amount of green forage in the diet of Modicana cows can resize the effect of the DGAT1 genotype on milk traits and fatty acids composition.

Polymorphisms at Candidate Genes for Fat Content and Fatty Acids Composition: Effects on Sheep Milk Production and Fatty Acid Profile Using Two Dietary Supplementations

“…These effects have been reported across different species, including cows, buffaloes, goats, and sheep [61]. Moreover, studies have reported the influence of DGAT1 polymorphisms on fatty acid composition in both cow milk [15,28,62] and sheep milk [24]. In the Assaf breed, Dervishi et al [24] observed significant effects of the SNP g8539C > T on the C4, C16:1 c9, and n6/n3 content.…”

“…Both genes contain SNPs in the 5 UTR promoter region, which are potential candidates for playing a crucial role in regulating gene expression [12,13]. Additionally, the regulation of these genes can also be influenced by environmental factors and feeding composition [14][15][16].…”

Overview of SNPs Associated with Trans Fat Content in Cow’s Milk

“…The breeding value for the amounts of milk (in kg) of animals with the AA genotype was significantly (p ≤ 0.0001) higher than in animals with the KK genotype [40]. The polymorphism of the DGAT1 gene in position p.A232K influenced the fatty acid composition: milk from AA cows had a more favorable fatty acid composition due to a lower total saturated fatty acids content and higher levels of oleic acid and total unsaturated fatty acids, a higher ratio of the saturated to unsaturated acids, and a higher atherogenic index [41].…”

Association of Single Nucleotide Polymorphism in the DGAT1 Gene with the Fatty Acid Composition of Cows Milked Once and Twice a Day

“…Several studies have reported the effect of the diacylglycerol acyltransferase 1 ( DGAT1 ) polymorphism in the bovine genome on major milk traits of cows [ 23 , 24 , 25 ]. Some studies have also reported the effect of DGAT1 polymorphism on the fatty acid composition of milk [ 25 , 26 , 27 ]. However, there are some other polymorphisms in proximity to DGAT1 genes that could contribute to the variation in the fatty acid composition of cow milk as the quantitative trait locus (QTL) which has a major effect on milk production traits is positioned at the centromere end of chromosome 14 where the DGAT1 gene is located.…”