The Effect Of Different Rearing Strategy On Growth And N Budget Of Penaeus Vannamei

This experiment is in indoor aquariums, studied different feeding strategies, density and sedimen. Shrimp growth and survival, digestive and immune enzyme activity, water, ammonia and nitrite nitrogen concentration farming systems nitrogen balance equation were compared. The results are as follows:1. Effects of ration level on Penaeus vannameiThe growth and feed conversion of Litopenaeus vannamei showed a quadratic curve rose with increasing of feeding level. Lipase activity of hepatopancreas, the activity of the AKP, the activity of the SOD increased first and then decreased, with increasing ration levels, there was no significant difference among the pepsin. Throughout the process, ration level of9%was given the significantly higher ammonia and nitrite nitrogen concentration.2%ration level group get the lowest feeding nitrogen, growth nitrogen and the highest efficiency of conversion of nitrogen. Nitrogen growth efficiency with ration level showed the logarithmic decrement.2. Effects of feeding frequency on Penaeus vannameiFeed conversion and feeding frequency was quadratic decreasing, growth was incremented with the increase of feeding frequency. Pepsin, hepatopancreas lipase activity of feeding2times per day group was significantly lower than the rest of the experimental group; Immune activity of feeding five or six times per day group was significantly different from2,3,4times group; amylase activity of hepatopancreas in the different feeding frequency did not change significantly. Feeding six times per day the ammonia nitrogen concentration is always higher than the same period in other groups, Also, it is higher than the others in. Feeding frequency changes significantly affect the growth nitrogen. The group feeding2times per day get the lowest nitrogen growth efficiency and a significant difference between the group of other, nitrogen growth efficiency and feeding frequency showed a quadratic slowdown in growth relationship.3. Effects of stocking density on Penaeus vannameiThe results indicated that the survival rate of shrimp showing a decreasing trend with increasing density, feed coefficient and stocking density showed a quadratic increment related. Litopenaeus vannamei hepatopancreas SOD activity increased with stocking density, ACP and AKP activity appeared to first decrease and then increase. During the same period, the ammonia nitrogen, nitrite nitrogen of high density group concentration is higher than the low-density group. In later stage of the experiment, ammonia nitrogen and nitrite nitrogen concentration of each experimental group is higher than the concentration of the beginning stage of the experiment. In nitrogen growth, the component of exeretion the largest one, and then growth, and other nitrogen smallest. Nitrogen growth efficiency and breeding density showed the quadratic increment related.4. Effects of substrate on Penaeus vannameiThe experimental set up sand substrate group and no substrate group. Litopenaeus vannamei body color changes between the two different substrate, have some differences in sensitivity to stimulate, activity frequency, feeding behavior and attack defense behavior. Survival, rate of weight gain and specific growth rate in sand substrate group was significantly higher than without sediment groups. ACP, AKP activity of sand substrate group was significantly higher than the group of no substrate, SOD activity had no significant effect between two different substrate as so as water quality indicators.