Oral microbiota in piglets at the nursery phase

The oral cavity of animals harbors an extensive microflora, including indigenous commensals and other microorganisms. Oral microbiota may play an important role in the protection of the host against pathogenic infection through the inhibition of colonization of pathogens or growth competition. Especially, the composition of oral microbiota of piglets at the nursery phase, at the critical time to establish a normal flora for life-time, would be drastically altered by external event, such as weaning, feeding, dietary change, and eventually influenced on the growth performance. Thus, the aim of the present study was performed to analyze oral microbiota of piglets from newborn to early stage of nursery in order to extend our understanding of the composition and alternation of oral microbiota.

One hundred samples were collected by vigorously scraping oral cavity with cotton swabs from clinically healthy piglets, assigned into 5 different groups; newborn, suckling only, suckling (with feeding), 6 weeks and 8 weeks of age. Ten swabs in the designated group were pooled into a single sample. Bacterial genomic DNA was directly extracted from the pooled samples and subjected to emulsion-based PCR to amplify 16S rRNA gene. Next Generation Sequencing (NGS) was applied for sequencing the amplified product with a Roche 454 GS-FLX plus (Macrogen, Korea). Taxonomy of 16S rRNA of all sequence reads was assigned by using Silva rRNA and NCBI taxonomy database.

NGS analysis results showed 111,389 of overall number of reads and 51,939,792 bases in the total length for 10 samples. At the level of phylum, both Firmicutes and Proteobacteria were dominant microflora in the range of 80~ 90 % of all number of reads. However, Streptococcaceae is main microflora, followed by Moraxcellaceae, Lactobacillaceae, Neisseriacease, and Pasteurellaceae, in all groups, except newborn piglets. Surprisingly, some major swine pathogens, such as Mollicutes, Pasteurella, Haemophilus, Actinobacillus and Erysipelothrix, were found as early as 2 weeks of age in piglets. Although these pathogens are opportunistic bacteria in the upper respiratory tract, it should be considered as a risk factor for swine health and management.

Oral microbiota of animals is constantly altered, dependent on the conditions encountered during growth phase, diet change, and environment. Thus, further studies should be needed to expand our knowledge on the composition and alteration of oral microbiota of pigs at differnt conditions, which may be eventually helpful to improve a herd performance.

Disclosure of Interest: None Declared.