For investigating the possible effect of Lactobacillus casei on the immune status of Shabot, Tor grypus, 480 fish weighing 40 ± 10 g were randomly divided into four groups in triplicate. The first group (control) was fed on a commercial diet without probiotic supplementation. Other groups (A, B, and C) were received diet supplemented by different levels of L. casei, i.e., 5 × 10⁶, 5 × 10⁷, and 5 × 10⁸ CFU g⁻¹, respectively. The feeding trial was performed for 60 continuous days followed by 15 days as withdraw period, i.e., day 75. Serum immune responses were determined on days 0, 30, 60, and 75 of feeding trial. Gene expression in the kidneys was analyzed on days 0, 60, and 75 as well as following bacterial challenge. The results showed that dietary L. casei supplementation significantly (P < 0.05) increased serum lysozyme, serum bactericidal, complement, and respiratory burst activities as compared with control group, while it was observed that treated fish did not show any significant differences in immune responses on day 75 (P < 0.05). Results of gene expression (TNF-α, IL-1β, and IL-8) showed significant increases among different experimental times (P < 0.05). According to obtained results, it might be concluded that the feeding by L. casei could likely enhance the immune responses and gene expression in T. grypus. Treatments A and C were better than B, but the lower concentration is better as an economic viewpoints and biosecurity. Therefore, concentration A is suggested.

中文翻译：

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干酪乳杆菌对Tor grypus bot中先天免疫应答和嗜水气单胞菌抗性的影响。

为了研究干酪乳杆菌对Shabot，Tor grypus免疫状况的可能影响，将480只体重为40±10 g的鱼随机分为三组，每组四份。第一组（对照组）在不添加益生菌的情况下以商业饮食喂养。其它基团（A，B，和C）接收到的饮食由不同级别的补充干酪乳杆菌，即5×10 ⁶，5×10 ⁷和5×10 ⁸  CFU克^-1， 分别。连续进行60天的喂养试验，然后在停药期75天（即第75天）进行15天。在喂养试验的第0、30、60和75天确定血清免疫反应。在第0、60和75天以及细菌攻击后分析肾脏中的基因表达。结果表明， 与对照组相比，日粮中添加干酪乳杆菌可显着提高（P <0.05）血清溶菌酶，血清杀菌，补体和呼吸爆发活性，同时观察到经处理的鱼在免疫反应方面没有任何显着差异在第75天（P  <0.05）。基因表达的结果（TNF-α，IL-1β和IL-8）在不同实验时间之间显着增加（P  <0.05）。根据获得的结果，可以得出的结论是，干酪乳杆菌的喂养可能增强了T. grypus的免疫反应和基因表达。处理A和C优于B，但从经济角度和生物安全性来看，较低的浓度更好。因此，建议使用浓度A。