Salmonella is an important foodborne pathogen, recognized globally, which can be introduced to humans through poultry products. Producers of poultry meat and eggs mitigate this threat through several means including vaccination. Salmonella Infantis has received recent attention due to outbreaks and contamination of processing facilities. Three floor pen experiments evaluated the efficacy of a modified live Salmonella typhimurium vaccine against Salmonella Infantis. In all experiments, chicks were vaccinated at placement and revaccinated on day 14. The first 2 experiments evaluated ceca enumeration and internal organ prevalence in broilers with and without vaccination at different Salmonella Infantis doses (10⁶ and 10⁹). In the third experiment, some broilers in each pen received 1.0 mL of 1.0 × 10⁸ CFU/bird of Salmonella Infantis in a horizontal exposure model. Liver or spleen, ceca, and feathers on rinse samples were collected at processing. The challenge dose administered in experiment 1 (10⁶) did not effectively colonize internal organs, while the 10⁹ dose in experiment 2 overwhelmed defenses. In experiment 3, ceca prevalence and enumeration as well as feathers on bird rinse enumeration were not different between vaccinated and unvaccinated broilers (P > 0.05). Salmonella prevalence in liver or spleen was lower in the vaccinated group (83.3%) compared to the control group (96.3%) (P < 0.05). Liver or spleen enumeration (log₁₀most probable number/g) was lower in vaccinated broilers compared to the unvaccinated control, 1.93 and 2.91, respectively (P < 0.05). The modified live vaccine promoted broiler resistance to Salmonella Infantis colonization in internal organs; however, this protection is not complete and requires additional measures to alleviate the risk of Salmonella.

沙门氏菌是一种重要的食源性病原体，已为全球所公认，可通过家禽产品引入人类。家禽肉和蛋的生产者通过疫苗接种等多种方式减轻了这种威胁。由于疫情爆发和加工设施受到污染，沙门氏菌沙门氏菌受到了最近的关注。三层笔实验评价修饰的活的功效鼠伤寒沙门氏菌对疫苗沙门氏菌婴儿。在所有实验中，雏鸡均在放置时接种疫苗，并在第14天进行疫苗接种。前2个实验评估了在不同剂量沙门氏菌感染下有无疫苗接种的肉鸡中盲肠计数和内脏器官患病率（10⁶和10 ⁹）。在第三个实验中，在水平暴露模型中，每只围栏中的一些肉鸡接受1.0 mL的1.0×10 ⁸  CFU /小沙门氏菌的鸡。在加工过程中收集冲洗样品上的肝脏或脾脏，盲肠和羽毛。实验1中的攻击剂量（10 ⁶）不能有效地定植于内部器官，而实验2中的10 ⁹剂量却使防御力不堪重负。在实验3中，接种和未接种的肉鸡的盲肠患病率和计数以及禽类漂洗计数中的羽毛没有差异（P  > 0.05）。沙门氏菌接种组的肝脏或脾脏患病率（83.3％）低于对照组（96.3％）（P  <0.05）。接种肉鸡的肝脏或脾脏计数（log ₁₀最可能数/ g）低于未接种对照，分别为1.93和2.91（P  <0.05）。改良的活疫苗可提高肉鸡对内脏沙门氏菌定殖的抵抗力；但是，这种保护尚不完善，需要采取其他措施来减轻沙门氏菌的风险。