摘要
本实验采用单因子浓度梯度法,以添加不同质量分数(0.0%,0.5%,1.0%,2.5%,5.0%,10.0%)聚β-羟基丁酸酯(PHB)的人工配合饲料饲喂凡纳滨对虾(Litopenaeus vannamei)20 d后,对其进行白斑综合症病毒(WSSV)感染测试;利用实时荧光定量PCR技术分析PHB对凡纳滨对虾抵御WSSV侵染能力的影响,并选择最高免疫保护率(RPS)组进行不同时间点基因表达量分析。研究发现,PHB对感染WSSV对虾的存活率无显著影响(P>0.05);但感染WSSV的对虾平均存活时间随PHB浓度上升呈现先上升后下降再上升的趋势,饲喂PHB对虾的平均存活时间均高于对照组,其中1.0%PHB浓度组对虾平均存活时间最长,且显著高于空白对照组及5.0%PHB浓度组(P<0.05)。分析各组对虾体内病毒含量,发现1.0%PHB浓度组对虾病毒含量在实验前期显著低于对照组(P<0.05)。对虾感染WSSV后,对对照组及1.0%PHB实验组对虾前48 h内6个采样时间点的超氧化物歧化酶(sod)、过氧化氢酶(cat)、谷胱甘肽过氧化物酶(gsh-px)、溶菌酶(lzm)及抗菌肽(abp)5个基因进行表达趋势分析,结果表明基因表达趋势在两组间无显著区别;投喂PHB的对虾在感染WSSV后血淋巴中sod、cat、gsh-px和lzm表达量呈现上升后下降再上升的趋势且分别在6 h、6 h、3 h、6 h达到最大值;abp在WSSV感染3 h内急速下降,随后在12 h达到最大值后又下降;另外饲喂PHB对虾体内免疫基因表达量均高于对照组。结果说明,PHB能够提高凡纳滨对虾对WSSV的抵抗力,且在一定程度上提高了对虾的免疫力。
White spot syndrome (WSS), an epizootic disease, has been prevalent in cultured shrimp in China since 1992 and results in high mortality. The economic loss caused by white spot syndrome virus(WSSV) is extensive and has been harmful to shrimp aquaculture worldwide. Poly-β-hydroxybutyrate (PHB) is a polymer of the short-chain fatty acidβ-hydroxybutyrate. β-hydroxybutyric acid can promote food digestion, nutrient absorption, and protein and mineral utilization. This study was conducted to investigate the anti-WSSV effects of PHB on and relative expression of non-specific immune genes in WSSV-infected Litopenaeus vannamei. Litopenaeus vannamei were supplied with 0.0%(control group), 0.5%, 1.0%, 2.5%, 5.0%, or 10.0% PHB in artificial compound feed at a daily ration of 5.0% body weight. After WSSV challenge, survival rates, mean survival time, relative percent survival (RPS), and number of WSSV copies were compared. The relative expression of the genes that encode superoxide dismutase (sod), catalase (cat), glutathione peroxidase (gsh-px), lysozymes (lzm), and antibacterial peptides (abp) in L. vannamei were analyzed by quantitative real-time reverse transcription PCR. The results showed that there was no difference in survival rates among different treatments (P〉0.05);nevertheless, the mean survival time of PHB-fed shrimp was higher than that of the control group. The mean survival time of 1.0%PHB-fed shrimp was the highest, and it was significantly higher than that of the control and 5.0%PHB-fed shrimp (P〈0.05). The number of WSSV copies in the experimental individuals fed with 0.5%, 1.0%and 2.5%PHB were lower than the contral group (P〈0.05). Moreover, sod, cat, gsh-px, lzm, and abp expression levels in 1.0%PHB were higher than that in the control group. The expression level of sod, cat, gsh-px, and lzm reached the acme at 6 h, 6 h, 3 h, and 6 h, respectively. After WSSV infection, abp dropped rapidly within 3 h and then steadily decreased after reaching the acme at 12 h. In addition, the gene expression levels of PHB-fed shrimps were higher than the control group. Consequently, PHB can help improve immunity and treat WSSV infections.
出处
《中国水产科学》
CAS
CSCD
北大核心
2015年第5期877-886,共10页
Journal of Fishery Sciences of China
基金
国家自然科学基金面上项目(31372523
31172402)