A novel strategy to select Bifidobacterium strains and prebiotics as natural growth promoters in newly weaned pigs Monica Modesto a , M. Rosaria D'Aimmo a , Ilaria Stefanini a , Paolo Trevisi b , Sara De Filippi b , Luisa Casini b , Maurizio Mazzoni b , Paolo Bosi b , Bruno Biavati a, ⁎ a Department of Agro-Environmental Science and Technology, University of Bologna, Bologna, Italy b Agri-food Protection and Improvement, Universty of Bologna, Reggio Emilia, Italy article info abstract Article history: Received 15 February 2008 Revised 22 July 2008 Accepted 19 August 2008 The study addresses the first two weeks of piglet weaning and is aimed at i) identifying new probiotic strains of Bifidobacterium spp. and non-digestible oligosaccharides (NDO) able to increase the level of autochthonous bifidobacteria in the gut, and ii) finding the best probiotic doses, and probiotic-NDO combinations for piglet growth and gut health. Initially, on a total of 60 pigs we administered 12 strains of 4 bifidobacteria species taken from our collection of strains of different ecological origin. We found the most promising probiotic candidates to be two strains of B. animalis subsp. lactis (M 354 and Ra 18) and one strain of B. choerinum (Su 891), as these led to an increase in the number of viable bifidobacteria in the caecum. In a second trial, a different set of 64 piglets were fed a diet containing a galacto- oligosaccharide (1%) from milk whey, and two fructo-oligosaccharides (4%) from chicory inulin and sugar beet (SbFOS). There was virtually no effect on the hindgut microbiota, except for SbFOS at 4% which tended to increase the endogenous bifidobacteria. Then, in a third trial employing 128 weaning pigs, the probiotic strains Ra 18 and Su 891 were tested individually, at different doses (0; 10 7 ; 10 9 ; 10 11 per pig per day) and combined with 0% or 2% SbFOS supplementation. It was found that Ra 18 improved the live weight growth linearly, while the Su 891 did not. The FOS supplementation showed no interaction with the Ra 18 or Su 891 probiotics for growth performance and no effect on this response criterion. Our selection procedure has highlighted that B. animalis subsp. lactis Ra 18, at 10 11 CFU per pig per day, appears to be the best probiotic choice for improved growth performance in weaning piglets. © 2008 Elsevier B.V. All rights reserved. Keywords: Bifidobacterium spp. Probiotics Prebiotics Synbiotics Newly weaned piglets Intestinal microbiota 1. Introduction In the pig rearing industry, weaning is one of the most crucial, and critical, periods in the animal's life as the piglet suffers the stress of being abruptly separated from the sow, and is simultaneously exposed to digestive disorders caused by the transition to cereal based feed. Furthermore, the sud- den removal of the maternal milk supply leads to the progressive withdrawal of the maternal protective IgA that acts locally in suckling piglet intestine (Salmon, 1999). All these factors, when combined, can affect piglet immunity function, and negatively disturb the intestinal microbiota equilibrium (Kostantinov et al., 2004; Melin et al., 2004; Kim et al., 2006). Normally, the gut microbiota composition and its balance is relatively stable, and this greatly influences the intestinal environment, contributing to the animal's health through a variety of mechanisms such as the activation of immune response, production of bacteriocine, nutritional and physi- cal competition with pathogens, maintenance of an acid environment etc. Weaning, however, can lead to a distur- bance of the ecological balance in the intestinal microbial community (Kostantinov et al., 2006). Indeed, changes in gut Livestock Science 122 (2009) 248–258 ⁎ Corresponding author. DISTA Microbiologia Agraria, Viale Fanin, 44- 40127 Bologna, Italy. Tel.: + 39 0512096275; fax: +39 051 2096274. E-mail address: bruno.biavati@unibo.it (B. Biavati). 1871-1413/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2008.08.017 Contents lists available at ScienceDirect Livestock Science journal homepage: www.elsevier.com/locate/livsci