The aim of the present study was to investigate the influence of dietary supplementation with Bacillus subtilis C-3102 on the productive, intestinal histomorphometry, haemato-immunological aspects, as well as evaluated the resistance of juvenile Pseudoplatystoma sp. after challenge with Aeromonas hydrophila. Inclusion levels of the commercial probiotic were set at 0 (control), 1, 2, 3 and 4% of CALSPORIN® kg feed⁻¹ with six replicates. Blood samples were collected on day 0, 10 and 20 for hematological analysis, and on the 20th day, samples were collected for intestinal histomorphometry, zootechnical and survival analyses. The results showed that probiotic supplementation with B. subtilis significantly improved intestinal morphology in fish from groups 1% and 2% and phagocytic activity in all supplemented groups, regardless of the applied dose. In addition, on the 20th day, improvements in non-specific immunity were observed, such as an increase in the number of monocytes (groups 2, 3 and 4%), eosinophils (group 3%), leukocytes (1%) and lymphocytes (group 4%) of the fish that received the supplemented feed. It was also possible to verify that the probiotic caused significant changes in the haemogram between the sampling periods on 0, 10th and 20th day, showing activation of specialized cells of the fish’s non-specific defense mechanism. At the end of the experimental period, supplementation of B. subtilis improved the productive indexes and survival of Pseudoplatystoma sp. after bacterial challenge.

本研究的目的是调查日粮中添加枯草芽孢杆菌C-3102对生产性，肠道组织形态学，血液免疫学方面的影响，并评估青少年假单胞菌属sp的抗性。用嗜水气单胞菌攻击后。商业益生菌的包容水平设置为0（对照），1、2、3和4％的CALSPORIN®kg饲料^-1，一式六份。在第0、10和20天收集血液样本进行血液学分析，并在第20天收集样本用于肠道组织形态测定，动物技术和存活率分析。结果表明，益生菌补充枯草芽孢杆菌不论施用何种剂量，所有添加组的1％和2％组的鱼的肠道形态和吞噬活性均显着改善。此外，在第20天，观察到非特异性免疫的改善，例如单核细胞（第2、3和4％组），嗜酸性粒细胞（第3％组），白细胞（1％）和淋巴细胞数量增加（第4％组）接受补充饲料的鱼。还可以验证益生菌在第0、10和20天的采样周期之间引起的血红蛋白显着变化，表明该鱼的非特异性防御​​机制的特化细胞被激活。在实验期结束时，补充枯草芽孢杆菌可提高生产效率并提高假铂菌瘤的存活率sp。细菌攻击后。