THE GROWTH OF JUVENILE CHINESE SHRIMP, FENNEROPENAEUS CHINENSIS OSBECK, AT CONSTANT AND DIEL FLUCTUATING TEMPERATURES

Abstract

The growth, food consumption, food conversion efficiency and apparent digestibility coefficient of juvenile Chinese shrimp, Fenneropenaeus chinensis Osbeck (body weight 0.36 ± 0.04 g) were examined under different temperature regimes. The animals were subjected to 6 constant temperatures of 18°C, 22°C, 25°C, 28°C, 31°C and 34°C and diel fluctuating temperatures of 22 ± 2°C, 25 ± 2°C, 28 ± 2°C and 31 ± 2°C. The results showed that the growth rate of Chinese shrimp at the constant temperature regimes increased from 18°C to 31°C, whereas decreased significantly at 34°C. The growth rates of shrimp at 22 ± 2°C, 25 ± 2°C and 28 ± 2°C were significantly greater than those at the corresponding constant temperatures of 22°C, 25°C and 28°C, respectively, whereas no significant difference was found between 31 ± 2°C and 31°C. As compared with those at constant temperature, the mean temperature at which maximum growth rate of shrimp occurred shifted to cooler temperature at diel fluctuating temperatures. The shrimp consumed more food at 25 ± 2°C, 28 ± 2°C and 31 ± 2°C than those at 25°C, 28°C and 31°CC, respectively, but no significant difference in apparent digestibility coefficient was found between the fluctuating and corresponding constant temperatures. The food conversion efficiency and energy assimilated into growth as percentage of energy from food for shrimp at 22 ± 2°C, 25 ± 2°C and 28 ± 2°C were significantly higher than at the corresponding constant temperatures. Therefore, more food consumption, high food conversion efficiency and more energy partitioned into growth might contribute to the enhanced growth rate at the fluctuating temperatures.