Abstract
Botanicals exhibit promising impacts on intestinal health, immune-regulation, and growth promotion in weaned pigs. However, these benefits may vary depending on major active components in the final feed additive products. Therefore, this study aimed to investigate two types of botanical blends (BB) that were comprised of 0.3% capsicum oleoresin and 12% garlic extracts from different sources on performance, diarrhea, and health of weaned piglets experimentally infected with a pathogenic Escherichia coli F18. Sixty weanling pigs (7.17 ± 0.97 kg body weight (BW)) blocked by weight and gender were assigned to one of five dietary treatments: negative control (NC), positive control (PC), or dietary supplementation with 100 mg/kg of BB1, 50 mg/kg or 100 mg/kg of BB2. This study lasted 28 d with 7 d before and 21 d after the first E. coli inoculation (day 0). All pigs, except negative control, were orally inoculated with 1010 cfu E. coli F18/3-mL dose for 3 consecutive days. Blood samples were collected periodically to analyze systemic immunity. Intestinal tissues and mucosa were collected on days 5 and 21 PI for analyzing histology and gene expression. All data, except for frequency of diarrhea, were analyzed by ANOVA using the PROC MIXED of SAS. The Chi-square test was used for analyzing frequency of diarrhea. Escherichia coli infection reduced (P < 0.05) growth rate and feed intake and increased (P < 0.05) frequency of diarrhea of weaned pigs throughout the experiment. Supplementation of 100 mg/kg BB1 or BB2 alleviated (P < 0.05) frequency of diarrhea of E. coli challenged pigs during the entire experiment. Escherichia coli infection also enhanced (P < 0.05) serum TNF-α and haptoglobin concentrations on day 4 post-inoculation (PI) but reduced (P < 0.05) duodenal villi height and area on day 5 PI, while pigs supplemented with 100 mg/kg BB1 or BB2 had lower (P < 0.05) serum TNF-α than pigs in PC on day 4 PI. Pigs fed with 100 mg/kg BB2 had higher (P < 0.05) jejunal villi height than pigs in PC on day 5 PI. Pigs fed with 100 mg/kg BB2 had reduced (P < 0.05) gene expression of IL1B, PTGS2, and TNFA in ileal mucosa than pigs in PC on day 21 PI. In conclusion, dietary supplementation of botanical blends at 100 mg/kg could enhance disease resistance of weaned pigs infected with E. coli F18 by enhancing intestinal morphology and regulating local and systemic immunity of pigs.