Gutwean
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Research partners: University of Bristol, Rowett Research Institute
Sponsors: Defra, SEERAD, BPEX
Project duration: 2005-2009
Losses that result from infection during the immediate post-weaning period represent a major financial penalty to the pig industry. Until recently, methods of disease control relied heavily on the use of antibiotic growth promoters, zinc oxide and copper sulphate. However, these substances cause environmental pollution and have potential effects on food safety due to the development of bacterial resistance. Identification of alternative methods of health promotion and disease control is now recognized as a priority in pig production.
Natural methods of promoting immunity and diseases resistance are clearly favoured by today’s environment/food safety conscious society. Growing evidence exists supporting the role of the gut microbiota in the development of the mucosal immune system particularly in early post-natal life. The microbiota has many important functions including improving nutrient availability, preventing pathogen colonization, and promoting the development of both mucosal and systemic immunity.
GUTWEAN investigated the interactions between rearing environment, post-weaning nutrition, microbial diversity and immune function in piglets. The main aim of this project was to establish whether microbial colonization in early life can impact on immune competence of the developing pig. Project goals included identification of bacterial groups/species that drive the functional maturation of the immune system and candidate molecular markers of the “healthy gut”.
Microbial diversity in the gastrointestinal tract of pigs raised intensive and extensive farms was characterized. Animals in an outdoor environment showed a dominance of lactobacilli species, whereas animals in indoor environments were colonized by potentially harmful bacteria belonging to Clostridia and Proteobacteria.
Given the observed differences in gut microbiota associated with rearing environment, gut-specific responses in gene expression patterns were also determined. Analysis of all gene data confirmed that the differences in microbiota between pigs reared in indoor and outdoor environments was also associated with significant difference in immune response genes.
In conclusion, rearing environment, whether indoor or outdoor, has a profound impact on the type of bacteria that colonise the pig gut in early life. These effects are ‘sustainable’ and also apparent in the adult animal gut.
Large numbers of lactobacilli were found in outdoor reared pigs. Importantly, many of these bacteria have not been previously investigated in terms of their health promoting properties. The increase in these bacteria in outdoor reared pigs was associated with a reduction in the numbers of pathogenic bacteria in the gut. Significantly, the outdoor reared animals also had enhanced immune function and gut barrier effects. The functional effects of the bacterial strains identified in outdoor farms may provide avenues for development of new probiotics. Furthermore, some of the genes that were observed in the outdoor pig gut may provide “healthy gut” biomarkers useful for assessing new dietary interventions or new rearing regimes for young pigs.