Pro-inflammatory cytokine expression and the STAT1/3 pathway in canine chronic enteropathy and intestinal T-cell lymphoma

The accumulation of intraepithelial lymphocytes (IELs) is a histopathological feature of canine chronic enteropathy (CE), and IELs are considered the cells of origin of intestinal T-cell lymphoma (ITCL). However, the pathogenic mechanism of IEL activation in CE remains unclear. This study hypothesized that the expression of proinflammatory cytokines, associated with cytotoxic T/NK-cell activation, is upregulated in CE and ITCL, and examined the expression of IFN-γ, IL-2, IL-12p35, IL-12p40, IL-15, and IL-21 and the downstream signal transducers and activators of transcription (STAT) pathway in the duodenal mucosa of dogs without lesions (n = 11; NC), with IEL-CE (n = 19; CE without intraepithelial lymphocytosis), IEL+CE (n = 29; CE with intraepithelial lymphocytosis), and with ITCL (n = 60). Quantitative polymerase chain reaction (PCR) revealed that IFN-γ and IL-21 were higher in IEL+CE than in IEL-CE or NC. Western blot revealed upregulation of STAT1 and STAT3 in IEL+CE. Double-labeling immunohistochemistry revealed a positive correlation between the Ki67 index of CD3+ T-cells and IFN-γ expression levels. Immunohistochemistry revealed a higher ratio of p-STAT1-positive villi in IEL+CE and ITCL than IEL-CE and NC, which positively correlated with IFN-γ expression levels. Among the 60 ITCL cases, neoplastic lymphocytes were immunopositive for p-STAT1 in 28 cases and p-STAT3 in 29 cases. These results suggest that IFN-γ and IL-21 contribute to the pathogenesis of IEL+CE, and IFN-γ may be involved in T-cell activation and mucosal injury in CE. STAT1 and STAT3 activation in ITCL cells suggests a role for the upregulation of the STAT pathway in the pathogenesis of ITCL.

Chlorogenic acid ameliorates intestinal inflammation by inhibiting NF-κB and endoplasmic reticulum stress in lipopolysaccharide-challenged broilers

Intestinal inflammation is a primary contributor to poor growth performance during poultry production. Chlorogenic acid (CGA) is a natural phenolic acid that exhibits superior anti-inflammatory activity and improved intestinal health. To investigate the protective effects and molecular mechanisms of CGA during intestinal inflammation in lipopolysaccharide (LPS)-challenged broilers, we randomly divided 288 one-day-old male Cobb broilers into 4 groups: a control group fed a basal diet (CON group), a basal diet + LPS group (LPS group), and 2 basal diet groups fed 500 or 750 mg/kg CGA + LPS (CGA_500 or CGA_750 groups). Broilers were injected with LPS or saline at 15, 17, 19, and 21 d old. Chlorogenic acid supplementation improved the growth performance of LPS-challenged broilers by increasing average daily gain (ADG) and reducing feed/gain (F/G) ratios (P < 0.05). CGA also improved intestinal barrier function in LPS-challenged boilers by enhancing jejunum morphology and integrity, decreasing intestinal permeability, and increasing occludin 3, zonula occludens-1, and mucin 2 expression (P < 0.05). CGA supplementation also improved systemic and jejunum antioxidant capacity by significantly enhancing glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activities (P < 0.05), and reducing malonaldehyde (MDA) and protein carbonyl (PCO) levels (P < 0.05). Chlorogenic acid supplementation reduced systemic and jejunum pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, and IL-12) and increased anti-inflammatory cytokines (IL-10) in LPS-challenged broilers (P < 0.05) by inhibiting the toll like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway (P < 0.05). In addition, the protective effects of CGA toward intestinal inflammation and apoptosis appeared to be correlated with inhibited endoplasmic reticulum (ER) stress (P < 0.05). In summary, CGA supplementation improved intestinal morphology and integrity by inhibiting TLR4/NF-κB and ER stress pathways, which potentially reduced oxidative stress and inflammation, and ultimately improved the growth performance of LPS-challenged broilers.

Research Note: The effect of photoperiod on the NLRP3 inflammasome and gut microbiota in broiler chickens

The present study aimed to investigate the effect of photoperiod on the intestinal inflammation and gut microbiota. A total of 96 broiler chickens were divided into 2 groups and fed separately under 2 different photoperiods (12L:12D group and 23L:1D group) for 21 d. The results showed that the photoperiod of 23L:1D damaged duodenal tissue structure (intestinal villus erosion, mucosal epithelial cell detachment, and inflammatory cell infiltration), significantly increased the concentration of inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α) and significantly increased the mRNA expression levels and protein expression levels of NOD-, LRR-, pyrin domain-containing protein 3 (NLRP3) and caspase1 (P <0.05) compared with 12L:12D, which indicating that extended photoperiod induced intestinal injury and activated NLRP3 inflammasome. 16S rRNA sequencing analysis revealed that Bacteroides was significantly decreased, Ruminococcus_torques_group, norank_f_Desulfovibrionaceae, GCA-900066575, Defluviitaleaceae_UCG-011, Lachnospiraceae_FCS020_group, norank_f_UCG-010 and norank_f_norank_o_Clostridia_vadinBB60_group and were significantly increased in the 23L:1D group, compared with the 12L:12D group (P < 0.05). The correlation analysis between differential microbial communities and intestinal inflammation showed that the relative abundance of Bacteroides was negatively correlated with the mRNA expression level of NLRP3 (P < 0.05) and the relative abundance of Ruminococcus_torques_group was positively correlated with the mRNA expression level of NLRP3 (P < 0.05). linear discriminant analysis (LDA) effect size (LEfSe) results (LDA > 4) showed that the relative abundance of Bacteroides was dramatically higher (P < 0.05) in the 12L:12D group, whereas the relative abundance of Ruminococcus_torques_group was noticeably higher (P < 0.05) in the 23L:1D group. By the comprehensive analysis of the gut microbiota, the interaction of gut microbiota (Bacteroides and Ruminococcus_torques_group) and NLRP3 inflammasome may contribute to the intestinal injury under the condition of extended photoperiod.

Hypocobalaminaemia in dogs with acute gastrointestinal diseases

OBJECTIVES

The objectives of this study were to investigate the prevalence of hypocobalaminaemia in dogs with acute gastrointestinal diseases and to evaluate its relationship with disease severity and outcome.

MATERIALS AND METHODS

Medical records of dogs presented for acute gastrointestinal signs that a serum cobalamin concentration measured between September 2019 and 2021 were included in this study. Hypocobalaminaemia was defined as serum cobalamin concentration <200 pmol/L, and low-normal cobalamin was defined as serum cobalamin concentration of 200 to 295 pmol/L. Duration of clinical signs prior to presentation, Acute Patient Physiologic and Laboratory Evaluation (APPLE) fast score, length of hospitalisation and outcome were recorded.

RESULTS

Thirty-three dogs were included. Seventeen dogs were diagnosed with acute gastrointestinal disease of unknown aetiology, seven dogs with parvoviral enteritis, three dogs with acute haemorrhagic diarrhoea syndrome and six dogs with miscellaneous diseases. The prevalence of hypocobalaminaemia in this population was 30.3% and low-normal cobalamin concentration was detected in 18.2% of dogs. There was no statistically significant relationship between the detection of hypocobalaminaemia or low-normal cobalamin and the duration of clinical signs before presentation, length of hospitalisation or Acute Patient Physiologic and Laboratory Evaluation fast score on admission. Mortality rate was 3%.

CLINICAL SIGNIFICANCE

Hypocobalaminaemia and low-normal cobalamin are common findings in dogs with acute gastrointestinal diseases. The therapeutic significance and potential implications for prognosis of hypocobalaminaemia in these patients requires further investigation.

Effects of fecal microbiota transplantation and fecal virome transplantation on LPS-induced intestinal injury in broilers

The interesting roles and efficiencies of fecal microbiota transplantation (FMT) have attracted considerable attention and have been gradually evidenced in specific animal models. While the growing evidence that bacteriophages play roles in FMT efficacy has attracted considerable interest. In this study, we aimed to explore the effects of FMT and fecal virome transplantation (FVT) in improving inflammatory damage and ileal microbiota disorder in broilers. A total of 224 Arbor Acres broilers were selected at 1-day-old and randomly divided into the following 4 groups, with 56 broilers in each group: the CON group (the negative control group, sterile physiological saline injection + sterile phosphate-buffered saline (PBS) solution gavage), LPS group (the positive control group, lipopolysaccharide (LPS) injection + sterile PBS solution gavage), LPS + FMT group (LPS injection + FMT solution gavage), LPS + FVT group (LPS injection + FVT solution gavage). The results showed that: LPS injection significantly upregulated the mRNA expression levels of IFN-γ (P < 0.05) and IL-8 (P < 0.001) in ileal mucosa of broilers at 11th day of age (D11), while LPS + FMT and LPS + FVT did not; LPS injection significantly upregulated the mRNA expression of ZO-1 in ileal mucosa at D11 (P < 0.01), while LPS + FMT and LPS + FVT did not; at D11, compare to CON group, LPS injection and LPS + FMT significantly increased the relative abundance of virulence factor Rab2 interacting conserved protein A-related genes in broiler ileum contents (P < 0.05), while LPS + FVT had no significant difference with CON group (P > 0.05); at D11, LPS injection significantly downregulated the biosynthesis of antibiotics pathway (P < 0.05) in the ileal contents, while LPS + FVT did not. In conclusion, both FMT and FVT could promote the recovery of inflammation caused by LPS. Furthermore, FVT had shown less disadvantage stimulation on the broilers and could reduce the risk of transmission of pathogenic genes, compared to FMT.

Evaluation of Natural Antimicrobial Substances Blend as a Replacement for Antibiotic Growth Promoters in Broiler Chickens: Enhancing Growth and Managing Intestinal Bacterial Diseases

In recent years, commercial use of antibiotic growth promoter (AGP) has restrictions due to drug resistance against intestinal pathogenic bacteria: Escherichia coli, Salmonella, and Clostridium perfringens. Currently there is no single non-antibiotic treatment approach that is effective against intestinal illnesses in broiler chicken. Hence, present study aimed to analyze efficacy of blend of natural antimicrobial substances (probiotics, prebiotics, organic acids, and essential oils blend named as AGPR) as replacers of AGPs (BMD and CTC) for promoting growth and controlling bacterial diseases in aforementioned three microbes challenged broiler chickens. Effects of treatments (5) and microbes (3) on growth and health performances in experimental birds were analyzed using two factorial ANOVA. Health performance like pathogen loads, morbidity and mortality was considerably reduced by AGPR. Similarly small intestine villi morphometry, nutrition utilization, serum immune response, and carcass yield, was improved significantly by AGPR equivalent to AGPs. Further, growth performance like body weight gain, feed efficiency was also improved by AGPR compared to control but, non-significantly. Among three microbes, E. coli infections had higher morbidity and mortality rates. It was concluded that AGPR blend could be used to improve growth and control the intestinal bacterial infections in broiler chickens as an alternative for AGPs.

MEDICAL-SURGICAL MANAGEMENT OF INTESTINAL INFECTION BY PROSTHENORCHIS ELEGANS IN NONHUMAN PRIMATES FROM COSTA RICA

Parasitism is one of the most important diseases in nonhuman primates (NHP). Parasitism by Prosthenorchis elegans can be a threat to health and conservation of NHP in Costa Rica. Surgical management of intestinal acanthocephalan infection in two squirrel monkeys (Saimiri oerstedii) and one white-faced monkey (Cebus imitator) is described as an alternative to the lack of pharmacologic control options when there is a high burden of parasites present. A complete physical evaluation, including medical ultrasound techniques, allow for diagnosis of the parasite and its lesions. When animals present with a high burden of parasites, surgical management has shown to promote good health outcomes and increase the probability of survival.

Caffeic acid supplementation ameliorates intestinal injury by modulating intestinal microbiota in LPS-challenged piglets

During weaning, piglets are susceptible to intestinal injuries caused by a range of infections, which result in serious economic losses for pig producers. Caffeic acid (CA) is a plant-derived phenolic acid that exhibits potential as a dietary supplement for enhancing intestinal health. There is, however, limited information available about the potential benefits of CA supplementation on intestinal injury and growth performance in piglets. A 28-day study was conducted to examine the effectiveness of CA supplementation in protecting against intestinal injury induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS) in piglets. Twenty-four piglets (7.43 ± 0.79 kg body weight; Duroc × Landrace × Large White; barrows) were randomly divided into 4 groups: the control group, the LPS group, the LPS + CA group, and the CA group. Piglets were administered with LPS or saline on d21 and d28 of the experiment. Supplementation with CA improved intestinal barrier function in LPS-challenged piglets by enhancing intestinal morphology and integrity, as well as increasing the expression of Claudin-1 and ZO-1. Meanwhile, CA supplementation improved the systemic and colonic inflammation responses, oxidative stress, and apoptosis induced by LPS. CA supplementation improved the alpha diversity and structure of the intestinal microbiota by increasing the abundance of beneficial microbiota. Additionally, it was found that it improves metabolic disorders of colonic bile acids (BAs) and short-chain fatty acids (SCFAs) in LPS-challenged piglets, including an increase in primary BAs and isovalerate. In conclusion, CA supplementation could enhance intestinal integrity and barrier function by modifying intestinal microbiota and its metabolites, which could lead to a reduction in inflammatory responses and oxidative stress and ultimately enhanced growth performance in piglets.

Laser Capture Microdissection, Culture Analysis, and Bacterial Sequencing to Evaluate the Microbiota of Focal Duodenal Necrosis in Egg Layers

Focal duodenal necrosis (FDN) is a common intestinal disease of table egg layers. In this research we aimed to identify the bacteria commonly found in FDN lesions as seen with histopathological analysis. Fifty-nine ethanol-fixed duodenum samples were collected from egg layers on eight FDN-affected farms, and 42 samples had typical FDN lesions. Excision of bacteria-containing lesions using laser capture microdissection was performed, followed by 16S rRNA gene sequencing of extracted DNA for bacterial identification. Bacterial sequencing analysis revealed no consistent bacterial species identified from samples with FDN. However, analysis of the relative phylum abundance revealed differences in the duodenal microbiota between layers with FDN and healthy birds. There were differences in the abundance of Proteobacteria, Firmicutes, and Actinobacteria between FDN-positive and FDN-negative control samples compatible with intestinal dysbiosis. In addition, 10 duodenal samples with FDN lesions were collected for bacteriological analysis, yielding 47 colonies on tryptone soy agar, MacConkey agar, and blood agar plates. Using 16S rRNA gene PCR, 39/47 (53.8%) colonies were identified as Escherichia coli. PCR for E. coli virulence genes identified 21/39 (53.8%) E. coli isolates as avian pathogenic E. coli-like. PCR analysis for 19 E. coli virulence genes associated with intestinal disease strains including inflammatory bowel disease found 11/39 (28.2%) isolates containing more than 10 of these virulence genes. In conclusion, FDN appears to be a multifactorial inflammatory intestinal disease associated with intestinal dysbiosis, and Gram-negative bacteria including E. coli may contribute to the pathogenesis of this disease.

Comparing effects of natural betaine and betaine hydrochloride on gut physiology in broiler chickens

Betaine is a well-known component of poultry diets with various effects on nutritional physiology. For example, increased water retention due to the osmolytic effect of betaine increases the volume of the cell, thereby accelerating the anabolic activity, integrity of cell membrane, and overall performance of the bird. Betaine is a multifunctional component (trimethyl derivative) acting as the most efficient methyl group donor and as an organic osmolyte, which can directly influence the gastrointestinal tract integrity, functionality, and health. So far, nothing is known about the effect of betaine on the intestinal barrier in chickens. In addition, little is known about comparing natural betaine with its synthetic form. Therefore, an animal study was conducted to ascertain the effects of betaine supplementation (natural and synthetic) on performance and intestinal physiological responses of broilers. One hundred and five 1-day-old broiler chicks were randomly assigned into 3 groups with 35 birds each: control, natural betaine (1 kg active natural (n)-betaine/ton of feed) and synthetic (syn)-betaine‐HCL (1 kg active betaine /ton of feed). Histological assessment showed lower jejunal crypt depth and villi height/crypt depth ratio in syn-betaine-HCL group compared with natural n-betaine fed birds. Furthermore, it was found that syn-betaine-HCL negatively affects the integrity of the intestine by increasing the intestinal paracellular permeability in both jejunum and cecum as evidenced by a higher mannitol flux. Additionally, syn-betaine-HCl significantly upregulated the IFN-γ mRNA expression at certain time points, which could promote intestinal permeability, as it plays an important role in intestinal barrier dysfunction. Body weight (BW) and body weight gain (BWG) did not differ (P > 0.05) between the control birds and birds supplemented with syn-betaine‐HCL. However, the BW and BWG were significantly (P < 0.05) improved by the dietary inclusion of n-betaine compared with other treatments. Altogether, the dietary inclusion of n-betaine had a positive effect on performance and did not negatively affect gut paracellular permeability. Furthermore, our results show that syn-betaine-HCl induces changes in the intestine, indicating an alteration of the intestinal histology and permeability. Thus, natural or synthetic betaine has different effects, which needs to be considered when using them as a feed supplement.

Enterotoxigenic Escherichia coli infection of weaned pigs: Intestinal challenges and nutritional intervention to enhance disease resistance

Enterotoxigenic Escherichia coli (ETEC) infection induced post-weaning diarrhea is one of the leading causes of morbidity and mortality in newly weaned pigs and one of the significant drivers for antimicrobial use in swine production. ETEC attachment to the small intestine initiates ETEC colonization and infection. The secretion of enterotoxins further disrupts intestinal barrier function and induces intestinal inflammation in weaned pigs. ETEC infection can also aggravate the intestinal microbiota dysbiosis due to weaning stress and increase the susceptibility of weaned pigs to other enteric infectious diseases, which may result in diarrhea or sudden death. Therefore, the amount of antimicrobial drugs for medical treatment purposes in major food-producing animal species is still significant. The alternative practices that may help reduce the reliance on such antimicrobial drugs and address animal health requirements are needed. Nutritional intervention in order to enhance intestinal health and the overall performance of weaned pigs is one of the most powerful practices in the antibiotic-free production system. This review summarizes the utilization of several categories of feed additives or supplements, such as direct-fed microbials, prebiotics, phytochemicals, lysozyme, and micro minerals in newly weaned pigs. The current understanding of these candidates on intestinal health and disease resistance of pigs under ETEC infection are particularly discussed, which may inspire more research on the development of alternative practices to support food-producing animals.

Protective Effects of Lactobacillus plantarum Lac16 on Clostridium perfringens Infection-Associated Injury in IPEC-J2 Cells

Clostridium perfringens (C. perfringens) causes intestinal injury through overgrowth and the secretion of multiple toxins, leading to diarrhea and necrotic enteritis in animals, including pigs, chickens, and sheep. This study aimed to investigate the protective effects of Lactobacillus plantarum (L. plantarum) Lac16 on C. perfringens infection-associated injury in intestinal porcine epithelial cell line (IPEC-J2). The results showed that L. plantarum Lac16 significantly inhibited the growth of C. perfringens, which was accompanied by a decrease in pH levels. In addition, L. plantarum Lac16 significantly elevated the mRNA expression levels of host defense peptides (HDPs) in IPEC-J2 cells, decreased the adhesion of C. perfringens to IPEC-J2 cells, and attenuated C. perfringens-induced cellular cytotoxicity and intestinal barrier damage. Furthermore, L. plantarum Lac16 significantly suppressed C. perfringens-induced gene expressions of proinflammatory cytokines and pattern recognition receptors (PRRs) in IPEC-J2 cells. Moreover, L. plantarum Lac16 preincubation effectively inhibited the phosphorylation of p65 caused by C. perfringens infection. Collectively, probiotic L. plantarum Lac16 exerts protective effects against C. perfringens infection-associated injury in IPEC-J2 cells.

Salmonella delivered Lawsonia intracellularis novel epitope-fusion vaccines enhance immunogenicity and confers protection against Lawsonia intracellularis in mice

Attenuated Salmonella-mediated vaccine constructs were designed by employing selected discontinuous immunodominant epitopes of LatA, FliC, and PAL antigens of Lawsonia intracellularis to create vaccines against porcine proliferative enteropathy (PPE). Whole protein sequences were subjected to in silico prediction of dominant epitopes, the stability of fusions, and hydropathicity and to ensure that the fused epitopes were feasible for expression in a Salmonella system. Two fusion constructs, one comprising LatA epitopes and the other FliC-PAL-FliC epitopes, were built into a prokaryotic constitutive expression system and transformed into the auxotrophic Salmonella host strain JOL1800. Epitope selection eliminated the majority of less immunodominant regions of target proteins and resulted in an efficient secretion platform that induced significant protective responses. Overall, our results demonstrated that the Salmonella-mediated LI- multi-epitope vaccines elicited significant humoral and cellular immune responses. Additionally, the challenge study suggested that the vaccinated mice were protected against experimental Lawsonia intracellularis infection. Based on the outcomes of the study, Salmonella-mediated LI- multi-epitope vaccines have the potential to prevent PPE.

Identification of a novel statovirus in a faecal sample from a calf with enteric disease

A novel clade of RNA viruses was identified in the mammalian gastrointestinal tract by next-generation sequencing. Phylogenetically, these viruses are related to the genera Tombusviridae (plant viruses) and Flaviviridae, which includes mammalian, avian and insect hosts. Named in line with their characterization as stool-associated Tombus-like viruses, it is unclear if statoviruses infect mammals or are dietary in origin. Here, metagenomic sequencing of faecal material collected from a 10-week-old calf with enteric disease found that 20 % of the reads mapped to a de novo-assembled 4 kb contig with homology to statoviruses. Phylogenetic analysis of the statovirus genome found a clear evolutionary relationship with statovirus A, but, with only 47 % similarity, we propose that the statovirus sequence presents a novel species, statovirus F. A TaqMan PCR targeting statovirus F performed on faecal material found a cycle threshold of 11, suggesting a high titre of virus shed from the calf with enteric disease. A collection of 48 samples from bovine enteric disease diagnostic submissions were assayed by PCR to investigate statovirus F prevalence and 6 of 48 (12.5 %) were positive. An ELISA to detect antibodies to the coat protein found that antibodies to statovirus F were almost ubiquitous in bovine serum. Combined, the PCR and ELISA results suggest that statovirus F commonly infects cattle. Further research is needed to elucidate the aetiological significance of statovirus infection.

The alleviation of skin wound-induced intestinal barrier dysfunction via modulation of TLR signalling using arginine in gilthead seabream (Sparus aurata L)

The present study sought to investigate the effect of arginine on the involvement of toll-like receptors (TLRs) in skin wound-induced intestinal barrier dysfunction in gilthead seabream (Sparus aurata L.). Two replicates of fish (n = 8) were fed a commercial diet (CON, total 2.75% arginine), CON diet enriched with 1% arginine (ARG1, total 3.65% arginine) and 2% arginine (ARG2, total 4.53% arginine) for 30 days. Half of the fish were sampled, whereas the others were injured and sampled 7 days post-wounding. The intestinal histology results showed that a more intense infiltration of mixed leucocytes was evident in the wounded fish, which was remarkably reduced in fish that were fed the ARG1 diet. Serum IgM levels were significantly higher in the ARG1 group than levels in the CON group at 7 days post-wounding. Compared with the fish in the CON group after wounding, dietary administration of 1% arginine markedly downregulated the gene expression of TLRs (TLR2 and TLR5), MyD88, and proinflammatory cytokines (CSF1R, IL-1β, and TNFα), but significantly enhanced the gene expression of IκBα, the anti-inflammatory cytokine TGF-β1, and tight junction proteins (tricellulin and occludin) in wounded fish. Furthermore, the ARG2 diet demonstrated no additional benefits on intestinal cells, compared to both the ARG1 and the CON diets, and it even appeared to induce negative effects. In summary, dietary administration of 1% arginine significantly inhibited intestinal inflammatory response and tight junction disruption in skin-wounded gilthead seabream by modulating TLR signalling in the intestine.

Survival of Lawsonia intracellularis in porcine peripheral blood monocyte-derived macrophages

Lawsonia intracellularis, an obligately intracellular enteric bacterium, infects intestinal epithelial cells, but may also be found within macrophages in the intestinal lamina propria of affected pigs. Macrophages play an important role in host defense against infectious agents, but the role of this cell in L. intracellularis infection is not well understood. The aim of this study was to evaluate the permissibility of macrophages to L. intracellularis infection in vitro. Pure culture of L. intracellularis was added to swine peripheral blood monocyte-derived macrophages. Viability of intracytoplasmic L. intracellularis was evaluated at different time points by transmission electron microscopy (TEM). Potential replication of L. intracellularis in macrophages was also evaluated by qPCR. By TEM, phagocytosis L. intracellularis within of phagolysosomes were observed 1-hour post-infection (hpi) and bacterial structures in binary fission at 48 hpi. The number of intracellular bacteria was determined at 1, 4, 24, 48, and 72 hpi by qPCR in infected macrophages and compared to the number of intracellular bacteria from culture in McCoy cells. In both cell lines, the amount of L. intracellularis was decreased at 4 hpiand increased at 24 hpi. The number of intracellular bacteria continued to increase in McCoy cells over time. This is the first study showing interaction, survival and propagation of L. intracellularis in macrophages. These findings are critical to establish an experimental model for future studies of the pathogenesis of porcine proliferative enteropathy and the potential persistence of L. intracellularis in macrophages during chronic infections.

Sodium Butyrate Protects the Intestinal Barrier by Modulating Intestinal Host Defense Peptide Expression and Gut Microbiota after a Challenge with Deoxynivalenol in Weaned Piglets

This study aims to determine whether sodium butyrate (SB) could antagonize deoxynivalenol (DON)-induced intestinal epithelial dysfunction. In a four-week feeding trial, twenty-eight barrows were randomly divided into four treatments: (1) uncontaminated basal diet (control); (2) 4 mg/kg DON-contaminated diet (DON); (3) basal diet supplemented with 0.2% SB (SB); and (4) 4 mg/kg DON + 0.2% SB (DON + SB). A decrease in performance was observed in DON-exposed animals, which was prevented by the dietary SB supplementation. DON exposure also depressed the expression of host defense peptides (HDPs) in the intestine, impaired the intestinal barrier integrity, and disturbed the gut microbiota homeostasis. These alterations induced by DON were attenuated by SB supplementation. The supplementation of 0.2% SB ameliorated the adverse effects of DON on the liver in terms of hepatic lesions as well as serum concentrations of alkaline phosphatase and aspartate aminotransferase. In IPEC-J2 cells, pretreatment with SB alleviated the DON-induced decreased cell viability. Additionally, the NOD2/caspase-12 pathway participated in the alleviation of SB on DON-induced diminished HDP expression. Taken together, these data demonstrated that SB protected piglets from DON-induced intestinal barrier dysfunction potentially through stimulation of intestinal HDP assembly and regulation in gut microbiota.

Metagenomic sequencing of clinical samples reveals a single widespread clone of Lawsonia intracellularis responsible for porcine proliferative enteropathy

Lawsonia intracellularis is a Gram-negative obligate intracellular bacterium that is the aetiological agent of proliferative enteropathy (PE), a common intestinal disease of major economic importance in pigs and other animal species. To date, progress in understanding the biology of L. intracellularis for improved disease control has been hampered by the inability to culture the organism in vitro. In particular, our understanding of the genomic diversity and population structure of clinical L. intercellularis is very limited. Here, we utilized a metagenomic shotgun approach to directly sequence and assemble 21 L. intracellularis genomes from faecal and ileum samples of infected pigs and horses across three continents. Phylogenetic analysis revealed a genetically monomorphic clonal lineage responsible for infections in pigs, with distinct subtypes associated with infections in horses. The genome was highly conserved, with 94 % of genes shared by all isolates and a very small accessory genome made up of only 84 genes across all sequenced strains. In part, the accessory genome was represented by regions with a high density of SNPs, indicative of recombination events importing novel gene alleles. In summary, our analysis provides the first view of the population structure for L. intracellularis, revealing a single major lineage associated with disease of pigs. The limited diversity and broad geographical distribution suggest the recent emergence and clonal expansion of an important livestock pathogen.

Vibrio parahaemolyticus infection impaired intestinal barrier function and nutrient absorption in Litopenaeus vannamei

The intestine is the primary target of pathogenic microbes during invasion. However, the interaction of Vibrio parahaemolyticus (V. parahaemolyticus) with intestinal epithelial cells and its effects on the intestinal function of Litopenaeus vannamei (L. vannamei) are poorly studied. Therefore, the aim of this study was to investigate the influence of V. parahaemolyticus infection on intestinal barrier function and nutrient absorption in L. vannamei. In the present study, a total of 90 shrimp were randomly divided into two groups including the control group and V. parahaemolyticus infection group (final concentration of 1 × 10⁵ CFU/mL), with three replicates per group. The result showed that compared with the control group, V. parahaemolyticus infection increased (P < 0.05) serum diamine oxidase activity and endotoxin quantification, and down-regulated (P < 0.05) the mRNA levels of intestinal peroxinectin, integrin, midline fasciclin at 48 h and 72 h; V. parahaemolyticus infection decreased (P < 0.05) the mRNA expression of intestinal amino acid transporter (CAT1, EAAT3 and ASCT1) and glucose transporter (SGLT-1, GLUT) at 24 h, 48 h and 72 h, and increased (P < 0.05) serum glucose and amino acid (Asp, Thr, Ser, Glu, Gly, Ala, Val, Ile, Leu, Tyr, Phe, Lys, His and Arg) concentration at 24 h. The results indicated that V. parahaemolyticus infection increased intestinal permeability, inhibited absorption of glucose and amino acid in L. vannamei.

Sodium acetate alleviated high-carbohydrate induced intestinal inflammation by suppressing MAPK and NF-κB signaling pathways in Nile tilapia (Oreochromis niloticus)

With the development of aquaculture industry, high-carbohydrate diet is used to stimulate protein-sparing effect and reduce feed cost. However, fish utilize carbohydrates poorly in general, and instead, high level of carbohydrates in the diet influence the growth condition of fish. How to alleviate the side effects of high carbohydrate diet on fish health has attracted more and more attentions. In the present study, Nile tilapia (Oreochromis niloticus) were fed with 25% and 45% of carbohydrate diet for eight weeks. Higher body weight but lower resistance to pathogen was found in 45% carbohydrate diet group. Higher expression level of inflammation cytokines, increased expression of total NF-κB protein and phosphorylated NF-κB protein (p-NF-κB) were detected in higher carbohydrate group. Concentration of short-chain fatty acids (SCFAs) was measured and the results indicated that high-carbohydrate diet decreased acetate content in the intestine. In order to detect the relationship between the decreased concentration of acetate and lower resistance to pathogen in high-carbohydrate group, 45% of carbohydrate diets (HC) supplemented with different concentrations of sodium acetate (HC + LA, 100 mmol/L; HC + MA, 200 mmol/L; HC + HA, 400 mmol/L) were used to raise Nile Tilapia for eight weeks. The results indicated that addition of 200 mmol/L sodium acetate (HC + MA) reduced the mortality when fish were challenged with Aeromonas hydrophila. Furthermore, we also found that addition of 200 mmol/L sodium acetate mainly inhibited p38 mitogen-activated protein kinase (p38MAPK) and NF-κB phosphorylation to decrease the expression level of inflammation cytokines (IL-8, IL-12, TNF-α and IL-1β) in the intestine. The present study indicated that certain concentration of sodium acetate could alleviate high-carbohydrate induced intestinal inflammation mainly by suppressing MAPK activation and NF-κB phosphorylation.

Time course determination of the effects of rapid and gradual cooling after acute hyperthermia on body temperature and intestinal integrity in pigs

Rapid cooling after acute hyperthermia may cause a sustained increase in body temperature and exacerbate intestinal damage in pigs. Therefore, the study objective was to evaluate the temporal effects of rapid and gradual cooling on body temperature response and intestinal integrity after acute hyperthermia in pigs. In three repetitions, 54 pigs [83.3 ± 6.7 kg initial body weight (BW)], balanced by sex were exposed to thermoneutral conditions for 6 h (TN; n = 6 pigs/repetition; 21.1 ± 2.0°C), or heat stress conditions (HS; 39.3 ± 1.6°C) for 3 h, followed by a 3 h recovery period of gradual cooling [HSGC; n = 6 pigs/repetition; gradual decrease from HS to TN conditions] or rapid cooling [HSRC; n = 6 pigs/repetition; rapid TN exposure and cold water (4.0°C) dousing every 30 min for 1.5 h]. Feed was withheld throughout the entire 6 h period, but water was provided ad libitum. Gastrointestinal (T_GI) and rectal (T_R) temperatures were recorded every 15 min during the HS and recovery periods. Six pigs per repetition (n = 2/treatment) were euthanized and jejunal and ileal samples were collected for histology immediately after (d 0), 2 d after, and 4 d after the recovery period. Data were analyzed using PROC MIXED in SAS 9.4. Overall, rapid cooling reduced T_R and T_GI (P < 0.01; 0.95°C and 0.74°C, respectively) compared to gradual cooling. Jejunal villus height was reduced overall (P = 0.02; 14.01%) in HSGC compared to HSRC and TN pigs. Jejunal villus height-to-crypt depth ratio was reduced overall (P = 0.05; 16.76%) in HSGC compared to TN pigs. Ileal villus height was reduced overall (P < 0.01; 16.95%) in HSGC compared to HSRC and TN pigs. No other intestinal morphology differences were detected. In summary, HSRC did not cause a sustained increase in body temperature and did not negatively impact biomarkers of intestinal integrity in pigs.

Narrative review of therapies for chronic enteropathies in dogs and cats

BACKGROUND

The optimal medical treatment for chronic enteropathy (CE) in dogs and cats is controversial. Sequential treatment using diet, antimicrobials, and immunosuppressive drugs is the most common strategy used by clinicians.

OBJECTIVES

To review the evidence for the effectiveness of dietary, drug, and alternative health interventions for inducing clinical remission in dogs and cats with CE.

ANIMALS

Retrospective study of dogs and cats with a diagnosis of chronic enteropathy.

METHODS

MEDLINE and Centre for Agriculture and Bioscience International (CABI) databases (1950 to March 2017) were searched for randomized controlled trials (RCTs), observational studies, and case series. The primary outcome was induction of clinical remission. All studies were evaluated using the quality of evidence grading guidelines (I-IV), which assign a score defining the strength and quality of the evidence.

RESULTS

Twenty-two studies (11 RCTs in dogs and 2 in cats and 9 cohort studies or case series) met the inclusion criteria for inducing remission of gastrointestinal (GI) signs. Of the 13 RCTs achieving grade I scores, 10 studies (totaling 218 dogs and 65 cats) compared single treatment: diet (n = 3), immunosuppressives (n = 3), antimicrobials (n = 2), anti-inflammatory drugs (n = 1), and probiotics (n = 1). Three case series (grade III) reported clinical remission using an elimination diet fed to 55 cats and use of enrofloxacin to induce remission in dogs with granulomatous colitis (2 studies totaling 16 dogs).

CONCLUSIONS AND CLINICAL IMPORTANCE

The current evidence for treatment of CE is much greater in dogs than in cats. There is sufficient strong evidence to recommend the use of therapeutic GI diets, glucocorticoids, enrofloxacin, or some combination of these in dogs with CE. Therapeutic GI diets and glucocorticoids are most useful in cats with CE.

Clinical utility of currently available biomarkers in inflammatory enteropathies of dogs

Chronic inflammatory enteropathies (CIE) in dogs are a group of disorders that are characterized by chronic persistent or recurrent signs of gastrointestinal disease and histologic evidence of mucosal inflammation. These CIEs are classified as either food-responsive, antibiotic-responsive, or immunosuppressant-responsive enteropathy. Patients not clinically responding to immunomodulatory treatment are grouped as nonresponsive enteropathy and dogs with intestinal protein loss as protein-losing enteropathy. Disease-independent clinical scoring systems were established in dogs for assessment of clinical disease severity and patient monitoring during treatment. Histopathologic and routine clinicopathologic findings are usually not able to distinguish the subgroups of CIE. Treatment trials are often lengthy and further diagnostic tests are usually at least minimally invasive. Biomarkers that can aid in defining the presence of disease, site of origin, severity of the disease process, response to treatment, or a combination of these would be clinically useful in dogs with CIE. This article summarizes the following biomarkers that have been evaluated in dogs with CIE during the last decade, and critically evaluates their potential clinical utility in dogs with CIE: functional biomarkers (cobalamin, methylmalonic acid, folate, α1 -proteinase inhibitor, immunoglobulin A), biochemical biomarkers (C-reactive protein, perinuclear anti-neutrophilic cytoplasmic antibodies, 3-bromotyrosine, N-methylhistamine, calprotectin, S100A12, soluble receptor of advanced glycation end products, cytokines and chemokines, alkaline phosphatase), microbiomic biomarkers (microbiome changes, dysbiosis index), metabolomic biomarkers (serum metabolome), genetic biomarkers (genomic markers, gene expression changes), and cellular biomarkers (regulatory T cells). In addition, important performance criteria of diagnostic tests are briefly reviewed.

The underlying microbial mechanism of epizootic rabbit enteropathy triggered by a low fiber diet

Epizootic rabbit enteropathy (ERE) is reproduced successfully in the present study by feeding rabbits a low-fibre diet, and high-throughput sequencing and quantitative real-time PCR (qPCR) analysis were applied to examine the microbial variations in the stomach, small intestine and caecum. The evenness was disturbed and the richness was decreased in the ERE groups. When the rabbits were suffering from ERE, the abundance of the Firmicutes was decreased in three parts of the digestive tract, whereas the Proteobacteria was increased in the stomach and caecum, the Bacteroidetes and Verrucomicrobia were increased in the small intestine. Correlation analysis showed that the reduced concentrations of TVFA and butyrate in the caeca of the ERE group were attributed to the decreased abundances of genera such as Lactobacillus, Alistipes and other fibrolytic bacteria and butyrate- producing bacteria such as Eubacterium and Faecalibacterium. It is concluded that, in terms of microorganisms, the overgrowth of Bacteroides fragilis, Clostridium perfringen, Enterobacter sakazakii and Akkermansia muciniphila and inhibition of Bifidobacterium spp. and Butyrivibrio fibrisolvens in the stomach, small intestine and caecum resulted in a decrease in butyrate yield, leading to the incidence of ERE, and the probability of developing ERE could be manipulated by adjusting the dietary fibre level.

Correlation of clinical, diagnostic and histopathological parameters in dogs with chronic lymphocytic-plasmacytic enteropathy

OBJECTIVE

The objective of this study was to correlate clinical signs and diagnostic parameters with duodenal inflammatory and architectural changes in dogs with lymphocytic-plasmacytic enteropathy.

MATERIAL AND METHODS

In a retrospective study dogs presented between 2003 and 2014 with chronic gastrointestinal signs (duration > 3 weeks) and histologic evidence of intestinal lymphocytic-plasmacytic inflammation were evaluated. Clinical signs, serum albumin, cobalamin and folic acid concentrations were recorded and a sonographic, endoscopic, histologic and cytological inflammatory score was determined. Furthermore, the presence of lacteal dilation, villus stunting, crypt lesions, epithelial integrity and increased intraepithelial lympho cytes was evaluated.

RESULTS

A total of 270 dogs were retrospectively evaluated. No significant correlation was found between clinical signs and sonographic, endoscopic or duodenal inflammatory score. Dogs with histological signs of lacteal dilation (p = 0.001) and increased intraepithelial lymphocytes (p = 0.005) had significantly higher clinical scores compared to dogs without these changes. No correlation was found between clinical score and villous stunting or crypt lesions. Hypoalbuminemia and hypocobalaminemia correlated significantly with lacteal dilation (p = 0.001, p = 0.009) and increased intraepithelial lymphocytes (p = 0.036, p = 0.018).

CLINICAL SIGNIFICANCE

Some clinical and diagnostic parameter correlate with histopathologic features whereas others do not. Morphological features seem to be more important than the intensity of the duodenal inflammation in the assessment of the disease.

Toxicity of zearalenone on the intestines of pregnant sows and their offspring and alleviation with modified halloysite nanotubes

BACKGROUND

The objective of this study was to examine the effects of maternal exposure to zearalenone (ZEN) on the intestines of pregnant sows and offspring on postnatal days (PD) 1, 21 and 188. Eighteen pregnant sows (six per treatment) were fed a control diet (ZEN, 0.03 mg kg^-1 ), ZEN diet (ZEN, 2.77 mg kg^-1 ) and ZEN + 1% modified halloysite nanotube (MHNT) diet (ZEN, 2.76 mg kg^-1 ) respectively from gestation days (GD) 35 to 70. At the end of the experiment, three sows of each group on GD70 and the offspring on PD1, PD21 and PD188 were killed to analyze the changes of intestines.

RESULTS

The results showed that ZEN caused oxidative stress, an inflammatory response, changes in the structure of jejunum and alterations of the bacterial numbers in cecal digesta in pregnant sows and PD1 and PD21 piglets. On PD188, bacterial numbers were also altered. MHNTs supplementation reduced the amount of ZEN in the intestine and reversed to a large extent the effects induced by ZEN on the intestines of pregnant sows and offspring.

CONCLUSION

The results obtained from this study indicated that MHNTs treatment was beneficial for the adsorption of ZEN in the intestine of sows. © 2017 Society of Chemical Industry.

Disseminated infection due to Exophiala pisciphila in Cardinal tetra, Paracheirodon axelrodi

Cardinal tetra, Paracheirodon axelrodi (Schultz, 1956), kept in an ornamental tank, was found to be affected by severe invasive mycosis. Externally, the disease manifested as abdominal swelling, and internally, the anterior part of the intestine was extremely bloated with abundant dematiaceous septate hyphae and an accumulation of fluid. Histopathologically, a granulomatous inflammatory response was observed in the intestine wall, kidney and spleen. We assume that the mycotic agent was primarily deposited in the intestine and was then gradually disseminated to the other organs. DNA sequencing of ITS and LSU rDNA regions and phenotypic characterization were used for identification of the isolated fungus. The obtained data confirmed that the infection was caused by Exophiala pisciphila. The disease was subsequently reproduced in the carp fingerling using intramuscular and intraperitoneal injection of a spore suspension. The 13th day after intramuscular infection, a marked elevation of neutrophils was recorded in the peripheral blood; this involved a proliferation of band forms and segmented forms. As far as we know, this is the first report of infection due to E. pisciphila in Cardinal tetra.

Disease resistance and response against Vibrio anguillarum intestinal infection in European seabass (Dicentrarchus labrax) fed low fish meal and fish oil diets

The aim of this study was to assess the effects of low levels of dietary fish meal (FM) and fish oil (FO) on disease resistance and gut associated lymphoid tissue (GALT) response after an experimental intestinal infection with V. anguillarum in European sea bass (Dicentrarchus labrax) For that purpose, sea bass juveniles were fed one of four diets containing combined levels of FO and FM as follows: 20%FM/6%FO, 20%FM/3%FO, 5%FM/6%FO and 5%FM/3%FO during 153 days. At the end of the feeding trial, fish were subjected to either an in vivo exposure to a sub-lethal dose of V. anguillarum via anal inoculation or to an ex vivo exposure to V. anguillarum. Additionally, inducible nitric oxide synthase (iNOS) and tumor necrosis factor α (TNFα) gut patterns of immunopositivity were studied. Growth performance was affected by dietary FM level, however ex vivo gut bacterial translocation rates and survival after the in vivo challenge test were affected by dietary FO level. After 5 months of feeding, low dietary FM levels led to a posterior gut up-regulation of interleukin-1β (IL-1β) and TNFα, major histocompatibility complex-II (MHCII) and cyclooxygenase-2 (COX2), which in turn reduced the gut associated lymphoid tissue (GALT) capacity of response after 24 h post infection and conditioned European sea bass capacity to recover gut homeostasis 7 days post infection. Immunoreactivity to anti-iNOS and anti-TNFα presented a gradient of increased immunopositivity towards the anus, regardless of the dietary FM/FO fed. Strong positive anti-TNFα isolated enterocytes were observed in the anterior gut in relation to low levels of dietary FM/FO. Submucosa and lamina propria immunoreactivity grade was related to the amount of leucocyte populations infiltrated and goblet cells presented immunopositivity to anti-iNOS but not to anti-TNFα. Thus, reducing FO content from 6% to a 3% by VO in European sea bass diets increases ex vivo and in vivo gut bacterial translocation rates, whereas reducing FM content from 20% down to 5% up-regulates the expression of several posterior gut inflammation-related genes conditioning fish growth and GALT capacity of response after bacterial infection.

Subclinical intestinal duplication in a cat

An abdominal mass was identified upon palpation of the abdomen in a normal, asymptomatic, 1-year-old female domestic shorthair cat presented for elective ovariohysterectomy. Radiographic and ultrasound examinations demonstrated a well-circumscribed caudal abdominal mass. Ultrasound guided needle aspiration cytology was consistent with an accumulation of squamous epithelial cells. The mass was associated with the jejunum and was excised via resection anastomosis of the intestinal segment after ovariohysterectomy. Histologic examination provided the diagnosis of an intestinal duplication lined with epithelium typical of that in the esophagus. The cat recovered without complications.

A Comparative Study of an Indirect Fluorescent Antibody Test and an Immunoperoxidase Monolayer Assay for the Diagnosis of Porcine Proliferative Enteropathy

The currently used indirect fluorescent antibody test (IFAT) for the detection of antibodies against porcine proliferative enteropathy (PPE) was compared to an immunoperoxidase monolayer assay (IPMA). Serum samples used in this comparison were collected from 5-week-old pigs on day 0 (pre-experimental challenge) and on days 7, 14, 21, and 28 after oral inoculation with intestinal homogenate from pigs affected by PPE (28 challenged pigs) and sucrose phosphate glutamate solution (2 control pigs). All animals were euthanized 4 weeks after inoculation. Immunohistochemistry staining was applied to formalin-fixed, paraffin-embedded sections of ileum for the detection of Lawsonia intracellularis antigen. The serology results with each method agreed in all samples, except on days 0 and 7 in 1 control animal, which was positive by IPMA, but negative by IFAT. The percentage of agreement between IFAT and IPMA was 98.6%.

Goat Paratuberculosis in Chile: First Isolation and Confirmation of Mycobacterium Avium Subspecies Paratuberculosis Infection in a Dairy Goat

In October 2004, 41 goats >2 years old from a Saanen dairy goat herd located in Purranque County, 10th Region, Chile, were sampled and tested for paratuberculosis. While collecting samples it was observed that several goats were thin and emaciated. One goat was sufficiently debilitated to warrant humane euthanasia. This animal was brought to the Veterinary School at the Universidad Austral de Chile for necropsy. The goat selected for necropsy was a 12-year-old doe. The animal showed classical clinical signs of caprine paratuberculosis: emaciation despite willingness to eat, dry and rough hair coat, and no evidence of diarrhea. Gross pathology and histopathology of the necropsied goat were consistent with paucibacillary paratuberculosis. Bacteriology, serology, and PCR confirmed the diagnosis. This is the first published report of goat paratuberculosis in Chile confirming a case of caprine paucibacillary paratuberculosis.

Cloacal Prolapse in Raptors: Review of 16 Cases

Sixteen cases of cloacal prolapse in raptors were reviewed in this study. Colonic prolapse was the most common presentation (56% of cases). Red-tailed hawks ( Buteo jamaicensis ) were overrepresented, comprising 66% of colonic prolapse cases. In cases of colonic prolapse, postsurgical stricture formation was a commonly identified complication after resection and anastomosis of the colon. A novel technique was used in 2 cases of colonic prolapse, in which sterile, semirigid rubber tubing was placed in the distal colon and removed per-cloaca at the end of the procedure; this facilitated a secure, fluid-tight anastomosis while maintaining sufficient intestinal lumen. Oviductal prolapse (31% of cases) was associated with the most guarded prognosis (40% treatment success). Cloacoliths were treated successfully in 2 birds (13% of cases) by minimally invasive per-cloacal manual removal.

Intestinal alterations in European sea bass Dicentrarchus labrax (Linnaeus, 1758) exposed to microplastics: Preliminary results

This study investigates, for the first time, the intestinal responses of European sea bass Dicentrarchus labrax chronically exposed to microplastics through ingestion. Fish (n = 162) were fed with 3 different treatment diets for 90 days: control, native polyvinyl chloride (PVC) and polluted polyvinyl chloride (PVC) pellets. Intestines were fixed and processed for histological analysis using standard techniques. Histopathological alterations were examined using a score value (from 0 to 4). The distal part of intestine in all samples proved to be the most affected by pathological alterations, showing a gradual change varying from moderate to severe related to exposure times. The histological picture that characterizes both groups especially after 90 days of exposure, suggests that the intestinal functions can be in some cases totally compromised. The worst condition is increasingly evident in the distal intestine of fish fed with polluted PVC pellets respect to control groups (p < 0.05) to different exposure times. These first results underline the need to assess the impact of increasing microplastics pollution on the marine trophic web.

Alterations of the Ileal and Colonic Mucosal Microbiota in Canine Chronic Enteropathies

Background

The intestinal microbiota is increasingly linked to the pathogenesis of chronic enteropathies (CE) in dogs. While imbalances in duodenal and fecal microbial communities have been associated with mucosal inflammation, relatively little is known about alterations in mucosal bacteria seen with CE involving the ileum and colon.

Aim

To investigate the composition and spatial organization of mucosal microbiota in dogs with CE and controls.

Methods

Tissue sections from endoscopic biopsies of the ileum and colon from 19 dogs with inflammatory bowel disease (IBD), 6 dogs with granulomatous colitis (GC), 12 dogs with intestinal neoplasia, and 15 controls were studied by fluorescence in situ hybridization (FISH) on a quantifiable basis.

Results

The ileal and colonic mucosa of healthy dogs and dogs with CE is predominantly colonized by bacteria localized to free and adherent mucus compartments. CE dogs harbored more (P < 0.05) mucosal bacteria belonging to the Clostridium-coccoides/Eubacterium rectale group, Bacteroides, Enterobacteriaceae, and Escherichia coli versus controls. Within the CE group, IBD dogs had increased (P < 0.05) Enterobacteriaceae and E. coli bacteria attached onto surface epithelia or invading within the intestinal mucosa. Bacterial invasion with E. coli was observed in the ileal and colonic mucosa of dogs with GC (P < 0.05). Dogs with intestinal neoplasia had increased (P < 0.05) adherent (total bacteria, Enterobacteriaceae, E. coli) and invasive (Enterobacteriaceae, E. coli, and Bacteroides) bacteria in biopsy specimens. Increased numbers of total bacteria adherent to the colonic mucosa were associated with clinical disease severity in IBD dogs (P < 0.05).

Conclusion

Pathogenic events in canine CE are associated with different populations of the ileal and colonic mucosal microbiota.

Low Vitamin D Status Is Associated with Systemic and Gastrointestinal Inflammation in Dogs with a Chronic Enteropathy

Introduction

Vitamin D deficiency, as assessed by serum concentrations of 25 hydroxyvitamin D (25(OH)D), has been linked to the development of over-zealous and inappropriate inflammation in humans. However, the relationship between vitamin D status and inflammation in dogs is ill-defined. Chronic enteropathies (CE) are frequently diagnosed in client owned dogs, have a wide range of serum 25(OH)D concentrations, and represent a spontaneous model in which to probe the relationship between vitamin D and inflammation. The hypothesis of this study was that vitamin D status would be negatively associated with systemic and gastrointestinal inflammation in dogs with a CE. The aim of this study was to examine the relationship between serum 25(OH)D concentrations and markers of systemic and gastrointestinal inflammation in a cohort of dogs with CE.

Methods and Materials

Serum 25(OH)D concentrations, together with neutrophil, monocyte, eosinophil and lymphocyte counts, duodenal histopathology scores, serum IL-2, IL-6, IL-8 and TNFα concentrations and were measured in 39 dogs with histologically confirmed CE. A linear regression model examined the relationship between serum 25(OH)D status and measures of inflammation.

Results

Serum 25(OH)D concentrations were negatively associated with neutrophil and monocyte counts, duodenal histopathology scores and serum IL-2 and IL-8 concentrations. Dogs with low serum 25(OH)D concentrations typically had an inflammatory signature characterised by high monocyte and neutrophil numbers together with low lymphocyte numbers. There is a need to establish whether low vitamin D status is a cause or consequence of inflammation.

Long-term prospective evaluation of intestinal anastomosis using stainless steel staples in 14 dogs

This prospective clinical study evaluated the use, complications, and clinical and ultrasonographic follow-ups of end-to-end intestinal anastomoses with skin staples in naturally occurring diseases in canine small and large intestines. Intestinal anastomoses were performed in 14 dogs and pre-, peri-, and postoperative data were recorded. Postoperative clinical and ultrasound evaluations were performed at regular intervals for 1 year. The mean time taken to construct the anastomosis was 5 min. There were no intraoperative complications. Hemorrhage and colonic stricture were the main postoperative complications. Staple loss occurred in 2 cases. Absence of wall layering and focal wall thickening were observed in all cases at each ultrasonographic follow-up. Hyperechoic fat was observed in all but 1 of the cases at month 1. Nine dogs were alive with normal digestive function at the end of the study. The skin stapler technique enabled rapid construction of consistent anastomoses with inexpensive stapling material.

Effects of ex-vivo and in-vivo treatment with probiotics on the inflammasome in dogs with chronic enteropathy

Inflammasomes coordinate the maturation of IL-1β and IL-18 in response to danger signals. They are vital for maintenance of intestinal homeostasis and have been linked to chronic intestinal inflammation in humans. Probiotics have been advocated as treatment in intestinal inflammation. So far, no study has investigated the role of the inflammasome in canine chronic enteropathy (CE). In this study the intestinal expression of inflammasome components was assessed in CE dogs compared to controls, when treated with probiotic Enterococcus faecium (EF) ex-vivo and in-vivo. RNA extraction from endoscopic biopsies and reverse-transcriptase quantitative PCR was performed for NLRP3, casp-1, IL-1β and IL-18. Immunohistochemistry was performed to investigate protein expression in tissues. Gene expression of casp-1 and NLRP3 was lower in CE samples than controls. Ex-vivo treatment with EF reduced NLRP3 expression in control samples. Treatment of CE dogs with EF alongside dietary intervention had no effect on gene expression. In contrast, IL-1β protein expression in CE decreased with dietary treatment (but not with probiotics). The results of this study suggest that the inflammasome or its components may be partially involved in the inflammatory process seen in CE, but distinct from intestinal inflammation in humans.

Impact of deoxynivalenol (DON) contaminated feed on intestinal integrity and immune response in swine

This study was performed to characterize the influence of consuming DON naturally contaminated feeds on pig's intestinal immune defenses, antibody response and cellular immunity. Sixteen 4-week-old piglets were randomly allocated to two dietary treatments: control diet or diet contaminated with 3.5 mg DON/kg. At days 7 and 21, animals were immunized with ovalbumin (OVA). On day 42, intestinal samples were collected for measurement of gene expression involved in immune response, oxidative status and barrier function. Primary IgG antibody response to OVA was increased in pigs fed DON diet compared to control animals. In the ileum of pigs fed DON diet, claudin, occludin, and vimentin genes involved in integrity and barrier function were down-regulated compared to controls. Results also revealed that expression of two chemokines (IL-8, CXCL10), interferon-γ, and major antioxidant glutathione peroxidase 2 (GPX-2) were up-regulated whereas expression of genes encoding enzymatic antioxidants including GPX-3, GPX-4 and superoxide dismutase 3 (SOD-3) were down-regulated in pigs fed DON-contaminated diet. These results strongly suggest that ingestion of DON naturally contaminated feed impaired intestinal barrier and immunological functions by modulating expression of genes coding for proteins involved in tight junctions, tissue remodelling, inflammatory reaction, oxidative stress reaction and immune response.

The role of nitric oxide and oxidative stress in intestinal damage induced by selenium deficiency in chickens

Nitric oxide (NO) is an essential messenger molecule and is associated with inflammation and oxidative stress. Although NO has important biological functions in mammals, its role in the mechanism that occurs after intestinal injuries in chickens remains unknown. The objective of the present study was to investigate the real role of NO and oxidative stress in the intestinal injuries of chickens induced by selenium (Se) deficiency. A total 150 chickens were randomly divided into the following two groups: a low-Se group (L group, fed a Se-deficient diet containing 0.020 mg/kg Se) and a control group (C group, fed a commercial diet containing 0.2 mg/kg Se). The activities and mRNA levels of glutathione peroxidase (GSH-Px), the production of glutathione (GSH) and NO, and the protein and mRNA levels of inducible nitric oxide synthase (iNOS) were examined in the intestinal tissues (duodenum, jejunum, and rectum) at 15, 25, 35, 45, and 55 days. Methane dicarboxylic aldehyde (MDA) levels were also detected by assay kits. Then, the morphologies of the tissues were observed under the microscope after hematoxylin and eosin staining (H&E staining). The results showed that Se deficiency induced higher inflammatory damage and MDA levels (P < 0.05), which were accompanied by higher levels of iNOS and NO but lower levels of GSH and GSH-Px (P < 0.05). Our results indicated that Se deficiency induced oxidative damage in the intestinal tracts of chickens and that low levels of GSH-Px and high contents of NO may exert a major role in the injury of the intestinal tract induced by Se deficiency.

Changes in cecal microbiota and mucosal gene expression revealed new aspects of epizootic rabbit enteropathy

Epizootic Rabbit Enteropathy (ERE) is a severe disease of unknown aetiology that mainly affects post-weaning animals. Its incidence can be prevented by antibiotic treatment suggesting that bacterial elements are crucial for the development of the disease. Microbial dynamics and host responses during the disease were studied. Cecal microbiota was characterized in three rabbit groups (ERE-affected, healthy and healthy pretreated with antibiotics), followed by transcriptional analysis of cytokines and mucins in the cecal mucosa and vermix by q-rtPCR. In healthy animals, cecal microbiota with or without antibiotic pretreatment was very similar and dominated by Alistipes and Ruminococcus. Proportions of both genera decreased in ERE rabbits whereas Bacteroides, Akkermansia and Rikenella increased, as well as Clostridium, γ-Proteobacteria and other opportunistic and pathogenic species. The ERE group displayed remarkable dysbiosis and reduced taxonomic diversity. Transcription rate of mucins and inflammatory cytokines was very high in ERE rabbits, except IL-2, and its analysis revealed the existence of two clearly different gene expression patterns corresponding to Inflammatory and (mucin) Secretory Profiles. Furthermore, these profiles were associated to different bacterial species, suggesting that they may correspond to different stages of the disease. Other data obtained in this work reinforced the notion that ERE morbidity and mortality is possibly caused by an overgrowth of different pathogens in the gut of animals whose immune defence mechanisms seem not to be adequately responding.

Ruminant self-medication against gastrointestinal nematodes: evidence, mechanism, and origins

Gastrointestinal helminths challenge ruminants in ways that reduce their fitness. In turn, ruminants have evolved physiological and behavioral adaptations that counteract this challenge. Ruminants display anorexia and avoidance behaviors, which tend to reduce the incidence of parasitism. In addition, ruminants appear to learn to self-medicate against gastrointestinal parasites by increasing consumption of plant secondary compounds with antiparasitic actions. This selective feeding improves health and fitness. Here, we review the evidence for self-medication in ruminants, propose a hypothesis to explain self-medicative behaviors (based on post-ingestive consequences), and discuss mechanisms (e.g., enhanced neophilia, social transmission) that may underlie the ontogeny and spread of self-medicative behaviors in social groups. A better understanding of the mechanisms that underlie and trigger self-medication in parasitized animals will help scientists devise innovative and more sustainable management strategies for improving ruminant health and well-being.

Epizootic and zoonotic helminths of the bobcat (Lynx rufus) in Illinois and a comparison of its helminth component communities across the American Midwest

A total of 6257 helminths of 19 taxa were recovered from the digestive tract and lungs of 67 bobcats in Illinois. Infections caused by Alaria mustelae, Diphyllobothrium latum, and Macracanthorhynchus ingens are reported for the first time in bobcats. From all the taxa recovered, only three species occurred in high prevalence and caused intense infections: Taenia rileyi, Alaria marcianae, and Toxocara cati, with prevalence and mean intensity of 70% and 6; 42% and 193, and 25% and 14 individuals, respectively. Prevalence lower than 15% of 14 helminth species suggests bobcats are not continuously exposed to infective stages of a single parasite, and may be exposed to a large variety of generalists during their lifespan. No significant difference in parasite species according to host sex or age was detected, except for Diphyllobothrium spp., which were found more frequently in females and in trapped bobcats, and the hookworm, Ancylostoma caninum, which infected juveniles more frequently. Average species richness per infracommunity was 2.4 (±1.2), and the parasite component community showed low qualitative similarity with neighbor communities. The taxa A. caninum, Alaria spp., Diphyllobothrium spp., Paragonimus kellicotti, and T. cati are etiological agents of epizootic and zoonotic diseases.

Effect of enteric biopsy closure orientation on enteric circumference and volume of saline needed for leak testing

This study describes the effect of enteric biopsy closure orientation on circumference and volume of saline needed for leak testing. There were significant differences in circumference measurements at baseline, central circumference of longitudinally closed sites, and volume of saline for leak testing.

Candida utilis and Chlorella vulgaris counteract intestinal inflammation in Atlantic salmon (Salmo salar L.)

Intestinal inflammation, caused by impaired intestinal homeostasis, is a serious condition in both animals and humans. The use of conventional extracted soybean meal (SBM) in diets for Atlantic salmon and several other fish species is known to induce enteropathy in the distal intestine, a condition often referred to as SBM induced enteropathy (SBMIE). In the present study, we investigated the potential of different microbial ingredients to alleviate SBMIE in Atlantic salmon, as a model of feed-induced inflammation. The dietary treatments consisted of a negative control based on fish meal (FM), a positive control based on 20% SBM, and four experimental diets combining 20% SBM with either one of the three yeasts Candida utilis (CU), Kluyveromyces marxianus (KM), Saccharomyces cerevisiae (SC) or the microalgae Chlorella vulgaris (CV). Histopathological examination of the distal intestine showed that all fish fed the SC or SBM diets developed characteristic signs of SBMIE, while those fed the FM, CV or CU diets showed a healthy intestine. Fish fed the KM diet showed intermediate signs of SBMIE. Corroborating results were obtained when measuring the relative length of PCNA positive cells in the crypts of the distal intestine. Gene set enrichment analysis revealed decreased expression of amino acid, fat and drug metabolism pathways as well as increased expression of the pathways for NOD-like receptor signalling and chemokine signalling in both the SC and SBM groups while CV and CU were similar to FM and KM was intermediate. Gene expression of antimicrobial peptides was reduced in the groups showing SBMIE. The characterisation of microbial communities using PCR-DGGE showed a relative increased abundance of Firmicutes bacteria in fish fed the SC or SBM diets. Overall, our results show that both CU and CV were highly effective to counteract SBMIE, while KM had less effect and SC had no functional effects.