Dietary riboflavin enhances immunity and anti-oxidative status against arsenic and high temperature in Pangasianodon hypophthalmus

Abstract

Climate change and pollution are the major global challenges causing severe abiotic stresses on aquaculture. The present study was conducted to delineate the role of dietary riboflavin (RF) on mitigation of abiotic stresses due to low dose of arsenic and high temperature (As+T) on Pangasianodon hypophthalmus. Four diets containing RF at 0, 5, 10 and 15 mg kg−1 were fed to fishes reared under low dose of arsenic (2.68 mg L−1) and temperature (34 °C) stresses for 90 days. Growth index viz. weight gain percentage, feed conversion ratio, FCR; protein efficiency ratio, PER; and specific growth rate, SGR significantly enhanced (p < 0.01) with supplementation of dietary RF at 10 mg kg−1 diet, whereas growth index of fish treated under stressors (As+T) and fed with control diet drastically reduced (p < 0.01). Anti-oxidative status viz. catalase, superoxide dismutase, glutathione-s-transferase and glutathione peroxidase was significantly improved (p < 0.01) with supplementation of dietary RF at 10 mg kg−1 diet. Moreover, the immunological status viz. total protein, albumin, globulin, albumin globulin ratio (A:G ratio), respiratory burst activities, myeloperoxidase, total immunoglobulin were significantly improved with supplementation of dietary RF in fish reared under stressors and non-stressors. The biochemical stress markers as blood glucose and HSP 70 was drastically reduced with dietary RF at 10 mg kg−1 diet, however, the level of glucose and HSP 70 were elevated with arsenic and high temperature and fed with control diet. Aeromonas hydrophilla was inducted to fishes to observe the immunological status of fishes fed with dietary RF. The protective role of dietary RF was observed in the histopathological study of liver and gill. Arsenic bioaccumulation in different fish tissues reduced (p < 0.01) with dietary supplementation of RF. The study revealed that As pollution and high temperature reduced the growth performance, anti-oxidative status and immunity of the fish but dietary RF mitigated it.