New insights into oxidative damage to yellow catfish ( Pelteobagrus fulvidraco) muscle by acute ammonia stress

Ammonia causes stress, inhibits fish growth, and damages tissues and organs. The muscle proliferation contributes to more than 50 % of the growth of fish. This study aimed to investigate the effects of acute ammonia stress on muscle damage, reactive oxygen species (ROS) production and scavenging, and endoplasmic reticulum stress (ERS) in yellow catfish (Pelteobagrus fulvidraco). In this study, yellow catfish were exposed to three concentrations of ammonia (0, 25, and 125 mg/L) for 96 h. The results showed that acute ammonia stress resulted in the deterioration of plasma biochemical parameters, histopathological injury, and oxidative damage in the muscle. In addition, ammonia stress led to the overproduction of muscle ROS, which may be partially related to the activation of the muscle NADPH oxidase (NOX) family. Ammonia stress reduces the ability to scavenge ROS, which may be partly related to the inhibition of the muscle antioxidant system. Ammonia stress leads to ERS, which may be related in part to the activation of muscle-activating transcription factor 6 (ATF6), inositolrequiring enzyme 1 (IRE1)/X-box binding protein 1 (XBP1), and protein kinase RNA-activating-like ER kinase (PERK)/eukaryotic translation initiation factor 2 alpha (eIF2 alpha)/transcription factor 4 (ATF4) pathways. In conclusion, the present study provides evidence for the study of muscle toxicity induced by ammonia stress in freshwater fish and provides a reference for the healthy culture of yellow catfish.