[Recent developments in the concept of essential fatty acids in fish].

Abstract

In fish, essential acids belong to the n-3 series. In trout, carp and salmon a dietary supply of 0.7 to 1% linolenate allows to prevent any symptoms of deficiency and ensures a normal growth. This is not the case for see fish such as daurade and turbot, where a supply of a similar proportion of n-3 high polyunsaturated fatty acids (HPUFA) appears to be necessary. However, recent experiments show that this requirement for HPUFA is not specific, since they can be replaced by linolenate in the turbot provided that the linolenate dietary amount is substantially higher than in the trout. The 6-desaturase activity seems to be lower in see fish than in freshwater fish and there is a good agreement between the nutritional tests of growth rate of fish and the biological tests of bioconversion rate of linolenate into HPUFA. Fish seem to be a highly valuable tool for determining the role and mechanism of action of essential fatty acids. In our opinion it is very interesting to use differences between fish and mammals to apprehend all the specific biological processes related to the presence of essential fatty acids in the organism.