壳聚糖对克氏原螯虾生长、血清相关免疫因子、肌肉成分和消化酶的影响

以体质量为(21.55±1.62)g的克氏原螯虾Procambarus clarkii为研究对象,投喂壳聚糖添加量分别为0(对照)、0.5%、1.0%、1.5%、2.0%、3.0%的饲料,研究壳聚糖对克氏原螯虾生长、血清相关免疫因子、肌肉成分和消化酶活性的影响。试验共进行60 d。结果表明:1.0%壳聚糖添加组试验虾的特定生长率显著高于其他各组(P<0.05),1.5%壳聚糖添加组试验虾的死亡率和蜕壳死亡率均最高,且显著高于对照组(P<0.05);1.0%和2.0%壳聚糖添加组试验虾血清中的酚氧化酶(PO)活性显著高于对照组(P<0.05),各添加组血清中碱性磷酸酶(ALP)活性均显著高于对照组(P<0.05);除1.0%、2.0%壳聚糖添加组外,其他添加组血清中谷丙转氨酶(ALT)活性均低于对照组;各添加组血清中谷草转氨酶(AST)的活性均显著低于对照组(P<0.05);除2.0%壳聚糖添加组外,其他添加组试验虾肌肉粗蛋白质含量较对照组均低;除2.0%壳聚糖添加组外,其他添加组粗脂肪含量较对照组均高,其中1.0%、1.5%和3.0%添加组显著高于对照组(P<0.05);仅1.0%添加组肌肉灰分显著低于对照组(P<0.05);仅2.0%添加组肌肉水分含量显著高于对照组(P<0.05);1.0%添加组试验虾肝胰腺中胰蛋白酶和脂肪酶活性以及肠道中的脂肪酶活性显著高于对照组(P<0.05);1.5%添加组试验虾肝胰腺和肠道中的淀粉酶活性均显著高于对照组(P<0.05)。研究表明,在本试验条件下,建议成虾饲料中壳聚糖的添加量为0.5%～1.5%,壳聚糖对克氏原螯虾起到一定的免疫保护作用,并能增强其消化生理机能。

Effects of dietary chitosan supplementation on growth, non-specific immune factors, muscle compositions and activities of digestive enzymes in red swamp crayfish Procambarus clarkii

Red swamp crayfish Procambarus clarkii with initial body weight of （21.55±1.62） g were fed the diets containing 0% （control group） ,0.5% , 1.0%, 1.5% , 2.0%, and 3.0% chitosan at water temperature of （22± 1 ） ℃ for 60 days to investigate the effects of dietary chitosan supplementation on growth, non-specific immune fac- tors, muscle compositions, and activity of digestive enzymes in the red swamp crayfish. Results showed that there was significantly higher specific growth rate in the crayfish in I. 0% chitosan group than that in the other groups （ P〈0.05 ）. The mortality rate and molting mortality rate were found to be significantly higher in the crayfish in 1.5% chitosan group than those in the control one （ P〈0.05 ）. The crayfish fed the diets containing 1.0% and 2.0% chitosan had significantly higher phenoloxidase activity than the crayfish in the control group did （ P〈0.05 ）. There were significantly higher alkaline phosphatase （ALP） activity in the chitosan addition groups than those in the control group （P 〈 0.05 ）. The chitosan addition led to significantly lower glutamic- pyruvic transaminase （ALT）, except in 1.0% and 2.0% chitosan groups. The significantly lower glutamie-oxalaeetie transaminease （AST） activities were observed in chitosan addition groups （P〈0.05）, except 2.0% chitosan addition group. Muscle composition analysis indicated that there was lower crude protein level in the chitosan addition groups than that in the control group, while there was significantly higher crude fat level in the 1.0% ,1.5% ,and 3.0% groups than that in the control one （ P〈0.05 ）, except in 2.0% chitosan group. The crayfish fed the diet containing 1.0% chitosan showed significantly lower ash content in muscle than the crayfish in the control group did. There was sig- nificantly higher moisture in 2.0% chitosan group than that in the control group （ P〈0.05 ）. The significantly high- er activities of trypsase and lipase in hepatopancreas and trypsin in intestinal tract were found in the 1.0% ehitosan group （ P〈0.05 ） compared with the control group. The crayfish fed the diet 1.5% chitosan had significantly higher amylase activities in hepatopancreas and intestine than the animals fed the control diet did （P〈0.05）. In conclu- sion, it is suggested that chitosan addition of 0.5%-1.5% improve the immune protection and promote digestive function in red swamp crayfish.