177 Modulation of fecal microbiome by phytogenics, a postbiotic, and mix of organic acids with essential oils in weaned pigs subjected to F18 Escherichia coli challenge
Authors: Knoell Allison , Sardi Maria I , Schut Corinne , Vega Caroline Gonzalez , Smith Brooke , Zhang Zhenbin , Farzan Vahab , Khafipour Ehsan 
Published: May 2024

This study evaluated the effects of bioactive feed ingredients on fecal microbiome of weaned pigs subjected to F18 enterotoxigenic Escherichia coli (ETEC) challenge. Two blocks of weaned pigs [n = 72; Yorkshire/Landrace/Duroc; initial body weight (BW) = 6.62 ± 1.37 kg] were balanced by gender and litter and randomly allocated to one of the six treatments with 12 pens/block and 6 pigs/pen. Treatments included: 1) basal diet (NC), 2) NC + 0.1% phytogenic (Fresta Protect, Delacon, Austria; PFP), 3) NC + 0.2% postbiotic (Dia-V Nursery, Diamond V, IA; PB), 4) NC + 0.2% new phytogenic prototype (Delacon, Austria; NPP), 5) NC + 0.2% organic acid and essential oil blend (OA+EO), and 6) NC + 0.1% phytogenic (Fresta Protect) + 0.2% postbiotic (Dia-V Nursery; PFP+PB). The trial lasted 15 d, with a 7-d pre-challenge and 8-d post-challenge periods. Pigs were orally inoculated with 5 x 1010 CFU/mL of F18 ETEC (O147:H2, LT:STb:STa:Stx2:F18) on d 8 and 9 of study after 5-h fasting. Fecal swabs were collected before challenge (d 8) and 3- and 8-d post-challenge (d 10 and 15 of study) and subjected to shotgun metagenomics. Diarrhea score and E. coli shedding (CFU/mL) were monitored daily and analyzed using a multi-level mixed effect ordinal logistic regression with block and pen as random effects. Microbiome data were center-log-ratio transformed and analyzed for diversity, abundance, and interaction networks. At 3-d post-challenge, the OA+EO, PFP+PB and NPP supplemented pigs had reduced (P &lt; 0.001) E. coli shedding compared with NC. Diarrhea score tended to be less (P = 0.054) in PFP+PB fed pigs 5-d post-challenge and was less (P = 0.02) in PFP+PB, OA+EO, and NPP 6-d post-challenge than NC. Alpha-diversity declined (P &lt; 0.01) 3-d post-challenge with most reduction in PFP and OA+EO but recovered 8-d post-challenge except for PFP and OA+EO (P &lt; 0.01). At the baseline and 8-d post-challenge, the largest number of differentially abundant taxa (P &lt; 0.05) were observed in PFP+PB compared with NC. The PFP+PB reduced the abundances of Escherichia.sp000208585 and Campylobacter.P585 which were negatively correlated (P &lt; 0.01) with average daily gain (ADG) and BW, and positively correlated (P &lt; 0.01) with diarrhea score and E. coli shedding. The PFP+PB increased beneficial species including Prevotella.sp900543585, Mitsuokella jalaludinii, and Faecalibacterium prausnitzii with the first two positively correlated (P &lt; 0.01) with ADG and BW, and negatively correlated (P &lt; 0.01) with diarrhea score and E. coli shedding. By d-8 post-challenge, PFP+PB microbial network had the highest degree of negative connections suggestive of a more competitive microbial ecosystem against opportunistic microorganisms compared with NC. In conclusion, co-supplementation of Fresta Protect phytogenic and postbiotic promoted a microbiome with greater beneficial and reduced detrimental bacteria resulting in low diarrhea score post-challenge.