Transcriptome Profile in Dairy Cows Resistant or Sensitive to Milk Fat Depression

Area of Science:

• Animal Science
• Genetics
• Nutritional Biochemistry

Background:

• Feeding linseed to dairy cows can cause milk fat depression (MFD), a condition with varying sensitivity among individual animals.
• Understanding the genetic basis of MFD resistance and sensitivity is crucial for dairy herd management and optimizing milk production.

Purpose of the Study:

• To identify specific genes with single nucleotide polymorphisms (SNPs) that regulate milk fat synthesis in dairy cows resistant or sensitive to MFD.
• To explore the potential role of these genes and their associated pathways in the response to linseed-rich diets.

Main Methods:

• RNA sequencing technology was employed for transcriptome and SNP discovery analyses in four dairy cows (two resistant, two sensitive to MFD).
• Differential gene expression analysis was conducted comparing control and linseed-rich diets.
• Candidate genes harboring SNPs under the linseed-rich diet were identified.

Main Results:

• A significant number of differentially expressed genes were observed under both control (1316 genes) and linseed-rich (1888 genes) diets.
• Fifteen key gene regulators harboring SNPs were identified in cows on the linseed-rich diet.
• Genes such as MTOR, PDPK1, EREG, NOTCH1, ZNF217, and TGFB3 were highlighted, potentially forming a network involved in milk fat synthesis via the PI3K/Akt/MTOR/SREBP1 axis.

Conclusions:

• The identified 15 genes represent novel candidates for explaining variations in dairy cow resistance or sensitivity to MFD.
• These findings provide a foundation for future research into genetic markers for MFD and targeted nutritional strategies.