日本刺沙蚕对饵料中氮的利用及其对盐度变化的响应

运用实验生态学的方法探讨不同盐度下(15、20、25、30和35)日本刺沙蚕(Neanthes japonica)对饵料中氮的利用情况.结果表明,盐度对日本刺沙蚕的摄食氮、生长氮、粪便氮、氮的饵料转化率和特定生长率均有显著性的影响,它们均有随盐度升高而增加的趋势,到达最大值后(盐度30左右),又随盐度的升高而下降.排泄氮随盐度的变化趋势与此相反.盐度对氮的表观消化率没有显著的影响.根据回归方程计算得到日本刺沙蚕的最佳氮生长盐度为28～29.实验结果还显示日本刺沙蚕在适宜盐度下获得较高的氮生长主要归因于较高的氮摄食和氮的饵料转化率.盐度对日本刺沙蚕氮收支各组分均存在显著性影响,其中排泄氮的比例在盐度25时最小,而后随盐度的升高或降低都明显增大,这与生长氮和粪便氮比例的变化趋势相反.粪便氮的比例变化并不剧烈,范围为7.50%～9.41%.因此,排泄氮的比例和生长氮的比例主导着日本刺沙蚕的氮收支模式.日本刺沙蚕在5个盐度下的平均氮收支方程为100CN＝49.01GN+42.45UN+8.54FN,其中,CN为摄食氮;GN为生长氮;UN为排泄氮;FN为粪便氮.此外,作者还对水生动物氮收支的模式做了初步的探讨.

NITROGEN UTILIZATION OF NEANTHES JAPONICA AND RESPONSE TO SALINITY CHANGE

In the present study,the effect of salinity on nitrogen growth and nitrogen budget of N.japonica was investigated at 15,20,25,30 and 35 by bioeologics method.The results showed that nitrogen consumption,nitrogen growth,nitrogen faeces,nitrogen food conversion efficiency and specific growth rate were significantly affected by salinity.They all increased with increasing salinity,peaked at about 30,and then decreased with increasing salinity.Reversed tendency was observed in nitrogen excretion.There was no sig...