摘要
采用氮平衡试验和无氮日粮法研究了体重为50、100、150、200和250g左右真鲷幼鱼,在饲喂粗蛋白质含量为38%～46%饲料条件下的维持氮需要量(Nm)。氮平衡试验结果表明:在总摄入氮中,氮沉积量的变化为0.15～0.30mg.g-1.d-1,占总摄入氮12.1%～20.3%;粪氮排泄量为0.20～0.32mg.g-1.d-1,占总摄入氮16.4%～21.6%;而内源氮排泄量是总摄入氮中主要的氮消耗部分,为0.80～0.96mg.g-1.d-1,占总摄入氮的62.8%～67.7%。维持氮需要量与体重呈正相关,体重越大,Nm越大;但单位体重的Nm与体重呈负相关,个体越小,单位体重的Nm越大。在试验的体重范围内,单位代谢体重的Nm′,各生长阶段中没有显著差异(P>0.05),平均为0.498mg.g-1.d-1。无氮日粮法的结果表明:Nm′与无氮日粮的采食量呈负相关;随着真鲷采食量下降,Nm′增加;当无氮日粮的采食量为零(绝食)时,Nm′值为0.510mg.g-1.d-1,与150g体重的氮平衡试验0.508mg.g-1结果相接近。考虑到试验鱼的应激反应和结果的稳定性,建议在维持氮测定时采用氮平衡试验方法。本试验还给出了不同生长期维持鱼体蛋白质所需要的饲料蛋白质含量。
The nitrogen balance method and nitrogen-free diet were used in present study to determine nitrogen requirement for maintenance （Nm） and nitrogen requirement for maintenance per unit metabolism body weight （Nm′） of red sea bream（ Pagrosomus major）. Fishes with body weights of 50, 100, 150, 200 and 250 g were fed by the diets containing a gradient protein level from 38 % to 46 %. The results from nitrogen balance experiment show that the amount of nitrogen deposition varied from 0.15 to 0.30 mg·g^-1·d^-1, accounting for total ingested nitrogen from 12.1% to 20.3 %. The amount of faecal nitrogen excretion varied from 0.20 to 0.32 mg·g^-1·d^-1, accounting for total ingested nitrogen from 16.4% to 21.6%. The endogenous nitrogen excretion, a main part of total ingested nitrogen consumption, varied from 0.80 to 0.96 mg·g^-1·d^-1, accounting for total ingested nitrogen from 62.8 % to 67.7 %. A positive correlation was observed between Nm and body weight, while a negative correlation was observed between Nm of unit body weight and growth duration. There is no significant difference （ P 〉 0.05） among Nm＇obtained from different growth stages. The average of Nm＇ was 0.498mg·g^-1·d^-1 . The results from nitrogen-free diet experiment show a negative correlation between nitrogen requirement for maintenance and feed intake of nitrogen-free diet; With the decrease of feed intake of fish, the nitrogen requirement for maintenance was increased; The average of Nm＇ was 0.510 mg·g^-1·d^-1 with fasting of fishes. This value is close to 0. 508 mg·g^-1 obtained from fishes with 150 g body weight in nitrogen balance experiment. The nitrogen balance method is recommended to be a right method for determining nitrogen requirement for maintenance in consideration of fish stress and result stability. This study also supplied a calculated result about the protein content levels in diets, which are necessary for maintaining fish body protein at different growth stages. The calculation is based on the amount of nitrogen necessary for maintaining body protein per kg fish weight.
出处
《水产学报》
CAS
CSCD
北大核心
2007年第3期329-334,共6页
Journal of Fisheries of China
基金
宁波市重大攻关项目(2004C100059)
关键词
真鲷
维持氮
氮平衡法
无氮日粮法
Pagrosomus major
nitrogen requirement for maintain
nitrogen balance
nitrogen-free diet
