Effects of Starvation and Refeeding on the Compensatory Growth of Juvenile Epinephelus coioides

The purpose of this study was to investigate the adaptive strategies and compensatory growth mechanisms of juvenile Epinephelus coioides under starvation stress. The fish with an initial body weight of 8.88 ± 0.06 g were starved for 0 day (F0, control), 3 days (F3), 6 days (F6), 9 days (F9), 12 days (F12), and 15 days (F15), followed by feeding periods of 30 days, 27 days, 24 days, 21 days, 18 days, and 15 days, respectively. The results are shown as follows: (1) E. coioides could achieve complete or partial compensatory growth by improving both feeding rate and feed conversion efficiency. (2) The viscerosomatic index and the hepatosomatic index of the test fish decreased linearly with the duration of starvation (P < 0.05), while the condition factor did not significantly decrease (P > 0.05). At the end of feeding, all the physical body indicators of the test fish recovered or exceeded the control levels. (3) The lipid and glycogen contents of the test fish decreased continuously throughout the entire starvation process, with noticeable protein consumption occurring in the later stages of starvation (P < 0.05). At the end of the feeding period, apart from a significant reduction in crude lipid contents in the F12 and F15 groups compared to the control group (P < 0.05), the biochemical composition of the test fish was restored or even surpassed that of the control group. (4) The activity of digestive enzymes could be stimulated by starvation, enabling the efficient utilization of energy storage substances. In conclusion, it is advisable to limit the period of starvation for juvenile E. coioides to 12 days, which means that the ratio of starvation period to feeding period should not exceed two-thirds.