饲料中添加抗菌肽和枯草芽孢杆菌对花鲈生长和非特异性免疫功能的影响

Effects of dietary antimicrobial peptide and Bacillus subtilis on growth performance and non-specific immunity of Lateolabrax japonicus

在基础饲料中分别添加300 mg/kg的抗菌肽和200 mg/kg的枯草芽孢杆菌(Bacillus subtilis),连续投喂花鲈(Lateolabrax japonicus)60 d,测定其特定生长率、存活率,并分别于试验的20 d、40 d和60 d测定肝胰脏、头肾、鳃的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)以及血清溶菌酶(LSZ)和一氧化氮合酶(NOS)活力水平。结果显示:试验组花鲈的特定生长率和存活率与对照组间均无显著差异(P>0.05)。抗菌肽组所测组织CAT、SOD以及血清LSZ、NOS活性水平在20 d时均显著高于对照组(P<0.05),40 d时以上指标(头肾SOD除外)与对照组间差异不显著(P>0.05)。枯草芽孢杆菌组所测组织CAT、SOD以及血清LSZ活性水平在20 d时均显著高于对照组(P<0.05),60 d时以上指标(头肾SOD除外)与对照组间差异不显著(P>0.05),而整个过程血清NOS活性水平与对照组不存在显著性差异(P>0.05)。结果表明:两种添加剂可增强机体消除活性氧自由基的能力,提高机体血清溶菌酶活性水平。此外,抗菌肽对花鲈血清一氧化氮合酶系统具有诱导调节作用。

The diets contained the common product dose of antimicrobial peptide （300 mg/kg） and Bacillus subtilis （200 mg/kg） was used to feed the Lateolabraxjaponicus continuously for 60 days. At the end of breeding cycle , the spe- cific growth rate （SGR） and survival of Lateolabraxjaponicus were determined. The activity of catalase （CAT）, superoxide dismutase （SOD） for hepatopancreas, head kidney and gills and lysozyme enzyme （LSZ） and nitric oxide synthase （NOS） for serum were investigated on the 20, 40 and 60 day, respectively. The results showed that compared with control group, the SGR and survival of experimental groups were not significantly different （P 〉 0. 05）. CAT, SOD for measured tissue and serum LSZ, NOS activities levels of peptide group were significantly higher than the control group on the 20 day （P 〈 0. 05）, and these were not significantly different to the control group on the 40 day except the SOD activity level of head kidney （P 〉 0. 05 ）. CAT, SOD for measured tissue and serum I_SZ activities level of B. subtilis group were signifi- cantly higher than the control group on the 20 day （ P 〈 0. 05 ）, and these were not significantly different to the control group on the 60 day except the SOD activity level of head kidney （ P 〉 0. 05 ）, but serum NOS level have no significant difference with the control group throughout the breeding cycle （P 〉 0. 05 ）. All of these showed that these two additives can enhance the body ability to eliminate active oxygen free radicals in the initial period, while improving the activity level of serum lysozyme. In addition, antimicrobial peptides can induce the activation of nitric oxide synthase system forL. japonicus.