龙须菜对翘嘴红鲌生长、消化和血液生化指标的影响

The effects of Gracilaria lemaneiformis in diets on the growth performance,digestion and blood biochemical parameters of the Erythroculter ilishaeformis,juvenile

为评估龙须菜藻粉作为饲料原料替代翘嘴红鲌饲料中鱼粉的可行性,及非淀粉多糖酶对摄食龙须菜饲料的翘嘴红鲌的影响,本研究以不含龙须菜的基础饲料为对照组,以质量分数为2.5%(D1),5%(D2),7.5%(D3),10%(D4)的龙须菜分别替代鱼粉及10%龙须菜饲料中添加0.2%非淀粉多糖酶(D5)为试验组。试验选取规格一致的翘嘴红鲌幼鱼[初重(13.2±0.2)g],每组3个重复,每个重复30尾幼鱼,试验持续8周。结果表明:(1)生长和消化方面,与对照组相比,D3组增重率和脏体比分别下降13.07%和11.19%(P<0.05),D4组增重率、脏体比、全鱼粗脂肪含量、干物质和粗脂肪表观消化率分别下降14.07%、11.72%、10.4%、4.01%和3.79%(P<0.05)。D3组和D4组翘嘴红鲌前肠脂肪酶活性分别下降19.18%和19.88%(P<0.05),D4组前肠碱性磷酸酶活性下降29.03%(P<0.05)。(2)血液生化指标方面,D1组翘嘴红鲌血清总蛋白含量上升15.18%(P<0.05),D2、D3和D4组血清甘油三酯含量分别下降20.79%、19.37%和27.06%(P<0.05)。D3组和D4组血清胆固醇含量分别下降24.11%和33.69%(P<0.05)。(3)D5组与D4组相比,摄食率和存活率分别提高9.85%和7.31%(P<0.05),饲料干物质表观消化率和前肠碱性磷酸酶活性分别提高4.19%和29.54%(P<0.05)。综上所述,龙须菜替代比例不超过5%对翘嘴红鲌生长性能无负面影响,替代比例超过7.5%会抑制翘嘴红鲌前肠消化相关酶的活性,影响鱼体脂肪代谢和生长性能。在饲料中添加0.2%非淀粉多糖酶,可使饲料中龙须菜的添加量达10%而不影响翘嘴红鲌的生长性能。

In order to evaluate the feasibility of using the Gracilaria lemaneiformis(GL) in instead of the fish meal as the feed ingredient for the Erythroculter ilishaeformis,and the effect of non starch polysaccharide(NSP) enzyme on Erythroculter ilishaeformis fed with GL based diet. The diet with out GL served as a control group,the GL-based diets which formulated to contain 2.5%(D1),5%(D2),7.5%(D3),10%(D4) GL by substituting fish meal and 10% GL feed contained 0.2% NSP enzyme(D5) were fed to Erythroculter ilishaeformis withs imilar size [initial weight(13.2 ±0.2)g]. The experiments were divided 6 groups and 3 repeats for each group,each group had 30 tail of test fish. The experiment lasted for 8 weeks. The results showed that:(1) In terms of growth and digestion,compare to the control group,the weight gain rate and visceral body ratio of D3 group decreased by 13.07% and 11.19%(P<0.05),while the weight gain rate,visceral body ratio,crude fat content of whole fish,apparent digestibility of dry matter and crude fat of D4 group decreased by 14.07%,11.72%,10.4%,4.01% and 3.79%(P<0.05),respectively. The activities of lipase in the anterior intestine of D3 and D4 groups decreased by 19.18% and 19.88%(P<0.05)respectively,and the activity of alkaline phosphatase in the anterior intestine decreased by 29.03%(P<0.05)in D4 group.(2) In terms of blood biochemical indicators,compare to the control group,the total protein in the serum of D1 group increased by 15.18%(P<0.05),the serum triglycerides of D2,D3 and D4 group decreased by 20.79%,19.37% and 27.06%(P<0.05) respectively.The serum cholesterol of D3 group and D4 group decreased by 24.11% and 33.69%(P<0.05),respectively.(3)Compare to the D4 group,the feeding rate and survival rate of D5 group were increased by 9.85% and 7.31%(P<0.05),the apparent digestibility of feed dry matter and the activity of alkaline phosphatase in anterior intestine were increased by 4.19% and29.54%(P<0.05),respectively. In general,there was no negative effect on the growth performance of Erythroculter ilishaeformis when the substitution level of GL was less than 5%. However,if the substitution level was more than 7.5%,the digestion related enzyme activities in anterior intestine would be inhibited,the fat metabolism and the growth performance of fish would be affected.When 0.2% NSP enzyme was added to the feed,the GL substitution level in the feed could reach 10% without affecting the growth performance of the fish.