PSII-19 Fecal microbiota composition of weaned piglets under mixed management and poor housing conditions fed diets increased in threonine, methionine and tryptophan

This study evaluated the effects of increased dietary Thr, Met and Trp supplementation on fecal microbiota composition of weaned piglets raised under contrasting sanitary conditions [(GOOD SC) or under mixed management and poor housing conditions (MM+POOR SC)] during the nursery phase. A total of 144 entire male piglets [body weight (BW) = 6.33 ± 0.91 kg] from a high sanitary status (HSS) farm were randomly housed following a 2×2 factorial arrangement regarding BW blocks. Factorial arrangement was composed of two contrasting SC (GOOD or MM+POOR) and two diets [control, with nutritional requirements according to NRC (2012); or supplemented with Thr:Lys, Met+Cys:Lys and Trp:Lys 20% more than the control]. In total, 12 pens with three piglets each were used for treatment. On d -2, the 144 HSS piglets were allocated to one of two facilities under contrasting SCs. Also on d -2, to mimic a mixed management in the MM+POOR SC, 48 entire male piglets, from a commercial farm with low sanitary status (LSS), were randomly allocated by two piglets per pen into the same pens where the three HSS piglets were. On d 0, the two LSS piglets were removed from the HSS pens and allocated as sentinels into the remaining pens (four/pen) located between pens with HSS piglets. The MM+POOR SC had a weekly cleaning routine only to remove the manure located under the slatted floor, while in the GOOD SC, a daily cleaning routine and a high level of biosecurity protocol were adopted. One fecal sample per pen was collected on d 0, 21 and 42. The V4 region of the bacterial 16S rRNA gene was amplified from each fecal sample to evaluate ecological changes into bacterial communities and taxonomy. Mean relative abundance for each family/genus/species (taxon) across groups were depicted as a heatmap using the log2 transformed relative abundance of the most dominant taxa based on a 2% cutoff and network analysis of clusters of co-occurrences of the most relevant taxa (Figure 1). Overall, fecal microbiome analyses revealed no differences (P >0.05) in bacterial community composition and individual taxon abundances at the bacterial genus level across treatments over time. The alpha- and beta-diversity analysis showed no diet or SC differences (P >0.05). Additional community structure analysis based on co-occurrence network mapping revealed the absence of major temporal changes in architecture or keystone nodes (taxa) for HSS animals housed in either GOOD or MM+POOR SCs, despite the AA+ supplementa