Free fatty acids and lipid peroxidation in normal and mastitic bovine milk

Milk levels of free fatty acids (FFA) and prostaglandins (PGs) were determined in healthy cows and in those with mastitis and compared with some parameters commonly used for diagnosing mastitis. A modified gas chromatography-mass spectrometry method was used. In mastitis there was a substantial overall increase in FFA levels in milk. Specific attention was paid to the fate of the long-chain polyunsaturated fatty acids, known as precursors for the production of PGs, leukotrienes and other eicosanoids. Both the omega-6 and omega-3 lines of these lipids were increased in mastitis, but only in proportion to other FFA. The milk levels of PGs (PGF2, PGF2 alpha, thromboxane B2) were elevated in the same proportion. The possible importance of lipid peroxidation, inflammatory reaction and host defence are evaluated in relation to tissue destruction and oxidative killing of pathogens. It may be possible to manipulate the intake and fate of FFA in the organism by dietary intake, antioxidants and proper storing of feed. It is concluded that in studies concerning FFA special attention should be given to those long-chain fatty acids that are precursors for the formation of eicosanoids.