饲料蛋白对翘嘴鲌氮排泄的影响

The Effect of Dietary Protein on Nitrogen Excretion in Culter alburnus Juveniles

选择健康的翘嘴鲌为试验鱼,以褐鱼粉为蛋白源,配制5个蛋白水平的等能、等必需氨基酸平衡关联度(EAA)的半精制饲料;又以豆粕替代鱼粉、大豆蛋白替代鱼粉蛋白,配制5个关联度的等蛋白、等能的半精制饲料,探讨饲料蛋白水平和大豆蛋白替代鱼粉蛋白对翘嘴鲌氮排泄的影响.结果表明,饲料蛋白水平对翘嘴鲌氮排泄具有显著性影响(P<0.05),翘嘴鲌每日氨氮和尿素氮平均排泄率和排泄峰值随饲料蛋白含量的增加而增加.每日氨氮排泄率和饲料蛋白水平呈正相关.当大豆蛋白替代鱼粉蛋白超过40.5%时,氨氮排泄量显著增加(P<0.05),内源氮不受饲料蛋白水平和大豆蛋白替代的影响(P>0.05).

Trials were conducted to examine the effect of protein levels and protein sources on nitrogen excretion in Culter alburnus juveniles. Tested fish were fed 5 isoenergetic semi-purified diets with same relativity of essential amino acid balance and graded levels of protein. And tested fish were fed another five isonitrigenous and isoenergetic semi-purified diets with various relativity of essential amino acid balance formulated by soybean replacing of fish meal protein. The results showed that nitrogen excretion were significantly affected by dietary protein levels （ P 〈 0.05 ）, the amount of postprandial ammonia and urea excreted by fish increased linearly and significantly with the protein level of the diet （ P 〈 0.05 ）. Mean 24 h postprandial accumulated mean ammonia and urea excretory ratios and excretion peak increased with the increasing of dietary soybean protein level （P 〈 0. 05 ）. The ammonia excretion became significantly high when the fish were fed a diet with soybean protein replacing 40. 5% of fish meal protein （P 〈 0.05 ）. The excretion rates of endogenous nitrogen of fish had no significant difference among treatments.