RELATIONSHIP BETWEEN RAT-LIVER MICROSOMAL DELTA-6 AND DELTA-5 DESATURASE ACTIVITIES AND FATTY-ACID COMPOSITION - COMPARATIVE EFFECTS OF COCONUT AND SALMON OILS DURING PROTEIN RESTRICTION

The aim of this work was to compare the effects of coconut and salmon oils on rat liver microsomal DELTA-6 and DELTA-5 desaturations, during protein restriction. A higher DELTA-6 desaturase activity was noted i n rats fed the low-protein coconut oil diet, in comparison with that o ccurring in rats fed either a low-protein or normal-protein salmon oil diet. No variation was observed in DELTA-5 desaturase activity or in 20:4n-6/18:2n-6 ratio. The fatty acid composition of liver microsomal phospholipids provided evidence of higher levels of 20:5n-3 and 22:6n- 3 in the normal-protein salmon oil group, when compared with the low-p rotein salmon oil group. No influence of experimental diets on the tot al n-3 and total n-6 fatty acids could be demonstrated. Aside from inv estigating the effects of protein restriction on the liver microsomal desaturases, this work shows that there is no correlation between micr osomal desaturation rates and microsomal phospholipid profiles even wh en diets are rich in polyunsaturated fatty acids (salmon oil).