高温下不同盐度对刺参幼参和1龄参呼吸排泄的影响

Effects of salinity on the respiration and ammonia excretion of sea cucumber Apostichopus japonicus under high temperature

在实验室中模拟研究了高温(25.3～26.5℃)条件下,不同盐度对刺参(Apostichopus japonicus)幼参和1龄刺参呼吸排泄的影响。根据对盐度的耐受性不同,分别将体质量为(0.03±0.002)g的幼参暴露于盐度梯度为20、23、26、30、35的水体中,体质量为(22.73±9.46)g的1龄刺参暴露于盐度梯度为16、20、25、30、35的水体中进行盐度变化对其呼吸排泄的影响实验,测定其耗氧率和排氨率。结果表明,盐度变化对刺参的呼吸排泄影响显著(P<0.05)。幼参在23～30盐度、1龄参20～30盐度范围内,耗氧率[Rwr,mg/(g·h)]和排氨率[Rwe,μmol/(g·h)]随着盐度的升高而降低,当盐度升高至35时,两者都明显升高(以盐度30为对照),当盐度降至20(幼参)、16(1龄参)时,刺参耗氧率和排氨率均降低。盐度对刺参O:N比值的影响不显著(P>0.05),各盐度条件下,2种规格刺参的O:N比值平均在14左右,表明本实验条件下该刺参代谢所需要的能量主要由脂肪和碳水化合物提供。从呼吸和排泄的角度来看,在本实验高温(25.3～26.5℃)条件下,幼参在23～35盐度、1龄参20～35盐度范围内具有较好的渗透压调节能力,而幼参在20盐度、1龄参在16盐度下代谢功能较弱。

Effects of salinity on the respiration and ammonia excretion of A.japonicus between the temperature of 25.3-26.5℃were studied in the laboratory.The animals were divided into two size groups with body weight o（0.03±0.002） g and（22.73±9.46）g respectively.Because of different salinity tolerance of the animals,the trail was set up with five salinity gradients（20,23,26,30,35 for juveniles and 16,20,25,30,35 for bigger ones）on a series of sudden and gradual salinity changes.The weight specific respiration rate[Rwr,mg/（g·h）]and the weight specific excretion rate[Rwe,μmol/（g·h）]were determined in order to investigate the impact of salinity changes on the respiration and ammonia excretion of A.japonicus.Results showed that the respiration and ammonia excretion were significantly affected by the salinity changes（P〈0.05）.At the salinity of 30,the animals respired and excreted at a low level.The respiration rate and ammonia excretion rate increased significantly at higher salinity of 35 and at lower salinity of 23 for the juvenile group or 20 for the one year old group.The salinity had no significant impacts on the ratio of O：N（P〉0.05）. The values of O：N ratios were 14.21±2.37（mean±SD）,which indicated that the sea cucumbers in the experiment mainly utilized carbohydrate and lipid as their energy sources.Results indicated that the sea cucumbers in the optimum salinity range have the ability of osmoregulation at temperature of 25.3-26.5℃while metabolic function weakened at the critical salinity.