A review on the interactions between gut microflora and digestive mucosal immunity. Possible ways to improve the health of rabbits
Résumé
Enteric diseases frequently occur in rabbits around weaning leading to extensive use of antibiotics in rabbit breeding. In this context, breeders as well as consumers ask for alternative strategies that improve the health of animals. But the maintenance of gut health is complex and relies on a delicate balance between the mucosa (including the absorptive epithelium and the digestive immune system), the gut microbiota and environmental factors including diet. Firstly, immune and non-immune mechanisms of protection against pathogens in the gut are presented, in relation with the installation and composition of the gut microbial ecosystem in the rabbit and its role on health. Finally, several strategies to stimulate digestive immune system or favour beneficial microbiota to exclude enteric pathogens were discussed. Several nutrients including fatty acids and fibres, were implicated in the development of immune response and could be used to improve immune ability of animals. Dietary fatty acids (ω3/ω6 ratio) could be of interest in the rabbit. The role of dietary fibre on digestive health has been demonstrated in weaned rabbits, and strong relations between fibre supply and cæcal microbiota were evidenced. Some works also reported an influence of fibre level in the diet given to the young before weaning on health status of rabbits after weaning. Therefore, nutritional needs of suckling rabbits, more especially fibre requirements, to enhance subsequent gut health need to be thoroughly studied, in relation with needs of their mothers. Exogenous flora could also be added to the diet to stimulate the digestive immune system and prevent the development of enteric pathogens. Finally, vaccines permit protection of the host against specific pathogens.