中文摘要：

本研究旨在探讨饲料中不同维生素D含量对鲈鱼幼鱼生长性能和钙磷代谢的影响。以初始体重为（2.26±0.03）g的鲈鱼幼鱼为试验对象,随机分为6组（每组3个重复,每个重复15尾鱼）,饲喂维生素D含量实测值分别为34.2、219.4、393.8、775.9、1 534.1和3 091.2 IU/kg的等氮等能饲料,进行9周的养殖试验。结果表明：1）当饲料中维生素D含量在34.2-393.8 IU/kg时,鲈鱼的增重率随着饲料中维生素D含量的升高显著上升（P〈0.05）,但是当饲料中维生素D含量高于393.8 IU/kg时,鲈鱼的增重率变化不显著并且出现平台期（P〉0.05）。同样,鲈鱼的特定生长率、饲料效率和蛋白质效率均表现出与增重率相似的变化趋势。2）饲料中维生素D含量显著影响了鱼体粗灰分、钙和磷含量,脊椎骨、鳃盖骨和鳞片粗灰分含量以及脊椎骨钙和磷含量（P〈0.05）,但对鱼体粗蛋白质、粗脂肪和水分含量没有显著影响（P〉0.05）。3）饲料中维生素D含量对鲈鱼血清碱性磷酸酶活性及羟脯氨酸、钙离子和无机磷含量均有显著影响（P〈0.05）。4）饲料中维生素D含量显著影响了鲈鱼肝体指数及肝脏脂肪和维生素D含量（P〈0.05）。随着饲料中维生素D含量的升高,肝脏维生素D含量呈现升高的趋势,并在饲料中维生素D含量达到1 534.1 IU/kg时变化趋于平稳。以增重率为评价指标,采用折线模型分析得出鲈鱼幼鱼获得最大生长时对饲料中维生素D的需求量为431.0 IU/kg饲料。以肝脏维生素D含量为评价指标,采用二次曲线模型分析得出鲈鱼幼鱼获得最大肝脏维生素D沉积量时对饲料中维生素D的需求量为2 444.4 IU/kg饲料。

英文摘要：

A 9-week feeding experiment was conducted to evaluate the effects of different dietary vitamin D contents on growth performance,calcium and phosphorus metabolism of juvenile Japanese seabass（Lateolabrax japonicas）.Juvenile Japanese seabass with the initial body weight of（2.26 ± 0.03） g as the experimental animal,and were randomly divided into 6 groups with 3 replicates each group and 15 fish per replicate.Fish in the 6 groups were fed six isonitrogenous and isoenergentic diets with the measured contents of vitamin D were 34.2,219.4,393.8,775.9,1 534.1 and 3 091.2 IU/kg,respectively.The results showed as follows：1） weight gain rare（W GR） was significantly increased with increasing dietary vitamin D content from 34.2 to393.8 IU/kg（P〈0.05）,and when the dietary vitamin D content more than 393.8 IU/kg,the W GR had no significant change and presented a trend of forgetting（P〉0.05）.Special growth rate（SGR）,feed efficiency ratio（FER） and protein efficiency ratio（PER） showed a similar tendency to W GR.2） Dietary vitamin D content significantly influenced the contents of ash,calcium and phosphorus in carcass,ash in vertebra,operculum and scale,and calcium and phosphorus in vertebra of juvenile Japanese seabass（P〈0.05）,but had no significant influences on the contents of crude protein,crude lipid and moisture in carcass（P〉0.05）.3） Serum alkaline phosphatase（AKP） activity,and hydroxyproline（HPro）,calcium ion（Ca2＋） and inorganic phosphorus（Pi） contents were all significantly affected by dietary vitamin D content（P〈0.05）.4） Dietary vitamin D content had significant influences on hepatosomatic index,liver lipid and vitamin D contents（P〈0.05）.Liver vitamin D content showed an increased trend with increasing dietary vitamin D content,and it changed to be steady when dietary vitamin D content up to 1 534.1 IU/kg.Broken-line model analysis with the W GR as the appraising index shows that juvenile Japanese seabass require 431.0 IU/kg diet vitamin