Dietary plant extracts alleviate diarrhea and alter immune responses of weaned pigs experimentally infected with a pathogenic Escherichia coli1

Abstract

A study was conducted to evaluate the effects of 3 different plant extracts on diarrhea, immune response, intestinal morphology, and growth performance of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli (E. coli). Sixty-four weaned pigs (6.3±0.2 kg BW, and 21 d old) were housed in individual pens in disease containment chambers for 15 d: 4 d before and 11 d after the first inoculation (d 0). Treatments were in a 2×4 factorial arrangement: with or without an F-18 E. coli challenge (toxins: heat-labile toxin, heat-stable toxin b, and Shiga-like toxin 2; 10(10) cfu/3 mL oral dose; daily for 3 d from d 0) and 4 diets [a nursery basal diet (CON) or 10 ppm of capsicum oleoresin, garlic botanical, or turmeric oleoresin]. The growth performance was measured on d 0 to 5, 5 to 11, and 0 to 11. Diarrhea score (1, normal, to 5, watery diarrhea) was recorded for each pig daily. Frequency of diarrhea was the percentage of pig days with a diarrhea score of 3 or greater. Blood was collected on d 0, 5, and 11 to measure total and differential white blood cell counts and serum tumor necrosis factor (TNF)-α, IL-10, transforming growth factor (TGF)-β, C-reactive protein, and haptoglobin. On d 5 and 11, half of the pigs were euthanized to measure villi height and crypt depth of the small intestine and macrophage and neutrophil number in the ileum. The E. coli infection increased (P<0.05) diarrhea score, frequency of diarrhea, white blood cell counts, serum TNF-α and haptoglobin, and ileal macrophages and neutrophils but reduced (P<0.05) villi height and the ratio of villi height to crypt depth of the small intestine on d 5. In the challenged group, feeding plant extracts reduced (P<0.05) average diarrhea score from d 0 to 2 and d 6 to 11 and frequency of diarrhea and decreased (P<0.05) TNF-α and haptoglobin on d 5, white blood cell counts and neutrophils on d 11, and ileal macrophages and neutrophils on d 5. Feeding plant extracts increased (P<0.05) ileal villi height on d 5 but did not affect growth performance compared with the CON. In the sham group, feeding plant extract also reduced (P<0.05) diarrhea score, frequency of diarrhea, and ileal macrophages compared with the CON. In conclusion, the 3 plant extracts tested reduced diarrhea and inflammation caused by E. coli infection, which may be beneficial to pig health.

Administration of a novel plant extract product via drinking water to post-weaning piglets: effects on performance and gut health

“…In the current study, E. coli challenge significantly impaired piglet performance, resulting in reduced ADG and G : F ratio in the week after the challenge and, consequently, a reduced ADG in the following week. These results are in agreement with those of other authors (Liu et al, 2010;Song et al, 2012;Liu et al, 2013). In our study, PE supplementation improved G : F only in non-challenged piglets with an AD feeding regimen; no further beneficial effect on growth performance was found during the enteric E. coli challenge.…”

“…The effect is particularly strong within 1 week of the E. coli challenge. These findings are in agreement with one recent study that showed an anti-diarrhoeal effect in piglets fed PE (Liu et al, 2013). The effect on faecal consistency may be related to an improved gastrointestinal microbial ecosystem in the PE-supplemented piglets.…”

“…Previous studies regarding the effects of PEs on growth performance in piglets have had inconsistent results. Increased feed intake, ADG and feed to gain ratio were reported by several authors (Kim et al, 2004;Lien et al, 2007), but other groups observed no effects on piglet growth performance Liu et al, 2013). These contradictory results may be explained by the PEs used, the compositions of the extracts, the dietary doses tested, the route of administration or the different experimental approaches used to test the effects of the substances (Windisch et al, 2008).…”

“…These results may indicate an activating and/or modulating effect of PEs on the gut immune system, which may increase an animal's ability to cope with stress and reduce the effects of E. coli challenge. Dietary supplementation with PEs may modulate immune functions (Liu et al, 2013) to reduce inflammation in the small-intestinal mucosa, which often occurs in weanling piglets. In the present study, challenge with E. coli caused an increase in MPO, indicating the involvement of the inflammatory response.…”

Use of Antimicrobials from Plants in Feed as a Control Measure for Pathogenic Microorganisms

“…These bioactive compounds act as plant survival mechanisms and defense mechanisms in response to environmental stressors, pathogen attack, competing plants and herbivory [43]. Phytocompounds have a large variety of principle actives and their effects expected are several as act on the improvement in the palatability of feed, feed intake, feed digestibility, stimulate the pancreatic secretions to increase endogenous enzyme activity, gut development/health, antimicrobial/antiviral, antioxidative and anti-inflammation effects and immune system that could benefit performance and health of farm animals [17,41,[44][45][46][47][48][49][50][51][52][53][54]. Therefore, pthytocompounds could be used to replace some antibiotic growth promoters [55,56].…”