Studies On Compensatory Growth In White Shrimp (Penaeus Vannamei) Following Starvation Stress

Two recovery growth experiments of Penaeus vannamei (initial weight: 5.042?.023g or 5.973?.091g) reared in seawater, following different food deprivation (starvation) or different refeeding time, were carried out at 28.3 ?1.1℃ from June to December , 2003, respectively. The ability of compensatory growth after food deprivation and refeeding and bioenergetics mechanism of Penaeus vannamei in relation to compensatory growth were discussed in this paper.In experiment I, group 82, 84 and 85 were deprived of food for 2, 4 and 6 days, respectively, and then fed to satiation for 12 and 16 days during the refeeding period. Their respective control group C2, C4 and C6 were fed formulated diet to satiation twice a day throughout the experiment. Experiment II was held according to the results of Experiment I. The shrimps were fed to satiation for 2, 4, 6, 12 and 20 days after suffering starvation for 4 days, respectively. The control groups were the same design as in Experiment I .Compared with control group, body weight and contents of energy, lipid and carbohydrate decreased, while the water content and ash increased significantly and the protein content did not significantly change in starved groups. After the shrimps were refed, their biochemical composition could reach the level of control group. At the end of the experiment, the mean body weight of group S2 and group S4 was similar to that of group C2 and group C4, while the body weight of group S6 was still significantly lower than that of group C6. During the recovery growth, the specific growth rate in each previously starved group was significantly higher than those in their respective control group.During the recovery growth following starvation pretreatment for 4 days, the specific growth rate in terms of dry weight and energy, food conversion efficiency (in dry weight and energy) were higher significantly than those in the control group, respectively. Whilefeeding rate (in dry weight and energy) and digestibility efficient (in dry weight and energy) were higher significantly than those in the control group only at the start of the recovery period. Energy intake is a little high in the deprived shrimps but not significant compared with that in the control shrimp. Growth energy is higher significantly in the deprived shrimp than that in the control shrimp, and meanwhile, metabolism energy is lower in the deprived shrimp than that in the control shrimp. However, the ratio of energy intake to body weight and the partition of fecal energy at the start of the recovery period were significantly larger in the deprived shrimp than that in the control shrimp. There were significant differences in energy budget between the deprived shrimp and the control shrimp. The proportions of the intake energy allocated to growth increased in response to the previous starvation, and that to metabolism reduced in response to the previous starvation.This paper suggested that: (1) During the food deprivation, shrimps mainly take good advantage of protein as energy material; (2) there was compensatory effect in recovery growth in the Penaeus vannamei following starvation; (3) the compensatory effect resulted from significant increase of the feeding level especially food conversion efficiency in the recovery growth; (4) the increase of energy allocated to growth was mainly attributed to the decrease of energy allocated to metabolism.