Effects of pathogenic E. coli on diarrhea, growth performance, and blood profile of weaned pigs

The experiment was conducted to evaluate the effects of pathogenic Escherichia coli on diarrhea, growth performance, and blood profile of weaned pigs. A total of 48 pigs were used and housed in individual pens of disease containment chambers for 16 d (4 d before and 12 d after the first challenge [d0]). The treatments were with or without the pathogenic E. coli challenge (F-18 E. coli strain; heat-labile, heat-stable, and Shiga-like toxins). Pigs were orally inoculated with a dose of $10^{10}cfu$ E. coli per 3 mL PBS daily for 3 days. The common nursery diet and water were available at all times. The ADG, ADFI, G:F, diarrhea score, ratio of fecal ${\beta}$-hemolytic coliforms from total coliforms (RHT), and blood profile were measured. The pathogenic E. coli reduced (P < 0.05) ADG from d0 to 6 (117 vs. 297 g/d) and from d0 to 12 (377 vs. 238 g/d) compared with the control. Meanwhile, the pathogenic E. coli increased (P < 0.05) diarrhea score (average 3.4 vs. 1.4) and RHT (average 82 vs. 11%) on d3, 6, and 9 and the number of white blood cells (17.59 vs. $13.48{\times}10^3/{\mu}L$) on d6 compared with the control. No differences were found on ADFI and others in the blood profile (total protein and hematocrit). In conclusion, pathogenic E. coli used in this experiment successfully caused mild diarrhea, increased number of white blood cells, and adversely affected growth rate of weaned pigs.