Liver Fatty Acid Composition and Peroxisomal Fatty Acid Oxidase Activity in Blue Foxes ( Alopex lagopus) and Mink ( Mustela vison) Fed Diets Containing Different Levels of Fish Oil

Abstract

At the time of pelting (Nov.), blue foxes had a lower liver lipid content (4–5%) than mink (7–10%), whereas the phospholipid (PL) content was 0.5–1% in both species. Dietary fat content had little influence on total liver fat content but affected the liver fatty acid composition. Levels of n3 fatty acids were higher in the PL fraction than in the remaining fraction of liver lipids in both species. Because PL accounted for a larger part of the total liver lipids in blue foxes than in mink, the proportion of the total liver lipids accounted for by n3 fatty acids was highest in blue foxes. On the other hand, the mink and foxes had about the same quantity of n3 per gram liver owing to higher fat content of mink liver. Analyses of liver lipid fatty acid composition did not reveal any differences between the species in their ability to metabolize n3 fatty acids originating from fish oil. Peroxisomal β-oxidation activity in the liver was significantly higher in blue foxes than in mink. For both species the total activity rose as the level of dietary fish oil increased.