Transfer of amino acids in the food chain of key species anchovy(Engraulis japonicus) of the Yellow Sea and East China Sea food web

采用活体饵料对黄东海生态系统食物网关键种食物链的中下营养层次"浮游植物—中华哲水蚤(Calanus sinicus)—鯷鱼(Engraulis japonicus)"进行了室内模拟实验研究,以了解氨基酸在该食物链中的传递过程。通过76 d的培养实验,对采集样品做了14种氨基酸含量的定量分析。结果表明,在3个营养层次中中华哲水蚤起着十分关键的承上启下作用,它不仅将小球藻的植物性蛋白转化为动物性蛋白,大幅度地提高了赖氨酸的含量,而且将氨基酸总含量从小球藻的6.10%提高到24.16%。作为该食物网主要经济鱼类重要饵料的鯷鱼则进一步将氨基酸含量提高到27.06%。中华哲水蚤的氨基酸相对组成与小球藻有明显的相关性(r=0.606,p<0.05),其中7种必需氨基酸的相关性相对较弱,而非必需氨基酸的相关性明显较强。鯷鱼的食性由合成饵料转变为活体中华哲水蚤时,其氨基酸量也随饵料的改变而有所变化,从与合成饵料相关转为与中华哲水蚤有更紧密的相关。鯷鱼排泄粪便中的氨基酸含量主要由新陈代谢的生理过程所决定。Live baits Calanus sinicus were used to make an indoor experimental study on the intermediate and lower levels "phytoplankton-Calanus sinicus-anchovy(Engraulis japonicus)" in key species food chain of the Yellow Sea and East China Sea food web so as to know the transfer process of amino acids in the food chain.After making a cultural experiment for 76 days,the quantitative analysis of contents of 14 amino acids in the collected samples was made.It is shown from the analysis results that the copepod Calanus sinicus forms an intermediate key link,that is,the copepod not only transforms the vegetable protein of chlorella into animal protein of copepod and greatly raises the lysine content,but also raises the total amino acid content from 6.10% of chlorella to 24.16% of copepod.As an important bait of commercial fish in this food web,anchovy(Engraulis japonicus) further raises the total amino acid content of copepod to 27.06% of anchovy.There is a significant correlation between relative amino acid compositions of Calanus sinicus and chlorella(r=0.606,p<0.05),among them,the correlation between the percent contents of 7 essential amino acids of Calanus sinicus and chlorella was relatively poor,and that between the percent contents of 7 non-essential amino acids is relatively strong.The percent contents of amino acid of anchovy Engraulis japonicus changed with the change in baits when food of anchovy changed from synthetic bait to live Calanus sinicus.The amino acid contents of anchovy egesta are dependent mainly on metabolic process of anchovy.国家自然科学基金资助项目(40276046);; 国家重点基础研究发展规划资助项目(G19990437)~