Apple polyphenols modulates the antioxidant defense response and attenuates inflammatory response concurrent with hepatoprotective effect on grass carp (Ctenopharyngodon idellus) fed low fish meal diet

Polyphenols are well known for its benefits to improve the antioxidant capacity and inflammation response in human but their positive response and underlying mechanism is not yet well established in fish. Therefore, a 60-day feeding trial was conducted to explore the effects of apple polyphenols (AP) for improving the health of grass carp. Fish were fed with plant protein based diets supplemented with 0, 1, 5, and 10 g of AP per kg. Results of the study showed that highest (10 g/kg) supplementation of AP exhibited lower growth of fish compared to other groups. Dietary inclusion of AP exhibited hepatoprotective effects via decreasing the activities of serum alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transaminase (P