Protective effect of phytogenic plus short and medium-chain fatty acids-based additives in enterotoxigenic Escherichia coli challenged piglets

Post Weaning Diarrhea (PWD) is the most important multifactorial gastroenteric disease of the weaning in pig livestock. Phytogenic (PHY) natural extracts are largely studied as alternatives to antibiotic treatments in combating the global concern of the antimicrobial resistance. The aim of this study was to evaluate the protective effect of innovative phytogenic premix with or without short and medium chain fatty acids (SCFA and MCFA) in O138 Escherichia coli challenged piglets. Twenty-seven weaned piglets were allotted into four groups fed different diets according to the following dietary treatments: CTRL (n = 13) group fed basal diet, PHY1 (n = 7) fed the basal diet supplemented with 0.2% of phytogenic premix, PHY2 (n = 7) fed the basal diet supplemented with 0.2% of phytogenic premix added with 2000 ppm of SCFA and MCFA. After 6 days of experimental diet feeding, animals were challenged (day 0) with 2 × 10⁹ CFU of E. coli and CTRL group was divided at day 0 into positive (challenged CTRL + ; n = 6) and negative control group (unchallenged CTRL-; n = 7). Body weights were recorded at -14, -6, 0, 4 and 7 days and the feed intake was recorded daily. E. coli shedding was monitored for 4 days post-challenge by plate counting. Fecal consistency was registered daily by a four-point scale (0-3; diarrhea > 1) during the post-challenge period. Tissue samples were obtained for gene expression and histological evaluations at day 7 from four animals per group. Lower average feed intake was observed in CTRL + compared to PHY2 and CTRL during the post-challenge period. Infected groups showed higher E. coli shedding compared to CTRL- during the 4 days post-challenge (p < 0.01). PHY2 showed lower frequency of diarrhea compared to PHY1 and CTRL + from 5 to 7 days post-challenge. No significant alterations among groups were observed in histopathological evaluation. Duodenum expression of occludin tended to be lower in challenged groups compared to CTRL- at 7 days post-challenge (p = 0.066). In conclusion, dietary supplementation of PHY plus SCFA and MCFA revealed encouraging results for diarrhea prevention and growth performance in weaned piglets.

Effect of Dietary Lactose Supplementation on Growth Performance and Intestinal Epithelium Functions in Weaned Pigs Challenged by Rotavirus

The purpose of this study was to investigate whether dietary lactose supplementation relieves rotavirus (RV)-induced diarrhea and gut dysfunction. Thirty-six crossbred weaned piglets were randomly allocated into three groups and fed diets containing 0, 4%, and 6% lactose for 20 days. On Day 15, half of the piglets in each group were orally infused with RV. RV infection impaired growth performance; induced severe diarrhea; decreased serum D-xylose concentration and morphology and sIgA level of jejunal mucosa; downregulated MUC1, MUC2, occludin, Bcl-2, IL-4, pBD3, pBD2, and pBD1 mRNA expression of jejunal mucosa and/or mesenteric lymph nodes; upregulated Bax, caspase-3, IL-2, IFN-γ, and IFN-β mRNA expression of jejunal mucosa and/or mesenteric lymph nodes; and damaged microbiota and metabolites of cecal digesta in weaned piglets (p < 0.05). Dietary lactose supplementation improved nutrient digestibility and growth performance and relieved the negative influence of RV challenge on intestinal barrier function, mRNA expression of cytokines, and host defense peptides of jejunal mucosa and/or mesenteric lymph nodes in weaned piglets (p < 0.05). Dietary administration of 6% lactose tended to relieve diarrhea (p = 0.07). These results suggest that lactose in feed increases growth performance and has a tendency to alleviate RV-induced diarrhea, derived from the improvement of nutrient utilization, gut barrier function, and immunity.

Heat Stress-Induced Dysbiosis of Porcine Colon Microbiota Plays a Role in Intestinal Damage: A Fecal Microbiota Profile

The pathological mechanisms of gastrointestinal disorders, including inflammatory bowel disease (IBD), in pigs are poorly understood. We report the induction of intestinal inflammation in heat-stressed (HS) pigs, fecal microbiota transplantation from pigs to mice, and explain the role of microorganisms in IBD. 24 adult pigs were subjected to HS (34 ± 1 °C; 75–85% relative humidity for 24h) while 24 control pigs (CP) were kept at 25 ± 3°C and the same humidity. Pigs were sacrificed on days 1, 7, 14, 21. Colonic content microbiome analyses were conducted. Pseudo-germ-free mice were fed by gavage with fecal microbiota from HS-pigs and CP to induce pig-like responses in mice. From 7 d, HS-pigs exhibited fever and diarrhea, and significantly lower colonic mucosal thickness, crypt depth/width, and goblet cell number. Compared with each control group, the concentration of cortisol in the peripheral blood of HS pigs gradually increased, significantly so on days 7, 14, and 21 (P < 0.01). While the concentration of LPS in HS pigs' peripheral blood was significantly higher on days 7, 14 (P < 0.01), and 21 (P < 0.05) compared with that of the control group. The colonic microbiome composition of HS-pigs was different to that of CP. By day 14, opportunistic pathogens (e.g., Campylobacterales) had increased in HS-pigs. The composition of the colonic microbiome in mice administered feces from HS-pigs was different from those receiving CP feces. Bacteroides were significantly diminished, Akkermansia were significantly increased, and intestinal damage and goblet cell numbers were higher in mice that received HS-pig feces. Moreover, we verified the relevance of differences in the microbiota of the colon among treatments. Heat stress promotes changes in gut microbiome composition, which can affect the colonic microbial structure of mice through fecal microbiota transplantation; the molecular mechanisms require further investigation. This study enhanced our understanding of stress-induced inflammation in the colon and the increase in diarrhea in mammals subjected to prolonged HS. Our results provide useful information for preventing or ameliorating deficits in pig production caused by prolonged exposure to high temperatures.

Effect of a Polyphenol-Based Additive in Pig Diets in the Early Stages of Growth

The weaning period is a stressful period for the gastrointestinal tract (GIT) of piglets. This work aims to evaluate the effects of the commercial polyphenol-based product GreenFIS^® on: (1) GIT health and performance of 60 weaned piglets; (2) digestibility in 18 growing pigs. Three diets were tested: a control diet (C), C plus 2.5 g of GreenFIS^®/kg C (T1), and C plus 5 g of GreenFIS^®/kg C (T2). After the post-weaning trial three piglets per treatment were sacrificed for the GIT histological analysis. No differences between diets were recorded in terms of growing performance or clinical and biochemical blood parameters. The GIT histological analysis did not show any indicators of inflammation for any of the groups. The feces of the two extreme treatments (C and T2) were analyzed for microbiota, revealing a greater presence of the Ruminococcus bromii group, positively associated with starch degradation, in T2. In the second experiment six pigs per treatment were randomly chosen for the digestibility study. The inclusion of GreenFIS^® at both levels led to a higher fecal digestibility of gross energy (86.2%, 89.1%, and 89.5%, for C, T1, and T2, respectively) and crude protein (87.0%, 90.2%, and 90.0%). In conclusion, the additive did not improve, in the excellent experimental hygienic conditions, the gut health, but it did increase nutrient digestibility.

Evaluation of Adhesive Characteristics of L. plantarum and L. reuteri Isolated from Weaned Piglets

Limosilactobacillus reuteri and Lactiplantibacillus plantarum strains, previously isolated from weaned piglets, were considered for the evaluation of their adhesive characteristics. Lactobacilli were treated with LiCl in order to remove the surface protein layer, and probiotic activity was compared with those of untreated strains. The autoaggregation, co-aggregation to E. coli F18+, and adhesive abilities of LiCl-treated Limosilactobacillus reuteri and Lactiplantibacillus plantarum were significantly inhibited (p < 0.05) compared with the respective untreated strain. The hydrophobic and basic phenotypes were observed due to the strong affinity to chloroform and low adherence to ethyl acetate. In particular, L. plantarum showed higher hydrophobicity compared to L. reuteri, which may reflect their different colonizing ability. After treatment with LiCl to remove surface proteins, the adherence capabilities of L. reuteri and L. casei on IPEC-J2 cells decreased significantly (p < 0.001) and L. reuteri adhered more frequently. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that both L. reuteri and L. plantarum had several bands ranging from 20 to 100 kDa. Two-dimensional gel electrophoresis showed an acidic profile of the surface-layer polypeptides for both bacterial strains, and more studies are needed to characterize their profile and functions. The results confirm the pivotal role of surface proteins in the probiotic potential of L. reuteri and L. plantarum.

Evaluation of Dietary Administration of Chestnut and Quebracho Tannins on Growth, Serum Metabolites and Fecal Parameters of Weaned Piglets

In pig livestock, alternatives to in-feed antibiotics are needed to control enteric infections. Plant extracts such as tannins can represent an alternative as a natural source of functional compounds. The aim of this study was to evaluate the in vitro digestibility and in vivo effects of oral supplementation of combined chestnut (Ch) and quebracho (Qu) tannins in order to establish if they can induce a positive effect on weaned piglets' performance, metabolic status and fecal parameters. In vitro digestibility (dry matter, DM) of diets was calculated using a multi-step enzymatic technique. In vitro digested diet samples were further tested on an intestinal porcine enterocyte cell line (IPEC-J2). Weaned piglets (n = 120; 28 ± 2 day old) were randomly allotted to two groups (12 pens in total with 10 pigs per pen): control (Ctrl) and treatment (Ch/Qu). After one week of adaptation (day 0), 35-day-old piglets in the Ctrl group were fed a Ctrl diet and the Ch/Qu group were fed with 1.25% Ch/Qu for 40 days. Body weight and feed intake per pen were recorded weekly. At day 40, blood and fecal samples were collected. Principal metabolic parameters were evaluated from blood samples by enzymatic colorimetric analysis. Total phenolic compounds, urea, and ammonia in feces were analyzed (Megazyme International, Bray, Ireland). In vitro digestibility and cell viability assays showed that the inclusion of 1.25% Ch/Qu slightly reduced diet digestibility compared with the Ctrl diet, while intestinal cell viability was not altered with low concentrations of Ch/Qu digesta compared with Ctrl. In vivo results did not show any adverse effects of Ch/Qu on feed intake and growth performance, confirming that dietary inclusion of Ch/Qu at a concentration of 1.25% did not impair animal performance. The decreased diet DM digestibility in the Ch/Qu diet may cause increased serum concentration of albumin (Ctrl: 19.30 ± 0.88; Ch/Qu: 23.05 ± 0.88) and albumin/globulin ratio (Ctrl: 0.58 ± 0.04; Ch/Qu: 0.82 ± 0.04), but decreased creatinine (Ctrl: 78.92 ± 4.18; Ch/Qu: 54.82 ± 4.18) and urea (Ctrl: 2.18 ± 0.19; Ch/Qu: 0.95 ± 0.19) compared with Ctrl. Pigs in the Ch/Qu group contained higher (p < 0.05) concentrations of fecal phenolic compounds and nitrogen than the Ctrl group, while fecal ammonia and urea were not affected by tannins. In conclusion, Ch/Qu tannin supplementation did not influence growth performance. Although lower digestibility was observed in the diet supplemented with Ch/Qu tannins, Ch/Qu supplementation did not show any adverse effect on intestinal epithelial cell viability.

Effects of Tributyrin Supplementation on Growth Performance, Insulin, Blood Metabolites and Gut Microbiota in Weaned Piglets

Simple Summary

In animal farming, alternatives to antibiotics are required due to the increase of antimicrobial resistance. In this contest, tributyrin showed the ability to promote gut health, to modulate gut microbiota and to improve protein digestibility, leading also to higher growth performance. However, although the mode of action of tributyrin on the intestinal epithelial cells has been partially explained, its effects on lipid and protein metabolism needs to be investigated. This paper provides information about the influence of tributyrin on production traits, blood parameters, faecal microbiota and faecal protein excretion in weaned piglets.

Abstract

The aim of this study was to investigate the effects of tributyrin supplementation on the production traits, the main metabolic parameters and gut microbiota in weaned piglets. One hundred and twenty crossbred piglets (Large White × Landrace) were randomly divided into two experimental groups (six pens each; 10 piglets per pen): the control group (CTRL), that received a basal diet, and the tributyrin group (TRIB) that received the basal diet supplemented with 0.2% tributyrin. The experimental period lasted 40 days. Production traits were measured at days 14, 28 and 40. A subset composed of 48 animals (n = 4 for each pen; n = 24 per group) was considered for the evaluation of serum metabolic parameters and hair cortisol by enzyme-linked immunosorbent assay (ELISA), and faecal microbiota by real-time polymerase chain reaction (PCR). Our results showed that the treatment significantly increased body weight (BW) at day 28 and day 40 (p = 0.0279 and p = 0.0006, respectively) and average daily gain (ADG) from day 28 to day 40 (p = 0.046). Gain to feed ratio (G:F) was significantly higher throughout the experimental period (p = 0.049). Even if the serum parameters were in the physiological range, albumin, albumin/globulin (A/G) ratio, glucose and high-density lipoproteins (HDL) fraction were significantly higher in the TRIB group. On the contrary, tributyrin significantly decreased the urea blood concentration (p = 0.0026), which was correlated with lean gain and feed efficiency. Moreover, serum insulin concentration, which has a regulatory effect on protein and lipid metabolism, was significantly higher in the TRIB group (p = 0.0187). In conclusion, this study demonstrated that tributyrin can be considered as a valid feed additive for weaned piglets.

In Vitro Digestion of Chestnut and Quebracho Tannin Extracts: Antimicrobial Effect, Antioxidant Capacity and Cytomodulatory Activity in Swine Intestinal IPEC-J2 Cells

Quebracho (Qu) and chestnut (Ch) are natural sources of tannins and they are currently used in animal nutrition as feed ingredients. However, to date the bio-accessibility, antimicrobial, antioxidant, and intestinal epithelial cell stimulatory doses of Qu and Ch have not been determined. Our study investigates the antioxidant and E. coli F4+ and F18+ growth inhibitory activity of Qu, Ch, and their combinations after solubilization in water (to evaluate the already bio-accessible molecules) and after simulated gastro-intestinal digestion in vitro. The effect of an in vitro digested Ch and Qu combination was also tested on intestinal epithelial IPEC-J2 cells experimentally stressed with hydrogen peroxide (H₂O₂) and Dextran Sodium Sulfate (DSS). The results showed that undigested Qu and Ch alone, and in combination, exerted a valuable antioxidant capacity and E. coli F4+ and F18+ growth inhibitory activity. The concentration of 1200 µg/mL exhibited the highest E. coli growth inhibitory activity for all the samples tested. In addition, after in vitro digestion, Qu and Qu50%-Ch50% maintained E. coli growth inhibitory activity and a modest antioxidant capacity. Three hours pre-treatment with in vitro digested Qu50%-Ch50% counteracted the H₂O₂ and DSS experimentally-induced stress in the intestinal IPEC-J2 cells. Ch and Qu tannin extracts, particularly when combined, may exert E. coli F4+ and F18+ growth inhibitory activity and valuable antioxidant and cell viability modulation activities.

TRPA1 and issues relating to animal model selection for extrapolating toxicity data to humans

The transient receptor potential ankyrin 1 (TRPA1) ion channel is a sensor for irritant chemicals, has ancient lineage, and is distributed across animal species including humans, where it features in many organs. Its activation by a diverse panel of electrophilic molecules (TRPA1 agonists) through electrostatic binding and/or covalent attachment to the protein causes the sensation of pain. This article reviews the species differences between TRPA1 channels and their responses, to assess the suitability of different animals to model the effects of TRPA1-activating electrophiles in humans, referring to common TRPA1 activators (exogenous and endogenous) and possible mechanisms of action relating to their toxicology. It concludes that close matching of in vitro and in vivo models will help optimise the identification of relevant biochemical and physiological responses to benchmark the efficacy of potential therapeutic drugs, including TRPA1 antagonists, to counter the toxic effects of those electrophiles capable of harming humans. The analysis of the species issue provided should aid the development of medical treatments to counter poisoning by such chemicals.

Lentinan administration relieves gut barrier dysfunction induced by rotavirus in a weaned piglet model

Rotavirus (RV) is a pathogen that induces severe diarrhea in infants and young animals. Shiitake mushroom is a traditional food, which can improve physiological function, including gut health. Lentinan (LNT) is the main functional component of Shiitake mushroom. This study aimed to verify whether LNT administration could improve intestinal barrier function, thereby decreasing RV-induced diarrhea in a porcine model. According to initial weight and origin, a total of 28 weaned piglets were randomly fed 2 diets containing 0 or 84 mg kg-1 LNT for 19 d (n = 14). On day 15, RV was orally infused to half of the pigs in each group. RV-induced diarrhea (P < 0.05), the positive rate of RV non-structural protein 4 (NSP4), impaired intestinal morphology, antioxidant capacity and microbiota (P < 0.05), and increased apoptosis of jejunal epithelial cells (P < 0.05) were assessed in the piglets. Dietary LNT supplementation was found to improve intestinal morphology, permeability, antioxidant capacity and microbiota (P < 0.05). Supplementation also further alleviated the effects of RV infection on diarrhea, intestinal morphology, permeability, antioxidant capacity, microbiota and apoptosis of jejunal epithelial cells in piglets (P < 0.05). Thus, these results suggest that LNT administration relieved RV-induced diarrhea in piglets, which could be due to the increase in antioxidant capacity, reduction in apoptosis and improvement of the microbiota-increased gut barrier.

Evaluation of the Probiotic Strain Bifidobacterium longum subsp. Infantis CECT 7210 Capacities to Improve Health Status and Fight Digestive Pathogens in a Piglet Model

Probiotics have been demonstrated to be useful to enhance gut health and prevent gastrointestinal infections. The objective of this study is to demonstrate the potential of the probiotic strain Bifidobacterium longum subsp. infantis CECT 7210 (B. infantis IM1) to prevent and fight intestinal disease by using a Salmonella Typhimurium (Trial 1) or an enterotoxigenic Escherichia coli K88 (Trial 2) oral challenge in a weaning piglet model. Seventy-two piglets were used in each trial. After an adaptation period, animals were orally challenged. One animal per pen was euthanized at Days 4 and 8/9 (Trial 1/Trial 2) post-inoculation (PI). Animal performance, clinical signs, pathogen excretion, fermentation, immune response, and intestinal morphology were evaluated. In Trial 1, most parameters responded to the challenge, whereas, in Trial 2, effects were much milder. Consistent effects of the probiotic were detected in both experiments: Reduction of pathogen excretion (P = 0.043 on Day 3 PI, Trial 1) or ileal colonization (33% reduction of animals with countable coliforms; P = 0.077, Trial 2); increases in intraepithelial lymphocytes (P = 0.002 on Day 8 PI in Trial 1, P = 0.091 on Day 4 PI in Trial 2), and improvement of the fermentation profile by increasing butyric acid in non-challenged animals [P challenge × probiotic (interaction) = 0.092 in Trial 1 and P = 0.056 in Trial 2] concomitant with an enhancement of the villus:crypt ratio on Day 8/9 PI (P interaction = 0.091 for Trial 1 and P = 0.006 for Trial 2). Challenged animals treated with the probiotic showed reduced feed intakes (P interaction = 0.019 in Trial 1 and P = 0.020 in Trial 2) and had lower short-chain fatty acid concentrations in the colon (P interaction = 0.008 in Trial 1 and P = 0.082 in Trial 2). In conclusion, this probiotic demonstrated potential to reduce the intestinal colonization by pathogens and to stimulate local immune response. However, effects on feed intake, microbial fermentation, and intestinal architecture showed a differential pattern between challenged and non-challenged animals. Effects of the probiotic intervention were dependent on the structure of the ecosystem in which it was applied.

Prevalence of adhesin and toxin genes in E. coli strains isolated from diarrheic and non-diarrheic pigs from smallholder herds in northern and eastern Uganda

Background

Enterotoxigenic E. coli (ETEC) significantly contribute to diarrhea in piglets and weaners. The smallholder pig producers in Uganda identified diarrhea as one of the major problems especially in piglets. The aim of this study was to; i) characterize the virulence factors of E. coli strains isolated from diarrheic and non-diarrheic suckling piglets and weaners from smallholder herds in northern and eastern Uganda and ii) identify and describe the post-mortem picture of ETEC infection in severely diarrheic piglets. Rectal swab samples were collected from 83 piglets and weaners in 20 herds and isolated E. coli were characterized by PCR, serotyping and hemolysis.

Results

The E. coli strains carried genes for the heat stable toxins STa, STb and EAST1 and adhesins F4 and AIDA-I. The genes for the heat labile toxin LT and adhesins F5, F6, F18 and F41 were not detected in any of the E. coli isolates. Where the serogroup could be identified, E. coli isolates from the same diarrheic pig belonged to the same serogroup. The prevalence of EAST1, STb, Stx2e, STa, AIDA-I, and F4 in the E. coli isolates from suckling piglets and weaners (diarrheic and non-diarrheic combined) was 29, 26.5, 2.4, 1.2, 16, and 8.4 %, respectively. However the prevalence of F4 and AIDA-I in E. coli from diarrheic suckling piglets alone was 22.2 and 20 %, respectively. There was no significant difference in the prevalence of the individual virulence factors in E. coli from the diarrheic and non-diarrheic pigs (p > 0.05). The main ETEC strains isolated from diarrheic and non-diarrheic pigs included F4/STb/EAST1 (7.2 %), F4/STb (1.2 %), AIDA/STb/EAST1 (8 %) and AIDA/STb (8 %). At post-mortem, two diarrheic suckling piglets carrying ETEC showed intact intestinal villi, enterocytes and brush border but with a layer of cells attached to the brush border, suggestive of ETEC infections.

Conclusion

This study has shown that the F4 fimbriae is the most predominant in E. coli from diarrheic piglets in the study area and therefore an F4-based vaccine should be considered one of the preventive measures for controlling ETEC infections in the piglets in northern and eastern Uganda.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0796-2) contains supplementary material, which is available to authorized users.

Medicinal plants--prophylactic and therapeutic options for gastrointestinal and respiratory diseases in calves and piglets? A systematic review

BACKGROUND

Gastrointestinal and respiratory diseases in calves and piglets lead to significant economic losses in livestock husbandry. A high morbidity has been reported for diarrhea (calves ≤ 35%; piglets ≤ 50%) and for respiratory diseases (calves ≤ 80%; piglets ≤ 40%). Despite a highly diverse etiology and pathophysiology of these diseases, treatment with antimicrobials is often the first-line therapy. Multi-antimicrobial resistance in pathogens results in international accordance to strengthen the research in novel treatment options. Medicinal plants bear a potential as alternative or additional treatment. Based on the versatile effects of their plant specific multi-component-compositions, medicinal plants can potentially act as 'multi-target drugs'. Regarding the plurality of medicinal plants, the aim of this systematic review was to identify potential medicinal plant species for prevention and treatment of gastrointestinal and respiratory diseases and for modulation of the immune system and inflammation in calves and piglets.

RESULTS

Based on nine initial sources including standard textbooks and European ethnoveterinary studies, a total of 223 medicinal plant species related to the treatment of gastrointestinal and respiratory diseases was identified. A defined search strategy was established using the PRISMA statement to evaluate 30 medicinal plant species starting from 20'000 peer-reviewed articles published in the last 20 years (1994-2014). This strategy led to 418 references (257 in vitro, 84 in vivo and 77 clinical trials, thereof 48 clinical trials in veterinary medicine) to evaluate effects of medicinal plants and their efficacy in detail. The findings indicate that the most promising candidates for gastrointestinal diseases are Allium sativum L., Mentha x piperita L. and Salvia officinalis L.; for diseases of the respiratory tract Echinacea purpurea (L.) MOENCH, Thymus vulgaris L. and Althea officinalis L. were found most promising, and Echinacea purpurea (L.) MOENCH, Camellia sinensis (L.) KUNTZE, Glycyrrhiza glabra L. and Origanum vulgare L. were identified as best candidates for modulation of the immune system and inflammation.

CONCLUSIONS

Several medicinal plants bear a potential for novel treatment strategies for young livestock. There is a need for further research focused on gastrointestinal and respiratory diseases in calves and piglets, and the findings of this review provide a basis on plant selection for future studies.

Protective effect of oral administration of transgenic tobacco seeds against verocytotoxic Escherichia coli strain in piglets

The use of transgenic plants as delivery system for antigenic proteins is attractive for its simplicity and increases likelihood for local immune response at sites of infection. The aim of this study was to evaluate the protective effect of oral administration of tobacco seeds, expressing the FedA, the major protein of the F18 adhesive fimbriae, and B subunit of verocytotoxin, against verocytotoxin-producing E. coli (VTEC) strain in piglets. Forty-three early weaned piglets, were randomly divided into 4 experimental groups: 3 test groups and a control. Treatment groups orally received a bolus, with different dose of tobacco seeds on 0, 1, 2, 14 days post primary administration. After challenge, with 1*10(10) CFU of O138 Escherichia coli strain, piglets showed clinical scores significantly higher in the control group compared to orally immunized groups (P < 0.05) and the latter showed a faster recovery than in CG. In conclusion, oral administration of recombinant tobacco seeds expressing antigenic proteins against VTEC strains can induce a protective effect against challenger strain in piglets.