This study investigated the effect of stocking density on growth performance, blood biochemical profiles, antioxidative capacity, and muscle quality of gibel carp (Carassius gibelio). Gibel carps (initial body weight 57.04 ± 1.89 g) were reared at high stocking density (HSD, 10.85 kg m-3), medium stocking density (MSD, 5.06 kg m-3), and low stocking density (LSD, 1.47 kg m-3) for 60 days. The LSD group exhibited the highest growth rate, while HSD significantly inhibited fish growth. The muscular compositions of crude fat, crude ash, and moisture were significantly changed by stocking density, but crude protein content did not differ significantly. The stocking density altered the muscular texture profiles of gibel carp. Compared to either the HSD group or the MSD group, the highest levels of resilience and springiness occurred in the LSD group. Significant differences were observed in the levels of plasma glucose, alanine aminotransferase, aspartate aminotransferase, cholesterol, and creatinine among three groups. The fish exhibited the highest level of plasma cortisol as well as the lowest levels of triiodothyronine and thyroxine in the HSD group. The fish stocked in the LSD group showed the highest activities of superoxide dismutase, glutathione peroxidase, and catalase as well as the highest content of glutathione in liver. The significant highest total antioxidant capacity occurred in the fish stocked in the LSD group. The results showed that HSD resulted in chronic crowding stress, and exerted negative impact on growth performance, muscle quality, and antioxidative capacity of gibel carp.
Keywords: Antioxidant capacity; Crowding stress; Growth; Hormone; Muscle quality.