Corn gluten meal diets supplemented with dietary L-carnitine for juvenile hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatus): Impacts on growth performance, immune response and flesh quality

Abstract

The focus of this research was to assess if corn gluten meal diet supplemented with L-carinitine (LC) LC0, LC0.2, LC0.4, LC0.6, LC1.2, LC1.4, LC1.6, with LC levels of 0 for the control group, 200, 400, 600, 1200, 1400, and 1600 mg/kg, respectively, may be a viable option for juvenile hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatus). It’s impact on juvenile hybrid grouper growth, immunity, gene expression, and disease resistance. Each group in the experiment had three replicates (initial weight = 13.57 ± 0.00 g) and were fed their respective diets for eight weeks. When LC0.2 was compared to LC0, it showed a significant improvement on growth (P < 0.05). The treatment groups had no differences in crude protein, moisture, or ash content. Serum acid phosphatase, alkaline phosphatase, total antioxidant capacity, and glutathione peroxidase all increased. Fish fed LC0.2 had more steatosis in their hepatocytes in the liver than fish fed LC0, however the differences were not significant in LC0 (P ˃ 0.05). In the LC0.6, LC1.2, and LC1.4 groups, FAS mRNA levels were significantly downregulated. The expression of PPARA and PPARR was higher in the LC0.2 and LC0.4 groups, but not significantly different (P ˃ 0.05) from the LC0. In comparison to LC0, the fish fed diets LC0.2 and LC0.6 had the lowest mortality rate (P < 0.05) in a bacterium challenge test. Finally, based on all of the factors, replacing FM with CGM supplemented with LC0.2 (200 mg/kg) might be used to meet the nutritional needs of fish.