Evidence for systemic spread of the potentially zoonotic intestinal spirochaete Brachyspira pilosicoli in experimentally challenged laying chickens.

Brachyspira pilosicoli is a potentially zoonotic anaerobic intestinal spirochaete that is one of several species causing avian intestinal spirochaetosis. The aim of this study was to develop a reproducible model of infection in point of lay chickens and compare the virulence of two strains of B. pilosicoli in a model using experimentally challenged laying chickens. Seventeen week-old commercial laying chickens were experimentally challenged by oral gavage with either B. pilosicoli strain B2904 or CPSp1, following an oral dose of 10% sodium bicarbonate to neutralise acidity in the crop. Approximately 80% of the chickens became colonised and exhibited increased faecal moisture content, reduced weight gain and delayed onset of lay. Tissues sampled at post-mortem examination were analysed to produce a quantitative output on the number of spirochaetes present and hence, the extent of colonisation. The liver and spleen were colonised and novel histopathology was observed in these tissues. The infection model we report here has potential use in studies to improve our understanding of the mechanisms by which Brachyspira elicit disease in poultry and in testing novel intervention strategies

Lactobacilli Antagonize the Growth, Motility, and Adherence of Brachyspira pilosicoli: a Potential Intervention against Avian Intestinal Spirochetosis.

Avian intestinal spirochetosis (AIS) results from the colonization of the ceca and colorectum of poultry by pathogenic Brachyspira species. The number of cases of AIS has increased since the 2006 European Union ban on the use of antibiotic growth promoters, which, together with emerging antimicrobial resistance in Brachyspira, has driven renewed interest in alternative intervention strategies. Probiotics have been reported as protecting livestock against infection with common enteric pathogens, and here we investigate which aspects of the biology of Brachyspira they antagonize in order to identify possible interventions against AIS. The cell-free supernatants (CFS) of two Lactobacillus strains, Lactobacillus reuteri LM1 and Lactobacillus salivarius LM2, suppressed the growth of Brachyspira pilosicoli B2904 in a pH-dependent manner. In in vitro adherence and invasion assays with HT29-16E three-dimensional (3D) cells and in a novel avian cecal in vitro organ culture (IVOC) model, the adherence and invasion of B. pilosicoli in epithelial cells were reduced significantly by the presence of lactobacilli (P < 0.001). In addition, live and heat-inactivated lactobacilli inhibited the motility of B. pilosicoli, and electron microscopic observations indicated that contact between the lactobacilli and Brachyspira was crucial in inhibiting both adherence and motility. These data suggest that motility is essential for B. pilosicoli to adhere to and invade the gut epithelium and that any interference of motility may be a useful tool for the development of control strategies

Oral treatment of chickens with Lactobacillus reuteri LM1 reduces Brachyspira pilosicoli-induced pathology.

Avian intestinal spirochetosis (AIS) results from the colonisation of the caeca and colon of poultry by pathogenic Brachyspira, notably B. pilosicoli. There have been increased reports in the number of cases of AIS since ban on the use of antibiotic growth promoters in the European Union in 2006 which, together with emerging antimicrobial resistance in Brachyspira, has driven renewed interest in alternative intervention strategies. Lactobacillus-based probiotics have been reported previously to protect against infection with common enteric pathogens in livestock. Our previous studies have shown that L. reuteri LM1 antagonises aspects of the pathobiology of Brachyspira in vitro. Here, we aimed to assess whether L. reuteri LM1 mitigates against the clinical symptoms of AIS in chickens experimentally challenged with B. pilosicoli. In this study, two groups of fifteen commercial laying hens were challenged experimentally by oral gavage with B. pilosicoli B2904 at 18 weeks of age; one group received un-supplemented drinking water and the other received drinking water supplemented with L. reuteri LM1 from one-week prior to challenge with Brachyspira and thereafter for the duration of the study. The group dosed with L. reuteri LM1 were protected against experimentally-induced B. pilosicoli infection and showed reduced clinical symptoms associated with AIS. Specifically, B. pilosicoli was detected by culture in fewer birds, bird weights were higher, faecal moisture contents were significantly lower (p<0.05) and egg production as assessed by egg weight and faecal staining score (p<0.05) were better. Also, at post-mortem examination, significantly fewer B. pilosicoli were recovered from treated birds (p<0.05), with only mild-moderate histopathological changes were observed

Prebiotic and probiotic agents enhance antibody-based immune responses to Salmonella Typhimurium infection in pigs

© 2014 Elsevier B.V.Salmonellosis causes significant economic losses to the pig industry and contaminated pork products are an important source of Salmonella for humans. The EU ban on the use of antibiotic growth promoters in pig production, and the emergence of antibiotic resistance has meant there is a pressing need for alternative control strategies for pathogenic bacteria such as S. Typhimurium in pigs. Here, we determined the effects of prebiotic, probiotic and synbiotic diet regimes on antibody responses to oral Salmonella challenge of pigs. The data demonstrate that the inclusion of the probiotic Lactobacillus plantarum B2984 in the diet of piglets (~1×1010cfu/animal/day) enhanced serum IgM (P<0.001), IgG (P=0.001) and IgA (P=0.039) responses to S. Typhimurium infection including cross-reacting antibodies to S. Enteritidis. Similarly, inclusion of the prebiotic lactulose at 1% (w/w) of the feed on a daily basis in the diet enhanced serum IgM (P=0.010), IgG (P=0.004) and IgA (P=0.046) responses to S. Typhimurium infection and also cross-reacting antibodies to S. Enteritidis. Inclusion of both additives in the synbiotic diet also elicited an enhanced immune response with IgM (P=0.009) and IgG (P=0.046) levels being increased, however a significant interaction of the pre and probiotics was observed when considering the immune responses to S. Typhimurium (IgM P=0.004; IgG and IgA, P<0.001 for interaction). With respect to immune responses, the effects of pre or probiotic administration were the same or reduced in the synbiotic diet compared to when used in isolation. The data support the use of Lactobacillus plantarum B2984 or lactulose as strategies to contribute to the protection of weaned piglets from zoonotic bacterial pathogens, but caution must be taken when combining dietary supplements as combinations can interact