西施舌的耗氧率与排氨率研究

采用室内实验生态学方法研究了不同栖息水温和不同溶解氧水平下处于标准代谢状态的西施舌耗氧率与排氨率，并测定了窒息点.结果表明,在25 ℃时，水中DO≥3.11±0.15 mg·L^-1时，西施舌的耗氧率和排氨率分别为0.74±0.05 mg·g^-1·h^-1和2.56±0.05 μmol·g^-1·h^-1,处于相对稳定状态；当DO低于此值则代谢出现异常，耗氧率随DO下降而下降，直到窒息为止，其窒息点为1.22±0.06 mg·L^-1，而排氨率也呈直线下降，但排氨停止滞后于耗氧停止.耗氧率与栖息水温呈二次线型关系：OCR=-0.0027T²+0.1367T-0.9557，R²=0.9724；水温为25.3 ℃时，西施舌的耗氧率达到最大,为0.77 mg·g^-1·h^-1.处于适温状态（15 ℃和20 ℃）的O/N值要高于低温（10 ℃）和高温（25 ℃和30 ℃）时的O/N值，西施舌在适宜条件下更多地依赖于脂肪供能维持标准代谢，而在环境不适时则更多地调用机体的蛋白质来维持生理代谢需要.

Oxygen consumption and ammonia-N excretion rates of Coelomactra antiquata

With laboratory experiments,this paper studied the oxygen consumption rate (OCR) and ammonia-N excretion rate (NR) of Coelomactra antiquata at different levels of dissolved oxygen (DO) and water temperature.The results indicated that at 25 ℃ and 3.11±0.15 mg DO·L^-1,C.antiquate had a comparatively stable OCR and NR,which maintained at 0.74±0.05 mg·g^-1·h^-1 and 2.56±0.05 μmol·g^-1·h^-1,respectively.When DO was lower than 3.11±0.15 mg·L^-1,the metabolism of C.antiquate became abnormal,and its OCR was decreased with decreasing DO until suffocate,with a suffocate point 1.22±0.06 mg·L^-1 at 25 ℃.The NR also declined with decreasing DO,which ceased later than oxygen consumption.There was a quadratic linear relationship between OCR and water temperature (OCR=-0.0027T²+0.1367T-0.9557,R²=0.9724).When water temperature was 25.3 ℃,the OCR arrived to its maximum value 0.77 mg·g^-1·h^-1.The O/N ratio at optimal temperature (15～20 ℃) was higher than that at low (10 ℃) and high temperature(25 ℃ and 30 ℃).To maintain its standard metabolism,C.antiquata consumed more fat under fit condition,while more protein under stress.