饲料低蛋白、高脂肪和高消化能对斑点叉尾鮰

为了探讨高脂肪条件下不同的蛋白和能量水平对斑点叉尾鮰生长及体组成的影响,试验设2个蛋白水平(22%,28%),2个脂肪水平(10.0%,14.0%),2个消化能水平(12.56 kJ/g,14.23 kJ/g),共8组,分别为P28L10E14.23,P28L14E14.23,P22L10E14.23,P22L14E14.23,P28L10E12.56,P28L14E12.56,P22L10E12.56和P22L14E12.56。试验饲料配方使用鱼粉和豆粕调节蛋白含量,混合油脂(鱼油∶玉米油=1∶1)调节脂肪含量,α-淀粉、次粉和麸皮调节消化能含量,并以微晶纤维素为填充物,每组3个重复,每个重复20尾鱼(141.5?1.0) g。饲养60 d后,进行生产性能测定,并采集组织样本,测定相关指标。结果表明,鱼体末重(FW)、增重率(WG)、特定生长率(SGR)和饵料系数(FCR)不受饲料蛋白、脂肪和消化能单一营养水平影响(P>0.05);但与饲料蛋白、脂肪和消化能三者的交互作用(P<0.01)有关。胴体蛋白、脂肪含量与饲料脂肪和消化能水平相关(P<0.05)。由此可见,饲料过高脂肪和消化能对斑点叉尾鮰没有额外的促生长作用;饲料蛋白水平达到22%时,即可满足140~300 g斑点叉尾鮰的营养需要;饲料中22%的蛋白、10%的脂肪、12.56 kJ/g的消化能即可满足斑点叉尾鮰仔鱼的生长需要,同时又能保证其正常生理机能,建议可在实际生产配方中作参考值。

Effects of different dietary protein,lipid and digestible energy levels on growth and body composition of juvenile channel catfish(Ictalurus punctatus)

A 60-day feeding trial including diets with two protein levels(22%,28%),two lipid levels(10.0%,14.0%)and two digestible energy levels(12.56 kJ/g,14.23 kJ/g)designed with three replications was conducted to investigate the growth,nutrient utilization and body composition of juvenile channel catfish.Four hundred and eighty fish(initial weight,141.5?1.0 g)were randomly distributed into 24 tanks(3.0 m?0.8 m?0.8 m)at a rate of 20 fish per tank and fed three times daily.Fish were fed respectively to apparent satiation by experimental diets named P28L10E14.23,P28L14E14.23,P22L10E14.23,P22L14E14.23,P28L10E12.56,P28L14E12.56,P22L10E12.56 and P22L14E12.56.Final weight,weight gain,specific growth rates(SGR)and feed conversion ratio(FCR)were not significantly affected by dietary protein or dietary lipid or dietary digestible energy(P>0.05),but were significantly affected by a dietary protein?lipid interaction(P<0.05),and extremely significantly affected by a dietary protein?lipid?digestible energy interaction(P<0.01).With the protein/energy ratio increasing,it took an increasing trend to final weight,weight gain and SGR(P<0.05),except that fish fed diet P28L10E12.56.The digestibility of dietary protein,lipid,energy and dry matter is increasing when dietary digestible energy decreased(P<0.05)and dietary lipid increased(P<0.05). With the dietary protein decreasing,it took a decreasing trend to the digestibility of dietary protein,energy and dry matter(P<0.05).The digestibility of dietary protein,lipid,energy and dry matter is increasing by dietary lipid levels(P<0.05).Nitrogen retention was significantly increased as dietary protein levels decreased(P<0.05),lipid retention decreased significantly with dietary digestible energy and lipid levels decreasing(P<0.05),protein efficiency ratio(PER)was significantly increased as dietary digestible energy decreased(P<0.05).Carcass protein and lipid were not significantly affected by dietary digestible energy concentrations(P>0.05);however,carcass lipid tended to improve(P=0.066) as dietary digestible energy levels increased.The results of this study indicated that the diet containing 28% protein with 14% lipid and 12.56 kJ/g digestible energy is optimal for growth of juvenile channel catfish(150 to 300 g weight).However,group P28L10E14.23 and P22L10E12.56 got second best weight,highest nutrient utilization and best body composition of juvenile channel catfish.It also indicates that lipid saved protein in diet of juvenile channel catfish.