中间球海胆饥饿代谢研究

Metabolism of sea urchin Strontgylocentrotus intermedius during starvation

于 2 0 0 2年 4月至 5月测定了饥饿状态下中间球海胆 (Strongylocentrotusintermedius)耗氧率和排氨率的变化情况 ,得出海胆饥饿后耗氧率、排氨率及氧氮比变化曲线 ,并对海胆性腺主要成分进行组织化学分析。结果表明 :随饥饿时间的延长 ,中间球海胆的耗氧率呈“稳定、急速下降、再稳定”的阶段性变化 ,在整个饥饿期间内下降了 4 5 .6 % ;排氨率经短暂稳定后 ,先上升再阶段性下降 ,实验结束时共下降了 32 .33% ;氧氮比则表现出平稳、下降、上升的趋势。组织化学的测定结果是海胆饥饿前后性腺的主要变化成分为蛋白质和糖类 ,综上可认为 ,海胆饥饿后能源物质利用顺序为 :蛋白质 +糖类、蛋白质、蛋白质

In starvation , animals usually have special consumption rate. For most animals the consumption rate decreased in experiment. Some reports on starvation study were concerned with fish, shellfish and crustacea. But on sea urchin’s starvation study, seldom reports were in details. In China, sea urchin Strontgylocentrotus intermedius has been one of the important economic species and cultured in some areas like Shangdong Province and Liaoning Province for some years. In this experiment, the effects of starvation on consumption rate, oxygen consumption rate , ammonia exertion rate and O/N varying curve were measured and calculated simultaneously in Strontgylocentrotus intermedius at temperature (18.0±0.5) ℃ during April and May, 2002. By the methods of iodometric and sodium hypobromite oxidation, DO and NH_4^+-N were measured. The results show that with the extension of starvation period, the oxygen consumption varying curves of Strontgylocentrotus intermedius displays three stages, which were “stability-sharp decrease -regained stability”. There was a 45.6% decrease in oxygen consumption and 32.33% decrease in ammonia excretion rate during the whole period, and from the curve of oxygen consumption variation, it showed that oxygen consumption remained constant at the first stage, then decreased sharply before it remained constant at a lower level. From the changes that ammonia excreted gradually, it can be seen that after a short constant , the ammonia excretion increased and then decreased .The changes of metabolism in sea urchin were different from the other reported animals, of which the metabolism rate experienced four phases “increase-stability-decrease-stability”. This is due to the characterization of special physiological structure in sea urchin. During the starvation period, the food can stay in the intestine for a long time, so at the beginning of starvation, the metabolism rate can maintain at normal level. The intestine and gonad were the exclusive organs which can be used to restore energy, so the metabolism rate has to fall to the lowest level. The histochemistry changes on gonad of sea urchin during the period of starvation were protein and carbohydrate. The gonad was composed of germ cell and nutritive cell which was full of nutritive granule .The protein, carbohydrate and fat were the main chemical materials in female gonad, and only protein and carbohydrate were found in male gonad. In this experiment, the protein, carbohydrate and fat in nutritive cell were decreased in great degree. On calculation, the change of O/N ratio showed stable-decreasing-increasing trend, then steady at lower level. Compared with other reported animals, the results showed that the use order of energy materials during the starvation period was : protein+carbohydrate →protein →protein +carbohydrate. During the period of starvation, the percentage of carbohydrate energy increased. The energy source in starvation came from the food had remained in intestine for 1-4 d, and the protein from intestinal epithelial tissue for 5-9 d, and protein and carbohydrate stored in the gonad in the rest time. The gonad studied in this experiment was at growing stage, so for the study in other developmental stage , a further research will be conducted.