饲料糖水平对方格星虫稚虫生长、体组成和消化酶活性的影响

摘要

本试验旨在研究饲料糖水平对方格星虫稚虫生长、体组成和消化酶活性的影响.选取平均体重为(15.49±0.03) mg的方格星虫稚虫7 200条,随机分为6组,每组3个重复,每个重复400条.6组方格星虫稚虫分别饲喂糖水平为1.89％、7.35％、12.81％、18.27％、23.73％和29.19％的等氮等脂饲料8周.结果表明:饲料糖水平对成活率没有显著影响(P＞0.05).当饲料糖水平为1.89％ ～ 18.27％时,增重率和特定生长率随着饲料中糖水平的增加而显著上升(P＜0.05),当饲料糖水平继续增加时,增重率和特定生长率则显著下降(P＜0.05).饲料糖水平对虫体粗蛋白质和粗脂肪含量有显著影响(P＜0.05),对虫体水分和灰分含量没有显著影响(P＞0.05).虫体粗蛋白质含量随着饲料糖水平的增加呈先升后降的趋势,饲料糖水平为23.73％时达到最大值.虫体粗脂肪含量随着饲料糖水平的增加呈升高的趋势,饲料糖水平为29.19％时达到最大值.饲料糖水平对虫体蛋白酶和淀粉酶活性有显著影响(P＜0.05),对虫体脂肪酶活性没有显著影响(P＞0.05).虫体蛋白酶和淀粉酶活性均随着饲料糖水平的增加呈先升后降的趋势,蛋白酶和淀粉酶分别在饲料糖水平为23.75％、18.27％时达到最大值.以增重率为评价指标,经回归分析得出方格星虫稚虫饲料中糖的适宜水平为18.52％.%This experiment was conducted to investigate the effects of dietary carbohydrate level on growth, body composition and digestive enzyme activities of juvenile peanut worm, Sipunculus nudus. A total of 7 200 juvenile peanut worm with an average body weight of (15. 49 ± 0. 03) mg were randomly divided into 6 groups with 3 replicates in each group and 400 worms in each replicate. The worms in the 6 groups were fed isonitrogenous and isoenergetic diets with different carbohydrate levels of 1. 89% , 7. 35%, 12. 81%, 18. 27% , 23. 73% and 29.19% for 8 weeks. The results showed that the dietary carbohydrate level had no significant effect on survival ratio (P >0. 05). With the dietary carbohydrate level increasing, weight gain rate and specific growth rate were significantly increased when dietary carbohydrate level was between 1. 89% and 18.27% (P <0. 05) , and then significantly decreased with dietary carbohydrate further increasing (P < 0.05). Dietary carbohydrate level had significant effects on the contents of crude protein and crude lipid in body (P <0. 05) , but had no significant effects on the contents of moisture and ash in body (P >0. 05). With the dietary carbohydrate level increasing, the body crude protein content was firstly increased and then decreased, and when the dietary carbohydrate level was 23. 73% , the body crude protein content had the maximum value. There was an upward trend in body crude lipid content with dietary carbohydrate level increasing, and when the dietary carbohydrate level was 29.19% , the body crude lipid content had the maximum value. Dietary carbohydrate level significantly affected protease and amylase activities of juvenile peanut worm (P < 0. 05). Both protease and amylase activities were firstly increased and then decreased with the dietary carbohydrate level increasing, and they had the maximum values when the dietary carbohydrate levels were 23. 75% and 18.27% , respectively. However, dietary carbohydrate level had no significant effect on Upases activity of juvenile peanut worm (P >0. 05). The regression model analysis shows that the optimal dietary carbohydrate level which can make juvenile peanut worm acquire the best weight gain rate is 18. 52% .