239 Growth performance and gut health indicators of <i>Escherichia coli</i>-challenged weaned pigs fed diets supplemented with <i>Bacillus subtilis</i> or <i>Enterococcus faecium</i>

Abstract A study evaluated the effects of adding B. subtilis or E. faecium based probiotics in diets for weaned pigs challenged with E. coli on growth performance and indicators of gut health. Pigs [n = 64; initial body weight (BW) = 6.95 kg] weaned at 22 d of age were obtained in 2 batches of 32 pigs each. The pigs were from sows that were homozygous susceptible to infection by F4 strain of E. coli. Pigs in each batch were housed in 16 pens in 2 rooms: first room with 4 pens and second room with 12 pens. Pigs were fed 3 diets for 14 d. The diets were control or control plus B. subtilis (1×10E6 CFU/kg) or E. faecium (1×10E6 CFU/kg). On d 7 and 8 of the experiment, all pigs in the second room were orally challenged with F4 strain of E. coli (5 mL with ~109 CFUּ mL-1ּ d-1) to create the following 4 treatments with 4 pensּ traetment-1ּ batch-1) (8 pens/treatment for the study): unchallenged pigs fed control diet, challenged pigs fed control diet, challenged pigs fed control diet plus E. faecium, and challenged pigs fed control diet plus B. subtilis. Challenging pigs with E. coli F4 reduced (P &amp;lt; 0.05) average daily gain (ADG) for d 7 to 11 and d 11 to 14 of the study from 81 to -67 g and 460 to 259 g, respectively; increased (P &amp;lt; 0.05) plasma haptoglobin concentration (PHC) on d 9 from 1.10 to 1.69 mg/mL and fecal E. coli F4 content (FEC) on d 11 from 4.92 to 7.86 log copies/g; and decreased (P &amp;lt; 0.05) volatile fatty acids (VFA) concentration in the cecum and colon on d 14 from 89.5 to 52.3 mmol/kg and 88.1 to 63.9 mmol/kg, respectively. The E. faecium supplementation did not affect ADG for d 0 to 7 of the study but increased (P &amp;lt; 0.05) ADG for d 7 to 11 by 161%. The E. faecium supplementation did not affect FEC, PHC, and VFA concentration in the cecum and colon. The B. subtilis supplementation did not affect ADG and ADFI, FEC, PHC, but tended to increase (P &amp;lt; 0.10) VFA concentration in the cecum and colon by 32 and 20%, respectively. In conclusion, challenging weaned pigs with the E. coli F4 reduced growth performance and microbial fermentation in the hindgut and increased fecal E. coli shedding. Supplemental E. faecium probiotic improved ADG of weaned pigs after their challenge with E. coli, implying that it can be included in diets for weaned pigs raised under commercial conditions to improve their performance. The B. subtilis probiotic can be included in diets for weaned pigs to counteract the reducing impact of E. coli infection on microbial fermentation in the hindgut.