Acute Thermal Stress Reduces Skeletal Muscle Growth and Quality in Gibel Carp (Carassius gibelio)

An acute elevation in temperature impacts fish physiology and in turn causes an alteration in growth performance. This study investigated the effect of acute thermal stress on skeletal muscle growth and quality in gibel carp (Carassius gibelio). The gibel carp were randomly assigned to three temperature treatments, 20 & DEG;C, 26 & DEG;C, and 32 & DEG;C, for 168 h. The muscular quality characteristics and the expressions of the genes related to muscle growth were assessed at 0 h, 1 h, 12 h, 24 h, 72 h, and 168 h. The muscle nutrient content was significantly higher in the 20 & DEG;C treatment, and the muscle was more tender and elastic. The gene expression levels of the MRFs family were significantly upregulated and then gradually decreased after 1 h. The expression level of MSTN-2 was increased in the 32 & DEG;C treatment at 168 h, in support of the slow growth rate under acute thermal stress. It is implied that gibel carp could adapt to acute thermal stress to a certain extent. Acute thermal stress, however, eventually led to a decrease in muscle growth rate and quality.