饲料中不同动植物蛋白比对大菱鲆营养物质消化率和氮收支的影响

Effects of different dietary animal-plant protein ratio on nutrient digestibility and nitrogen budget of juvenile Turbot(Scophthalmus maximus)

文章旨在研究不同动植物蛋白比配合饲料对大菱鲆消化率和氮收支平衡的影响。采用膨化大豆、谷朊粉、发酵豆粕、啤酒酵母为植物蛋白源,白鱼粉和乌贼肝粉为动物蛋白源,按照一定比例配制成4种动植物蛋白比为1?1、2?1、3?1、4?1的试验饲料(分别为饲料1、饲料2、饲料3和饲料4),对初体重为140 g的大菱鲆进行56 d的养殖试验。每个处理组3个重复,每个重复48尾鱼。试验结果表明:随着动物蛋白比例的降低,各营养物质的表观消化率呈降低趋势,各组之间的干物质消化率和磷消化率均有显著差异(P<0.05);饲料1组的能量消化率显著低于其它各组(P<0.05);粗蛋白消化率除饲料2组和饲料3组间无显著差异外,其它均有显著差异(P<0.05)。在氮收支中,吸收氮占摄入氮的比例达到了显著的差异(P<0.05),饲料4组显著高于其它各组,饲料1组显著低于其它各组(P<0.05),饲料2组和饲料3组间无显著差异;饲料1组的生长氮占摄入氮的比例(氮的生长效率)显著低于其它各组(P<0.05),其它各组间无显著差异;排泄氮占吸收氮的比例在各组间无显著差异(P>0.05)。结果提示,植物蛋白源替代大菱鲆配合饲料中的动物蛋白源后显著降低了各营养物质的消化率,当动植物蛋白比在2?1以上,氮的生长效率没有受到显著影响,试验中大菱鲆配合饲料中的最适动植物蛋白比为2?1。

This paper was designed to study the effects of different animal-plant protein rado ill diet on digestibility and nitrogen budget of turbot, l）ifferent plant protein sources including exlruded soybean, wheat gluten, t＇ermented soybean meal and brewer＇s yeast were designed to replace animal protein. Four animal-plant protein ratios were 1 ： 1, 2 ： 1, 3 ： I and 4 ： 1 respectively. Each group has lhree repli- tales with 4-8 turbot per lank. After 56 d growth trial, the nutrient apparent digestibility decreased signif- icantly with decreasing of the animal-plant pro｜ein ratios, there were significant differences among each group in dry matter and phosphorus digestibility （P〈O.05）. The energy digestibility in I ： 1 group was significantly lower than other groups in which no significant differences were observed. There were sig- nificant differences in protein digestibility among groups except fi^r 2 ： 2 and 3 ： 3 groups. In the nitro- gen budget, there were significant differences in absorption-intake nitrogen ratio （P〈O.05）. which was significantly higher in 4 ： 4 group than any other groups, but the ralio i,l I ： 1 group was signifi- cantly lower than other groups. The growlh-in- take nitrogen ratio （growth efficiency of nitrogen） in 1 ： l group was significantly lower than other groups. No significant dift^rences in urea-intake ratio were observed among all groups （P〉0.05）. In conclusion, the nutrient apparent digestibility decreased significantly with decreasing of the animal- plant protein ratios, the growth efficiency of nitrogen was not significantly affected when the animal- plant protein ratio in turbot diet was more than 2 ： 1.