Probiotics and herbals are highly recommended in aquaculture; however, little is known about their combined effects. Therefore, the present study evaluated the possible synergistic impacts of Spirulina platensis (SP) and Bacillus amyloliquefaciens (BA) on the growth performance, histomorphology, and immune response of Nile tilapia (Oreochromis niloticus). A control and three test diets were enriched with SP, BA, or both SP and BA and fed for tilapia for 60 days. The obtained results displayed higher final body weight, weight gain, and specific growth rate in fish fed SP or/and BA with respect to the control with the highest being in fish fed both SP and BA (P < 0.05). The feed conversion ratio was lower in fish fed SP or/and BA with the lowest being in fish fed both SP and BA (P < 0.05). In the three intestinal segments, the mucosal length, villi length, and number of goblet cells were increased by dietary SP or/and BA (P < 0.05). The histological structure of the intestinal villi revealed increased length and regular structure which confirm that the tilapia intestine is out of inflammation. The biochemical variables displayed non-significant differences among the groups with normal values. The blood total protein and immunoglobulin M were significantly higher in fish fed BA alone or both SP and BA than fish fed the control (P < 0.05). The mRNA level of TNF-α gene was significantly increased by dietary SP or/and BA with respect to the control group while HSP70 was decreased (P < 0.05). The transcription of SOD was higher in fish fed both SP/BA than the other groups (P < 0.05). The obtained results revealed the importance of including both SP and BA in tilapia diets to enhance the growth rate, intestinal histomorphology, and health status.

强烈建议在水产养殖中使用益生菌和草药。然而，关于它们的综合效果知之甚少。因此，本研究评估了螺旋藻（SP）和解淀粉芽孢杆菌（BA）对尼罗罗非鱼（Oreochromis niloticus）的生长性能，组织形态和免疫应答的可能的协同作用。对照和三种测试日粮均富含SP，BA或SP和BA，并饲喂罗非鱼60天。获得的结果显示，与对照相比，SP或/和BA饲喂的鱼的最终体重，体重增加和比生长速率更高，SP和BA饲喂的鱼最高（P <0.05）。饲喂SP或/和BA的鱼的饲料转化率较低，饲喂SP和/或BA的鱼的饲料转化率最低（P  <0.05）。在三个肠段中，饮食SP或/和BA可增加粘膜长度，绒毛长度和杯状细胞数量（P  <0.05）。肠绒毛的组织学结构显示其长度增加且结构规则，这证实罗非鱼肠没有发炎。生化变量显示正常值各组间无显着差异。单独饲喂BA或同时饲喂SP和BA的鱼的血液总蛋白和免疫球蛋白M均显着高于对照饲喂的鱼（P  <0.05）。TNF-α的mRNA水平饮食SP或BA和BA与对照组相比，HSP70基因显着增加，而HSP70降低（P  <0.05）。饲喂SP / BA的鱼中SOD的转录均高于其他组（P  <0.05）。获得的结果表明，在罗非鱼日粮中同时添加SP和BA对于提高生长速度，肠道组织形态和健康状况至关重要。