摘要:
以体质量为（0.163±0.07） g的凡纳滨对虾为研究对象,在饲料中分别添加0.2%,0.5%和1.0%微生物抗菌肽S200,养殖12周以后,分别进行白斑综合症病毒、哈维氏弧菌和副溶血弧菌攻毒,研究饲料中添加微生物抗菌肽S200对凡纳滨对虾攻毒实验结果和免疫指标的影响。结果表明,饲料中添加0. 2%和0. 5%微生物抗菌肽S200可以显著提高凡纳滨对虾攻毒后的存活率和溶菌酶、超氧化物岐化酶活性,当添加量为0. 2%时,凡纳滨对虾感染副溶血弧菌的累计死亡率最低,为10.0%。当添加量为0.5%时,凡纳滨对虾感染哈维氏弧菌和白斑综合症病毒的累计死亡率最低,分别为13.0%和20.0%,感染副溶血弧菌的累计死亡率为40. 0%,溶菌酶和超氧化物岐化酶活性分别为44.35和60.8 U·mg-1prot,比对照组显著提高（P <0. 05）。当添加量为1. 0%时,凡纳滨对虾感染白斑综合症病毒、哈维氏弧菌、副溶血弧菌的累计死亡率分别为53. 33%,20. 0%和40. 0%,溶菌酶和超氧化物岐化酶活性分别为9.8和50.17 U·mg-1prot,与添加量为0. 5%相比,除了感染副溶血弧菌的累计死亡率相同（都是40. 0%）外,其他各项数据都低,说明过高剂量的微生物抗菌肽S200对凡纳滨对虾对病毒的抵抗力有一定的负面影响,与对照组相比,溶菌酶活性无显著性差异（P> 0. 05）,感染副溶血弧菌和白斑综合症病毒的累计死亡率较对照组显著提高（P <0. 05）。结果表明,在饲料中添加适量的微生物抗菌肽S200可以提高凡纳滨对虾感染细菌和白斑综合症病毒后的成活率和超氧化物岐化酶、溶菌酶的活性,提高凡纳滨对虾的免疫力,有助于凡纳滨对虾养殖成功。
Abstract:
Litopenaeus vannamei weighing（ 0. 163 ± 0. 07） g were cultured with feed added with 0. 2%,0. 5% and 1. 0% of microbial antimicrobial peptide S200（ AMP S200）. After 12 weeks,the L. vannamei were inoculated with white spot syndrome virus（ WSSRV）,Vibrio harveyi and Vibrio parahaemolyticus,respectively and cultured for 16 weeks. The results showed that the addition of 0. 2% and 0. 5% of the AMP S200 in the feed significantly increased the survival rate and the activity of lysozyme and superoxide dismutase of L. vannamei challenged. When the AMP S200 was added at a rate of 0. 2% into the feed,the cumulative mortality rate of L.vannamei challenged with V. parahaemolyticus was 10. 0%,the lowest. When the feed was added with AMP S200 at a rate of 0. 5%,the L. vannamei showed cumulative mortality rates of 13. 0% and 20. 0%,respectively when challenged with V. harveyi and WSSV,and 40. 0% when challenged with V. parahaemolyticus. The activities of lysozyme and superoxide dismutase were 44. 35 U · mg-1 prot and 60. 8 U · mg-1 prot,respectively,which were significantly higher than those of the control group（ P ＜ 0. 05）. When the feed was added with AMP S200 at a rate of 1. 0%,the cumulative mortality rates of L. vannamei challenged with WSSV,V. harveyi,and V. parahaemolyticus were 53. 33%,20. 0% and 40. 0%,respectively. The activities of lysozyme and superoxide dismutase were 9. 8 U·mg-1 prot and 50. 17 U·mg-1 prot,respectively. Compared with the group treated with the feed added with AMP S200 at a rate of 0. 5%,all the figures were low in the group treated with the AMP S200 at a rate of 1. 0% except for the cumulative mortality rate of L. vannamei challenged with V. parahaemolyticus（ 40. 0%）. The higher rate of AMP S200 showed a certain negative effect on the virus resistance of L.vannamei. Compared with the control groups,the L. vannamei treated with AMP S200 at a higher ratewas not significantly different in lysozyme activity（ P ＞ 0. 05）. The cumulative mortality rates of L. vannamei challenged with V. parahaemolyticus and WSSV were significantly higher than those of the control groups（ P ＜ 0. 05）. These results showed that adding of an appropriate amount of AMP S200 in feed can increase the survival rate and the activities of superoxide dismutase and lysozyme of L. vannamei challenged with WSSV,V. harveyi,and V. parahaemolyticus,and improve the immunity of L. vannamei,contributing to the success of L. vannamei culture.
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