Effects of dietary terrestrial oils supplemented with <scp>l</scp>-carnitine on growth, antioxidant capacity, lipid metabolism and inflammation in large yellow croaker (<i>Larimichthys crocea</i>)
Xueshan Li, Qiang Chen, Qiuchi Chen, Kangsen Mai, Qinghui Ai
Abstract
The present study was conducted to determine the effects of dietary terrestrial oils (TO) supplemented with L-carnitine on growth performance, biochemical and antioxidant response, lipid metabolism and inflammation in large yellow croaker (Larimichthys crocea). Three iso-nitrogenous and iso-lipidic experimental diets were formulated with FO (fish oil, the control group), 75% TO (75% FO was substituted by the oil mixture with equal amounts of soybean oil, linseed oil and pork lard) and 75% TOC (75% TO supplemented with 800 mg/kg L-carnitine), respectively. Compared to the control group, feed efficiency ratio and specific growth rate were significantly increased in fish fed diets with 75% TO and 75% TOC. Hepatic lipid content, serum triglyceride level, low-density lipoprotein-cholesterol level and the mRNA expression of pro-inflammatory genes (tnfα and ifnγ) were significantly increased in fish fed the diet with 75% TO compared to the control group. However, the supplementation of 800 mg/kg L-carnitine in the 75% TO diet repressed hepatic lipid content, serum low-density lipoprotein-cholesterol level and the mRNA expression of tnfα and ifnγ in fish compared to fish fed the diet with 75% TO. Total antioxidant capacity, the activity of superoxide dismutase, the mRNA expression of cpt-I and the activity of CPT-I were significantly increased in fish fed the diet with 75% TOC compared to 75% TO. In conclusion, these results suggested that the supplementation of 800 mg/kg L-carnitine in the diet with terrestrial oils mixture could increase growth, antioxidant capacity, fatty acid oxidation and decrease the expression of inflammatory genes in large yellow croaker.