Screening the ability of natural feed ingredients to interfere with the adherence of enterotoxigenic Escherichia coli (ETEC) K88 to the porcine intestinal mucus

Modulation of soy flour bioactivity against enterotoxigenic Escherichia coli by fermentation with exopolysaccharides-producing lactic acid bacteria

Enterotoxigenic Escherichia coli (ETEC)-mediated diarrhea can be mitigated by inhibiting bacterial adhesion to intestinal surface. Some lactic acid bacteria (LAB) produce exopolysaccharides (EPS) that can inhibit ETEC adhesion. In this study, we fermented soy flour-based dough (SoyD) with EPS-producing LAB strains Pediococcus pentosaceus TL (PpTL), Leuconostoc citreum TR (LcTR), Leuconostoc mesenteroides WA (LmWA) and L. mesenteroides WN (LmWN) to improve anti-adhesive activity of the dough against ETEC. The strains LcTR, LmWA and LmWN produced EPS in SoyD fermentation with similar polysaccharide yields and compositions as when grown in liquid medium, whereas PpTL was unable to produce EPS in SoyD. LcTR produced high molecular weight (Mw) dextran (∼900 kDa) while LmWA and LmWN produced dextran and levan with diverse Mw (∼20-1000 kDa). SoyD fermentation by EPS-producing LAB increased the capability of the SoyD extracts to adhere to ETEC cells and block ETEC adhesion to porcine mucin. After Mw-based fractionation, all extract-fractions (>3 kDA) of LmWA- and LmWN-fermented SoyD retained their blocking activity indicating that various Mw populations of the EPS contributes to bioactivity against ETEC. This study shows the potential of EPS-producing LAB strains as fermenting microorganisms in the development of a functional food product with anti-diarrheal properties.

Natural anti-adhesive components against pathogenic bacterial adhesion and infection in gastrointestinal tract: case studies of Helicobacter pylori, Salmonella enterica, Clostridium difficile, and diarrheagenic Escherichia coli

Antimicrobial resistance (AMR) poses a global public health concern. Recognizing the critical role of bacterial adhesion in pathogenesis of infection, anti-adhesive therapy emerges as a promising approach to impede initial bacterial attachment, thus preventing pathogenic colonization and infection. Natural anti-adhesive agents derived from food sources are generally safe and have the potential to inhibit the emergence of resistant bacteria. This comprehensive review explored diverse natural dietary components exhibiting anti-adhesive activities against several model enteric pathogens, including Helicobacter pylori, Salmonella enterica, Clostridium difficile, and three key diarrheagenic Escherichia coli (i.e., enterotoxigenic E. coli, enteropathogenic E. coli, and enterohemorrhagic E. coli). Investigating various anti-adhesive products will advance our understanding of current research of the field and inspire further development of these agents as potential nutraceuticals or adjuvants to improve the efficacy of conventional antibiotics.

Ovomucin Hydrolysates Reduce Bacterial Adhesion and Inflammation in Enterotoxigenic Escherichia coli (ETEC) K88-Challenged Intestinal Epithelial Cells

Enterotoxigenic Escherichia coli (ETEC) K88 is the most common cause of diarrhea in neonatal and postweaning pigs. After adhering to small intestinal epithelial cells via glycoprotein receptor recognition, the pathogen can produce enterotoxins, impair intestinal integrity, trigger watery diarrhea, and induce inflammation via nuclear factor κB (NF-κB) and mitogen-activated protein kinase phosphatase (MAPK) pathways. Inhibiting ETEC K88 adhesion to cell surfaces by interfering with the receptor-fimbriae recognition provides a promising strategy to prevent the initiation and progression of infection. Ovomucin is a highly glycosylated protein in chicken egg white with diverse bioactivities. Ovomucin hydrolysates prepared by the enzymes Protex 26L (OP) and pepsin/pancreatin (OPP) were previously revealed to prevent adhesion of ETEC K88 to IPEC-J2 cells. Herein, we investigated the protective effects of ovomucin hydrolysates on ETEC K88-induced barrier integrity damage and inflammation in IPEC-J2 and Caco-2 cells. Both hydrolysates inhibited ETEC K88 adhesion to cells and protected epithelial cell integrity by restoring transepithelial electronic resistance (TEER) values. Removing sialic acids in the hydrolysates reduced their antiadhesive capacities. Ovomucin hydrolysates suppressed ETEC-induced activation of NF-κB and MAPK signaling pathways in both cell lines. The ability of ETEC K88 in activating calcium/calmodulin-dependent protein kinase 2 (CaMK II), elevating intracellular Ca2+ concentration, and inducing oxidative stress was attenuated by both hydrolysates. In conclusion, this study demonstrated the potential of ovomucin hydrolysates to prevent ETEC K88 adhesion and alleviate inflammation and oxidative stress in intestinal epithelial cells.

Potassium diformate alleviated inflammation of IPEC-J2 cells infected with EHEC

Potassium diformate (KDF) is a kind of formate, which possesses the advantages of antimicrobial activity, growth promotion and preventing diarrhea in weaned piglets. However, the researches of KDF in animal production mostly focused on apparent indexes such as growth performance and the mechanisms of KDF on intestinal health have not been reported. Thus, porcine small intestinal epithelial cells (IPEC-J2) infected with Enterohemorrhagic Escherichia coli (EHEC) was used to investigate the role of KDF on alleviating intestinal inflammation in this study. The 0.125 mg/mL KDF treated IPEC-J2 cells for 6 h and IPEC-J2 cells challenged with 5 × 107 CFU/mL EHEC for 4 h were confirmed as the optimum concentration and time for the following experiment. The subsequent experiment was divided into four groups: control group (CON), EHEC group, KDF group, KDF+EHEC group. The results showed that KDF increased the cell viability and the gene expression levels of SGLT3 and TGF-β, while decreased the content of IL-1β compared with the CON group. The cell viability and the gene expressions of SGLT1, SGLT3, GLUT2, Claudin-1, Occludin and TGF-β, and the protein expression of ZO-1 in EHEC group were lower than those in CON group, whereas the gene expressions of IL-1β, TNF, IL-8 and TLR4, and the level of phosphorylation NF-кB protein were increased. Pretreatment with KDF reduced the content of IgM and IL-1β, the gene expressions of IL-1β, TNF, IL-8 and TLR4 and the level of phosphorylation NF-кB protein, and increased the gene expression of TGF-β and the protein expression of Occludin in IPEC-J2 cells infected EHEC. In conclusion, 0.125 mg/mL KDF on IPEC-J2 cells for 6 h had the beneficial effects on ameliorating the intestinal inflammation because of reduced pro-inflammatory cytokines and enhanced anti-inflammatory cytokines through regulating NF-кB signaling pathway under the EHEC challenge.

Dextran and levan exopolysaccharides from tempeh-associated lactic acid bacteria with bioactivity against enterotoxigenic Escherichia coli (ETEC)

Soybean tempeh contains bioactive carbohydrate that can reduce the severity of diarrhea by inhibiting enterotoxigenic Escherichia coli (ETEC) adhesion to mammalian epithelial cells. Lactic acid bacteria (LAB) are known to be present abundantly in soybean tempeh. Some LAB species can produce exopolysaccharides (EPS) with anti-adhesion bioactivity against ETEC but there has been no report of anti-adhesion bioactive EPS from tempeh-associated LAB. We isolated EPS-producing LAB from tempeh-related sources, identified them, unambiguously elucidated their EPS structure and assessed the bioactivity of their EPS against ETEC. Pediococcus pentosaceus TL, Leuconostoc mesenteroides WA and L. mesenteroides WN produced both dextran (α-1,6 linked glucan; >1000 kDa) and levan (β-2,6 linked fructan; 650-760 kDa) in varying amounts and Leuconostoc citreum TR produced gel-forming α-1,6-mixed linkage dextran (829 kDa). All four isolates produced EPS that could adhere to ETEC cells and inhibit auto-aggregation of ETEC. EPS-PpTL, EPS-LmWA and EPS-LmWN were more bioactive towards pig-associated ETEC K88 while EPS-LcTR was more bioactive against human-associated ETEC H10407. Our finding is the first to report on the bioactivity of dextran against ETEC. Tempeh is a promising source of LAB isolates that can produce bioactive EPS against ETEC adhesion and aggregation.

Protocatechuic acid and quercetin attenuate ETEC-caused IPEC-1 cell inflammation and injury associated with inhibition of necroptosis and pyroptosis signaling pathways

BACKGROUND

Necroptosis and pyroptosis are newly identified forms of programmed cell death, which play a vital role in development of many gastrointestinal disorders. Although plant polyphenols have been reported to protect intestinal health, it is still unclear whether there is a beneficial role of plant polyphenols in modulating necroptosis and pyroptosis in intestinal porcine epithelial cell line (IPEC-1) infected with enterotoxigenic Escherichia coli (ETEC) K88. This research was conducted to explore whether plant polyphenols including protocatechuic acid (PCA) and quercetin (Que), attenuated inflammation and injury of IPEC-1 caused by ETEC K88 through regulating necroptosis and pyroptosis signaling pathways.

METHODS

IPEC-1 cells were treated with PCA (40 μmol/L) or Que (10 μmol/L) in the presence or absence of ETEC K88.

RESULTS

PCA and Que decreased ETEC K88 adhesion and endotoxin level (P < 0.05) in cell supernatant. PCA and Que increased cell number (P < 0.001) and decreased lactate dehydrogenases (LDH) activity (P < 0.05) in cell supernatant after ETEC infection. PCA and Que improved transepithelial electrical resistance (TEER) (P < 0.001) and reduced fluorescein isothiocyanate-labeled dextran (FD4) flux (P < 0.001), and enhanced membrane protein abundance of occludin, claudin-1 and ZO-1 (P < 0.05), and rescued distribution of these tight junction proteins (P < 0.05) after ETEC infection. PCA and Que also declined cell necrosis ratio (P < 0.05). PCA and Que reduced mRNA abundance and concentration of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-8 (P < 0.001), and down-regulated gene expression of toll-like receptors 4 (TLR4) and its downstream signals (P < 0.001) after ETEC infection. PCA and Que down-regulated protein abundance of total receptor interacting protein kinase 1 (t-RIP1), phosphorylated-RIP1 (p-RIP1), p-RIP1/t-RIP1, t-RIP3, p-RIP3, mixed lineage kinase domain-like protein (MLKL), p-MLKL, dynamin- related protein 1 (DRP1), phosphoglycerate mutase 5 (PGAM5) and high mobility group box 1 (HMGB1) (P < 0.05) after ETEC infection. Moreover, PCA and Que reduced protein abundance of nod-like receptor protein 3 (NLRP3), nod-like receptors family CARD domain-containing protein 4 (NLRC4), apoptosis-associated speck-like protein containing a CARD (ASC), gasdermin D (GSDMD) and caspase-1 (P < 0.05) after ETEC infection.

CONCLUSIONS

In general, our data suggest that PCA and Que are capable of attenuating ETEC-caused intestinal inflammation and damage via inhibiting necroptosis and pyroptosis signaling pathways.

Effects of high- and low-fiber diets on intestinal oxidative stress in growing-finishing pigs

Feed is the most expensive facet of commercial pork production. In order to reduce feed costs, using high-fiber ingredients has become a common practice. Moderate levels of fiber can maintain intestinal physiological function and promote intestinal health. Oxidative stress is linked to impaired nutrient absorption and growth performance. This study investigated the effects of high-fiber (5.26% crude fiber) and low-fiber (2.46% crude fiber) diets on growth performance and intestinal oxidative stress parameters in growing-finishing pigs. Forty growing pigs with initial body weight (27.07 ± 1.26 kg) were randomly assigned to 2 treatment groups with 10 replicates of 2 pigs per pen. Pigs were weighed on day 35, 42, and 70. The feed intake was recorded daily to calculate growth performance parameters. On day 70, eight pigs in each treatment group were randomly selected and euthanized to obtain jejunum to measure oxidative stress status. Pigs fed a high-fiber diet were heavier than those fed a low-fiber diet on days 35, 42, and 70 (P < 0.05). During the whole feeding period, pigs fed a high-fiber diet had a higher average daily gain than those fed a low-fiber diet (P < 0.05). The low-fiber diet resulted in increased levels of malondialdehyde (P < 0.05) in the jejunum, suggesting that the low-fiber diet contributed to oxidative stress in the jejunum. The low-fiber diet also led to a significant increase in glutathione and oxidized glutathione levels (P < 0.05) in the jejunum, indicating that pigs fed a low-fiber diet needed to produce more antioxidant substances to cope with oxidative stress in the intestine. This was accompanied by a significant increase in the expression of glutathione synthesizing enzymes in the jejunum of the low-fiber group (P < 0.05). These results suggest that the high-fiber diet can improve growth performance and maintain intestinal health in growing-finishing pigs by reducing intestinal oxidative stress.

Review on Preventive Measures to Reduce Post-Weaning Diarrhoea in Piglets

In many countries, medical levels of zinc (typically as zinc oxide) are added to piglet diets in the first two weeks post-weaning to prevent the development of post-weaning diarrhoea (PWD). However, high levels of zinc constitute an environmental polluting agent, and may contribute to the development and/or maintenance of antimicrobial resistance (AMR) among bacteria. Consequently, the EU banned administering medical levels of zinc in pig diets as of June 2022. However, this may result in an increased use of antibiotic therapeutics to combat PWD and thereby an increased risk of further AMR development. The search for alternative measures against PWD with a minimum use of antibiotics and in the absence of medical levels of zinc has therefore been intensified over recent years, and feed-related measures, including feed ingredients, feed additives, and feeding strategies, are being intensively investigated. Furthermore, management strategies have been developed and are undoubtedly relevant; however, these will not be addressed in this review. Here, feed measures (and vaccines) are addressed, these being probiotics, prebiotics, synbiotics, postbiotics, proteobiotics, plants and plant extracts (in particular essential oils and tannins), macroalgae (particularly macroalgae-derived polysaccharides), dietary fibre, antimicrobial peptides, specific amino acids, dietary fatty acids, milk replacers, milk components, creep feed, vaccines, bacteriophages, and single-domain antibodies (nanobodies). The list covers measures with a rather long history and others that require significant development before their eventual use can be extended. To assess the potential of feed-related measures in combating PWD, the literature reviewed here has focused on studies reporting parameters of PWD (i.e., faeces score and/or faeces dry matter content during the first two weeks post-weaning). Although the impact on PWD (or related parameters) of the investigated measures may often be inconsistent, many studies do report positive effects. However, several studies have shown that control pigs do not suffer from diarrhoea, making it difficult to evaluate the biological and practical relevance of these improvements. From the reviewed literature, it is not possible to rank the efficacy of the various measures, and the efficacy most probably depends on a range of factors related to animal genetics and health status, additive doses used, composition of the feed, etc. We conclude that a combination of various measures is probably most recommendable in most situations. However, in this respect, it should be considered that combining strategies may lead to additive (e.g., synbiotics), synergistic (e.g., plant materials), or antagonistic (e.g., algae compounds) effects, requiring detailed knowledge on the modes of action in order to design effective strategies.

Lactobacillus reuteri 1 Enhances Intestinal Epithelial Barrier Function and Alleviates the Inflammatory Response Induced by Enterotoxigenic Escherichia coli K88 via Suppressing the MLCK Signaling Pathway in IPEC-J2 Cells

Intestinal epithelial barrier injury disrupts immune homeostasis and leads to many intestinal disorders. Lactobacillus reuteri (L. reuteri) strains can influence immune system development and intestinal function. However, the underlying mechanisms of L. reuteri LR1 that regulate inflammatory response and intestinal integrity are still unknown. The present study aimed to determine the effects of LR1 on the ETEC K88-induced intestinal epithelial injury on the inflammatory response, intestinal epithelial barrier function, and the MLCK signal pathway and its underlying mechanism. Here, we showed that the 1 × 109 cfu/ml LR1 treatment for 4 h dramatically decreased interleukin-8 (IL-8) and IL-6 expression. Then, the data indicated that the 1 × 108 cfu/ml ETEC K88 treatment for 4 h dramatically enhanced IL-8, IL-6, and tumor necrosis factor-α (TNF-α) expression. Furthermore, scanning electron microscope (SEM) data indicated that pretreatment with LR1 inhibited the ETEC K88 that adhered on IPEC-J2 and alleviated the scratch injury of IPEC J2 cells. Moreover, LR1 pretreatment significantly reversed the declined transepithelial electrical resistance (TER) and tight junction protein level, and enhanced the induction by ETEC K88 treatment. Additionally, LR1 pretreatment dramatically declined IL-8, IL-17A, IL-6, and TNF-α levels compared with the ETEC K88 group. Then, ETEC K88-treated IPEC-J2 cells had a higher level of myosin light-chain kinase (MLCK), higher MLC levels, and a lower Rho-associated kinase (ROCK) level than the control group, while LR1 pretreatment significantly declined the MLCK and MLC expression and enhanced ROCK level in the ETEC K88-challenged IPEC-J2 cells. Mechanistically, depletion of MLCK significantly declined MLC expression in IPEC-J2 challenged with ETEC K88 compared to the si NC+ETEC K88 group. On the other hand, the TER of the si MLCK+ETEC K88 group was higher and the FD4 flux in the si MLCK+ETEC K88 group was lower compared with the si NC+ETEC K88 group. In addition, depletion of MLCK significantly enhanced Claudin-1 level and declined IL-8 and TNF-α levels in IPEC-J2 pretreated with LR1 followed by challenging with ETEC K88. In conclusion, our work indicated that L. reuteri LR1 can decline inflammatory response and improve intestinal epithelial barrier function through suppressing the MLCK signal pathway in the ETEC K88-challenged IPEC-J2.

Invited review: strategic adoption of antibiotic-free pork production: the importance of a holistic approach

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage.

In Vitro Evaluation of Dietary Fiber Anti-Infectious Properties against Food-Borne Enterotoxigenic Escherichia coli

Dietary fibers have well-known beneficial effects on human health, but their anti-infectious properties against human enteric pathogens have been poorly investigated. Enterotoxigenic Escherichia coli (ETEC) is the main agent of travelers’ diarrhea, against which targeted preventive strategies are currently lacking. ETEC pathogenesis relies on multiple virulence factors allowing interactions with the intestinal mucosal layer and toxins triggering the onset of diarrheal symptoms. Here, we used complementary in vitro assays to study the antagonistic properties of eight fiber-containing products from cereals, legumes or microbes against the prototypical human ETEC strain H10407. Inhibitory effects of these products on the pathogen were tested through growth, toxin production and mucus/cell adhesion inhibition assays. None of the tested compounds inhibited ETEC strain H10407 growth, while lentil extract was able to decrease heat labile toxin (LT) concentration in culture media. Lentil extract and specific yeast cell walls also interfered with ETEC strain H10407 adhesion to mucin beads and human intestinal cells. These results constitute a first step in the use of dietary fibers as a nutritional strategy to prevent ETEC infection. Further work will be dedicated to the study of fiber/ETEC interactions within a complex gut microbial background.

Tripartite relationship between gut microbiota, intestinal mucus and dietary fibers: towards preventive strategies against enteric infections

The human gut is inhabited by a large variety of microorganims involved in many physiological processes and collectively referred as to gut microbiota. Disrupted microbiome has been associated with negative health outcomes and especially could promote the onset of enteric infections. To sustain their growth and persistence within the human digestive tract, gut microbes and enteric pathogens rely on two main polysaccharide compartments, namely dietary fibers and mucus carbohydrates. Several evidences suggest that the three-way relationship between gut microbiota, dietary fibers and mucus layer could unravel the capacity of enteric pathogens to colonise the human digestive tract and ultimately lead to infection. The review starts by shedding light on similarities and differences between dietary fibers and mucus carbohydrates structures and functions. Next, we provide an overview of the interactions of these two components with the third partner, namely, the gut microbiota, under health and disease situations. The review will then provide insights into the relevance of using dietary fibers interventions to prevent enteric infections with a focus on gut microbial imbalance and impaired-mucus integrity. Facing the numerous challenges in studying microbiota-pathogen-dietary fiber-mucus interactions, we lastly describe the characteristics and potentialities of currently available in vitro models of the human gut.

Pathogen Challenge and Dietary Shift Alter Microbiota Composition and Activity in a Mucin-Associated in vitro Model of the Piglet Colon (MPigut-IVM) Simulating Weaning Transition

Enterotoxigenic Escherichia coli (ETEC) is the principal pathogen responsible for post-weaning diarrhea in newly weaned piglets. Expansion of ETEC at weaning is thought to be the consequence of various stress factors such as transient anorexia, dietary change or increase in intestinal inflammation and permeability, but the exact mechanisms remain to be elucidated. As the use of animal experiments raise more and more ethical concerns, we used a recently developed in vitro model of piglet colonic microbiome and mucobiome, the MPigut-IVM, to evaluate the effects of a simulated weaning transition and pathogen challenge at weaning. Our data suggested that the tested factors impacted the composition and functionality of the MPigut-IVM microbiota. The simulation of weaning transition led to an increase in relative abundance of the Prevotellaceae family which was further promoted by the presence of the ETEC strain. In contrast, several beneficial families such as Bacteroidiaceae or Ruminococcaceae and gut health related short chain fatty acids like butyrate or acetate were reduced upon simulated weaning. Moreover, the incubation of MPigut-IVM filtrated effluents with porcine intestinal cell cultures showed that ETEC challenge in the in vitro model led to an increased expression of pro-inflammatory genes by the porcine cells. This study provides insights about the etiology of a dysbiotic microbiota in post-weaning piglets.

Source of fiber influences growth, immune responses, gut barrier function and microbiota in weaned piglets fed antibiotic-free diets

This study examined the impacts of different fiber sources on growth, immune status and gut health in weaned piglets fed antibiotic-free diets. Sixty piglets (BW = 8.18 ± 1.35 kg) were assigned to 3 dietary treatments based on BW and gender in a randomized complete block design (5 replicates/treatment and 4 piglets [2 barrows and 2 gilts]/replicate): (1) an antibiotic-free diet (control, CON); (2) CON + 6% wheat bran (WB); (3) CON + 4% sugar beet pulp (SBP). Dietary WB supplementation tended to increase ADG compared with CON from d 1 to 14 (P = 0.051) and from d 1 to 28 (P = 0.099). Supplementation of WB increased (P < 0.05) G:F compared with CON and SBP from d 1 to 14 and from d 1 to 28. Compared with CON, the addition of WB reduced (P < 0.05) diarrhea rate from d 1 to 14 and tended (P = 0.054) to reduce diarrhea rate from d 1 to 28. The addition of WB decreased (P < 0.05) serum diamine oxidase activity on d 14, and up-regulated (P < 0.05) ileal mRNA levels of occludin on d 28 when compared with CON. Piglets fed WB showed decreased (P < 0.05) serum interleukin-6 levels compared to those fed SBP and decreased (P < 0.05) ileal interleukin-8 levels compared to those fed CON and SBP on d 28. Supplementation of WB increased (P < 0.05) serum levels of immunoglobulin A (IgA), IgG and IgM compared with SBP on d 14, and increased (P < 0.05) the levels of serum IgA and ileal sIgA compared with CON and SBP on d 28. Piglets fed WB showed an enhanced (P < 0.05) α-diversity of cecal microbiota than those fed SBP, while piglets fed SBP showed reduced (P < 0.05) α-diversity of cecal microbiota than those fed CON. Compared with CON, the addition of WB elevated (P < 0.05) the abundance of Lachnospira and cecal butyric acid level. Piglets fed WB also showed increased (P < 0.05) abundances of Lachnospira and unclassified_f_Lachnospiraceae compared with those fed SBP. Collectively, the supplementation of WB to antibiotic-free diets improved performance, immune responses, gut barrier function and microbiota compared with the CON and SBP fed piglets. Therefore, supplementing weaned piglets with WB was more effective than SBP.

Impact of food-derived bioactive peptides on gut function and health

The gastrointestinal tract (GIT) is the largest interface between our body and the environment. It is an organ system extending from the mouth to the anus and functions for food intake, digestion, transport and absorption of nutrients, meanwhile providing protection from environmental factors, like toxins, antigens, and pathogens. Diet is one of the leading factors modulating the function of the GIT. Bioactive peptides presenting naturally in food or derived from food proteins during digestion or processing have been revealed multifunctional in diverse biological processes, including maintaining gut health and function. This review summarizes the available evidence regarding the effects of food-derived bioactive peptides on gut function and health. Findings and insights from studies based on in vitro and animal models are discussed. The gastrointestinal mucosa maintains a delicate balance between immune tolerance to nutrients and harmful components, which is crucial for the digestive system's normal functions. Dietary bioactive peptides positively impact gastrointestinal homeostasis by modulating the barrier function, immune responses, and gut microbiota. However, there is limited clinical evidence on the safety and efficacy of bioactive peptides, much less on the applications of dietary peptides for the treatment or prevention of diseases related to the GIT. Further study is warranted to establish the applications of bioactive peptides in regulating gut health and function.

Towards Zero Zinc Oxide: Feeding Strategies to Manage Post-Weaning Diarrhea in Piglets

Simple Summary

Zinc oxide (ZnO) supplementation at pharmacological doses in post-weaning piglets is a consolidated practice that allows efficient control of post-weaning diarrhea (PWD), a condition exacerbated by Escherichia coli F4 (K88) infections. Far from being completely elucidated, the multifactorial ZnO mechanism of action is in all likelihood exerted at the gastrointestinal level. However, increasing environmental concerns are arising from prolonged ZnO use. This article reviews the utilization of ZnO in piglets, the biological rationale behind its powerful activity, and the emerging threats that are leading towards a significant reduction in its use. Finally, a wide analysis of the strengths and weaknesses of innovative alternative strategies to manage PWD at the nutritional level is given.

Abstract

Zinc oxide (ZnO) at pharmacological doses is extensively employed in the pig industry as an effective tool to manage post-weaning diarrhea (PWD), a condition that causes huge economic losses because of its impact on the most pivotal phase of a piglet’s production cycle. In a multifactorial way, ZnO exerts a variety of positive effects along the entire gastrointestinal tract by targeting intestinal architecture, digestive secretions, antioxidant systems, and immune cells. ZnO also has a moderate antibacterial effect against Escherichia coli F4 (K88), the main causative agent of PWD. However, the environmental impact of ZnO and new emerging threats are posing serious questions to the sustainability of its extensive utilization. To work towards a future free from pharmacological ZnO, novel nutritional approaches are necessary, and many strategies have been investigated. This review article provides a comprehensive framework for ZnO utilization and its broad mode of action. Moreover, all the risks related to pharmacological ZnO levels are presented; we focus on European institutions’ decisions subsequently. The identification of a novel, complete solution against PWD should be accompanied by the adoption of holistic strategies, thereby combining good management practices to feeding approaches capable of mitigating Escherichia coli F4 (K88) infections and/or lowering ZnO utilization. Promising results can be obtained by adjusting diet composition or employing organic acids, natural identical compounds, polyphenol-rich extracts, prebiotics, and probiotics.

Marine Microalgae Biomolecules and Their Adhesion Capacity to Salmonella enterica sv. Typhimurium

Different molecules have been tested as analog receptors due to their capacity to bind bacteria and prevent cell adhesion. By using in vitro assays, the present study characterized the aqueous and alkaline extracts from microalgae Pavlova lutheri and Pavlova gyrans and evaluated the capacity of these extracts to adhere to enterobacteria (Salmonella Typhimurium). The aqueous and alkaline extracts of both species were fractionated via freeze-thawing, giving rise to soluble and insoluble (precipitate) fractions in cold water. The obtained fractions were studied using thermogravimetric, methylation analyses, and using 1D and 2D NMR techniques. The cold-water-soluble fractions obtained from the aqueous extracts were mainly composed of highly branched (1→3),(1→6)-β-glucans, whereas the cold-water-precipitate fractions were constituted by (1→3)-β-glucans. The alkaline extract fractions showed similar compositions with a high protein content, and the presence of glycosides (sulfoquinovosylglycerol (SQG), digalactosylglycerol (DGG)), and free fatty acids. The linear (1→3)-β-glucans and the alkaline extract fractions showed an adhesion capacity toward Salmonella. The chemical composition of the active fractions suggested that the presence of three-linked β-glucose units, as well as microalgal proteins and glycosides, could be important in the adhesion process. Therefore, these microalgal species possess a high potential to serve as a source of anti-adhesive compounds.

Microbiota Composition and Functional Profiling Throughout the Gastrointestinal Tract of Commercial Weaning Piglets

Dietary, environmental, and social stresses induced by weaning transition in pig production are associated with alterations of gut microbiota, diarrhea, and enteric infections. With the boom of -omic technologies, numerous studies have investigated the dynamics of fecal bacterial communities of piglets throughout weaning but much less research has been focused on the composition and functional properties of microbial communities inhabiting other gastrointestinal segments. The objective of the present study was to bring additional information about the piglet bacterial and archaeal microbiota throughout the entire digestive tract, both at the structural level by using quantitative PCR and high-throughput sequencing, and on functionality by measurement of short-chain fatty acids and predictions using Tax4Fun tool. Our results highlighted strong structural and functional differences between microbial communities inhabiting the fore and the lower gut as well as a quantitatively important archaeal community in the hindgut. The presence of opportunistic pathogens was also noticed throughout the entire digestive tract and could trigger infection emergence. Understanding the role of the intestinal piglet microbiota at weaning could provide further information about the etiology of post-weaning infections and lead to the development of effective preventive solutions.

The use of starter cultures in the table olive fermentation can modulate the antiadhesive properties of brine exopolysaccharides against enterotoxigenic Escherichia coli

The present study aimed to evaluate different mates of Candida boidinii and Lactobacillus pentosus strains as starters in green table olive fermentation. Changes in fermentation characteristics as well as changes in the functional properties of the microbial exopolysaccharides (EPS) produced during the process were registered. The in vitro adhesion test demonstrated that most EPS samples could specifically attach ETEC K88. In vitro studies with porcine intestinal cells showed the improved blocking activity of the fimbria (blocking test) when the mutant strain L. pentosus 119-14MT was used alone as a starter. All EPS samples showed the ability to block receptors in the cells (exclusion test) although without differences between starter treatments. In the displacement test, EPS samples failed to remove the pathogen once attached. According to these results, L. pentosus 119-14MT, a high EPS variant, seemed to be the most effective starter improving the anti-adhesive properties of brine EPS and increasing its ability to block the ETEC K88 fimbria. These results illustrate that the anti-adhesive properties of the EPSs produced during the traditional fermentation of olives could be modulated by the use of defined starters. This opens the door to new fermentation processes aimed to produce green table olives as functional food to prevent ETEC diarrhea.

A soluble and highly fermentable dietary fiber with carbohydrases improved gut barrier integrity markers and growth performance in F18 ETEC challenged pigs1

This study aimed to evaluate the effects of a source of dietary soluble (SF) and insoluble fiber (IF) without or with exogenous carbohydrases (xylanase, β-glucanase, and pectinase) on diarrhea incidence, selected immune responses, and growth performance in enterotoxigenic Escherichia coli (ETEC)-challenged pigs. Sixty weaned pigs (6.9 ± 0.1 kg BW, ~23 d of age) were blocked by initial BW and placed in individual pens. Pens were randomly assigned to one of six treatments (n = 10 per treatment), including a nonchallenged control (NC), a positive challenge control (PC), the PC + a soluble fiber diet (10% sugar beet pulp) without (SF-) or with carbohydrases (SF+), and PC + an IF diet (15% corn distillers dried grains with solubles) without (IF-) or with carbohydrases (IF+). The control diet was primarily based on corn and soybean meal with 13.5% whey powder. The two sources of fiber were added at the expense of cornstarch in the control diet. Pigs were orally inoculated with 6 mL hemolytic F18 ETEC (~3.5 × 109 cfu/mL) or sham infected with 6 mL phosphate-buffered saline on day 7 (0 d postinoculation, dpi) postweaning. All ETEC challenged pigs were confirmed to be genetically susceptible to F18 ETEC. Pigs had free access to feed and water throughout the 14-d trial. Pig BW and feed intake were recorded on dpi -7, 0, and 7 or 8. Fecal swabs were collected on dpi -7, 0, 1, 2, 3, 5, and 7 or 8 to evaluate hemolytic E. coli shedding. Fecal score was visually ranked daily postchallenge to evaluate diarrhea incidence. Blood samples were collected on dpi -1, 3, and 7 or 8 at necropsy and intestinal tissues were collected at necropsy. Pigs on PC had lower dpi 1 to 7 ADG and ADFI than those on NC (P < 0.05). Compared with PC pigs, SF+ pigs had greater ADG during both pre- and postchallenge period (P < 0.05). The IF- increased postchallenge diarrhea incidence compared with PC (P < 0.05). Pigs on SF- had lower ileal E. coli attachment than PC (P < 0.05). The SF+ reduced haptoglobin and IF+ reduced C-reactive protein on dpi 3 compared with PC (P < 0.05). Compared with PC pigs, SF+ pigs tended to have lower ileal tumor necrosis factor alpha and greater ileal occludin (OCLN) mRNA (P < 0.10) and had greater (P < 0.05) colonic OCLN mRNA levels. Collectively, IF- increased incidence of diarrhea and fecal E. coli shedding compared with PC. The SF+ pigs had improved growth compared with PC pigs, likely due in part to a reduction in inflammatory intermediates.

ANTIMICROBIAL ACTIVITY OF ETHANOLIC EXTRACTS FROM Commiphora leptophloeos (MART.) J. B. GILLETT AGAINST Staphylococcus SPP. ISOLATED FROM CASES OF MASTITIS IN RUMINANTS

Abstract Considering the therapeutic potential of medicinal plants as alternatives to antibiotic therapy, the research aims to evaluate the antimicrobial activity of Commiphora leptophloeos against isolates of Staphylococcus spp. from the milk of ruminants with subclinical mastitis. For this, the crude ethanolic extract from the bark and leaves of Commiphora leptophloeos was prepared, with these being chemically characterized by HPLC-DAD-MS and by MALDI-TOF. The extracts were then evaluated as to their antimicrobial effects against 60 isolates of Staphylococcus spp. through the broth microdilution technique to determine the minimum bactericidal concentration. In addition, the extracts were evaluated as to their ability to interfere with biofilm formation and with the already established biofilm. Although all tested extracts showed antimicrobial action, lower MBC values were recorded for the bark extract in the concentration 781.2 µg/mL (25/60). The extracts of the bark and leaves were able to interfere with the initial stages of biofilm formation, but there was no interference of the extract on the established biofilm. There was a high sensitivity of Staphylococcus spp. isolates from subclinical mastitis cases in ruminants when subjected to the extracts from bark and leaves of Commiphora leptophloeos, as well as regarding the ability of extracts to interfere in biofilm formation, indicating their potential in the use for ruminant mastitis therapy.

Exopolysaccharides from olive brines could reduce the adhesion of ETEC K88 to intestinal epithelial cells

This study aims to explore the biological functions of the isolated exopolysaccharides (EPSs) produced during the industrial fermentation of olives against enterotoxigenic E. coli (ETEC) K88. Exopolysaccharides were isolated from five industrial fermenters. Analysis of their monosaccharide composition by GLC revealed that the main components were glucose (27%-50%) and galactose (23%-33%) followed by rhamnose (4-23%) and arabinose (6-17%). The 1H NMR spectrum showed a very similar profile between samples, and a more in-depth analysis revealed the presence of an α-pyranose in the form of α-d-Glcp-(1→) and two different α-furanoses, with chemicals shift values, suggesting the presence of α-d-Glcf and α-d-Galf. Miniaturized in vitro tests demonstrated the ability of EPS samples to attach specifically to ETEC K88 (P < 0.05) with variable intensities. The competition test did not show the ability to block the ETEC K88 adhesion to IPEC-J2 cells; however, in the displacement test, all EPS samples were shown to effectively remove the pathogens attached to the cells (P < 0.01). These results suggest that the EPSs produced during the fermentation of table green olives could interfere with the attachment of opportunistic pathogens onto the intestinal epithelial cells. This would open the possibility of novel functional properties for this traditional Mediterranean fermented food and for the isolated EPSs as candidates for nutraceutics to be used in human and/or animal diets in the prevention and treatment of ETEC diarrhoea.

Glycomacropeptide Reduces Intestinal Epithelial Cell Barrier Dysfunction and Adhesion of Entero-Hemorrhagic and Entero-Pathogenic Escherichia coli in Vitro

In recent years, the potential of glycosylated food components to positively influence health has received considerable attention. Milk is a rich source of biologically active glycoconjugates which are associated with antimicrobial, immunomodulatory, anti-adhesion, anti-inflammatory and prebiotic properties. Glycomacropeptide (GMP) is the C-terminal portion of kappa-casein that is released from whey during cheese-making by the action of chymosin. Many of the biological properties associated with GMP, such as anti-adhesion, have been linked with the carbohydrate portion of the protein. In this study, we investigated the ability of GMP to inhibit the adhesion of a variety of pathogenic Escherichia coli strains to HT-29 and Caco-2 intestinal cell lines, given the importance of E. coli in causing bacterial gastroenteritis. GMP significantly reduced pathogen adhesion, albeit with a high degree of species specificity toward enteropathogenic E. coli (EPEC) strains O125:H32 and O111:H2 and enterohemorrhagic E. coli (EHEC) strain 12900 O157:H7. The anti-adhesive effect resulted from the interaction of GMP with the E. coli cells and was also dependent on GMP concentration. Pre-incubation of intestinal Caco-2 cells with GMP reduced pathogen translocation as represented by a decrease in transepithelial electrical resistance (TEER). Thus, GMP is an effective in-vitro inhibitor of adhesion and epithelial injury caused by E. coli and may have potential as a biofunctional ingredient in foods to improve gastrointestinal health.

Enzymatic Synthesis and Purification of Galactosylated Chitosan Oligosaccharides Reducing Adhesion of Enterotoxigenic Escherichia coli K88

Enterotoxigenic Escherichia coli (ETEC) K88 causes diarrhea in weaned piglets and represent a suitable model system for ETEC causing childhood diarrhea. This study aimed to evaluate the effects of oligosaccharides against ETEC K88 adhesion to porcine erythrocytes with two bioassays. Galactosylated chitosan-oligosaccharides (Gal-COS) were synthesized through transgalactosylation by β-galactosidase. Fractions 2-5 of Gal-COS were obtained through cation exchange and size exclusion chromatography. Fractions 2-5 of acetylated Gal-COS were obtained through chemical acetylation followed by size exclusion chromatography. Gal-COS F2 containing the largest oligosaccharides had the highest antiadhesion activity with the minimum inhibitory concentration of 0.22 g/L, followed by F3 and F4. Acetylation of Gal-COS decreased their ability to reduce ETEC K88 adhesion. The composition of active oligosaccharides was determined with LC-MS. Galactosylation of COS produces oligosaccharides which reduce ETEC K88 adhesion; moreover, resulting oligosaccharides match the composition of human milk oligosaccharides, which prevent adhesion of multiple pathogens.

Review on the effects of potential prebiotics on controlling intestinal enteropathogens Salmonella and Escherichia coli in pig production

Salmonella enterica serotypes (Salmonella sp.) are the second cause of bacterial foodborne zoonoses in humans after campylobacteriosis. Pork is the third most important cause for outbreak-associated salmonellosis, and colibacillosis is the most important disease in piglets and swine. Attachment to host cells, translocation of effector proteins into host cells, invasion and replication in tissues are the vital virulence steps of these pathogens that help them to thrive in the intestinal environment and invade tissues. Feed contamination is an important source for Salmonella infection in pig production. Many on-farm feeding strategies intervene to avoid the introduction of pathogens onto the farm by contaminated feeds or to reduce infection pressure when pathogens are present. Among the latter, prebiotics could be effective at protecting against these enteric bacterial pathogens. Nowadays, a wide range of molecules can potentially serve as prebiotics. Here, we summarize the prevalence of Salmonella sp. and Escherichia coli in pigs, understanding of the mechanisms by which pathogens can cause disease, the feed related to pathogen contamination in pigs and detail the mechanisms on which prebiotics are likely to act in order to fulfil their protective action against these pathogens in pig production. Many different mechanisms involve the inhibition of Salmonella and E. coli by prebiotics such as coating the host surface, modulation of intestinal ecology, downregulating the expression of adhesin factors or virulence genes, reinforcing the host immune system.

Effects of medium-chain fatty acids on the structure and immune response of IPEC-J2 cells

Medium-chain fatty acids (MCFAs) have been suggested as an alternative to the use of antibiotics in animal nutrition with promising results. First, we studied the sensitivity of Salmonella Enteritidis and an enteropathogenic Escherichia coli strain against caprylic (C8), capric (C10) and lauric (C12) acids. A porcine in vitro model using the porcine cell line IPEC-J2 was used to test the effects of MCFAs on structural and immunological traits without and with a concomitant challenge with E. coli or S. Enteritidis. The three MCFAs exerted an inhibitory effect on bacterial growth, stronger for C12 than C8 or C10, S. Enteritidis being more sensitive than the E. coli strain. Flow cytometry showed a numeric concentration dependent increase in the adhesion of E. coli or S. Enteritidis to IPEC-J2 cells. Measurement of transepithelial electrical resistance after bacterial challenge showed negative effects of all MCFAs on IPEC-J2 cells at the highest concentrations. Immune parameters were affected by C8, since a concentration dependent effect starting at 5 mM was observed for mRNA expression of IL-6 and TLR-4 (up-regulated) and IL-8 (down-regulated). TLR-4 was up-regulated with C10 at 2 and 5 mM. The three MCFAs affected also the epithelial morphology through down-regulation of Occludin and up-regulation of Claudin-4 expression. In conclusion, the three MCFAs under study influenced bacterial growth rates and modified the gene expression to a different degree in the cell line IPEC-J2 but the effect on the morphological structure and response of the cells after bacterial challenge could not be assessed. Although these tests show a prior estimation of MCFAs effects in intestinal epithelium, in vivo confirmation is still needed.

Effects of casein glycomacropeptide supplementation on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses in Escherichia coli K88 challenged piglets

Casein glycomacropeptide (CGMP) is a bioactive peptide derived from milk with multiple functions. This study was aimed at evaluating the effects of CGMP as a potential feed additive on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses of Escherichia coli K88 (E. coli K88) challenged piglets. Eighteen weaning piglets were randomly assigned to three groups. Control group and K88 challenged group received a basal diet, and CGMP treated group received the basal diet supplemented with 1% of CGMP powder. The trail lasted for 12 days, K88 was orally administered to the piglets of K88 challenged group and CGMP treated group on days 8-10. The results showed that the diet containing 1% CGMP significantly alleviated the decrease in average daily gain (P < 0.05), increase in pathogenic bacteria amounts in intestinal contents (P < 0.05), intestinal morphology (P > 0.05) and barrier permeability damage (P < 0.05), and acute inflammatory response (P < 0.05) induced by E. coli K88 infection. In conclusion, CGMP supplementation in the diet protected the weaning piglets against E. coli K88 infection.

Surfaces for competitive selective bacterial capture from protein solutions

Active surfaces that form the basis for bacterial sensors for threat detection, food safety, or certain diagnostic applications rely on bacterial adhesion. However, bacteria capture from complex fluids on the active surfaces can be reduced by the competing adsorption of proteins and other large molecules. Such adsorption can also interfere with device performance. As a result, multiple upstream processing steps are frequently employed to separate macromolecules from any cells, which remain in the buffer. Here, we present an economical approach to capture bacteria, without competitive adsorption by proteins, on engineered surfaces that do not employ biomolecular recognition, antibodies, or other molecules with engineered sequences. The surfaces are based on polyethylene glycol (PEG) brushes that, on their own, repel both proteins and bacteria. These PEG brushes backfill the surface around sparsely adsorbed cationic polymer coils (here, poly-L-lysine (PLL)). The PLL coils are effectively embedded within the brush and produce locally cationic nanoscale regions that attract negatively charged regions of proteins or cells against the steric background repulsion from the PEG brush. By carefully designing the surfaces to include just enough PLL to capture bacteria, but not enough to capture proteins, we achieve sharp selectivity where S. aureus is captured from albumin- or fibrinogen-containing solutions, but free albumin or fibrinogen molecules are rejected from the surface. Bacterial adhesion on these surfaces is not reduced by competitive protein adsorption, in contrast to performance of more uniformly cationic surfaces. Also, protein adsorption to the bacteria does not interfere with capture, at least for the case of S. aureus, to which fibrinogen binds through a specific receptor.

Recent advances in adherence and invasion of pathogenic Escherichia coli

PURPOSE OF REVIEW

Colonization of the host epithelia by pathogenic Escherichia coli is influenced by the ability of the bacteria to interact with host surfaces. Because the initial step of an E. coli infection is to adhere, invade, and persist within host cells, some strategies used by intestinal and extraintestinal E. coli to infect host cell are presented.

RECENT FINDINGS

This review highlights recent progress understanding how extraintestinal pathogenic E. coli strains express specific adhesins or invasins that allow colonization of the urinary tract or the meninges, while intestinal E. coli strains are able to colonize different regions of the intestinal tract using other specialized adhesins or invasins. Finally, evaluation of different diets and environmental conditions regulating the colonization of these pathogens is discussed.

SUMMARY

Discovery of new interactions between pathogenic E. coli and the host epithelial cells unravels the need for more mechanistic studies that can provide new clues regarding how to combat these infections.

Exopolysaccharides synthesized by Lactobacillus reuteri protect against enterotoxigenic Escherichia coli in piglets

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in piglets; ETEC cells colonize the intestinal mucosa with adhesins and deliver toxins that cause fluid loss. This study determined the antiadhesive properties of bacterial exopolysaccharides (reuteran and levan) and related glycans (dextran and inulin) in a small intestinal segment perfusion (SISP) model. The SISP model used 10 jejunal segments from 5-week-old piglets. Five segments were infected with ETEC expressing K88 fimbriae (ETEC K88), while five segments were treated with saline. Every two segments (ETEC and non-ETEC infected) were infused with 65 ml of 10 g liter(-1) of glycans or saline (control) for 8 h. High-resolution melting-curve (HRM) quantitative PCR (qPCR) indicated that E. coli is the dominant bacterium in infected segments, while other bacteria were predominant in noninfected segments. Infection by ETEC K88 was also verified by qPCR; gene copy numbers of K88 fimbriae and the heat-labile toxin (LT) in mucosal scrapings and outflow fluid of infected segments were significantly higher than those in noninfected segments. Genes coding for K88 fimbriae and LT were also detected in noninfected segments. LT amplicons from infected and noninfected segments were 99% identical over 481 bp, demonstrating the presence of autochthonous ETEC K88. All glycans reduced fluid loss caused by ETEC K88 infection. Reuteran tended (P = 0.06) to decrease ETEC K88 levels in mucosal scraping sample, as judged by qPCR. Fluorescent in situ hybridization analysis demonstrated that reuteran significantly (P = 0.012) decreased levels of adherent ETEC K88. Overall, reuteran may prevent piglet diarrhea by reducing adhesion of ETEC K88.

A proteinaceous fraction of wheat bran may interfere in the attachment of enterotoxigenic E. coli K88 (F4+) to porcine epithelial cells

Wheat bran (WB) from Triticum aestivum has many beneficial effects on human health. To the best of our knowledge, very little has been published about its ability to prevent pathogenic bacterial adhesion in the intestine. Here, a WB extract was fractionated using different strategies, and the obtained fractions were tested in different in vitro methodologies to evaluate their interference in the attachment of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal porcine epithelial cells (IPEC-J2) with the aim of identifying the putative anti-adhesive molecules. It was found that a proteinaceous compound in the >300-kDa fraction mediates the recognition of ETEC K88 to IPEC-J2. Further fractionation of the >300-kDa sample by size-exclusion chromatography showed several proteins below 90 kDa, suggesting that the target protein belongs to a high-molecular-weight (MW) multi-component protein complex. The identification of some relevant excised bands was performed by mass spectrometry (MS) and mostly revealed the presence of various protease inhibitors (PIs) of low MW: Serpin-Z2B, Class II chitinase, endogenous alpha-amylase/subtilisin inhibitor and alpha-amylase/trypsin inhibitor CM3. Furthermore, an incubation of the WB extract with ETEC K88 allowed for the identification of a 7S storage protein globulin of wheat, Globulin 3 of 66 kDa, which may be one of the most firmly attached WB proteins to ETEC K88 cells. Further studies should be performed to gain an understanding of the molecular recognition of the blocking process that takes place. All gathered information can eventually pave the way for the development of novel anti-adhesion therapeutic agents to prevent bacterial pathogenesis.