Abstract
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.