Abstract Study objectives were to evaluate the effects of protected benzoic acid (2.5kg/Ton; Provenia/ Novus PB Feed Solution; PBA) on E. coli F18 challenged pigs and on performance and health of nursery pigs under commercial conditions. In Exp 1, a total of 54 weaned pigs (18d old; Hypor boar×Genesis sow; BW = 5.57kg) were housed in 18 pens and assigned to 1 of 3 treatments: an unchallenged control (UC), E. coli F18 challenged control (CC), and E. coli F18 challenged group fed PBA (CPBA). There was a 10-d adaptation period followed by an 11-d post-E. coli F18 inoculation (dpi) recovery period. One pig per pen was euthanized at 4 dpi. The remaining pigs were euthanized at 11dpi for distal jejunum mucosa-associated microbiome determination. Serum was collected at 0, 4, and 11 dpi for analysis of C-reactive protein (C-RP) and interleukin-10 (IL-10). In Exp 2, a total of 840 weaned pigs (21d old; PIC 337 × 1050; BW 5.4kg) were allotted to 28 pens either to a control (Ctl) or 2.5 kg PBA in all phases (0 to 42d). All diets contained 1,500 mg/kg Zn as zinc oxide. In Exp 2, diets included chlortetracycline and tiamulin (0 to 21d). Data for C-RP and IL-10 were analyzed with Proc Mixed of SAS V9.4 using repeated measures. Microbiome was analyzed by pairwise Pearson correlations using the rcorr function from Hmisc package in R. Exp 2 data was analyzed by Proc Mixed of SAS with treatment as fixed effect and block as random effect. In Exp 1, C-RP was higher in CC compared with UC (67.8 vs 43.0µg/mL; P = 0.049) whereas CPBA was intermediate (50.0µg/mL). IL-10 remained similar from dpi 4 to dpi 11 for UC (10.84 to 13.07ng/mL; P = 0.692) and CPBA (8.73 to 14.92ng/mL; P = 0.284) but increased for CC (8.32 to 26.43ng/mL; P = 0.003). Abundance of butyric acid producing bacteria (Clostridium butyricum, Terrisporobacter mayombei, and Intestinibacterbartlettii) was enriched and had significant inverse correlation to E. coli in CPBA (adjusted P 0.05). There were no significant inverse correlations between these butyric acid bacteria and E. coli for UC and CC (P 0.100). In Exp 2, pigs fed PBA had greater final BW (d42) compared with Ctl (21.11 vs 20.24kg; P = 0.012). Close-out gain to feed was improved 12% for PBA (0.612) compared with Ctl (0.546; P = 0.006). Pigs removed was 18.8% for PBA and 26.9% for Ctl (P = 0.025). Mortality was 6.2% for PBA and 9.1% for Ctl (P = 0.119). Pigs medicated was 32.1% for PBA and 37.6% for Ctl (P = 0.235). In conclusion, PBA supplementation mitigated the inflammatory response and shifted microbiome towards butyric acid producing bacteria in E. coli F18 challenged pigs. In commercial conditions, even in diets containing pharmacological zinc oxide and antibiotics, PBA improved feed efficiency, nursery exit weight, and reduced removals.
Camargo et al. (Wed,) studied this question.