The microorganisms that reside in and on a particular body site constitute the microbiota. The composition of microbiota differs in states of health and disease, playing different roles in immune system development, nutrition, and resistance to infection. Respiratory disorders are considered the most common and costly diseases in pigs, including Glässer’s disease as one of the most relevant problems in nursery piglets. Antimicrobials are used to control bacterial livestock diseases, however they can also damage beneficial bacteria from the resident microbiota.
In this work, the effect of early-life antibiotic treatment on the nasal microbiota composition of piglets at weaning was established. For this purpose, ten piglets from five sows (2 piglets per sow) were sampled from two farms subjected to two antibiotic usages. Piglets in farm A received penicillin and streptomycin at 3-5 days of age and tulatromycin at 7-10 days of age, while piglets in farm B received ceftifur at 3-5 days of age and tulatromycin at 7-10 days of age. Piglets reared under these antibiotic treatments were sampled at weaning. In a second sampling, piglets were not treated and when possible, nasal swabs were taken from piglets born to the same sows. Total DNA was extracted from nasal swabs and subjected to 16S sequencing using Illumina MiSeq. Sequence data analysis was done using QIIME software. When the antibiotic treatments were removed, significant differences in the nasal microbiota composition were found at various taxonomical levels, with Firmicutes showing increased relative abundance and Proteobacteria showing the opposite tendency. At genus level Prevotella was increased while Bergeyella and Moraxella were decreased, among others changes. In addition, higher species richness and diversity was also detected, which has been previously shown to be associated to healthier status.