Effects of dietary replacement of fish oil by vegetable oil on fatty acid composition of Chinese mitten crab (Eriocheir sinensis)

Abstract:

In order to study the effect of dietary replacement of fish oil by vegetable oil on the crude lipid content and fatty acid composition of Chinese mitten crab, vegetable oil[m (soybean oil):m (rapeseed oil)=3:1] was used to replace different levels (0%, 50% and 100%) of fish oil to make three kinds of feeds with equal nitrogen and fat (F1, F2 and F3). The results showed that there was no significant difference (P<0.05) in the crude fat content between the meat, gonads and hepatopancreas of three groups of crabs. The fatty acid composition of each feed was different. The content of polyunsaturated fatty acid (PUFA) in meat was about 50%, and there was no significant difference (P>0.05) among dietary groups. The gonad fatty acid composition was affected by the fatty acid composition of feed. The content of n-6 PUFA increased with the increase of the replacement level. The hepatopancreas fatty acid composition was the most affected by the substitution of vegetable oil in the feed for fish oil, and the total content of monounsaturated fatty acid (MUFA) and PUFA increased with the replacement level. Compared with F1 and F3 groups, the contents of EPA+DHA in the edible parts of F2 group was relatively higher. It could be seen that 50% vegetable oil replacing fish oil was beneficial to the fatty acid composition of edible parts of female Chinese mitten crab. This study provided a reference for the substitution ratio of fish oil in the fattening feed and further improvement of the quality.