School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom.
Fish Shellfish Immunol. 2012 Jun;32(6):1051-7. doi: 10.1016/j.fsi.2012.02.028. Epub 2012 Mar 2.
The objective of the present study was to determine the action of β-glucans as feed additives on the gene expression profile of some inflammatory-related cytokines from common carp (Cyprinus carpio L.) during the early stages of a non-lethal bacterial infection with Aeromonas salmonicida. β-glucan (MacroGard(®)), was administered daily to carp (6 mg per kg body weight) in the form of supplemented commercial food pellets for 14 days prior to infection. Control and treated fish were then intraperitoneally injected with PBS or 4×10(8) bacteria per fish and were sampled at time 0 and 6h, 12h, 1 day, 3 days and 5 days post-injection. Head kidney and gut were collected and the gene expression patterns for tnfα1, tnfα2, il1β, il6 and il10 were analyzed by quantitative PCR. Results obtained showed that treatment with β-glucans generally down-regulated the expression of all measured genes when compared to their corresponding controls. After injection, highest changes in the gene expression levels were obtained at 6h; particularly, in head kidney there was higher up-regulation of tnfa1 and tnfa2 in infected fish fed β-glucans in comparison to control feed; however, in gut there was a significant down-regulation of tnfα1, tnfα2, il1β and il6 in infected fish fed β-glucans. Analysis of carp specific antibodies against A. salmonicida 30 days after injection revealed their levels were reduced in the infected β-glucan group. In conclusion, a diet supplemented with β-glucan (MacroGard(®)) reduced the gene expression levels of some inflammation-related cytokines in common carp. Such a response appears to be dependent of organ studied and therefore the immunostimulant may be preventing an acute and potential dangerous response in gut, whilst enhancing the inflammatory response in head kidney when exposed to A. salmonicida.
本研究的目的是确定 β-葡聚糖作为饲料添加剂对鲤鱼（Cyprinus carpio L.）在遭受非致死性嗜水气单胞菌感染早期阶段某些炎症相关细胞因子基因表达谱的作用。β-葡聚糖（MacroGard®）以补充商业饲料丸的形式每天给鲤鱼（每公斤体重 6 毫克）投喂 14 天，然后在感染前给对照组和处理组鲤鱼进行腹腔注射 PBS 或每鱼 4×10(8)个细菌，并在注射后 0、6h、12h、1 天、3 天和 5 天时间点取样。采集头肾和肠道，并用定量 PCR 分析 tnfα1、tnfα2、il1β、il6 和 il10 的基因表达模式。结果表明，与对照组相比，β-葡聚糖处理通常会下调所有测量基因的表达。注射后，基因表达水平的最高变化发生在 6h；特别是在头肾中，与对照饲料相比，喂食 β-葡聚糖的感染鱼中的 tnfa1 和 tnfa2 上调更高；然而，在肠道中，喂食 β-葡聚糖的感染鱼中的 tnfα1、tnfα2、il1β 和 il6 显著下调。注射 30 天后分析鲤鱼针对嗜水气单胞菌的特异性抗体发现，感染 β-葡聚糖组的抗体水平降低。总之，饮食补充 β-葡聚糖（MacroGard®）可降低鲤鱼某些炎症相关细胞因子的基因表达水平。这种反应似乎取决于所研究的器官，因此免疫刺激剂可能在肠道中阻止了潜在的危险的急性反应，同时在头肾中增强了对嗜水气单胞菌的炎症反应。
