盐度对不同规格黄边糙鸟蛤呼吸排泄的影响

呼吸与排泄是贝类新陈代谢的基本生理活动,不同盐度对贝类的生长起着至关重要的作用。本研究在28℃条件下,设八个盐度梯度(16、20、24、28、32、36、40、44),采用Winkle滴定法和次溴酸盐氧化法测定了大、中、小三种规格的黄边糙鸟蛤的耗氧率和排氨率。结果表明,黄边糙鸟蛤壳长与组织干重之间符合幂函数关系W=0.004 4H3.852 0,R2=0.949 6;在盐度16~28范围内,黄边糙鸟蛤单位体重耗氧率随盐度的升高而增加,在盐度28取得最大值,其后随盐度上升,耗氧率呈下降趋势。方差分析(ANOVA)显示,盐度变化对黄边糙鸟蛤的耗氧率有显著影响(F=3.50,P<0.01,n=7)。单位体重耗氧率和组织干重之间的关系用幂函数RO=aWb表示,其中a值范围为0.619 8~0.956 7,b值范围为0.371 5~0.582 8。排氨率与耗氧率呈现相同的变化趋势,不同盐度下黄边糙鸟蛤的排氨率有显著差异(F=13.37,P<0.01,n=7)。其排氨率和组织干重之间的关系也可用幂函数ER=aWb表示,其中a值范围为92.94~136.65,b值范围为0.397 0~0.564 3;规格大小对黄边糙鸟蛤单位体重耗氧率和排氨率有显著影响(F=28.57,P<0.01;F=130.66,P<0.01)。在盐度44条件下,驯化养殖3 d后黄边糙鸟蛤全部死亡,表明黄边糙鸟蛤的最高耐受盐度为44。

Effects of salinity on oxygen consumption and ammonia-N excretion rate of different-size of Trachycardium flavum

Respiration and excretion are the basic physiological activities of bivalves and salinity also has a significant influence on the growth of bivalves. The oxygen consumption and ammonia-N excretion rate of clam Trachycardium flavum with different body sizes (L, M and S) at eight salinity gradients (16, 20, 24, 28, 32, 36, 40 and 44) (28 ℃) were studied by Winkle titration method and hypobromite oxidation method. The shell length and dry tissue weight has the power function relationship: W = 0.004 4 H~(3.852 0), R~2 = 0.949 6. The results showed that within the salinity range of 16-28, the oxygen consumption rate of T. flavum per unit dry tissue weight increased with the increasing salinity, reached the maximum at salinity 28 and then decreased with the increasing salinity. Variance analysis showed that salinity changes had significant influence on the oxygen consumption rate of T. flavum (F=3.50, P<0.01,n=7). The relationship between oxygen consumption rate and dry tissue weight could be expressed as power function equation: RO = aW~b, where a value ranged from 0.619 8 to 0.956 7, b ranged from 0.371 5 to 0.582 8. The ammonia-N excretion rate showed the same tendency with the respiration rate and significant differences were found among various salinities (F=13.37, P<0.01, n=7). The relationship between ammonia-N excretion rate and dry tissue weight could be expressed as power function equation: ER = aW~b, where a value ranged from 92.94 to 136.65, b ranged from 0.3970 to 0.5643. Body weight also had significant influences on both parameters (F=28.57, P<0.01; F=130.66, P<0.01).At salinity 44, the clams all died after three days of post-acclimation, indicating that 44 could be the maximum tolerance salinity for T. flavum.