192 Effects of inclusion of a probiotic and/or a postbiotic in diets containing a phytogenic feed additive on growth performance and fecal microbiome composition and function of nursery pigs

This study investigated the effects of inclusion of a Bacillus-based probiotic and a postbiotic from Lactobacillus acidophilus fermentation (Dia-V Nursery, Diamond V, IA) in diets containing a phytogenic feed additive (Fresta Protect, Delacon, Austria) on growth performance and fecal microbiome of pigs. Weaned pigs [n = 1,840; 19 d old; initial body weight (BW) = 6.1 ± 0.2 kg] were allotted to 16 replicate pens/ treatment (23 pigs/pen) in 2 barns. Pens were blocked by location within barn and randomly allotted to 5 treatments: 1) Basal diet (NC), 2) NC without specialty fats (soy oil blend and medium chain fatty acid blend) + 0.1% phytogenic (PC), 3) PC + 0.05% probiotic (1.1 x 106 CFU/kg of complete feed; PC+Prob), 4) PC + 0.2% postbiotic (PC+Post), and 5) PC + 0.05% probiotic + 0.2% postbiotic (PC+Prob+Post). Pigs were fed experimental diets during phase 1 (d 0-10) and 2 (d 10-23). Pig and feed weights were recorded at the beginning and end of each phase. Fecal samples were collected from 2 pigs/pen (n = 32/treatment) on d 7 and 25 post-wean and subjected to DNA extraction and shotgun metagenomics to evaluate gut microbiome. Performance data were analyzed using the lme4 package of R with treatment as fixed effect and barn and pen location within barn as random effects. Microbiome data were center-log-ratio transformed and analyzed for alpha- and beta-diversity, differentially abundant taxa and genes, microbial network, and carbohydrate active enzymes (CAZy). No differences on performance, mortality or removals were observed during phase 1, phase 2, or overall among treatments (Table 1). Microbiome features were similar between NC and PC. The PC+Prob did not affect alpha- and beta-diversities of microbiome. The PC+Post reduced (P < 0.05) alpha-diversity on d 7 compared with PC and affected (P < 0.05) beta-diversity on both timepoints. The PC+Post had the greatest number of differentially abundant taxa (P < 0.05) compared with PC both on d 7 (27 taxa) and 25 (14 taxa). The PC+Post had greater (P < 0.05) presence of CAZy including glycoside hydrolases, glycosyltransferases and carbohydrate-binding modules on both timepoints. Inclusion of probiotic and postbiotic separately or in combination reduced (P < 0.05) the number of positive connections within the microbial network suggesting these additives promoted a more competitive microbial ecosystem against opportunistic microorganisms compared with PC. Inclusion of postbiotic speeded up the progression of micr