不同糖源对卵形鲳鲹(Trachinotus ovatus)日增重、饲料利用和消化酶活性的影响

以葡萄糖、蔗糖、糊精、玉米淀粉和糊化玉米淀粉为糖源制成5种等氮等脂饲料,投喂卵形鲳碜(Trachinotus ovatus)8周,研究不同糖源对其日增重、饲料利用和肝脏消化酶活性的影响.结果显示,不同糖源对卵形鲳鲹日增重、饲料效率和蛋白效率均有显著影响(P＜0.05).糊化玉米淀粉组的日增重、饲料效率和蛋白效率均最高,显著高于非淀粉糖源组(P＜0.05),而与玉米淀粉组无显著差异(P＞0.05);葡萄糖组的日增重、饲料效率和蛋白效率均最低,显著低于其他糖源组(P＜0.05).消化酶活性结果显示,饲料中的不同糖源对卵形鲳鲹的肝脏消化酶活性有显著影响(P＜0.05).两个淀粉组的蛋白酶活性显著低于分子量较低其他三组(P＜0.05);蔗糖组的淀粉酶活性最高,显著高于除糊精组外的其他糖源组(P＜0.05);脂肪酶活性随着糖分子量的增大而增大.本研究中淀粉类大分子糖类对卵形鲳鲹的促生长效果优于葡萄糖、蔗糖和糊精,糊化玉米淀粉组的促生长效果最好.

Effect of Different Carbohydrate Sources on Daily Weight Growth, Feed Utilization and Digestive Enzyme Activities of Trachinotus ovatus

A cost-efficient formula of feed in fish farming usually contains a large amount of low-cost energy sources supplemented with sufficient level of high-cost essential nutrients such as protein. Carbohydrate is the least costly dietary energy for animals. However, the utilization of carbohydrate varies a lot between different fish species, and the mechanisms underlying distinctive carbohydrate-consuming abilities have been obscure. In this study we aimed to explore the effects of different carbohydrate sources on daily weight growth (DWG), feed utilization and digestive enzyme activities of Trachinotus ovatus. Fish (initial weight 31.24±0.58 g) were fed with 5 groups of isonitrogenous and isolipidic diets each of which contained 1 type of carbohydrate at 20% including glucose, sucrose, dextrin, corn starch or gelatinized corn starch. Each group was fed for 8 weeks. The results showed that different carbohydrate sources significantly affected the DWG, feed efficiency (FE) and the protein efficiency ratio (PER) (P<0.05). The gelatinized corn starch group had significantly higher DWG (2.19 g/d), FE (0.82%) and PER (1.88) than other groups (P<0.05), and there was no significant difference between the two starch groups (P>0.05). The glucose group had the lowest DWG, FE and PER (P<0.05). Dietary carbohydrate sources also had great effects on activities of digestive enzymes (P<0.05). The protease activity of the two starch groups was significantly lower than that of the other three groups (P<0.05). The sucrose group displayed the highest amylase activity (P<0.05). The lipase activity was boosted along with the increase in the molecular weight of the dietary carbohydrate, and was the highest in the gelatinized corn starch group. In conclusion, large-molecule carbohydrates may have better effects on the growth of T. ovatus than glucose, sucrose and dextrin. Gelatinized corn starch was the optimal carbohydrate source in this study.