Effects of dietary vitamin B1 on growth performance, intestinal digestion and absorption, intestinal microflora and immune response of juvenile golden pompano (Trachinotus ovatus)

Abstract

The study was conducted to investigate the effects of dietary vitamin B1 on growth performance, intestinal digestion and absorption, intestinal microflora, and the immune response of juvenile golden pompano. Six isonitrogenous and isolipidic diets were formulated, containing diet-1 (0 mg/kg), diet-2 (4.88 mg/kg), diet-3 (8.15 mg/kg), diet-4 (12.00 mg/kg), diet-5 (17.40 mg/kg) and diet-6 (20.40 mg/kg) of vitamin B1. The diets were fed to juvenile golden pompano (initial body weight:11.20 ± 0.15 g) for 8 weeks. The study indicated that dietary vitamin B1 significantly increased weight gain rate (WGR) (P < .05), specific growth rate (SGR) (P < .05), and feed efficiency ratio (FER) (P < .05) of golden pompano. Dietary vitamin B1 levels had a significant effect on serum total cholesterol (TC) (P < .05), glucose (GLU) (P < .05), C4 complement (C4) (P < .05) and lysozyme (LZM) (P < .05). A diet supplemented with 12.00 mg/kg vitamin B1 increased the activities of hepatic total antioxidant capacity catalase (CAT) (P < .05), superoxide dismutase (SOD) (P < .05), glutathione peroxidase (GPX) (P < .05), glutathione reductase (GR) (P < .05), transketolase (TK) (P < .05) and hepatic vitamin B1 accumulation (P < .05), decreasing the activities of hepatic malondialdehyde (MDA) (P < .05). A diet supplemented with 12.00 mg/kg vitamin B1 improved intestinal digestion and absorption by increasing the activities of intestinal chymotrypsin (P < .05), γ-glutamyl transferase (γ-GT) (P < .05), and creatine kinase (CK) (P < .05). Dietary vitamin B1 also increased the intestinal microvilli length and microvilli numbers to a certain degree. Dietary vitamin B1 increased the richness and the diversity of the microbial community (P < .05; Tukey test). Dietary vitamin B1 increased the number of Pseudomonas and restricted the number of Mycoplasma and E. shigella in intestine. A quadratic regression analysis on weight gain and hepatic vitamin B1 concentrations indicated that the optimum dietary vitamin B1 levels for the optimal growth of juvenile pompano were 12.94 and 12.61 mg/kg, respectively.