Impact of Host Genetics on Caecal Microbiota Composition and on Salmonella Carriage in Chicken

Abstract

Background Salmonella Enteritidis (SE) is one of the major causes of human foodborne intoxication through the consumption of contaminated poultry products. Genetic selection of animals more resistant to Salmonella carriage and the modulation of gut microbiota are two promising ways of decreasing individual Salmonella carriage. This study aims to identify the main genetic and microbial factors controlling the individual levels of Salmonella carriage in chickens (Gallus gallus) in controlled experimental conditions. Two-hundred and forty animals from the White Leghorn inbred lines, N and 61, were infected by SE at 7 days of age. After infection, animals were kept in isolators to reduce the recontamination of birds by Salmonella. Caecal contents were sampled at 12 days post-infection and used for DNA extraction. Microbiota DNA was used to measure individual counts of SE by digital PCR and to determine the bacterial taxonomic composition through a 16S rRNA gene high-throughput sequencing approach. Results Results confirmed that the N line is more resistant to Salmonella carriage than the 61 line, and that intra-line variability is higher for the 61 line. Furthermore, the 16S analysis showed strong significant differences in microbiota taxonomic composition between the two lines. Out of 617 Operational Taxonomic Units (OTUs), over 390 were differentially abundant between the two lines. Furthermore, within the 61 line, we found a difference in the microbiota taxonomic composition between high and low Salmonella carriers, with 39 differentially abundant OTUs. Finally, via metagenome functional prediction based on 16S data, we identified several metabolic pathways potentially associated to microbiota taxonomic differences (e.g. butyrate metabolism) between high and low carriers. Conclusions Overall, this study demonstrates that the caecal microbiota composition of the N and 61 lines is influenced by the host genetics, which could be one of the reasons why these lines differ for their Salmonella carriage in experimental infection conditions.