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饲料酵母替代鱼粉对大菱鲆生长、免疫及肠道显微结构的影响

标题: 饲料酵母替代鱼粉对大菱鲆生长、免疫及肠道显微结构的影响
英文标题: Effects of Feed Yeast on Growth Performance, Immunity and Intestinal Microscopic Structure of Turbot Scophthalmus Maximus
作者: 崔敏
出版时间: 2012-01-01
所在大学: 河北农业大学
关键词: 大菱鲆,饲料酵母,生长性能,免疫机能,肠道显微结构
英文关键词: Scophthalmus maximus,Candida utilis,growth performance,immunity,intestinal microscopic structure
论文级别: 硕士
学位: 学位论文
导师: 郭冉
专业: 水产养殖
提交时间: 2012
摘要: 本试验采用鱼粉(粗蛋白68%)为动物蛋白源,添加0、15%、30%、45%、60%的饲料酵母(粗蛋白46.3%)分别替代0%、17%、34%、51%、68%的鱼粉,配制五种等氮、等能的试验饲料,分别表示为B1(对照组)、B2、B3、B4和B5.选取195条大小均匀(9.02±0.15g)、体格健壮的大菱鲆幼鱼,随机分配于15个水族箱(5个组,每组3个重复)每个重复放养13尾鱼,投饲率为体重的3%~ 4%,每14 d根据体重变化调整投喂量.试验持续56d,旨在研究饲料酵母替代鱼粉对大菱鲆生长、免疫及肠道显微结构的影响.结果表明,增重率、摄食率、特定生长率、肝体指数、内脏指数和肥满度均随着饲料酵母添加量的增加出现先升高后降低的趋势,饲料系数则出现先下降后上升的趋势.B2的增重率、特定生长率和成活率分别比对照组高16.82%、4.95%和11.99%,饲料系数比对照组低12.42%,说明饲料中添加适宜的饲料酵母对大菱鲆的生长有一定的促进作用.但饲料酵母超过一定量时,会显著降低大菱鲆的生长.饲料酵母对鱼体的水分和粗脂肪没有显著的影响(P>0.05),但导致粗蛋白含量逐渐降低(P<0.05),粗灰分含量逐渐升高(P<0.05).B2组的粗蛋白显著高于对照组5.84%,粗灰分低于对照组22.44%,说明适量的饲料酵母会增加鱼体内蛋白质的沉积,避免脂肪的堆积.添加30%的饲料酵母时,对大菱鲆的免疫力没有显著影响(超氧化物歧化酶除外),超过此添加量就会显著降低大菱鲆的免疫指标.随着饲料酵母添加量的增加,肠道皱襞高度逐渐下降,而肠道菌群的数量没有显著的变化(P>0.05).过量的饲料酵母会破坏大菱鲆的肠道结构.B5的前肠和中肠肠道组织结构完整性被破坏,部分肠绒毛脱落,后肠的肠绒毛变短且固有层变宽,粘膜层与肌层结缔组织连接疏松.添加15%饲料酵母时,大菱鲆饲料原料成本、饲料成本以及生产成本均较对照组低,原料成本每kg节约1.19元,饲料成本每kg节约1.62元,结合饲料系数看,生产每kg鱼节约4.76元.综合考虑大菱鲆的生长指标、形体指标、鱼体成分、免疫机能、肠道显微结构和饲料成本等因素,要获得最佳的养殖效益,大菱鲆饲料中的添加量以15%为宜.
英文摘要: A 8-week feeding trial was conducted to study the effects of feed yeast on growth performance, immunity and intestinal microscopic structure of Scophthalmus maximus. Five kinds of isocaloric and isonitrogenous diets ( 0 (B1), 17% (B2), 34% (B3), 51% (B4) and 68% (B5) fish meal were replaced with 0, 15%, 30%, 45% and 60% of feed yeast) were formed. A total of 195 fish (initial weight: 9.02±0.15g) were averagely allocated to 15 glasses tanks with 3 replicates of 13 turbot in each replicate. The fish were fed 3%-4% body weight thrice daily and the amount of feed given was increased as the fish grew. The results showed that weight gain, feeding ratio, special growth ratio, hepatopancreas indexes, viscera indexes and condition factor were all suffered from the trend of first increased and then decreased, the trend of feed conversion ratio was opposite. Weight gain, specific growth rate and survival rate of B2 were 16.82%, 4.95% and 11.99%, respectively, which were higher than that of the control group, and it's feed conversion rate (12.42%) was lower than that of the control group.This proved that appropriate dietary feed yeast to some extent could promote the growth of turbot. However, a over certain ration of feed yeast addition will significantly reduce the growth of turbot. With the increase of feed yeast, crude protein decreased, while crude ash gradually increased, moisture and crude lipid had no significant differences. Compare with the control group, the crude protein of B2 was significantly higher than 5.84% and crude ash was lower than 22.44%. It proved that appropriate dietary feed yeast to some extent could also promote the nutritional quality of turbot. The effect of feed yeast on immunity was not obvious when the addition of feed yeast was 30% (except SOD activity), it will have a significant reduction in the immune indexes when over 30%. As the addition of feed yeast increased, intestinal folds were gradually decreased, while the numbers of intestinal flora were not changed significantly. The intestinal construction of the turbot was damaged by excessive feed yeast. The structural integrity of anterior intestine and mid-intestine in B5 was destroyed, the part of intestinal villi shed. The intestinal villi of posterior intestine were shorter, the proper layer became wider and the connective tissue of proper layer loosened. The ingredient cost, feed cost and production cost were all lower than the control group when 15% feed yeast was added. The ingredient cost saved 1.19 yuan per kg, feed cost saved 1.62 yuan per kg and production cost saved 4.76 yuan per kg. The overall conclusion was that the optimal feed yeast addition in diets may be set at 15% based on the results of growth performance, physical indicators, body composition, immunity, intestinal microscopic structure and feed cost.