THE EFFECTS OF REPETITIVE 'STARVATION-AND-REFEEDING' CYCLES ON THE COMPENSATORY GROWTH RESPONSE IN CHINESE SHRIMP, FENNEROPENAEUS CHINENSIS (OSBECK, 1765) (DECAPODA, PENAEIDAE)

Abstract

[A feeding experiment was conducted to examine the effects of various starvation-and-refeeding cycles on the growth, food intake, food conversion efficiency, and body composition of the Chinese shrimp, Fenneropenaeus chinensis fed on the polychaete worm, Neanthes japonica. Five groups of shrimp with an initial wet weight of 2.189 ± 0.087 g (mean ± SE) were established: the control (C40) fed ad libitum throughout the experiment; the four treatment groups were subjected to repetitive cycles of starvation-and-refeeding (1 : 4, 2 : 8, 4 : 16, and 8 : 32 days for groups S1F4, S2F8, S4F16, and S8F32, respectively), with each treatment group experiencing 8-day food deprivation and 32-day refeeding during the course of the experiment. Within the same feeding period (32 days), the shrimp subjected to periods of starvation-and-refeeding showed a higher mean percentage weight gain than those fed ad libitum continuously (P < 0.05), however, at the end of the experiment all the treatment shrimp failed to catch up the controls in body weight. This indicated that compensatory growth occurred only partially in the present study. Increased appetite was displayed by the shrimp experiencing cyclic 'nutritional stress', of which those in group S1F4 showed significantly higher food intakes (FIs) in terms of wet weight, dry matter, protein, and energy content than the controls (P < 0.05). Food conversion efficiencies (FCEs) in the most frequently starved and refed group (S1F4) were significantly lower than those in the control group (P < 0.05), while these indices in the other three treatment groups were similar to those in the control group. Feeding regimes significantly affected body lipid content but not water, protein, ash, or energy content. At the end of the experiment, the shrimp in the group S8F32 had the highest lipid content, while those in the S1F4 and the control group had the lowest. All the above results suggest that the Chinese shrimp regulate their appetite and growth rate in relation to different feeding regimes., A feeding experiment was conducted to examine the effects of various starvation-and-refeeding cycles on the growth, food intake, food conversion efficiency, and body composition of the Chinese shrimp, Fenneropenaeus chinensis fed on the polychaete worm, Neanthes japonica. Five groups of shrimp with an initial wet weight of 2.189 ± 0.087 g (mean ± SE) were established: the control (C40) fed ad libitum throughout the experiment; the four treatment groups were subjected to repetitive cycles of starvation-and-refeeding (1 : 4, 2 : 8, 4 : 16, and 8 : 32 days for groups S1F4, S2F8, S4F16, and S8F32, respectively), with each treatment group experiencing 8-day food deprivation and 32-day refeeding during the course of the experiment. Within the same feeding period (32 days), the shrimp subjected to periods of starvation-and-refeeding showed a higher mean percentage weight gain than those fed ad libitum continuously (P < 0.05), however, at the end of the experiment all the treatment shrimp failed to catch up the controls in body weight. This indicated that compensatory growth occurred only partially in the present study. Increased appetite was displayed by the shrimp experiencing cyclic 'nutritional stress', of which those in group S1F4 showed significantly higher food intakes (FIs) in terms of wet weight, dry matter, protein, and energy content than the controls (P < 0.05). Food conversion efficiencies (FCEs) in the most frequently starved and refed group (S1F4) were significantly lower than those in the control group (P < 0.05), while these indices in the other three treatment groups were similar to those in the control group. Feeding regimes significantly affected body lipid content but not water, protein, ash, or energy content. At the end of the experiment, the shrimp in the group S8F32 had the highest lipid content, while those in the S1F4 and the control group had the lowest. All the above results suggest that the Chinese shrimp regulate their appetite and growth rate in relation to different feeding regimes.]