Effect of ration level on body composition,growth,faecal production,nitrogenous excretion and nitrogen budget of juvenile mandarin fish (Siniperca chuatsi (Basilewsky)) | 摄食水平对翘嘴鳜幼鱼体组成、生长、排粪、排泄及氮收支的影响

Chinese. 利用生物能量学的方法研究翘嘴鳜[Siniperca chuatsi（Basilewsky）]幼鱼（初始体质量2.52～3.79 g,平均体质量3.11 g）在不同摄食水平（饥饿、1%、2%、3%、4%、饱食）下的体组成、生长、排泄、排粪及氮收支,建立生长、氮排泄、排粪与摄食水平的回归方程。试验水温为26.5～28.0℃,平均水温27.3℃。试验结果表明,随着摄食水平的增加,鱼体干物质、蛋白质、脂肪含量呈增加趋势,灰分含量呈降低趋势。随着摄食水平的增加,食物转化效率呈增大趋势,吸收效率略微增加,特定生长率呈线性增长趋势。排泄氮（UN）、粪便氮（FN）随着摄食水平增加显著增加,排泄氮、粪便氮与摄食水平（LR）的关系可分别用回归方程描述为：UN=0.449 6LR＋0.097 9,FN=0.078 1LR＋0.019 2。随着摄食水平的增加,用于生长的氮所占比例呈增大趋势,排泄氮和粪便氮比例呈减少趋势,饱食时的氮收支方程为：100CN=45.20GN＋7.46FN＋47.34UN。

English. Body composition,growth,faecal production,nitrogenous excretion and nitrogen budget of juvenile mandarin fish [Siniperca chuatsi (Basilewsky)] (initial body weight 2.52-3.79 g,average 3.11 g) at different ration levels (starvation,1%,2%,3%,4% of initial body weight per day,and satiation) were investigated in this study. The relationships between growth, nitrogenous excretion, faecal production and ration were studied and the regression equations were established. Water temperature was controlled between 26.5 ℃ and 28.0 ℃,and the average level was 27.3 ℃.The results showed that with the ration level increasing, the contents of dry matter, protein and lipid increased, but ash content decreased. With the increasing of ration level, feed conversion efficiency (FCE,%) tended to increase, feed absorption efficiency (FAE,%) tended to increase within a narrow range and specific growth rate increased with a linear pattern. Excretion nitrogen [UN, mg/（g•d）] and faecal nitrogen [FN,mg/(g•d)] increased markedly with increased ration level (LR,% per day),with the regression equations of UN=0.449 6LR＋0.097 9 and FN=0.078 1LR＋0.019 2,respectively.With the ration level increasing,allocation of nitrogen to growth increased, proportions of excretion nitrogen and faecal nitrogen decreased, and the nitrogen budget of juvenile mandarin fish at satiation was: 100CN=45.20GN＋7.46FN＋47.34UN.