Mølbak Lars, Johnsen Kaare, Boye Mette, Jensen Tim K, Johansen Markku, Møller Kristian, Leser Thomas D
National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, Copenhagen V, Denmark.
Vet Microbiol. 2008 Apr 1;128(1-2):96-107. doi: 10.1016/j.vetmic.2007.09.012. Epub 2007 Sep 29.
Pigs with and without naturally occurring Lawsonia intracellularis infection were fed diets with different texture. In a previous study from 79 pig herds using a similar feeding on pelleted or non-pelleted form showed that the non-pelleted diet was associated with a reduced prevalence of L. intracellularis. In this study a mechanistic approach was taken for explaining and testing this observation by studying the microbiota and the occurrence of L. intracellularis in the distal ileum of 54 pigs by terminal restriction fragment length polymorphism (T-RFLP) analysis, Real-Time PCR and in situ hybridization. The texture of the diet influenced the microbiota, and from a quantitative discriminative analysis of the terminal restriction fragments (T-RFs) of ileum samples it was deduced that Clostridium spp. and Lactobacillus spp. were associated with the non-pelleted diet and Streptococcus spp. with the pelleted diet. In experimentally infected pigs it was verified that 89bp and 90bp sized T-RFs (HhaI) from ileum represented L. intracellularis. The non-pelleted diet seemed to reduce the relative amount of L. intracellularis in the total microbiota of the ileum, but the number of pigs detected positive with L. intracellularis by Real-Time PCR was not influenced. The five pigs with highest L. intracellularis content showed T-RFs that were not present in profiles from less or non-infected pigs, which may indicate that some bacterial species were associated with L. intracellularis infection.
对自然感染和未感染胞内劳森菌的猪饲喂不同质地的日粮。在之前一项对79个猪群的研究中，采用颗粒料或非颗粒料形式进行类似饲喂，结果表明非颗粒料日粮与胞内劳森菌感染率降低有关。在本研究中，采用了一种机制性方法来解释和验证这一观察结果，通过末端限制性片段长度多态性（T-RFLP）分析、实时荧光定量PCR和原位杂交技术，研究了54头猪回肠末端的微生物群和胞内劳森菌的发生情况。日粮质地影响微生物群，通过对回肠样本末端限制性片段（T-RFs）的定量判别分析推断，梭菌属和乳杆菌属与非颗粒料日粮有关，链球菌属与颗粒料日粮有关。在实验感染的猪中，已证实回肠中大小为89bp和90bp的T-RFs（HhaI）代表胞内劳森菌。非颗粒料日粮似乎降低了回肠总微生物群中胞内劳森菌的相对含量，但通过实时荧光定量PCR检测到的胞内劳森菌阳性猪的数量并未受到影响。胞内劳森菌含量最高的5头猪显示出的T-RFs在感染较轻或未感染猪的图谱中不存在，这可能表明某些细菌物种与胞内劳森菌感染有关。
