Dietary lipid sources modulate the intestinal transport of fatty acids in the red swamp crayfish Procambarus clarkii

Abstract

The optimization of feed formulations is an effective strategy to increase the growth of aquatic animals, but the effects of dietary lipid sources other than fish oil are not well established in most of crustacean. In this study, we investigated how different dietary lipid sources influence fatty acid absorption, synthesis, and transport in the red swamp crayfish (Procambarus clarkii). Six isonitrogenous and isocaloric diets were formulated with the following lipid sources: fish oil (FO), corn oil (CO), rapeseed oil (RO), soybean oil (SO), palm oil (PaO), and beef tallow (BT). The crayfish fed FO, SO, or BT exhibited a significantly higher weight gain rate (WGR) and specific growth rate (SGR) and a lower feed conversion ratio (FCR) than those of crayfish fed PaO. Polyunsaturated fatty acid (PUFA) profiles in the hepatopancreas and muscle tissues closely mirrored those in the diets. Low total triglyceride (TG) and total cholesterol (TC) contents were observed in the hemolymph and hepatopancreas of crayfish fed FO or BT diet. In the lipid anabolism pathway, fatty acid synthase (fas), sterol regulatory element-binding protein 1 (srebp1), and retinoid X receptor (rxr) were down-regulated by dietary FO but up-regulated by some vegetable oils. A gene involved in fatty acid (FA) uptake and transport, fatty acid binding protein (fabp), was up-regulated by CO in the hepatopancreas and by BT in muscle tissues. With respect to intestinal fatty acid transporters, fatty acid transport protein 4 (FATP4) was up-regulated in the BT diet, diacylglycerol transferase1 (DGAT1) was down-regulated in the FO or BT diet, and Niemann-Pick C1-like 1 (NPC1L1) was down-regulated in the SO diet. Apolipoprotein B-48 (Apo B-48) and fatty acid translocase (FAT/CD36) were not influenced by dietary lipid sources. According to the observed results, BT is the more suitable candidate for FO replacement in crayfish diets, whereas PaO is not recommended.