ORIGINAL ARTICLE The effect of lactating rabbit does on the development of the caecal microbial community in the pups they nurture L. Abecia 1,2 , M. Fondevila 1 , J. Balcells 1 and N.R. McEwan 2,3 1 Departamento de Produccio ´ n Animal y Ciencia de los Alimentos, Universidad de Zaragoza, Spain 2 Rowett Research Institute, Aberdeen, Scotland 3 Institute of Rural Studies, University of Wales, Aberystwyth, Wales Introduction The microbial community of the gastrointestinal tract is characterized by its high concentration, wide diversity and complexity of interactions, having a profound influ- ence on immunological, nutritional, physiological and protective processes in the host animal (Berg 1996; Gaskins 1997). In domestic herbivorous species, the insta- uration and development of a functional digestive micro- bial community is a key step in the early adaptation of young animals, for fermentation, nitrogen recycling and competence against pathogens. During the lactation period in rabbits, the caecal microbiota of pups does not develop significantly until the food source of the young rabbit shifts from milk to dry feed, around 3 weeks of age (Padilha et al. 1995), which also promotes the beginning of caecotro- phy (de Blas and Wiseman 1998). By the time weaning takes place, the caecal ecosystem of pups has not yet fully developed and stabilized (Boulahrouf et al. 1991; Gidenne 1997), and thus is more susceptible to several enteric infections (Licois and Gidenne 1999), reaching mortality levels of nearly 0Æ25 around weaning (Koehl 1997). The largest loss at this time is associated with diarrhoea, whose aetiology is multifactorial (Peeters et al. 1988). It is hypothesized that during lactation, the microbial digestive community of the litter is significantly Keywords caecal colonization, mother effect, rabbit microbiota. Correspondence Manuel Fondevila, Departamento de Produccio ´ n Animal y Ciencia de los Alimentos, Universidad de Zaragoza, Zaragoza 50013, Spain. E-mail: mfonde@unizar.es 2006/0654: received 8 May 2006, revised and accepted 13 November 2006 doi:10.1111/j.1365-2672.2007.03277.x Abstract Aims: To study the effect of microbial community of the rabbit does as influ- enced by dietary factors, on the development of the gut microbiota of their litters. Methods and Results: Twenty-four lactating does were given a diet unsupple- mented (NAB) or with 100 ppm of bacitracin (BAC) or tiamulin (TIA) to modify their digestive microbiota. Litters were adjusted to six pups. In Trial 1, four does per diet milked their own six pups. In Trial 2, two does per diet nursed three of their pups and three fostered from the doe given the same diet. In Trial 3, two does on each diet nursed three of their pups and three fostered from another doe fed on another diet. Denaturing gradient gel electrophoresis (DGGE) analyses of the litter microbiota showed that the effect of the milking mother was greater than the influence of the biological mother. TIA had a strong effect on the bacterial profile even prevailing over that of the milking mother, in contrast to BAC. Conclusions: Nursing mother microbiota plays an important role over that of the litter. Caecal colonization that occurs during the lactation process prevailed over that during the partum. Significance and Impact of the Study: Manipulation of the mother’s micro- biota may help for adaptation of the litter microbial community against patho- logic digestive processes. Journal of Applied Microbiology ISSN 1364-5072 ª 2007 The Authors Journal compilation ª 2007 The Society for Applied Microbiology, Journal of Applied Microbiology 103 (2007) 557–564 557