Variation in mouse milk fatty acid profile across genetically diverse strains

Open Access
Author:
Robinson, Kristen
Area of Honors:
Veterinary and Biomedical Sciences
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Kevin John Harvatine, Thesis Supervisor
  • Dr. Lester C Griel Jr., Honors Advisor
Keywords:
  • milk fat
  • fatty acid profile
  • quantitative trait loci
Abstract:
Fat is the most variable component of milk in both concentration and composition. Differences can be attributed to diet, environmental conditions, and genetics. The study of milk fat has important implications nutritionally and economically. Diets higher in saturated fatty acids increase the risk of cardiovascular disease. Conversely, diets higher in long-chain omega-3 fatty acids decrease the risk of heart disease. In the dairy industry, milk prices are based on the fat and protein yield, which makes milk fat a valuable component for producers. The objective of the present thesis was to determine if significant variation in milk lipid concentration exists between inbred mouse strains. Milk fatty acids (FA) from 325 mice of 31 different strains were extracted and methylated, then quantified via gas chromatography. Statistical analysis software was used to fit a model that included strain effect for each of the 22 fatty acids. Further genetic analysis was conducted for the following groups: FA with less than 16C, FA with 16C, FA with greater than 16C, and C14 and C16 desaturation indexes. Significant variation in fatty acid profile was shown between strains, particularly when comparing de novo synthesis in the mammary gland (FA less than 16C) and preformed fatty acids from the plasma (greater than 16C). Analysis of genetic variation identified SNPs associated with selected milk fatty acids. We can conclude that the variation in milk fatty acid profile between strains is due to specific genes, but further research is required to determine the functional important of the SNPs.