饲料中不同淀粉源及水平对大口黑鲈肝脏组织学的影响

为了评估饲料中不同淀粉源及水平对大口黑鲈肝脏组织学的影响,采用4种淀粉(蜡质玉米淀粉、高直链玉米淀粉、小麦淀粉和木薯淀粉)各按两水平(5%和10%)配制成8种等氮和等能的饲料,投喂初始体质量为(23.45±0.08)g的大口黑鲈,经45 d的饲养后,采集肝脏样本进行肝脏组织的生化测定和切片观察。结果显示,摄食全部5%淀粉饲料和10%高直链玉米淀粉饲料的实验鱼的肝脏颜色呈正常的鲜红色;而摄食其他10%淀粉饲料的实验鱼肝脏均显现出发白现象,同时,肝细胞体积、肝体指数和肝糖原含量均显著高于5%淀粉饲料组和10%高直链玉米淀粉饲料组,肝细胞的细胞核移至细胞边位,出现空泡化现象。在5%和10%的淀粉水平上,高直链玉米淀粉饲料组的肝体指数、肝糖原含量和肝细胞体积均显著小于其他淀粉源的饲料组,肝细胞也没有出现细胞肿胀现象。本研究得出,饲料的碳水化合物来源与水平均对大口黑鲈肝脏组织的肝糖原含量和组织结构产生显著的影响;高直链玉米淀粉优于小麦淀粉、蜡质玉米淀粉和木薯淀粉,5%的饲料淀粉水平优于10%的水平。

Effects of dietary starch sources and levels on liver histology in largemouth bass, Micropterus salmoides

A 45-day feeding test was conducted to investigate the effects of different kinds and levels of dietary starch on liver histology of largemouth bass (LMB) with an initial body weight (23.45±0.08) g. Eight iso-nitrogenous and iso-energetic diets were formulated with four kinds of starch (wheat starch, waxy corn starch, high-amylose corn starch, and cassava starch) at 5% and 10% levels, respectively. At the end of the feeding test, liver samples of test fish were collected. Biochemical analysis and histological observation of the liver tissues were performed. The results showed that the liver of fish, fed to all diets containing 5% starch and diet containing 10% high-amylose corn starch, was found bright red as usual, while the liver of fish, fed to the other diets with 10% starch, turned pale. Meanwhile, compared to fish with diets including 5% starch and 10% high- amylase corn starch, the hepatocyte size, hepatosomatic index, hepatic glycogen content and occurrence rates of the hepatocyte vacuolization and nuclei shifting to the cellular periphery were much higher in fish fed other 10% starch diets. It would be concluded that both dietary starch kind and its level can make a significant effect to glycogen content and tissue structure of the liver in LMB, high-amylose corn starch is more suitable than wheat starch, waxy corn starch and cassava starch, and that an inclusion level of 5% dietary starch is more suitable than of 10%.