Southern Plains Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, College Station, Texas 77845, USA.
Foodborne Pathog Dis. 2010 Jan;7(1):23-30. doi: 10.1089/fpd.2009.0346.
The BT/TAMUS 2032 (BT) cationic peptides are a group of related cationic peptides produced by a Gram-positive soil bacterium, Brevibacillus texasporus. Cationic amphiphilic peptides produced by host cells have been found to stimulate or prime the innate immune responses in mammals, but little information is available on the effects of bacterial-produced peptides on host immunity. We have previously shown that BT, provided as a feed additive for 4 days after hatch, significantly induced protection against extraintestinal colonization by Salmonella enterica serovar Enteritidis. We also found that feeding BT significantly upregulated the functional efficiency of heterophils, the avian equivalent to mammalian neutrophils. The objective of the present study was to further evaluate the effect of BT as a nonantibiotic, antibacterial compound and a stimulator of the innate immune response of young chickens. BT, provided as a feed additive at three different concentrations (12, 24, or 48 ppm) for 4 days after hatch, significantly increased protection against Salmonella enterica serovar Enteritidis cecal colonization in a concentration-dependent manner. We also confirmed our previous results that the functional activities of heterophils from chickens fed the BT rations were significantly upregulated. In addition, we also found that the functional activities of peripheral blood monocytes were significantly increased in a concentration-dependent manner when compared with monocytes isolated from chickens fed a control diet. This is the first report of bacterial cationic peptides providing protection against Salmonella cecal colonization. The significance of these data is that the orally delivered cationic peptides stimulate the innate response during the first week after hatch, normally a time of immunologic inefficiency and increased susceptibility to bacterial infections. We speculate that BT given as a feed additive during the first week after hatch could provide increased protection against a variety of bacterial pathogens because of the nonspecific nature of the innate response.
BT/TAMUS 2032（BT）阳离子肽是一组由革兰氏阳性土壤细菌 Brevibacillus texasporus 产生的相关阳离子肽。已发现宿主细胞产生的阳离子两亲肽可刺激或启动哺乳动物的固有免疫反应，但关于细菌产生的肽对宿主免疫的影响的信息很少。我们之前已经表明，BT 作为孵化后 4 天的饲料添加剂提供，可以显著诱导对肠炎沙门氏菌肠外定植的保护。我们还发现，饲喂 BT 可显著上调异嗜性粒细胞的功能效率，异嗜性粒细胞是禽类相当于哺乳动物中性粒细胞的细胞。本研究的目的是进一步评估 BT 作为非抗生素、抗菌化合物和刺激幼鸡固有免疫反应的刺激物的作用。BT 作为饲料添加剂，在孵化后 4 天内以三种不同浓度（12、24 或 48 ppm）提供，可显著增加对肠炎沙门氏菌肠定植的保护作用，呈浓度依赖性。我们还证实了我们之前的结果，即饲喂 BT 日粮的鸡异嗜性粒细胞的功能活性显著上调。此外，与饲喂对照日粮的鸡分离的单核细胞相比，单核细胞的功能活性也呈浓度依赖性显著增加。这是细菌阳离子肽提供对肠炎沙门氏菌定植保护的首次报道。这些数据的意义在于，口服给予的阳离子肽在孵化后第一周刺激固有反应，通常是免疫效率低下和易受细菌感染的时期。我们推测，由于固有反应的非特异性，在孵化后第一周作为饲料添加剂给予 BT 可以提供对各种细菌病原体的增加保护。
