The practice of adding probiotics in shrimp diet has increased significantly because of its beneficial effects on growth performance and disease resistance. However, little attention has been paid to marine-derived probiotics, which might be more suitable for aquatic animals. In the present study, an 8-week feeding trial was carried out to explore the effects of Shewanella sp. MR-7 in shrimp diet. Three concentrations of Shewanella sp. MR-7 (SS-MR-7, 10⁶ colony forming units (CFU)/g diet, F1; 10⁷ CFU/g diet, F2; 10⁸ CFU/g diet, F3) were added to the basal diet (F0) of Pacific white shrimp. At the end of the trial, an acute ammonia stress test was performed. The results showed that supplementation with 10⁷ CFU SS-MR-7 per g diet significantly improved shrimp weight gained and specific growth rate. A significantly higher shrimp survival rate was also observed in the F2 group after acute ammonia stress. Meanwhile, dietary SS-MR-7 induced the hepatopancreatic mRNA expression of antioxidation-related genes encoding heat shock protein 70, thioredoxin 1, and glutathione peroxidase, as well as immunity-related genes, such as those encoding lipopolysaccharide and beta-1,3-glucan-binding protein, prophenoloxidase activating factor, and prophenoloxidase. Furthermore, the intestinal microbiota was responsive to the diets. The abundance of the beneficial bacteria Pseudomonas was enriched, while the contents of potential pathogens (such as Bacteroides and Escherichia-shigella) decreased. Overall, our results indicate that SS-MR-7 could be an effective probiotic in shrimp culture as it increase growth performance, immunity and the abundance of intestinal beneficial bacterial.

在虾饲料中添加益生菌的做法由于其对生长性能和抗病性的有益作用而显着增加。但是，很少关注海洋来源的益生菌，它可能更适合水生动物。在本研究中，进行了为期8周的喂养试验，以探讨希瓦氏菌的影响。虾饮食中的MR-7。三种浓度的希瓦氏菌。将MR-7（SS-MR-7，10 ⁶菌落形成单位（CFU）/ g饮食，F1; 10 ⁷ CFU / g饮食，F2; 10 ⁸ CFU / g饮食，F3）添加到基础饮食（F0 ）太平洋白虾。在试验结束时，进行了急性氨压力测试。结果表明，补充10每克日粮添加⁷ CFU SS-MR-7，可显着提高虾的增重和特定生长率。急性氨胁迫后，F2组的虾成活率也显着提高。同时，膳食SS-MR-7诱导了抗氧化相关基因的编码热休克蛋白70，硫氧还蛋白1和谷胱甘肽过氧化物酶的肝胰腺mRNA表达，以及免疫相关基因，例如编码脂多糖和β-1,3的基因。 -葡聚糖结合蛋白，酚氧化酶原激活因子和酚氧化酶原。此外，肠道菌群对饮食有反应。丰富的有益细菌假单胞菌丰富了，而潜在病原体（如拟杆菌和大肠杆菌（Escherichia-shigella）减少。总的来说，我们的结果表明SS-MR-7在虾类养殖中可能是有效的益生菌，因为它可以提高生长性能，免疫力和肠道有益细菌的含量。