饲料蛋白质水平和加工工艺对克氏原螯虾生长性能、消化力和抗氧化性能的影响

Effects of Dietary Protein Levels and Processing Techniques on the Growth Performance,Digestibility,and Antioxidant Capacity of Red Swamp Crayfish(Procambarus clarkii)

为研究不同蛋白质水平和加工工艺饲料对克氏原螯虾(Procambarus clarkii)生长性能、消化力和抗氧化能力的影响,本研究采用4个蛋白质水平(28%、30%、32%和36%)和2种加工工艺即膨化饲料(EF)和硬颗粒饲料(PF)的4×2双因素实验设计,进行为期13周的养殖实验。结果显示,蛋白质水平和加工工艺对克氏原螯虾增重率和肝体比有显著的交互作用(P<0.05)。主效应结果显示,28%蛋白质可显著提高增重率和特定生长率,EF组的末重和增重率显著高于PF组(P<0.05)。蛋白质水平和加工工艺对肝胰脏的胰蛋白酶和淀粉酶活性有交互作用(P<0.05)。主效应结果显示,肝胰脏的胰蛋白酶、淀粉酶和肠道胰蛋白酶、淀粉酶均在28%蛋白质水平时最高,EF组肝胰脏胰蛋白酶、淀粉酶和肠道胰蛋白酶活力高于PF组(P<0.05)。蛋白质水平和加工工艺对肝胰脏的丙二醛和碱性磷酸酶活性有显著的交互作用(P<0.05)。主效应结果显示,肝胰脏碱性磷酸酶活性以及血清的碱性磷酸酶和酸性磷酸酶均在28%蛋白质水平时最低。PF组肝胰脏丙二醛含量显著低于EF组(P<0.05),碱性磷酸酶活性显著低于EF组(P<0.05)。4种模型(Logistic、Gompertz、Von Bertalanffy和Brody)均能很好地模拟克氏原螯虾体重和体长的生长曲线,拟合度均大于0.97,其中,以Logistic模型拟合克氏原螯虾体重和体长最优,且幂函数可以反映体重和体长之间的关系。综上所述,28%蛋白质水平和膨化加工工艺使克氏原螯虾具有最优的生长性能和消化力,28%蛋白质水平的硬颗粒饲料可提高克氏原螯虾的抗氧化能力。

The red swamp crayfish(Procambarus clarkii)is the largest freshwater shrimp cultured in China.Protein is a critical factor affecting red swamp crayfish growth performance and feed cost.Too high or too low protein levels in feed negatively affect crustaceans.However,the results of the optimal dietary protein content of red swamp crayfish identified in different studies vary considerably.There are mainly two types of feed for red swamp crayfish on the market:extruded and pellet feed.There have been few reports on the impact of processing technique on red swamp crayfish.Many studies have shown that the growth-promoting effects of extruded and pellet feed on diverse aquatic animals differ considerably.Moreover,there have been few studies on the impact of different protein levels and processing techniques on the growth of aquatic species.This study aimed to investigate the effects of dietary protein levels and processing techniques on the growth performance,digestibility,and antioxidant capacity of red swamp crayfish.The two-factor experiment(4×2)with four different protein levels(28%,30%,32%,and 36%)and two processing techniques(expanded feed[EF]and pellet feed[PF])was conducted for 13 weeks as a feeding trial,aiming to provide theoretical support for optimizing the feed formula and processing technique of red swamp crayfish.The results showed that the protein levels and processing technique significantly influenced the weight gain rate(WGR)and hepatosomatic index of red swamp crayfish(P<0.05).The main effects showed that 28%protein could significantly increase the WGR of red swamp crayfish.The WGR and SGR(specific growth rate)of the EF group were significantly higher than those of the PF group(P<0.05).There was an interaction between the protein level and processing technique and the trypsin and amylase activities in the hepatopancreas of the red swamp crayfish(P<0.05).The activities of trypsin and amylase in the hepatopancreas and intestine were highest,with 28%of dietary protein.Trypsin and amylase activities in the hepatopancreas and trypsin activity in the intestine of red swamp crayfish from the EF group were higher than those from the PF group(P<0.05).The impact of dietary protein levels and processing technique on the malondialdehyde(MDA)content and alkaline phosphatase(AKP)activity in the hepatopancreas of the red swamp crayfish was observed(P<0.05).The results revealed that AKP activities in the hepatopancreas,and AKP and acid phosphatase activities in the serum were significantly lower at 28%dietary protein(P<0.05).The MDA content in the hepatopancreas of the PF group was significantly lower than that in the EF group,respectively(P<0.05).The AKP activity in the hepatopancreas of the PF group was significantly lower than that of the EF group(P<0.05).Logistic,Gompertz,von Bertalanffy,and Brody models could be suitable for fitting the growth curves of body weight and body length of red swamp crayfish with a R2 value of no less than 0.97.The Logistic model was the most suitable for fitting the body weight and length,and the power function could reflect the relationship between the body weight and length.Overall,a dietary protein level of 28%and expanded processing could optimize the growth performance and digestibility of red swamp crayfish,and supplementation with a 28%dietary protein level and pellet processing could improve their antioxidative ability.