Dietary lipid concentrations influence growth, liver oxidative stress, and serum metabolites of juvenile hybrid snakehead (Channa argus × Channa maculata)

Abstract

The study was conducted to evaluate the effect of dietary lipid levels on growth, liver oxidative stress, and serum metabolites of juvenile hybrid snakehead (Channa argus × Channa maculata). Five isonitrogenous (crude protein 420 g kg⁻¹) practical diets containing 58, 87, 115, 144, and 173 g kg⁻¹ crude lipid (named L58, L87, L115, L144, and L173, respectively) were fed to triplicate groups of 30 fish (mean initial weight 24 g) for 8 weeks. The results showed that the final body weight (58.68–78.81 g), specific growth rate (1.41–1.75 % day⁻¹), and protein efficiency ratio (1.66–2.64) increased significantly with the increasing dietary lipid levels. Liver lipid contents (71.65–101.80 g kg⁻¹) and crude lipid (52.10–83.63 g kg⁻¹) of whole body increased with increasing dietary lipid levels and reached the highest values in fish of L173. Fish of L173 showed lower alkaline phosphatase (23.81 King Unit gprot⁻¹) and catalase activities (4.44 U mgprot⁻¹) but higher malondialdehyde content (0.69 nmol mgprot⁻¹) in liver than the other groups. Higher alanine transaminase activity (8.20 U L⁻¹), aspartate transaminase activity (63.65 U L⁻¹), and triglyceride (0.29 mmol L⁻¹) in serum were observed in fish of L173 compared to the other treatments. Fish of L144 showed higher superoxide dismutase activity and glutathione peroxidase activities in liver than that of fish fed diet L58. Fish fed diet L58 showed lower total cholesterol (3.61 mmol L⁻¹), high-density lipoprotein cholesterol (1.39 mmol L⁻¹), and low-density lipoprotein cholesterol (0.46 mmol L⁻¹) in serum. These results suggested that juvenile snakehead (Channa argus × Channa maculata) achieved good growth performance with dietary lipid level 173 g kg⁻¹. Diet with 143 g kg⁻¹ lipid was more conductive to liver health. The appropriate dietary lipid supplementation needs to be determined in further studies .