两种配合饲料对刀鲚幼鱼消化系统显微结构和功能的影响

在水温为23℃条件下,将体质量为（2.78±0.09）g的刀鲚Coilia nasus幼鱼饲养在室内水泥池循环水系统中,分别投喂人工配合饲料1（缓沉软颗粒料）和饲料2（缓沉硬颗粒料）.饲养60 d后,分析两组刀鲚幼鱼的形体指标、消化酶和脂质代谢酶活性的差异;并采用H.E染色法从肝、胃、肠组织等方面比较了两组刀鲚幼鱼消化系统的组织结构差异.试验结果表明：两组刀鲚幼鱼的增重率分别为76.64％和104.17％,且组间有显著性差异（P＜0.05）;两组幼鱼的肥满度、特定生长率有显著性差异（P＜0.05）,两组幼鱼的肝体比和脏体比以及胃淀粉酶、胃蛋白酶、肝脏脂肪酶活性均无显著性差异（P＞0.05）.消化系统组织学观察表明：饲料2组幼鱼的肝脏细胞质中存在明亮的脂肪滴,饲料1组幼鱼胃壁上的皱褶多且较高;饲料2组幼鱼的前肠直径、黏膜褶高度和肌层厚度均比饲料1组高,表明两组幼鱼胃和肠的消化能力和对饲料的消化速度存在差异;结合食物消化动态过程,饲料2组幼鱼的消化吸收能力比饲料1组幼鱼强.研究表明,饲料2更适合刀鲚幼鱼生长,适合于刀鲚幼鱼驯养阶段使用.

Histological,and enzymatic comparison of digestive system in juvenile estuarine tapertail anchovy Coilia nasus fed formulated diets

Effects of two formulated diets on growth and digestive enzymatic activity related to lipid metabolism,and digestive system histology were studied in estuarine tapertail anchovy Coilia nasus juveniles with body weight of （2.78±0.09） g fed two formulated diets （diet 1,dry powder,and diet 2,hard sinking pellet） at water temperature of 23 ℃ for 60 days.The results showed that the fish fed diet 1 had weight gain rate of 76.64% and the juveniles fed diet 2 had weight gain rate of 104.17%,with significant difference （P〈0.05）.There were significant differences in condition factor and specific growth rate （P〈0.05）,and no significant difference was observed in activities of amylase,pepsin,and lipase,hepatosomatic index and viserosomatic index in the fish fed the two diets（P〉0.05）.The histological observation revealed that the distinct oil droplets were found in the hepatic cells of the fish in diet 2 group.On the other hand,there were thicker and higher mucosal fold in gastric walls in the fish in diet 1 group than those in diet 2 group.The fish fed diet 2 showed higher foregut diameter,mucosal fold height and muscularis in the midgut in the fish fed the diet 2 than those in the fish fed the diet 1,indicating that the diet 2 is suitable for rearing estuarine tapertail anchovy juveniles.