Effects of partial replacement of fish meal with porcine meat meal on growth performance, antioxidant status, intestinal morphology, gut microflora and immune response of juvenile golden pompano (Trachinotus ovatus)

Abstract

This study was conducted to investigate the effects of partial replacement of fish meal (FM) with porcine meat meal (PMM) on growth performance, plasma antioxidant parameters, intestine morphological parameters, gut microflora and expression of intestinal Nrf2 and Nf-κB signaling pathway of juvenile golden pompano. Fish were fed with six experimental diets (0 (PC), 10% (P10), 20% (P20), 30% (P30), 40% (P40) and 50% (P50) replacement levels) for 8-weeks. The percent weight gain and specific growth rate in fish fed with P40 and P50 diets were significantly lower than those of the control group (P < 0.05). Compared with the control group, the plasma antioxidant indexes including the activities of superoxide dismutase, catalase, glutathione peroxidase, total antioxidant capacity and malondialdehyde content in fish fed with P30, P40 and P50 diets were significantly affected (P < 0.05). With dietary replacement of FM with PMM increasing 0 to 30%, the relative expressions of IL-10, TGF-β, Nrf2, SOD, Cu/Zn-SOD and GSH-Px were significantly down-regulated, while the relative expressions of NF-κB, TNF-α, IL-1β and IL-8 were significantly up-regulated (P < 0.05). Villus heights and crypt depths of proximal and mid intestine were significantly affected with dietary replacement of FM with PMM increasing 0 to 40% (P < 0.05). The structure of the intestinal microbial flora showed that the relative abundances of beneficial bacteria decreased, and the relative abundances of pathogenic bacteria increased in fish fed with P50 diet compared with the control group. In conclusion, replacing FM with PMM up to 30% had no significant impact on growth performance and feed utilization of golden pompano. However, 30% replacements of FM with PMM exerted adverse effects on antioxidant capacity and immune response of fish. In addition, replacement of a high proportion of FM with PMM negatively affect the gut microflora of fish.