Effect of Water Temperature on the Desaturation of Fatty Acids in Carp

Abstract

The specific activity of Δ9-desaturase from carp reared at water temperature of 15-18°C was higher than that reared at 28-30°C. The levels of polyunsaturated fatty acids increased in hepatopancreas microsomes from carp raised in lower temperature. When carp were fed fat-free diet for 62 days, specific activity of Δ9-desaturase increased. Supplementation of 5% fatty acids to fat-free diet resulted in the decrease of the specific activity of the enzyme, regardless of the species of fatty acids, including saturated fatty acids. In contrast, suppressing effect of saturated fatty acids to Δ9-desaturase was not observed in vitro. Alloxan injection resulted in decrease and insulin injection resulted in the increase of the specific activity of Δ9-desaturase in carp and was less than in rats. The control mechanism of the enzyme by hormone in carp seems to be reduced. © 1986, The Japanese Society of Fisheries Science. All rights reserved.