#18-050

Complete

Date Full Report Received

10/04/2019

Date Abstract Report Received

10/04/2019

Investigation

Institution:
Primary Investigator:

The impact of antibiotic treatments on the swine respiratory microbiota is poorly understood. It was hypothesized that antibiotic administration to piglets during the lactation period interferes with normal colonization patterns of the respiratory microbiota. It was also hypothesized that an impaired immune response play a role in antibiotic-mediated disturbances of the nasal microbiome. This study aimed, therefore, to characterize the impact of Tulathromycin administration, at either processing or weaning age, on the diversity of the nasal microbiota over a 56-day period (lactation and post-weaning phases). Additionally, this study also sought to determine host genetic variations associated with the immune response in the context of a hypothetical antibiotic-associated dysbiosis. To accomplish with the abovementioned objectives, three groups of piglets were followed up from birth to 56-day old. One group consisted of piglets that did not receive antibiotics. Two other groups received a single intramuscular injection of Tulathromycin at either 4 or 19 days of age, respectively. Nasal swabs were collected from sows post-farrowing and from piglets on days 4 (T1), 12 (T2), 19 (T3), 28 (T4) and 56 (T5) of age. In addition, a blood sample from all piglets was obtained to perform genome-wide association studies (GWAS). The results showed that the nasal microbiota was stable regardless of antibiotic treatment. However, the nasal bacterial diversity significantly increased with age, thus, significant changes in diversity were observed between pre-weaning and post-weaning time points. Although GWAS revealed single-nucleotide polymorphisms (SNPs) related to nasal microbiome diversity, these genetic variations could not be linked to the host immune response. In conclusion, the present results point out that the age and the transition to nursery/finisher sites may exert a greater influence over the nasal microbiome of piglets than early-life antibiotic treatments.