Effects of high-fat diet on growth performance, lipid accumulation and lipid metabolism-related MicroRNA/gene expression in the liver of grass carp (Ctenopharyngodon idella).

Abstract

An 8\u202fweek experiment was conducted to evaluate the effects of dietary fat on growth and on the accumulation of lipids and the expression of lipid metabolism-related microRNAs (miRNAs) and genes in grass carp (Ctenopharyngodon idella). Two diets (normal fat diet (NFD), 60\u202fg/kg lipid content; high fat diet (HFD), 160\u202fg/kg lipid content) were fed to triplicate groups of 35 fish [initial weight of (40.0\u202f±\u202f0.5) g]. The results showed that increased dietary fat did not lead to significant differences in the feed conversion rate (FCR) and specific growth rate (SGR) (P\u202f>\u202f.05), but the HFD significantly increased the hepatosomatic index (HSI) (P\u202f<\u202f.05). The serum high density lipoprotein-cholesterol (HDLC) level was significantly increased in the HFD group (P\u202f<\u202f.05). Oil Red O staining showed that both the size and amounts of lipid droplets in the liver of fish fed a diet with 2\u202fg/kg lipid content increased significantly. In the liver of fish fed with 160\u202fg/kg dietary fat, the expression of mir-33a, mir-30, mir-122 and mir-16 significantly decreased (P\u202f<\u202f.05). In contrast, the expression of sterol regulatory element-binding transcription factor 1 (SREBP1), peroxisome proliferator-activated receptor gamma (PPARγ), liver X receptor alpha (LXRα) and ATP-binding cassette transporter A1 (ABCA1) significantly increased (P\u202f<\u202f.05). In conclusion, 2\u202fg/kg dietary fat did not influence growth but altered the expression of miRNAs and genes related to lipid metabolism in the liver of grass carp, which caused severe lipid deposition.