The Compensatory Growth Following Starvation Or In The Different Repetitive 'Starvation-and-Refeeding' Cycles In Sea Urchin, Hemicentrotus Pulcherrimus

This paper studies the sea urchin alongshore in Qingdao. A series of feeding experiments were conducted to investigated the compensation growth following starvation or in the different repetitive'Starvation-and-refeeding'Cycles in sea urchin, Hemicentrotus pulcherrimus. The results are as follows:The water temperature is 15±1℃. On this condition, the effects of previous periods of starvation on the compensatory growth in the sea urchin, H. pulcherrimus (initial shell diameter: 52.6±1.32mm and initial wet weight: 44.14±3.29g) and how to use some energy matter were investigated. The recovery growth experiment in the sea urchin, following different periods of starvation, was conducted. Four tested groups (marked as C, S7, S14 and S21) were established. The experiment lasted for 28 days for each tested group. Group C, S7, S14 and S21 were deprived food for 0(control), 7, 14 and 21 days, respectively. Then each group was refed for the rest experiment time. At the end of experiment the mean shell diameter and wet weight of each starved group (S7, S14 and S21) were a little higher than that of group C. But the difference was not remarkably. And the growth rate of each starved group was higher than the control group in the recovery period. This indicated that the completely compensatory growth occurred in the recovery period in the sea urchin following starvation. In the experiment, the protein level in the sea urchin's gonad went down under starvation. And it increased again at the end of experiment. The reason may be that the sea urchin used the protein to deal with starvation.The water temperature is 13±1℃. On this condition, the effects of different'starvation-and-refeeding'cycles on the compensatory growth in the sea urchin: H. pulcherrimus, was investigated. And discuss how the compensatory growth phenomenon happen by observing the change of the food intake rate and the food conversion rate in the sea urchin. Four groups of sea urchin with initial shell diameter of 48.41±3.16mm and initial wet weight of 40.45±7.20g were established: the control fed dry kelp throughout the experiment; the treatment groups were subjected to repetitive cycles of starvation-and-refeeding (3:6, 6:12 and 12:24 days for group S3F6, S6F12 and S12F24, respectively by fixing no-feed period of 12 days and feeding period of 32 days). At the end of experiment all the treatment sea urchin nearly caught up to the controls in shell diameter and wet weight. Besides, in the recover period the growth rates of all the treatment sea urchin are higher than the controls. And the difference isn't remarkable in the biostatistics. This indicated that there was completely compensatory growth effect in the recovery growth in the sea urchin. But the food intake rate and food conversion rate of the treatment sea urchin did not different remarkably from the controls. Therefore, the compensatory growth in the sea urchin doesn't happen by the way of increasing food intaking rate or food conversion rate. The reason may be that the sea urchin reduced the metoblism level and kept on a low level under starvation. This situation lasted a period even the food was supplied, which induced the growth energy rate is increasing. So the compensatory growth is happen. In the different repetitive'starvation-and-refeeding'cycles, the group S3F6 made the best use of compensatory growth. Because of the too long recovery period, the compensatory growth of the group S12F24 is partly weakened.