Amelioration of ammonia‐induced oxidative stress, ferroptosis and intestinal damage in Pelteobagrus fulvidraco through dietary tea polyphenols

Abstract To investigate the impact of tea polyphenols on the health of Pelteobagrus fulvidraco under ammonia stress, a total of 480 juvenile P. fulvidraco were divided into four groups receiving tea polyphenols supplemented diets at 0 mg kg −1 (C group), 200 mg kg −1 (L group), 400 mg kg −1 (M group) and 600 mg kg −1 (H group) for 56 days. Ammonia stress was applied from days 28 to 56. The results showed that intestinal histological damage was alleviated in the L and M groups under ammonia stress. In the M group, the levels of total antioxidant capacity and Nrf2 , HO‐1 and Occludin were the highest. Regarding ferroptosis‐related genes, DMT1 , FTM and FPN1 exhibited their highest expression in the L group, while TF , TFR1 , FTL , SLC7A11 and GPX4 showed their highest expression in the M group. FTH demonstrated its highest expression in the H group. Furthermore, the expression of ACSL4 in the L and M groups was significantly lower than that in the C group. Intestinal microbiome analysis revealed enhanced microbial diversity in the tea polyphenol‐added groups, accompanied by reduced relative abundance of dominant phylum Fusobacteriota and genus Cetobacterium compared to the C group. These results suggested that dietary supplementation of 200–400 mg kg −1 tea polyphenols could alleviate ammonia‐induced intestinal ferroptosis and histological damage, as well as protect intestinal health by regulating the compositional structure and diversity of the intestinal microflora. Specifically, the 400 mg kg −1 dose exerted the most comprehensive protective effects. This study provides mechanistic insights into the development of tea polyphenol‐based anti‐ammonia feed additives for P. fulvidraco aquaculture.