Regulatory role of myo-inositol in vegetable oil-mediated lipid metabolism and health of Chinese mitten crab (Eriocheir sinensis)

Vegetable oils (VOs) are widely used in the aquatic feed industry because of their stable source and low price, but they can cause a series of adverse effects on aquatic animals. Myo-inositol (MI) plays a vital role in regulating lipid metabolism and the health of aquatic animals. However, it remains unclear whether MI has a regulatory role on the utilization of different VOs. An 8-week study was conducted to investigate the effects of MI on the growth, lipid metabolism, and health of the Chinese mitten crab under four oil sources, including palm oil (PO), olive oil (OO), safflower oil (SO), and perilla oil (PFO) in diets. The highest growth performance and the lowest lipid levels in the whole body, hepatopancreas and muscle were observed in crabs fed the PFO diet without MI supplementation. Dietary MI markedly reduced the lipid deposition in the hepatopancreas when crabs were fed the PO and OO diets. Moreover, dietary MI increased the expression of genes related to the uptake and β-oxidation of fatty acid when crabs were fed the PO and OO diets. A high correlation was observed between dietary fatty acid composition and fatty acid composition in the hepatopancreas and muscle. The highest malondialdehyde content was observed in the PFO group. Dietary MI could decrease malondialdehyde content in the hepatopancreas when crabs were fed the PO and PFO diets. However, the lowest inflammation-related genes expression was observed in crabs fed the PFO diet without MI supplementation. Dietary MI could decrease the mRNA levels of these genes when crabs were fed the PO and OO diets. This study indicates that MI is a functional nutrient to improve the low lipid utilization and inflammatory responses caused by dietary palm oil and olive oil in E. sinensis.