The effects of temperature and dissolved oxygen on the growth, survival and oxidative capacity of newly hatched hybrid yellow catfish larvae (Tachysurus fulvidraco♀ × Pseudobagrus vachellii♂).

ABSTRACT

Demand for yellow catfish fry, an economically important farmed fish in China, has increased dramatically. Newly hatched larvae are highly sensitive to changes in environmental conditions, with water temperature (T) and dissolved oxygen (DO) being two important factors that affect their early development. We investigate optimal T (between 19.0 and 33.0 °C) and DO (between 2.0 and 12.0 mg L-1) concentrations on growth and antioxidant enzyme activity of newly hatched hybrid yellow catfish larvae (Tachysurus fulvidraco × Pseudobagrus vachellii) using a central composite design. We use a response surface method to optimize the response variables for survival (S) and growth, and the reduction of oxidative stress, over a 50-day experimental duration. T has a significant effect on specific growth rate (SGR), hepatic malondialdehyde (MDA) content, and superoxide dismutase (SOD) and catalase (CAT) activities (P < 0.05). DO concentration has a significant effect on SGR, S, hepatic MDA content, and SOD and CAT activities (P < 0.05). T and DO also have significant second order effects on SGR, S, SOD, and CAT activities (P < 0.05). Increased DO at low T stimulates SOD and CAT activities and alleviates oxidative damage. Adjusted R2 values for SGR, S, CAT, SOD, and MDA models are 0.734, 0.937, 0.916, 0.894 and 0.826, respectively. A combination of 26.8 °C and 7.3 mg L-1 represents optimal rearing conditions, in that larval growth and antioxidant ability is improved. Results show that T and DO during larviculture of yellow catfish have important implications for aquaculture.