Effects of Botanicals on Diarrhea, Systemic Immunity, and Intestinal Health of Weaned Pigs

Botanicals, phytogenic feed additives, and essential oils may have potential benefits in swine production for their health, immunity, and growth promoting effects. Therefore, the objective of this study was to investigate the effects of dietary botanical supplementation on blood profiles and intestinal morphology of weaned piglets experimentally infected with a pathogenic F18 Escherichia coli (E. coli). Sixty weaned piglets (around 21 days old; 7.15 ± 0.97 kg) were individually housed and randomly allotted to one of five dietary treatments (n = 12): negative control (NC), positive control (PC), high dose of botanicals blend 1 (BB1, 100 mg/kg), and low or high dose of botanicals blend 2 (BB2, 50 mg/kg and 100 mg/kg). Both botanical blends were comprised of capsicum oleoresin but different garlic extract varieties. The experiment lasted 28 days from day -7 to +21 relative to E. coli inoculation. All piglets except the NC group were orally inoculated with F18 E. coli (1010 cfu per dose, 3 doses) for 3 consecutive days. Growth performance and diarrhea scores were recorded throughout the experiment. Blood samples were collected on d 0, 5, 14, and 21 post-inoculation (PI) for complete blood count test. Intestinal segments were collected on d 5 and 21 PI for intestinal morphology analysis. Data were analyzed by ANOVA in PROC MIXED of SAS with a randomized complete block design. E. coli infection reduced (P < 0.05) pig body weight and growth rate throughout the experiment and reduced (P < 0.05) neutrophils and lymphocytes but increased (P < 0.05) monocytes on d 4 PI. No differences in weight gain or average daily gain were observed among the botanical blend treatments compared with the control. Supplementation of high dose BB1 or BB2 reduced (P < 0.05) frequency and severity of diarrhea of challenged pigs during the experimental period. Pigs supplemented with 100 mg/kg of BB2 had less (P < 0.05) lymphocytes than pigs in PC on d 4 PI. Pigs fed with 50 mg/kg of BB2 had lower (P < 0.05) lymphocytes and monocytes than pigs in PC on d 21 PI. Pigs supplemented with 100 mg/kg of BB2 had the greatest (P < 0.05) duodenal villi width, jejunum villi height and area, and colon crypt depth than pigs in PC on d 5 PI. In conclusion, dietary supplementation of botanicals reduced diarrhea and tended to affect systemic immunity and enhance intestinal morphology of weaned pigs infected with E. coli