饲料中非蛋白能源物质对红螯光壳螯虾幼虾生长、生理、生化指标的影响

在等蛋白质、等能量基础上,研究碳水化合物与脂类比例(CHO∶L)为10.75∶1、4.81∶1、2.66∶1、1.52∶1和0.87∶1的5组试验饲料对红螯光壳螯虾初始体质量(1.72±0.01)g]相关生长、生理、生化指标的影响。8周试验结果表明,CHO∶L比例为2.66∶1时,红螯光壳螯虾的增重率、特定生长率和饲料利用率达到最高。高比例的CHO∶L(10.75∶1)和低比例的CHO∶L(0.87∶1)都会显著地抑制(P<0.05)红螯光壳螯虾的生长和饲料的利用。饲料脂肪水平为40～145 g/kg时,虾的脂肪酶和碱性磷酸酶活力显著升高(P<0.05),己糖激酶和丙酮酸激酶活力则呈显著降低趋势(P<0.05)。CHO∶L对虾胃蛋白酶活力影响显著(P<0.01),CHO∶L为2.66∶1和1.52∶1表现出比较高的活力,显著高于(P<0.05)其它试验组。碳水化合物为156.3～360.4 g/kg范围内,虾淀粉酶活力随饲料中碳水化合物的升高而显著升高(P<0.01)。红螯光壳螯虾增重率分别与饲料中碳水化合物和脂肪水平进行二次回归分析得出,红螯光壳螯虾对配合饲料中碳水化合物和脂肪的最适需求量分别为268.28和120.22 g/kg,相对应的CHO∶L为2.20∶1,且红螯光壳螯虾对碳水化合物的利用能力要高于对脂肪的利用。

Dietary non-protein energy sources:growth,physiology and biochemisty by the juvenile Australian redclaw crayfish,Cherax quadricarinatus(Von Martens)

A growth experiment was conducted to determine the optimal carbohydrate-to-lipid(CHO∶ L)ratio for juvenile Australian redclaw crayfishinitial weight(1.72±0.01) g(mean±SD)]cultured in indoor recirculating aquaculture system.Five isonitrogenous(31.130±0.004) g/kg]and around isoenergetic(17.490±0.396) MJ/kg]diets with dietary CHO∶ L ratios are 10.75∶ 1,4.81∶ 1,2.66∶ 1,1.52∶ 1 and 0.87∶ 1,were fed twice a day to apparent satiation.Over 8-week growth trial,the best final weight,weight gain,specific growth rate and feed conversion ratio value(P<0.05)were observed in redclaw crayfish fed diets with a CHO∶ L ratio of 2.66∶ 1.Redclaw crayfish fed either the lowest(0.87∶ 1)or highest(10.75∶ 1)CHO∶ L ratio tended to produce lower growth and poorer feed conversion ratio.Dietary lipid levels was 40-145 g/kg,the lipase and alkaline phosphatase activities were stimulated by elevated levels of dietary lipid.However,the activities of hexokinase and pyruvate kinase showed opposite trend.The pepsin and intestine amylase activities were significantly(P<0.01)affected by CHO∶ L ratios.The higher activity of pepsin were observed when the CHO∶ L were 2.66∶ 1 and 1.52∶ 1(P<0.05).The intestine amylase activity was significantly increased(P<0.01)as dietary CHO levels(156.3-360.4 g/kg)increased.Based on a second-order polynomial regression analysis of WG against dietary carbohydrate and lipid levels,growth maximum was observed when the dietary carbohydrate and lipid levels were 268.82 g/kg and 122.20 g/kg,corresponding to a CHO∶ L ratio of 2.20∶ 1.These results indicated that the utilization of dietary lipid and carbohydrate was moderate in redclaw crayfish and the preferential utilization of carbohydrate was higher than that of lipid.