Effects of rapid temperature changes on HK,PK and HSP70 of <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> in different seasons

Activities of hexokinase(HK), pyrnvate kinase(PK)and levels of HSPT0 were measured to evaluate the response of Litopenaeus vannamei to rapid temperature changes under controlled laboratory conditions. Shrimps were subjected to a quick temperature change from 27℃ to 17℃ for the summer case(Cold temperature treatment), or from 17℃ to 27℃ for the winter case(Warm temperature treatment). After 0. 5, 1, 3, 6, 12, 24, 48, and 72 h of exposure time, shrimps were sampled and prepared for further analysis. The results showed that the effect of acute temperature changes on activities of HK was significant. Patterns of variations of the two glycolytic enzymes suggested that enzymes in the glycolysis cycle could adjust their activities to meet the acute temperature change. The HSP70 level increased in both cold and warm temperature treatments, suggesting that the rapid temperature changes activated the process of body's self-protection. But the difference in expression peak of HSP70 might be related to the different body size and the higher thermal sensitivity to temperature increase than to temperature decrease of L. Vannamei.