Comparison of effects of hypoxia on glutathione and activities of related enzymes in livers of Tibet chicken and Silky chicken

Abstract

The Tibet chicken originates from the Qinghai-Tibet Plateau and has adapted well to hypoxia, whereas the Silky chicken is a lowland chicken breed from an area with an altitude of 750 m. The objective of the present study was to investigate whether differences exist in glutathione and related metabolism between the Tibet chicken and the Silky chicken when birds were housed in a normoxic or hypoxic chamber for 20 h. Activities of glutathione peroxidase, glutathione S-transferase, and glutathione reductase and levels of glutathione were determined spectrophotometrically. Under normoxia conditions and moderate hypoxia (14% oxygen concentration) conditions, no differences were found in levels of total glutathione, reduced glutathione (GSH), disulfide-oxidized glutathione (GSSG), the GSH:GSSG ratio, and activities of glutathione peroxidase and glutathione S-transferase between the Tibet chicken and the Silky chicken. Under extreme hypoxia conditions (14% oxygen concentration for 14 h and then 10.5% oxygen concentration for 6 h), values for the GSH content, the GSH:GSSG ratio, and the activity of glutathione reductase in the liver of the Tibet chicken were higher than those of the Silky chicken. The results indicate that the Tibet chicken responded better than the Silky chicken to oxidative stress in extreme hypoxia through glutathione enzymes of detoxification. This work provides reference for future studies on the association of glutathione metabolism with the adaptation to hypoxia.