Effect of dietary alanyl-glutamine dipeptide against chronic ammonia stress induced hyperammonemia in the juvenile yellow catfish (Pelteobagrus fulvidraco).

Triplicate groups of juvenile yellow catfish (1.98 ± 0.01 g) were fed diets supplemented with 0% and 1% alanyl-glutamine dipeptide (AGD) for 56 days under three ammonia concentrations (0.01, 5.70 and 11.40 mg L-1 total ammonia nitrogen). The results showed that ammonia poisoning could induce growth (weight gain and specific growth rate) and survival reduction, live ammonia and serum malondialdehyde accumulation, and subsequently lead to blood deterioration (serum total protein, albumin, globulin, alkaline phosphatase and acid phosphatase reduced), oxidative stress (superoxide dismutase and glutathione peroxidase activities declined), and induce down-regulation of antioxidant enzymes (SOD, GPX and GRX) genes transcription. However, dietary supplemented with 1% AGD could mitigate the adverse effect of ammonia poisoning on fish growth performance.