大规格花鲈对饲料中缬氨酸的需求量研究

Nutrient Requirement of Valine in Large-sized Japanese Seabass

试验旨在研究大规格花鲈饲料缬氨酸的需求量。配制饲料缬氨酸水平为1.12%、1.54%、1.96%、2.28%、2.54%和2.87%的6组饲料,将初重(182.33±1.08)g的花鲈随机放入18个网箱(分为6组,每组3个重复)进行10周的养殖试验。结果表明,末重、增重率、特定生长率和饲料效率随饲料缬氨酸的升高呈先升高后降低的趋势,最高点在1.96%组。摄食率、蛋白质效率和蛋白质沉积率随饲料缬氨酸的增加呈先升高后趋于平缓的趋势。饲料缬氨酸水平对鱼体组成及肌肉必需氨基酸含量无显著影响(P>0.05)。肝脏谷草转氨酶和谷丙转氨酶的活性随饲料缬氨酸的升高呈先升高后降低的趋势。本试验条件下,以特定生长率和饲料效率为评价指标,大规格花鲈饲料缬氨酸的需求量为2.14%~2.17%饲料干物质(5.07%~5.14%饲料蛋白)。

The aim of this study was to investigate dietary valine requirement for Japanese seabass(Lateolabrax japonicus).Six isonitrogenous and isolipidic experimental diets were formulated to contain graded valine levels(1.12%,1.54%,1.96%,2.28%,2.54%and 2.87%dry matter of diet).Large-sized Japanese seabass[initial weight(182.33±1.08)g]were reared in sea cages and fed for 10 weeks.Fish were randomly allotted into 18 sea cages(6 treatments with 3 replicates).Final body weight,weight gain,specific growth rate(SGR)and feed efficiency(FE)firstly increased and then decreased with dietary valine level,and reached the highest value when experimental diets contained 1.96%valine dry matter of diet.Feed intake(FI),protein efficiency ratio(PER)and protein productive value(PPV)increased at first and then changed to be steady with the increase of dietary valine.Whole body composition and essential amino acid concentrations of muscle were not affected by graded levels of dietary valine.Aspartate aminotransferase and alanine aminotransferase in liver firstly increased and then decreased with dietary valine level.Our data indicate that optimum dietary valine requirements of Japanese seabass are estimated to be 2.14%-2.17%dry matter of diet(5.07%-5.14%of dietary protein)based on SGR and FE.