Abstract

Bao Lou, Dongdong Xu , Hanxiang Xu, Wei Zhan, Guomin Mao and Huilai Shi

To investigate the effect of high water temperature on growth performance and antioxidant enzyme activities of Japanese flounder (Paralichthys olivaceus), the juveniles were reared at 4 different temperatures: 25°C (control), 28, 30, and 32°C for a period of 18 days. The survival rate was 20.83 ± 2.20% at 32°C, which was significantly lower than that at other temperatures (P < 0.05). The water temperature significantly affected the specific growth rate (SGR), feeding rate (FR), and feed conversion efficiency (FCE) of juveniles. A quadratic regression model was fit to describe the relationship between the SGR, FR, FCE, and the water temperature (SGR: r 2 = 0.94; FR: r 2 = 0.94; FCE: r 2 = 0.86; P < 0.01). Additionally, superoxide dismutase (SOD) and catalase (CAT) activities in the liver were significantly influenced by high water temperature. Bivariate analysis revealed that the SOD and CAT activities at different temperatures were highly associated with growth performance of juveniles. The results of present study indicated that the temperature of 32°C may be the upper limit of Japanese flounder. The high water temperature has a significant effect on growth performance and antioxidant enzyme activities of the Japanese flounder and results in poor health condition of the Japanese flounder