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Poultry products are an important source of foodborne Salmonella infections in humans. Amongst these, the prevalence of S. Infantis is rising. In this study, the protection efficacy of an authorized live-attenuated S. Typhimurium vaccine against S. Infantis, was examined using a seeder-bird model in broilers. Vaccinated birds displayed a significantly lower colonization of S. Infantis bacteria in the caeca compared to the non-vaccinated counterparts (P = 0.017), with no significant differences observed in the spleen among the groups, three days post-infection. Thirty-two days post-infection, the disparity in average S. Infantis concentration between all-vaccinated and non-vaccinated birds was significant in both caeca (P = 0.0003) and spleen (P = 0.0002). Interestingly, a third group, consisting of seeder birds that were not vaccinated but housed with vaccinated penmates, exhibited significantly lower S. Infantis levels in both caeca (P = 0.0014) and spleen (P < 0.0001) compared to the non-vaccinated group. These findings underscore the potential of a live-attenuated S. Typhimurium vaccine administered to 2-day-old chicks in conferring protection against S. Infantis in broilers up to slaughter age. [ABSTRACT FROM AUTHOR]

Maintaining optimal gut health is a key driver for a well-performing broiler flock. Histology of intestinal sections and quantification of villus structure can be used to evaluate gut health. While these measurements have been used in experimental models to evaluate gut health, less is known about the associations of these parameters with performance in commercial broiler farms. The objective of the present study was to evaluate possible associations of intestinal villus structure and the inflammatory condition of the gut with Ross 308 broiler performance in 50 commercial farms. On day 28 of the production round, 20 randomly selected broilers per farm were weighed, euthanized, and a duodenal section was collected to determine villus length, crypt depth and the CD3+ T-lymphocytes area percentage (CD3+ %). We found a relatively low coefficient of variance (CV) for the villus length (between farms; 9.67%, within farms; 15.97%), while the CD3+ (%) had a high CV (between farms; 29.78%, within farms; 25.55%). At flock level, the CD3+ (%) was significantly correlated with the villus length (r = −0.334), crypt depth (r = 0.523) and the villus-to-crypt ratio (r = −0.480). The crypt depth was significantly correlated with the European production index (EPI) (r = −0.450) and feed conversion ratio (FCR) (r = 0.389). At broiler level, a significant association was found between the individual body weight (day 28), CD3+ (%) and villus-to-crypt ratio. These data thus show that gut villus structure is significantly associated with bird performance under commercial conditions. Gut histology parameters vary between and within farms. Broiler performance is associated with gut morphology. [ABSTRACT FROM AUTHOR]

An outbreak of necrotic enteritis (NE) is a complex process requiring one or a number of predisposing factors rather than just the presence of pathogenicClostridium perfringens.Examples are dietary influences, such as high levels of non-starch polysaccharides and fishmeal, and factors that evoke epithelial cell damage, such asFusariummycotoxins in feed andEimeriainfections. Recent studies have shown that different predisposing factors induce similar shifts in the intestinal microbiota composition. Butyrate-producing-strains of theRuminococcaceaefamily are decreased in abundance by both fishmeal andEimeria. Similarly, a decreased abundance of butyrate-producing-strains belonging to theLachnospiraceaefamily has been induced by fishmeal. Also shifts are observed in the lactic acid-producing bacteria, such as decreased abundance ofLactobacillus johnsoniiorWeissella confusa, when broilers were fed a fishmeal-based diet or aFusariummycotoxin contaminated diet. Finally, the abundance of CandidatusSavagellawas decreased in broilers followingEimeriachallenge or feeding a fumonisins contaminated diet. The nature of the microbiota shifts indicate that immune modulatory actions of the intestinal microbiota may play a critical role in the effect on the necrosis inducing activity ofC. perfringens.Indeed, colonization with butyrate-producing bacteria plays a key role in counteracting inflammation in the gut and preserving intestinal integrity, whileCandidatusSavagella is involved in stimulating Th17 and immunoglobulin A responses. Lactic acid bacteria stimulate colonization of lactate-utilizing and butyrate-producingLachnospiraceae. Future research needs to clarify the role of the microbiota changes in the pathogenesis of NE. [ABSTRACT FROM PUBLISHER]