To evaluate the effects of a patented Bacillus subtilis probiotic, weaned Holstein steers, not shedding Salmonella (n = 40; ∼90 kg), were supplemented (CLO) or not (CON) with CLOSTAT^® (13 g/hd per day; Kemin Industries, Des Moines, IA) in a starter ration for 35 d. The calves were assigned to one of four treatments in a 2 × 2 factorial design with CLO and CON calves that were orally administered Salmonella (STM) or not (NoSTM). Calves were challenged with 1.6 × 10⁶ colony-forming unit (CFU) Salmonella Typhimurium (resistant to 50 μg/mL nalidixic acid) in 1 L of milk replacer on day 0. Blood samples were collected through jugular catheters every 6 h for 96 h, and body temperature was measured every 5 min through indwelling rectal temperature recording devices. Five calves from each treatment were harvested 48 h postchallenge, and the remaining calves were harvested 96 h postchallenge. During necropsy, tissues were collected for the isolation and quantification of the inoculated STM from various tissues. The CLOSTM group had reduced STM concentrations in the jejunum, ileum, and transverse colon 48 h after the challenge (p ≤ 0.03), but were not different 96 h postchallenge (p > 0.05). Decreased (p < 0.01) pyrexia was observed after the challenge in CLOSTM calves when compared with CONSTM calves. White blood cells and lymphocyte counts were increased (p ≤ 0.05) in CLOSTM calves after the challenge in comparison with other treatments. In calves given STM, the CLO group had greater feed intake before and after the challenge (p < 0.01) compared with the CON group. Increased serum IL-6 and IFN-γ concentrations were observed in the CONSTM group compared with other treatments. Overall, CLO reduced Salmonella presence and concentrations in gastrointestinal tissues while simultaneously reducing the severity of the challenge as indicated by blood parameters and the reduced febrile response.

中文翻译：

---

在实验性沙门氏菌挑战期间，断奶荷斯坦牛中的枯草芽孢杆菌 PB6 补充剂。

为了评估专利的影响枯草芽孢杆菌的益生菌，断奶荷斯坦公牛，不脱落沙门氏菌（Ñ  = 40;〜90千克），分别添加（CLO）否（CON）与CLOSTAT ^®（13克/ HD每天;克敏工业，得梅因，爱荷华州）在 35 天的开胃菜中。小牛被分配到 2 × 2 因子设计中的四种治疗之一，CLO 和 CON 小牛口服沙门氏菌(STM) 或不口服(NoSTM)。用 1.6 × 10 ⁶菌落形成单位 (CFU)沙门氏菌攻击小牛第 0 天，1 L 代乳品中的鼠伤寒杆菌（耐 50 μg/mL 萘啶酸）。每 6 小时通过颈静脉导管采集血样，持续 96 小时，并通过留置的直肠温度记录装置每 5 分钟测量一次体温。来自每个处理的五头小牛在攻击后 48 小时收获，其余小牛在攻击后 96 小时收获。在尸检过程中，收集组织用于从各种组织中分离和量化接种的 STM。CLOSTM 组在攻击后 48 小时的空肠、回肠和横结肠中的 STM 浓度降低 ( p  ≤ 0.03)，但在攻击后96 小时没有差异 ( p  > 0.05)。减少（p < 0.01) 与 CONSTM 小牛相比，在 CLOSTM 小牛攻击后观察到发热。 与其他治疗相比，攻击后 CLOSTM 小牛的白细胞和淋巴细胞计数增加 ( p ≤ 0.05)。在接受 STM 的小牛中， 与 CON 组相比，CLO 组在攻击前后的采食量更高（p < 0.01）。与其他治疗相比，在 CONSTM 组中观察到血清 IL-6 和 IFN-γ 浓度增加。总体而言，CLO 减少了胃肠组织中沙门氏菌的存在和浓度，同时降低了血液参数所表明的挑战的严重程度，并降低了发热反应。