COMPENSATORY GROWTH RESPONSES IN JUVENILE CHINESE SHRIMP, FENNEROPENAEUS CHINENSIS, AT DIFFERENT TEMPERATURES

Abstract

The effects of six-day starvation and subsequent 30-day ad libitum refeeding on the growth responses of juvenile Chinese shrimp, Fenneropenaeus chinensis, (with weight range 0.486–0.569 g) reared under different temperatures (18, 22, 26, and 30°C) have been examined. The shrimp responded to a switch from starvation to ad libitum feeding by exhibiting hyperphagia and a growth spurt. At the end of the experiment, the starved-ad libitum fed shrimp maintained at 18, 22, and 26°C weighed approximately the same as the controls fed ad libitum throughout the experiment, whereas those at 30°C failed to catch up in weight to the control shrimp. In the initial six days of realimentation, the previously starved shrimp showed significantly lower food conversion efficiency (wet weight gain per unit food intake) than the controls, but from then on, there were no significant differences. The results suggest that hyperphagia was the mechanism responsible for compensatory growth in Chinese shrimp. Six-day starvation led to significant increase in moisture and reductions in protein, lipid, and energy content of the shrimp. At the end of the experiment, however, there were no significant differences in body composition. This indicated that compensatory growth was accompanied by a full recovery in body composition. Molt increment (g) and intermolt period (days) were greatly affected by starvation in combination with temperature: at 18, 22 and 30°C, not at 26°C, the previous six-day starvation brought about a significant prolongation in the intermolt over the whole experiment; at two lower temperatures (18 and 22°C), not at two higher temperatures (26 and 30°C), the starved-ad libitum fed shrimp had markedly increased molt increment compared with the controls.