ORIGINAL ARTICLE Composition of diet modifies colonization dynamics of Campylobacter jejuni in broiler chickens A. Moln ar 1 , C. Hess 2 , L. P al 1 , L. W agner 1 , W.A. Awad 2,3 , F. Husv eth 1 , M. Hess 2 and K. Dublecz 1 1 Department of Animal Science and Animal Husbandry, Georgikon Faculty, University of Pannonia, Keszthely, Hungary 2 Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria 3 Department of Animal Hygiene, Poultry and Environment, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt Keywords broiler chicken, Campylobacter jejuni, enzyme, histomorphology, poultry. short-chain fatty acids, viscosity, wheat. Correspondence Andor Moln ar, Georgikon Faculty, University of Pannonia, Hungary, 8360 Keszthely, De ak F. utca 16. E-mail: andor.molnar@vetmeduni.ac.at 2014/1309: received 26 June 2014, revised 9 October 2014 and accepted 23 October 2014 doi:10.1111/jam.12679 Abstract Aims: To evaluate the impact of diet composition on colonization dynamics of Camp. jejuni and on related physiological parameters in the chicken intestine. Methods and Results: A total of 54 1-day-old Ross 308 broiler chicks were randomly divided into three isocaloric and isonitrogenous dietary groups: maize-based (MB), wheat-based (WB) diet and wheat-based diet with NSP- degrading enzyme supplementation (WBES). Chickens were orally infected with 10 8 CFU Camp. jejuni on day 14, and samples (n = 6) were collected on 7, 14 and 21 days postinfection (DPI), respectively. Colony forming units of Camp. jejuni of caecum and jejunum, short-chain fatty acid (SCFA) concentrations, pH values of the caecum, jejunal histomorphology and viscosity of jejunal chymus were measured. In case of WBES diet, lower Camp. jejuni colonization 14 DPI, higher jejunal viscosity, higher total SCFA concentrations in the caecum and enhanced jejunal histomorphology were observed compared to those measured in chickens fed MB diet. Conclusions: The WBES diet altered Camp. jejuni colonization dynamics in the chicken intestine which resulted by higher SCFA concentrations in the caecum and by the change of gut morphology. Significance and Impact of the Study: Our study proves that diet composition can modify Camp. jejuni colonization depending on sampling time point postinfection. Introduction Recently, Campylobacter infections remain a prominent cause of human bacterial gastroenteritis in the developed world (EFSA 2011; Ghareeb et al. 2013). Broiler chickens are generally considered as a natural host for Campylo- bacter spp. carrying these pathogens in their intestinal tract leading to carcass contaminations at slaughterhouses (Hermans et al. 2011a). Decreasing the number of Campylobacters in the chicken intestine at slaughter would reduce the risk of infections in humans (EFSA 2011). Although many measures such as the use of biose- curity restrictions, feed additives, vaccines, antibiotics, pre- and probiotics have been studied, an overwhelmingly successful technique to reduce Campylobacter prevalence has not been found yet (Hermans et al. 2011a; Ghareeb et al. 2013). A typical poultry diet contains either maize, wheat or a combination of these as the main cereal component. Both cereals are used as energy sources in poultry diets, but they differ in water-soluble nonstarch polysaccharides (NSP) contents. Wheat contains higher levels of soluble NSP— mainly arabinoxylans—than corn. These compounds can only be degraded in animals by microbial fermentation (de Lange 2000). Soluble NSP—at moderately higher lev- els—have some adverse effects on digestion by increasing the viscosity of the digesta, decreasing passage rate, thus extending the time for bacteria to thrive (de Lange 2000). Journal of Applied Microbiology 118, 245--254 © 2014 The Society for Applied Microbiology 245 Journal of Applied Microbiology ISSN 1364-5072