The effects of different lipid sources on the growth, intestinal health, and lipid metabolism of the pacific white shrimp (Litopenaeus vannamei)

It is an urgent problem to find suitable replacement of fish oil (FO) in aquatic feeds due to the stagnant production and rising prices of FO. To evaluate the substitution of vegetable oils for FO in the diet of Litopenaeus vannamei (L. vannamei), four diets containing FO, linseed oil (LO), soybean oil (SO) or rapeseed oil (RO) have been fed to L. vannamei for 30 days in this study, and the effects of different lipid sources on the growth, body composition, intestinal health, disease resistance and lipid metabolism of the shrimps were investigated. The results showed that the profiles of fatty acids in four diets and the muscles of the shrimps were discrepant. Further analysis demonstrated that the growth performance of the shrimps in LO and SO groups was similar as that in FO group. Moreover, it seemed that the intestinal health in the shrimps fed with LO or SO diet was improved. In contrast, RO diet reduced the weight gain rate and weakened the intestinal health of the shrimps. Consistently, the shrimps fed with RO diet displayed the highest mortality after Vibrio parahaemolyticus (V. parahaemolyticus) infection among all groups. Additionally, the contents of total cholesterol (T-CHO) and the gene expression of fatty acid synthase (FAS) in the hepatopancreas of the shrimps in RO group was significantly higher than that in FO group. In conclusion, LO or SO could be utilized as the substitution for FO in the diet of L. vannamei, while the replacement of FO with RO in the diet might induce the impaired intestinal health and the imbalance of lipid metabolism, leading to the reduced growth and disease resistance of the shrimp. The present study has provided the research basis for the further development of vegetable oils as a substitute for fish oil in shrimp diets.