【作者】 王秀英；

【导师】 邵庆均；

【作者基本信息】 浙江大学 ， 动物营养与饲料科学， 2004， 硕士

【摘要】 维生素C是水产动物所必需的微量营养成分。本研究以黑鲷仔鱼为研究对象，研究维生素C对黑鲷仔鱼生长、鱼体常规营养成分含量、鱼体维生素C含量、鱼体抗氧化性能及RNA／DNA比值等的影响。并探讨其对饲料中以多聚磷酸酯维生素C形式添加的维生素C适宜水平的需要。 选取同一放养批次、体质健康的黑鲷仔鱼，随机分为6组，每组3个重复，每个重复25尾，平均体重为5.78±0.03g，进行为期56d的养殖试验。其中的一组作为对照组，对其投喂基础饲料，另外的五组为试验组，分别对其投喂以多聚磷酸酯维生素C形式添加20、40、80、160和320mg／kg维生素C的试验饲料1—5。养殖试验结束后，分析、计算黑鲷仔鱼的饲养指标和饲料指标，并宰杀所有试验鱼，分别采集全鱼、肝脏、肌肉、脑、鳃和血浆样品，进行常规营养成分和维生素C含量等的分析。 试验结果表明，饲料中添加维生素C能够促进黑鲷仔鱼的生长。在整个56d的试验期中，只有对照组黑鲷仔鱼表现出明显的维生素C缺乏表观症状，而饲料中添加了维生素C的各试验组都无此症状。随着饲料中维生素C水平的提高，黑鲷仔鱼的增重率、特定生长率、存活率、饲料效率和蛋白质效率也呈升高趋势，维生素C水平为325.29mg／kg的试验组-5这些数值最高。但是，饲料中不同水平的维生素C对各组黑鲷仔鱼的肥满度和肝体指数没有显著影响(P＞0.05)。 饲料中添加维生素C还能够影响黑鲷仔鱼肌肉和肝脏的常规营养成分含量。对照组黑鲷仔鱼肌肉中的粗脂肪含量显著低于各试验组(P＜0.05)，但是饲料中不同水平的维生素C对肌肉粗蛋白和水分含量无显著影响(P＞0.05)。随着饲料中维生素C水平的提高，肝脏中的粗脂肪含量呈上升趋势，水分含量呈下降趋势，但是粗蛋白含量无显著变化(P＞0.05)。饲料中不同水平的维生素C对黑鲷仔鱼全鱼的常规营养成分含量无显著影响(P＞0.05)。 饲料中添加维生素C能够提高维生素C在黑鲷仔鱼体内的蓄积量。随着饲料中维生素C水平的提高，黑鲷仔鱼全鱼、肌肉、肝脏、脑、鳃和血浆中的维浙江大学硕士论文生索C含量呈__匕升趋势。并且，鳃中的维生素C含量与饲料中维生素C添加量一叮司存在明显的线性相关性。但未发现全鱼、肌肉、肝脏、脑和血浆中的维生素C含量与饲料中维生素C添加量之间存在明显的线性相关性。 价!料，中添加维生素C能够提高黑绸仔鱼的抗氧化性能。随着饲料中维生素又水平的提高，黑酮仔鱼肌肉、肝脏和血浆中的超氧化物歧化酶(SOD)活力呈犷升趋势，肝脏和血浆中的谷肤甘肤过氧化物酶(GSH一Px)活力也呈上升趋势，南肌肉、肝脏和血浆中的丙二醛(MDA)含量则呈下降趋势。 另外，饲料中添加维生素C能够影响黑绸仔鱼碱性磷酸酶(AKI〕)活力与背肌中的1之NA、DNA含量及其比值。随着饲料中维生素C水平的提高，黑绸仔鱼肝脏和血浆中的碱性磷酸酶(AKP)活力呈上升趋势。各试验组背肌中的RNA含量高于对照组，而DNA含量则随着饲料中维生素C水平的升高呈下降趋势，因此RN刀DNA比值呈上升趋势。 分别以黑酮仔鱼的增重率和肝脏中维生素C蓄积浓度达到最适宜水平为评价指标，得到在水温28士l℃、试验初始体重约5.789和以多聚磷酸醋维生素C作为维生素C源的条件下，黑绸仔鱼对饲料中维生素C的最低需要量分别为42.36川g/kg和86.35mgfkg。更多还原

【Abstract】 Vitamin C is an essential micronutrient for aquatic animals. Juvenile black seabream (Sparus macrocephalus) was used as target animal in this research which aimed at finding out the optimal dietary vitamin C (added in L-ascorbyl-2-polyphosphate form) level of juvenile black seabream for its growth. The influences of vitamin C on growth performance, body proximate composition, vitamin C contents of tissues, antioxidant abilities and RNA/DNA ratio were also studied in this research.Juvenile black seabream used in the growth trial were randomly allotted to six groups with three replicates. Each replicate was composed of twenty five fish with average initial weight 5.78g. Experimental diets supplemented with six levels of vitamin C 0, 20, 40, 80, 160, 320 mg per kg in form of L-ascorbyl-2-polyphosphate were respectively fed to trial fish twice daily for 56 days. At the end of growth trial, fish grow performance and feed utilization were calculated, and all fish were killed to collect tissue and blood samples for analysis.The results showed that the supplement of dietary vitamin C in juvenile blackseabream can improve their growth performance. During growth trial, only the control fish showed obvious vitamin C deficient symptoms, whereas the other groupsdid not. Weight gain rate (WGR), specific growth rate (SGR), survival, feed efficiency (FE) and protein conversion efficiency (PCR) of fish elevated with the elevation of dietary vitamin C level. However, dietary vitamin C levels had no significant influence on conditon factor (CF) and hepatosomatic index (HSI) (P > 0.05).Dietary vitamin C levels also had influences on the muscle and liver proximate compositions of juvenile black seabream. The proximate muscle fat content of the control fish was significantly lower than other groups (P < 0.05) , but no significant influence on the muscle proximate protein and moisture contents could be found among treatments (P > 0.05). The proximate liver fat contents elevated with the elevation of dietary vitamin C levels, contrarily the liver moisture content declined. There was no apparent difference in liver proximate protein content and whole body proximate composition among vitamin C treatments (P > 0.05).Supplementation of dietary vitamin C could elevated the deposition of vitamin C in juvinile black seabream. Vitamin C concentrations in whole body, muscle, liver, brain, gill and plasma enhanced as the dietary vitamin C level increased. Moreover, A significant positive correlation could be found in gill vitamin C concentration with dietary vitamin C supplemented levels. But no significant positive correlation could be found with whole body, muscle, liver, brain and plasma vitamin C concentration among treatments.Dietary vitamin C supplementation could improve the antioxidant abilities of juvinile black seabream. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the muscle, liver and plasma of juvenile black seabream enhanced as increase of dietary vitamin C levels. Meanwhile, maleic dialdehyde (MDA) contents in muscle, liver and plasma decreased as increase of dietary vitamin C levels.Dietary vitamin C supplementation also influenced alkaline phosphatase (AKP) activity, contents of RNA and DNA, and the ratio of RNA/DNA of juvinile black seabream. AKP activity increased as the dietary vitamin C level increased. RNA content of control group was lower than other groups.whereas DNA content decreased- 6 6 -as dietary vitamin C level increased. As a result, the ratio of RNA/DNA increased as dietary vitamin C level increased.Based on broken-line model analyses at this study, the minimum dietary vitamin C level from L-ascorbyl-2-polyphosphate is 42.36 mg/kg to get optimal weight gain rate or 86.35 mg/kg to get optimal liver vitamin C concentration for juvenile black seabream, with intial body weight 5.78g and water temperature 28+ 1更多还原