Pig nasal and rectal microbiotas are involved in the antibody response to Glaesserella parasuis

Background Vaccination stands as one of the most sustainable and promising strategies to control infectious diseases in animal production. Nevertheless, the causes for antibody response variation among individuals are poorly understood. The animal microbiota has shown to be involved in the correct development and function of the host immunity, including the antibody response. Here, we studied the nasal and rectal microbiota composition and the association with the antibody response against the pathobiont Glaesserella parasuis . We sampled the nasal and rectal microbiota of 24 piglets before vaccination (two farms) and at similar time in an unvaccinated farm (naturally exposed to the pathobiont). Microbiota composition was inferred by v3v4 16S rRNA gene sequencing and bioinformatic analysis. The antibody response to either vaccination or natural exposure to G. parasuis was measured by ELISA and the variation between the levels before and after vaccination (normalized per farm) was used in the analyses. Results Piglets with higher antibody responses showed more diverse microbial communities compared to piglets with lower responses. Moreover, we were able to associate swine nasal core microbiota colonizers with higher antibody levels, such as several members from Bacteroidales and Clostridiales orders and genera including Moraxella , Staphylococcus , Fusobacterium and Neisseria . Regarding taxa found in the rectal microbiota, only associations at order level were detected with antibody responses pointing towards a positive role for Clostridiales while negative for Enterobacteriales . Conclusions Altogether, these results suggest that the microbiota is associated with the antibody response to G. parasuis (and probably to other pathogens) and serves as starting point to understand the factors that contribute to immunization in pigs.