Effets de la salinité et de la température du milieu sur le degré de saturation des acides gras et sur les différentes catégories lipidiques des alevins de Mugil cephalus

Abstract

In this study changes in lipid composition of Mugil cephalus fry is measured according to salinity and temperature acclimation. At 14 degree C, the fish acclimated to freshwater presents an increase of 6.5% in the polyunsaturated fatty acids/saturated fatty acids quotient compared to those acclimated to the seawater. Moreover, the low salinity involves a decrease of triacylglycerols and polar lipids (respectively 65 and 37%). The transition of the acclimation temperature from 26 degree C to 14 degree C in seawater is followed by an increase of the polyunsaturated fatty acids/saturated fatty acids quotient. This variation is more important at 35ppt than at 0,5ppt. The low temperature (14 degree C) involves also (at 35ppt) an increase of the triacylglycerols and polar lipids by 356 and 53% respectively. We conclude that the changes made in the salinity and temperature of acclimation are followed by a quantitative and qualitative variation in the lipids of Mugil cephalus fry. The decrease of these two parameters offers an improvement of the synthesis of the polyunsaturated fatty acid from the essential ones in Mugil cephalus fry.