Effects of choline on the growth performance, antioxidant function and lipid metabolism in juvenile largemouth bass fed with high-fat diet

This study carried out an 8-week feeding experiment to evaluate the influence of dietary choline supplementation on the growth performance, antioxidant function and lipid metabolism in juvenile largemouth bass fed with high-fat diet. Accordingly, five experimental diets included the positive control diet (PC, 10% fat without choline supplementation), negative control diet (NC, 15% fat without choline supplementation) and high-fat diet (15% fat) supplemented with 0.3% (NC+CH0.3), 0.6% (NC+CH0.6) and 1.2% (NC+CH1.2) choline. The analyzed choline contents in experimental diets were 2.56, 2.61, 4.25, 6.58 and 9.89 g/kg, respectively. Accordingly, each experiment diet was randomly divided into 3 replicates containing 25 fish with 6.84 & PLUSMN; 0.01 g initial weight. Results showed that compared with the PC group, NC group decreased growth performance and increased vis-cerosomatic index and intraperitioneal fat ratio (P<0.05). Liver superoxide dismutase activity and serum total antioxidant capacity were decreased while serum malondialdehyde content was increased in NC group (P<0.05). NC group significantly increased lipid deposition, which was identified by increased lipid contents in the whole body especially back muscle and liver, liver fatty acids composition (16:1n-7, 18:1n-9, 20:1n-9,18:3n-3), he-matological parameters (total cholesterol, triacylglycerol). Compared with NC group, dietary choline supple-mentation increased (P<0.05) growth performance and 6.58 mg/kg choline supplementation reached highest value. Liver n-3/n-6 PUFA, DHA/EPA contents and superoxide dismutase capacity were increased (P<0.05) while serum malondialdehyde content was decreased (P<0.05). 9.89 mg/kg choline supplementation increased expression levels of fatty acid synthase, acetyl-CoA carboxylase, elongase of very long-chain fatty acid 5 (elovl 5), & UDelta;6 fatty acyl desaturase genes, while diet supplemented with 6.58 mg/kg choline increased levels of elovl 5 and glucose 6-phosphate dehydrogenase genes (P<0.05). Our results concluded: (1) 8-week high-fat feeding induced growth suppression, lipid accumulation and oxidative damage in juvenile largemouth bass; (2): Appropriate choline supplementation could alleviate the growth suppression, oxidative damage and lipid accumulation induced by high fat diet, and recommended choline dosage in largemouth bass compound feed was 6.58 g/kg.

Automated summary

This study conducted an 8-week feeding experiment to evaluate the effects of dietary choline supplementation on the growth, antioxidant function, and lipid metabolism in juvenile largemouth bass fed a high-fat diet. The results showed that appropriate choline supplementation could alleviate the negative impacts of high fat diet, including growth suppression, oxidative damage, and lipid accumulation. The recommended choline dosage for largemouth bass compound feed was found to be 6.58 g/kg.