Effects of Different Fat Supplements on Growth and Hepatic Lipids and Fatty Acids in Male Mink

Male mink kits (n=10 for each group) were fed diets supplemented with different fats for 12 weeks (September-November). The levels of digestible fat (8%) and energy content (7 MJ kg-1) of the diets were equal. The supplements used were beef pork fat, mink fat, broiler offal, rainbow trout offal, capelin oil, soybean oil and linseed oil. The growth and hepatic lipids (analysed by a thin-layer chromatography- flame ionization detection analyser) and fatty acid composition (analysed by gas-liquid chromatography) were studied. The pattern of weight gain of the mink fed the beef pork diet differed from that of the other mink. These kits reached high but delayed weight maxima compared with the other mink but then during November they lost weight rapidly. In liver, both the capelin oil- and linseed oil-fed mink had large concentrations of total lipids and triacylglycerols. The mink fed capelin oil were significantly heavier. The fatty acid analyses of hepatic total lipids and phospholipids revealed that the f -linolenic acid (18:3 n-3) of linseed oil was not efficiently metabolized to longer chain and more unsaturated fatty acids important for cellular membranes. It is discussed that 18:3 n-3 may not be as valuable for growing mink kits as the polyunsaturated fatty acids of the fish oils.