Effects of dietary sodium butyrate on growth performance, antioxidant capacity, intestinal histomorphology and immune response in juvenile Pengze crucian carp (Carassius auratus Pengze)

Abstract

The current study was done to assess the effects of dietary sodium butyrate (SB) on growth performance, antioxidative capacities, intestinal microvilli morphology and intestinal immune response in juvenile Pengze crucian carp (Carassius auratus Pengze). Three treated diets and a control containing 0, 1,000, 2,000, 4,000 mg/kg SB (CON, SB1, SB2, SB3) were fed for juvenile Pengze crucian carp (5.49 ± 0.41 g) for 8 weeks. The results revealed that fish in SB2 and SB3 groups showed significantly higher growth performance compared to the control (P < 0.05). The body lipid was significantly decreased in SB-containing groups compared with that of the control (P < 0.05). Trypsin and lipase activities of fish fed SB2 and SB3 diets were both significantly higher than those of fish fed CON and SB1 diets (P < 0.05). However, no significant difference was found in α-amylase activity among all groups (P > 0.05). The intestinal total antioxidant capacity, catalase and superoxide dismutase activities were significantly enhanced in SB groups compared to the control (P < 0.05). The activities of brush border enzymes such as alkaline phosphatase, γ-glutamyl transpeptidase and Na+/K+-ATPase of fish fed SB2 and SB3 diets were both significantly higher than those of fish fed CON and SB1 diets (P < 0.05). However, the malondialdehyde contents of intestines in fish fed SB diets were remarkably reduced (P < 0.05). In addition, the serum total antioxidant capacity, superoxide dismutase, lysozyme activities and complement C3 content of fish fed SB2 and SB3 diets were significantly increased than those of fish in the CON (P < 0.05). The analysis of scanning electron microscopy and transmission electron microscopy demonstrated that density and length of microvilli were increased in the SB2 and SB3 groups (P < 0.05). The mRNA expression levels of pro-inflammatory gene IL-1β was significantly down-regulated in the SB2 and SB3 groups (P < 0.05). Moreover, the mRNA expression levels of anti-inflammatory gene TGFβ and IL-10 were significantly up-regulated in SB groups (P < 0.05). The mRNA expression levels of TNFα were not significantly different among all the groups (P > 0.05). Conclusively, our results showed the positive effects of the SB in Pengze crucian carp diets to improve the growth, intestinal microvilli morphology and intestinal immune response.