The Effects Of Starvation On Growth And Some Physiological Indexes In The Shrimp Macrobrachium Nipponense

The effect of starvation on the shrimp Macrobrachium nipponense were investigated for the first time. Some growth and physiological indexes were measured in experimental regime, including weight or heaviness, specific growth rate, feeding rate, food-conversion efficiency, oxygen consumption rate, some biochemical composition (such as water, ash, protein, lipid) content, value of RNA/DNA, some digestive enzymes (such as pepsin, tryptase, lipase, amylase) activities, quantity of ROS and some immune enzymes (such as superoxide dismitase and catalase) activities. Each experimental index was synthesized, and effects of starvation on growth, biochemical composition, some digestive and immune function in the shrimp Macrobrachium nipponense were analysed. This rearch would provide the physiological and ecological counter -measures to starvation, and provide the scientific basis for enhancing efficiency breeding for the shrimp Macrobrachium nipponense.The recovery growth experiment in the shrimp Macrobrachium nipponense following different periods of starvation. The experiment lasted for 18days for each test group. Group C, S2, S4 and S8 were deprived food for 0 (control), 2, 4 and 8 days, respectively. Then each group was refed at ad libitum ration level for its rest experimental time.1. At the end of starvation mean, the body weight of each starved group (S2, S4 and S8) was significantly lower than that of group C. At the end of experiment, the mean body weight of group S2 and S4 were similar to that of group C, while the body weight of group S8 was still significantly lower than that of group C. Upon realimentation after periods of starvation, specific growth rate, feeding rate and food conversion efficiency in terms of wet weight in each previously starved group were higher than those in group C. Meanwhile the oxygen consumption rate decreased and this trend stoped when the shrimp were refed, then the oxygen consumption rate gradually increased to the level of the control group. The results in dicated that there was completely or partially compensatory effect in the recovery growth in the Macrobrachium nipponense following starvation, and that the compensatory effect mainly resulted from significant increase of the feeding level and food conversion efficiency in there covery growth. So, the compensatory growth in the shrimp Macrobrachiumnipponense is the result of the two physiological factors working together.2. During starvation, the water and ash content within the shrimp body increased slightly; the protein and lipid content decreased, but the losing of lipid was higher than that of protein. The results suggest lipid is the source energy mostly during starvation. The test shrimp were divided into 4 experiment groups which were deprived of food for O(control), 2, 4 and 8 days respectively. At the end of the recovery growth, chemical composition in each group were similar with control group.3. The change of pepsin, tryptase and lipase activity in Macrobrachium nipponense was sameness during starvation and after recovery growth, decrease significantly and then increases, but the trent of lipase was more evidently. While the activity of amylase increases a little and then decrease significantly. At the end of the recovery growth, the indexes of the digestive system of the shrimp in each group were similar with control group.4. With time of starvation, the quantity of ROS is rising too. While the activity of superoxide dismitase and catalase increases a little and then decrease significantly. At the end of the recovery growth, the indexes of the immune system of the shrimp in each group were similar with control group.