Response of lipid molecular structure to dietary lipid type in Chinese mitten crab Eriocheir sinensis : A deep lipidomics analysis

Lipid molecules and fatty acids were analyzed using lipidomics to understand the change of lipid structure and metabolism in the hepatopancreas of Chinese mitten crab (Eriocheir sinensis). The crabs fed diets with four oil sources (palm oil, olive oil, safflower seed oil and purple perilla oil) for 8 weeks. Palmitic acid, oleic acid, linoleic acid, and linolenic acid were the most abundant fatty acids in these oil types, respectively. Sixteen lipid classes were identified in the hepatopancreas. Triglycerides, phosphatidylcholines, diacylglycerols, and phosphatidylethanolamines in hepatopancreas were analysis deeply in this study. The relative contents of main lipid classes in the hepatopancreas were all significantly influenced by dietary oil sources. A similar pattern of lipid metabolism was observed in the E. sinensis fed palm oil and olive oil diets with an increasing quantity of C18:2n-6 in sn-1, 3 of triglycerides. Polyunsaturated fatty acids were distributed mainly in the sn-1, 3 position in triglycerides and in the sn-2 position in diacylglycerols and phospholipids. The abundance of C18:3n-3 in the diet could not significantly increase the contents of EPA and DHA in the hepatopancreas. Meanwhile, there was no C18:3n-3 at the sn-1 and no C18:0 at the sn-2 positions in phosphatidylcholines. This study was the first attempt on using lipidomics in crustaceans to understand the impact of dietary oil source on the structure of lipids stored in crustaceans. It provides a new insight and theoretical basis to understand the mechanism on the difference in lipid composition in the diet and in the tissue of crustaceans.