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The synthesis of fatty acids plays a critical role in shaping milk production characteristics in dairy cattle. Thus, identifying effective haplotypes within the fatty acid metabolism pathway will provide novel and robust insights into the genetics of dairy cattle. This study aimed to comprehensively examine the individual and combined impacts of fundamental genes within the fatty acid metabolic process pathway in Jersey cows. A comprehensive phenotypic dataset was compiled, considering milk production traits, to summarize a cow's productivity across three lactations. Genotyping was conducted through PCR-RFLP and Sanger sequencing, while the association between genotype and phenotype was quantified using linear mixed models. Moderate biodiversity and abundant variation suitable for haplotype analysis were observed across all examined markers. The individual effects of the FABP3 , LTF and ANXA9 genes significantly influenced both milk yield and milk fat production. Additionally, this study reveals novel two-way interactions between genes in the fatty acid metabolism pathway that directly affect milk fat properties. Notably, we identified that the GGAAGG haplotype in FABP3 × LTF × ANXA9 interaction may be a robust genetic marker concerning both milk fat yield and percentage. Consequently, the genotype combinations highlighted in this study serve as novel and efficient markers for assessing the fat content in cow's milk.

Peroxisome proliferator-activated receptor gamma (PPARγ) is a critical transcription factor regulating lipid and glucose metabolism. However, the regulatory effect of PPARγ on milk fat synthesis in buffalo mammary gland is not clear. In order to explore the role of buffalo PPARG gene in milk fat synthesis, lentivirus-mediated interference was used to knock it down and then the recombinant fusion expression vector was transfected into buffalo mammary epithelial cell (BMEC) to overexpress it. PPARG gene knockdown significantly decreased the expression of CD36, FABP3, FABP4, ACSS2, ELOVL6, DGAT2, BTN1A1, AGPAT6, LPIN1, ABCG2, PPARGC1A, INSIG1, FASN, and SREBF2 genes and significantly upregulated the expression of INSIG2 gene but had no significant effect on the expression of ACSL1, GPAM, and SREBF1 genes. PPARG overexpression significantly increased the relative mRNA abundance of CD36, FABP3, FABP4, ACSS2, ELOVL6, DGAT2, BTN1A1, AGPAT6, LPIN1, PPARGC1A, INSIG1, and SREBF2 genes and significantly downregulated the expression of INSIG2 gene but had no significant effect on the expression of ACSL1, GPAM, ABCG2, FASN, and SREBF1 genes. In addition, knockdown/overexpression of PPARG gene significantly decreased/increased triacylglycerol (TAG) content in BMECs. This study revealed that buffalo PPARG gene is a key gene regulating buffalo milk fat synthesis., (© 2021 Japanese Society of Animal Science.)

The aim of this study was to determine the effects of isonitrogenous and isocaloric diets containing different qualities of forages and concentrate content on milk fat composition and genes that encode mammary lipogenic enzymes in dairy cows. A total of 20 Holstein cows were assigned to 1 of 2 treatment diets composed of either mixed forages (MF, starch : 21.50%) or corn stover forage (CS, starch : 25.39%). Mammary tissue biopsies were performed to analyze the mRNA expression of lipogenic enzymes. Dry matter intake, body weight, milk protein, and lactose were not affected by treatments. The milk yield, fat content and saturated fatty acid (SFA) and short- and medium-chain fatty acid (SMFA) contents in milk were lower in the CS diet than in the MF diet, but the unsaturated FA and long-chain FA contents were higher. Genes involved in de novo FA synthesis, FA uptake and transport, and Δ9-desaturation were lower in the CS treatment than in the MF treatment. No effects on the nuclear transcription factors were observed between the two treatments. The data indicated that corn stover diet reduced the milk yield, fat content, SMFA, and SFA contents in milk, as well as the gene expression of mammary lipogenic enzymes in dairy cows., (© 2018 Japanese Society of Animal Science.)

In this study, we investigated the genetic variation within 3'UTR of Mammary-Derived Growth Inhibitor (MDGI) gene of buffalo using PCR-SSCP and sequencing; and also analyzed association of polymorphism with the milk production traits. The study revealed two conformational patterns, 'A' and 'B' among 234 Mehsana buffaloes maintained with their records in the field and at farm. The frequency of SSCP variant 'A' was found to be invariably high in the buffalo population under study. Further, association analysis of SSCP variants with various milk production and milk quality traits indicated no significant effect on any of the traits investigated. Sequencing of SSCP variant 'A' showed homozygous G/G and A/A and 'B' had heterozygous G/C and A/G at positions +124 and +140 respectively, in the 3'UTR of buffalo MDGI. The preliminary results showed the substantial variations in the distribution of SSCP variants' frequencies within Mehsana buffaloes, however these variants had non-significant association with milk yield, fat yield and fat percentage in Mehsana buffaloes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)