饲料蛋白质水平对红螯螯虾生长、消化酶和抗氧化系统的影响

为了探讨饲料不同蛋白质水平对红螯螯虾(Cherax quadricarinatus)生长及生理生化的影响,按照等能量不等蛋白的原则,配置蛋白质水平分别为20%、24%、28%、32%、36%、40%的6组饲料投喂初始体重为(0.35±0.07)g的红螯螯虾幼虾60 d,然后测定各相关指标。存活率随着饲料蛋白质水平的增加逐渐升高(P<0.05)。当饲料蛋白质水平为28%时,特定生长率、肥满度最高,饲料系数最低。饲料不同蛋白质水平对红螯螯虾胃中的蛋白酶活性影响显著(P<0.05),胃蛋白酶活力先升高后下降,32%组活性最大。肝胰腺中的淀粉酶、谷草转氨酶(GOT)、过氧化物歧化酶(SOD)活性变化不显著(P>0.05)。谷丙转氨酶(GPT)活性随着蛋白质水平的增加逐渐升高(P<0.05)。过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPX)活性先升高后降低,腮Na+-K+ATP酶则相反(P<0.05)。36%组和40%组的丙二醛(MDA)含量最高,其次为20%组,均显著高于其他各组(P<0.05)。结果表明红螯螯虾对饲料蛋白质含量的要求较低,28%即可满足其要求。豆粕含量过高可能会影响其生长。

Effects of dietary protein level on growth,activities of digestive enzyme and antioxidant system of Cherax quadricarinatus

To study the effects of different dietary protein levels on the growth,physiology and biochemistry of Cherax quadricarinatus,the diets were formulated the same energy but containing six levels of protein level(20%,24%,28%,32%,36%,and 40%) to feed juvenile C.quadricarinatus(0.35±0.07 g).After 60 days of feeding,the survival rate increased with the increase of dietary protein levels(P<0.05).Those fed the diet containing 28% protein level showed the highest specific growth rate(SGR),condition factor(CF) and the lowest feed conversion ratio(FCR)(P<0.05).Activities of pepsin in stomach of juvenile C.quadricarinatus were significantly affected by dietary protein level(P<0.05).As dietary protein level increased,pepsin activity rose first and had the highest value in the 32% group.Activities of amylase,GOT and SOD in hepatopancreas remained unchanged in all groups(P>0.05).GPT rose as dietary protein level increased(P<0.05).CAT and GSH-Px first increased and then decreased,while Na+-K+ ATP in gill reversed.36% and 40% protein levels had the highest MDA,followed by 20% level,and all of the above 3 levels had significant higher MDA levels than the other groups(P<0.05).The results showed that 28% dietary protein level would be sufficient for juvenile C.quadricarinatus in culture.A high level of soybean meal in diet might have a negative effect on the growth and immunity of juvenile C.quadricarinatus.