PSVI-16 Fecal microbiome of nursery pigs fed phytogenics and antibiotics
Abstract The objective of this study was to evaluate effects of feeding two phytogenic products (PHY1 and PHY2; blends of essential oils and plant extracts) in diets with or without antibiotics (AureoMix S 10-10; AB) on fecal microbiome of nursery pigs. A total of 400 nursery pigs (6.8 kg BW; 20 d of age) were fed one of the six dietary treatments (9 pens/treatment), including: control (0% AB; 0% phytogenics), 0.5% AB, phytogenics (0.02% PHY1 or 0.03% PHY2) or the combination of phytogenic and AB (PHY1 x AB or PHY2 x AB). On d 46 postweaning, 48 fecal samples were collected (1 pig/pen; 7–9 pigs/treatment) and were subjected to the analyses of microbial communities by using 16S rRNA V4 amplicon sequencing with Illumina MiSeq. The sequence data were analyzed by using Qiime and the rarefied OTU table was submitted to Calypso to evaluate the alpha and beta diversity, taxonomic classification, and the differential taxa associated to the dietary treatments. There were differences among treatments on alpha diversity, where the control and PHY2 pigs had lower OTU richness (P = 0.05) and chao1 index (P < 0.10) compared to pigs fed AB alone or AB with phytogenics. There were also differences among treatments on microbial beta diversity of pigs (P < 0.01). The most abundant phyla included Firmicute, Bacteroidetes, Actinobacteria, Tenericutes, Proteobacteria, Spirochaetes, and TM7. At family level, pigs fed AB had greater Ruminococcaceae compared to the control, but lower Coriobacteriaceae and Erysipelotrichaceae compared to PHY1 or PHY2 group (P < 0.05). Feature selection by LEfSe indicated that dominant genus associated to AB treatment was Unclassified RF39, while dominant genera associated to PHY2 treatment were Cantenibacterium, unclassified Coriobacteriaceae, Blautia, Eubacterium, and Collinsella. In conclusion, feeding AB and phytogenic products had different impacts on the fecal bacteria of nursery pigs.