饲料脂肪水平对克氏原螯虾亲虾生长性能、肌肉成分、繁殖性能以及血淋巴生化指标的影响

为研究克氏原螯虾亲虾对脂肪的需要量,本实验采用初始体质量为(15.46±0.20)g的克氏原螯虾亲虾324尾,分为6组(每组设置3个重复,每个重复18尾,雌雄比例为2:1),投喂粗蛋白质水平为30%,脂肪水平分别为1.98%(对照组)、4.12%、5.84%、7.89%、10.48%和11.89%的6组半精制饲料,饲养8周后,测定并分析亲虾的生长性能、肌肉成分、繁殖性能、肝胰腺消化酶活性以及血淋巴部分生化指标。结果发现:①随着饲料脂肪水平的升高,增重率和特定生长率先上升,在饲料脂肪水平达到7.89%后呈下降趋势;饲料系数和肝体比呈上升趋势,11.89%组最高。②饲料脂肪水平对亲虾肌肉水分和灰分含量无显著影响;随着饲料脂肪水平的升高,肌肉粗脂肪含量呈现先升高后降低最后趋于稳定的趋势,在饲料脂肪水平为5.84%时最高。③随着饲料脂肪水平的升高,性腺指数、抱卵率、抱卵量均呈现先上升后降低的变化规律,均在饲料脂肪水平为7.89%时达到最大。④血淋巴中总蛋白含量随饲料脂肪水平呈现先下降后上升趋势;谷草转氨酶、谷丙转氨酶活性均随饲料脂肪水平升高而升高,均在11.89%组最高;血淋巴中葡萄糖含量各组间无显著性差异。⑤饲料脂肪水平对实验虾肝胰腺蛋白酶和脂肪酶活性有显著影响,对淀粉酶活性无显著性影响。利用增重率与饲料脂肪水平进行折线回归分析,克氏原螯虾亲虾获得最佳增重率时对饲料的脂肪需要量为7.60%。对实验虾生长性能、肌肉成分、繁殖性能、肝胰腺消化酶活性、血淋巴生化指标进行综合分析,显示本实验条件下克氏原螯虾亲虾对脂肪需要量为7.60%～7.89%。

Effects of dietary lipid levels on growth performance, muscle composition, reproductive performance and hemolymph biochemical indices of Procambarus clarkii broodstock

The objective of this study was to assess the optimal dietary lipid requirement of red swamp crayfish broodstock(Procambarus clarkia), In present study, 324 crayfish with average initial body weight of (15.46±0.20) g were randomly divided into 6 groups with 3 replicates of 18 crayfish in each replicate. Crayfish in each group were hand-fed a semi-purified diets containing different lipid levels 1.98% (control group), 4.12%, 4.98%, 7.89%, 10.48% and 11.89%] for 8 weeks. At the end of feeding trial, growth performance, muscle composition, reproductive performance, activities of digestive enzyme in hepatopancreas, and hemolymph biochemical indexes were measured. The results showed as follow, 1) as dietary lipid level increasing, the weight gain rate(WGR) and specific growth rate(SGR) of crayfish broodstock increased at first and then decreased. The feed conversion ratio(FCR) and hepatosomatic index(HSI) showed a increase trend, and were highest in 11.89% group. 2)The dietary lipid levels did not significantly affect the muscle moisture and ash contents. The lipid content of the muscle gradually increased as dietary lipid level increasing, and then tended to decrease, and was highest in 5.84% group. 3)With the increase of lipid levels, gonad index, egg-carrying rate and egg carrying capacity of crayfish broodstock were increased at first and then decreased; all of them in 7.89% group were highest. 4)The total protein (TP) content of haemolymph trended to decrease as dietary lipid level increasing. Alanine aminotransferase(ALT) activity and aspartate aminotransferase(AST) activity in haemolymph significantly increased as dietary lipid level increasing, both of them in 11.89% group was highest. The dietary lipid level did not significantly affect the glucose content of haemolymph. 5)The dietary lipid level significantly affected the activities of hepatopancreas protease and lipase, but not amylase activities. Broken-line regression analysis using WGR as response criteria shows that the optimal requirement of dietary lipid for red swamp crayfish broodstock is 7.60%. The comprehensive analysis of growth performance, muscle composition, reproductive performance, activities of digestive enzyme in liver, and hemolymph biochemical indexes showed that appropriate lipid level for red swamp crayfish broodstock was 7.60%~7.89% under this trial condition.