Effects of astragaloside Ⅳ on antioxidant capacity and intestinal microbiota of heat-stressed grass carp

WANG Qi; YANG Ying; ZHOU Junhao; LAI Mingjian; WU Liya; YU Hui

doi:10.13557/j.cnki.issn1002-2813.2025.09.010

Abstract：The study was to investigate the effect of astragaloside Ⅳ(AS-Ⅳ)on the antioxidant capacity and intestinal microbiota of heat-stressed grass carp(Ctenopharyngodon idella).A total of 240 healthy,(16±2)cm healthy grass carp were randomly divided into four groups,with three replicates in each group and 20 grass carp in each replicate.The blank control group,low-dose group,medium-dose group,and high-dose group were mixed with 0,0.312 5,1.250 0,and 5.000 0 mg/(kg·d)AS-Ⅳ,respectively,and grass carp were fed at(28.0±0.5)℃ for 3 days and then subjected to heat stress treatment at(32.0±0.5)℃,and samples were collected at high temperature for 0,6,12 and 24 h.The results showed that the serum malondialdehyde(MDA)content and aspartate aminotransferase(AST)activity in the high-dose group were significantly higher than those in the other groups at 24 h(P＜0.05).At 12 h of high temperature,compared with the blank control group,the activities of quinone oxidoreductase 1(NQO1)in the liver of the low-dose group,heme oxygenase-1(HO-1)in the liver of the low-dose group and high-dose group,and glutathione peroxidase(GSH-Px)in the liver of the medium-dose group and high-dose group were significantly increased(P＜0.05).At 0 h of high temperature,the relative expression of Kelch-like ECH-related protein 1(Keap1)and transcription factor NF-E2-related factor 2(Nrf2)in the livers of the medium-dose group and the high-dose group was significantly higher than that of the blank control group(P＜0.05).At 6 h of high temperature,the relative expression levels of copper-zinc superoxide dismutase(Cu/Zn-SOD)in the liver of the low-dose group and high-dose group and GSH-Px in the liver of the high-dose group were significantly higher than those in the blank control group(P＜0.05).16S rRNA sequencing analysis showed that low-dose AS-Ⅳ had a positive effect on the intestinal flora of grass carp,while the relative abundance and diversity of the intestinal flora of grass carp in the high-dose group showed a decreasing trend.The study indicates that AS-Ⅳ can enhance the antioxidant capacity of grass carp liver.Feeding 1.250 0 mg/(kg·d)AS-Ⅳ has a good effect in preventing and alleviating the oxidative stress caused by high temperature on grass carp.