Higgins S E, Erf G F, Higgins J P, Henderson S N, Wolfenden A D, Gaona-Ramirez G, Hargis B M
Center of Excellence in Poultry Science, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 2007 Nov;86(11):2315-21. doi: 10.3382/ps.2007-00123.
Previous data have indicated that a Lactobacillus-based probiotic culture (FM-B11) is efficacious in reducing Salmonella Enteritidis colonization within 24 h when administered within 1 h of challenge. We hypothesized that the innate immune system, specifically macrophages, may play a role in the observed reduction of Salmonella Enteritidis colonization with probiotic treatment. Day-of-hatch chicks were challenged with Salmonella Enteritidis and then treated with the probiotic culture 1 h later. Three other treatment groups were not treated (negative control), challenged only, or treated with probiotic only. In all experiments, probiotic treatment on the day of hatch reduced (P < 0.05) cecal Salmonella Enteritidis recovery as compared with the control treatment. In experiments 1 and 2, immunohistochemistry was used to evaluate the presence of macrophages (KUL01+) in the ileum and cecum of 7 to 10 chicks per group at 24 h posttreatment. In experiment 1, the number of macrophages observed per 10,000 microm(2) in the ileum of Salmonella Enteritidis-challenged chicks was higher (P < 0.05) than that of nonchallenged chicks (4.87 +/- 0.31 vs. 3.05 +/- 0.19). In the cecum, there were more (P < 0.05) macrophages per 10,000 microm(2) in chicks receiving probiotic treatment without challenge than in negative control chicks (5.32 +/- 0.41 vs. 3.66 +/- 0.35). However, in experiment 2 we found no differences among treatments in the numbers of macrophages for both the ileum and cecum. Experiments 3 and 4 were performed to evaluate the ability of Sephadex-elicited abdominal exudate cells (AEC) from chicks to phagocytose Salmonella Enteritidis in vitro. Abdominal exudate cells were isolated from the abdominal cavity, maintained in tissue culture plates overnight, and then assayed for phagocytic activity by coincubating with Salmonella Enteritidis. In experiment 3, more (P < 0.05) Salmonella Enteritidis was recovered from AEC derived from probiotic-treated chicks than in any other treatment. However, in experiment 4, all treatments resulted in similar levels of elicited AEC, and phagocytosis of Salmonella Enteritidis was at low levels in all groups. Although not conclusive, the modest differences detected in experiments 1 and 3, and the fact that those differences were not repeatedly detectable, suggest that these macrophage-related changes were not solely responsible for the reductions of Salmonella Enteritidis following probiotic treatment.
先前的数据表明，一种基于乳酸杆菌的益生菌培养物（FM-B11）在攻击后1小时内给药时，能在24小时内有效减少肠炎沙门氏菌的定植。我们假设先天免疫系统，特别是巨噬细胞，可能在益生菌治疗后观察到的肠炎沙门氏菌定植减少中发挥作用。出壳当天的雏鸡用肠炎沙门氏菌攻击，然后在1小时后用益生菌培养物治疗。另外三个治疗组未接受治疗（阴性对照）、仅接受攻击或仅接受益生菌治疗。在所有实验中，与对照治疗相比，出壳当天进行益生菌治疗可降低（P<0.05）盲肠中肠炎沙门氏菌的回收率。在实验1和2中，采用免疫组织化学法评估每组7至10只雏鸡在治疗后24小时回肠和盲肠中巨噬细胞（KUL01+）的存在情况。在实验1中，受肠炎沙门氏菌攻击的雏鸡回肠中每10000平方微米观察到的巨噬细胞数量高于（P<0.05）未受攻击的雏鸡（4.87±0.31对3.05±0.19）。在盲肠中，未受攻击接受益生菌治疗的雏鸡每10000平方微米的巨噬细胞数量比阴性对照雏鸡更多（P<0.05）（5.32±0.41对3.66±0.35）。然而，在实验2中，我们发现回肠和盲肠中巨噬细胞数量在各治疗组之间没有差异。进行实验3和4以评估雏鸡经葡聚糖诱导的腹腔渗出细胞（AEC）在体外吞噬肠炎沙门氏菌的能力。从腹腔分离出腹腔渗出细胞，在组织培养板中培养过夜，然后通过与肠炎沙门氏菌共孵育来检测吞噬活性。在实验3中，从接受益生菌治疗的雏鸡来源的AEC中回收的肠炎沙门氏菌比其他任何治疗组都多（P<0.05）。然而，在实验4中，所有治疗导致诱导的AEC水平相似，并且所有组中肠炎沙门氏菌的吞噬水平都很低。尽管尚无定论，但在实验1和3中检测到的适度差异以及这些差异不可重复检测的事实表明，这些与巨噬细胞相关的变化并非益生菌治疗后肠炎沙门氏菌减少的唯一原因。
