Paiva Aline D, Fernandes Kenner M, Dias Roberto S, Rocha Alípio S, de Oliveira Leandro L, Neves Clóvis A, de Paula Sérgio O, Mantovani Hilário C
Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
PLoS One. 2012;7(10):e48313. doi: 10.1371/journal.pone.0048313. Epub 2012 Oct 29.
Antimicrobial peptides have been suggested as an alternative to classical antibiotics in livestock production and bacteriocin-producing bacteria could be added to animal feeds to deliver bacteriocins in the gastrointestinal (GI) tract of ruminant and monogastric animals. In this study, viable (V) and heat-killed (HK) Streptococcus bovis HC5 cells were orally administered to pre-sensitized mice in order to assess the effects of a bacteriocin-producing bacteria on histological parameters and the immune response of the GI tract of monogastric animals. The administration of V and HK S. bovis HC5 cells during 58 days to BALB/c mice did not affect weight gain, but an increase in gut permeability was detected in animals receiving the HK cells. Viable and heat killed cells caused similar morphological alterations in the GI tract of the animals, but the most prominent effects were detected in the small intestine. The oral administration of S. bovis HC5 also influenced cytokine production in the small intestine, and the immune-mediated activity differed between V and HK cells. The relative expression of IL-12 and INF-γ was significantly higher in the small intestine of mice treated with V cells, while an increase in IL-5, IL-13 and TNF-α expression was only detected in mice treated with HK cells. Considering that even under a condition of severe challenge (pre-sensitization followed by daily exposure to the same bacterial immunogen) the general health of the animals was maintained, it appears that oral administration of S. bovis HC5 cells could be a useful route to deliver bacteriocin in the GI tract of livestock animals.
抗菌肽已被提议作为家畜生产中传统抗生素的替代品，并且可以将产生细菌素的细菌添加到动物饲料中，以便在反刍动物和单胃动物的胃肠道中递送细菌素。在本研究中，将活的（V）和热灭活的（HK）牛链球菌HC5细胞口服给予预先致敏的小鼠，以评估产生细菌素的细菌对单胃动物胃肠道组织学参数和免疫反应的影响。在58天内将V和HK牛链球菌HC5细胞给予BALB/c小鼠不会影响体重增加，但在接受HK细胞的动物中检测到肠道通透性增加。活细胞和热灭活细胞在动物胃肠道中引起了相似的形态学改变，但最显著的影响出现在小肠中。口服牛链球菌HC5也影响小肠中的细胞因子产生，并且V和HK细胞之间的免疫介导活性有所不同。在用V细胞处理的小鼠的小肠中，IL-12和INF-γ的相对表达显著更高，而仅在用HK细胞处理的小鼠中检测到IL-5、IL-13和TNF-α表达增加。考虑到即使在严重挑战的条件下（预先致敏然后每天暴露于相同的细菌免疫原）动物的总体健康状况仍得以维持，看来口服牛链球菌HC5细胞可能是在家畜动物胃肠道中递送细菌素的有用途径。
