Effects of heat stress on the chemical composition, oxidative stability, muscle metabolism, and meat quality of Nile tilapia (Oreochromis niloticus)

The present study investigated the effects of chronic heat stress (HS) on the chemical composition, oxidative stability, muscle metabolism, and meat quality of Nile tilapia (Oreochromis niloticus). Compared with the control (26 degrees C), chronic HS (32 degrees C) lowered growth performance, the contents of whole-body lipid, muscle protein, and muscle lipid. Also, HS significantly increased the contents of reactive oxygen species (ROS) and decreased antioxidative status, causing a decline in meat quality, including increased lipid and protein oxidation, the centrifugal water loss, and cooking loss as well as decreased the fragmentation index and pH at 24 h, which may be attributed to induced apoptosis by excessive ROS in Nile tilapia meat. Moreover, metabolomic analysis showed HS lowered flavor and nutritional value by affecting amino acid, lipid, and nucleotide metabolism. These results reveal that HS adversely affects oxidative stability, meat quality, flavor, and nutrition, warranting its recognition and prevention.