盐度和规格对波纹巴非蛤Paphia undulate耗氧率和排氨率的影响

Effects of salinity and the body size on the oxygen consumption and ammonia excretion rates of Paphia undulate

2007年3月,将采集于湛江雷州的波纹巴非蛤Paphia undulate,根据其个体大小分为A组和B组,外壳长度分别为(4.51±0.17)cm和(3.69±0.11)cm,并采用Winkler碘量法和次溴酸盐氧化法分别测定了其单位质量的耗氧率、排氨率及其氧氮比(O∶N),研究了盐度和规格对波纹巴非蛤代谢的影响。实验盐度设为20,24,28,32和36共5个梯度,实验期间水温为25℃。研究结果表明:盐度和规格对波纹巴非蛤单位质量的耗氧率和排氨率均存在显著性影响(P<0.05)。当盐度由20升高至28时,波纹巴非蛤单位质量的耗氧率和排氨率均随盐度的升高而升高;当盐度由28升高至36时,其单位质量的耗氧率和排氨率均随盐度的升高而降低;相同盐度条件下,个体较小的B组波纹巴非蛤单位质量的耗氧率均显著大于个体较大的A组(P<0.05)。当盐度为28和32时,B组波纹巴非蛤单位质量的排氨率显著大于A组(P<0.05),而当盐度为20,24和36时,2组波纹巴非蛤单位质量的排氨率没有显著差异(P>0.05)。在设定的实验盐度范围内,波纹巴非蛤的氧氮比平均值为14.75～20.35,说明其体内代谢以蛋白质和脂肪供能为主。

Oxygen consumption and ammonia excretion rates as well as the oxygen-nitrogen ratio of individual Paphia undulate was measured using Winkler iodimetry and hypobromite oxidation process and the effects of salinity and the body size on metabolism of the species were studied under controlled conditions indoors. Paphia undulate was collected at Leizhou of Zhanjiang in March of 2007 and cultured for a week in the laboratory at salinity levels of 20, 24, 28, 32 and 36. The samples were divided into two groups according to the shell length, which was（4.51±0.17） cm for Group A and （3.69±0.11） cm for Group B. The water temperature was 25℃. The results show that salinity and the body size of Paphia undulate both have significant effects on the oxygen consumption and ammonia excretion rates. We found that the oxygen consumption and ammonia excretion rates increased with increasing salinity from 20 to 28, but decreased from 28 to 36. At the salinity of 20, 24, 28, 32 and 36, the oxygen consumption rate of Group B was much larger than that of Group A （P〈0.05）. The ammonia excretory rate of Paphia undulate increased with increasing salinity from 20 to 28, but decreased with increasing salinity from 28 to 36. At the salinity of 28 and 32, the ammonia excretory rate of Group B was much larger than that of Group A （P〈0.05）. However, there were no evident differences in the ammonia excretory rate between the two groups at the salinity of 20, 24 and 36 （P〉0.05）. The ratio （atomicity O ＂ N） of Paphia undulate ranged from 14.75 to 20.35 at the salinity levels set in the experiment.