Non-challenged Group Research Articles

Impacts of increasing challenge with Eimeria maxima on the growth performance and gene expression of biomarkers associated with intestinal integrity and nutrient transporters

This study was conducted to investigate the impacts of graded severity of Eimeria maxima infection on the growth performance and intestine health of broiler chickens. Four different levels of E. maxima-challenged treatments were used, including a non-challenged control group, a low challenge (12 500 oocysts), a medium challenge (25 000 oocysts), and a high challenge dose (50 000 oocysts). There were eight replicate cages per treatment, with 12 birds in each cage, and chickens in the challenged groups orally received sporulated oocysts on day 14. Gastrointestinal permeability was measured by fluorescein isothiocyanate dextran at 5 days post-infection (dpi), whereas intestinal morphology and gene expression of nutrient transporters and tight junction proteins were determined at 6 dpi. The results demonstrate a linear reduction in growth performance, jejunal villus height, and jejunal integrity with graded challenge doses of E. maxima (P < 0.01). Moreover, linear regulation of nutrient transporters and tight junction proteins was a consequence of increasing Eimeria infection levels (P < 0.01). The linear increase of Claudin 1, cationic amino acid transporter, glucose transporter 1, and L-type amino acid transporter genes was associated with increased severity of coccidiosis (P < 0.01). Furthermore, expression of nutrient transporters located at the brush border membrane were down-regulated (P < 0.01) with increasing E. maxima inoculation dose. In conclusion, growth performance and key intestinal integrity biomarkers in broiler chickens were adversely influenced in a dose-dependent manner by E. maxima infection.

Sensitivity of field isolates of Eimeria acervulina and E. maxima from three regions in Brazil to eight anticoccidial drugs

Rotation with different active ingredients is among the most effective and recommended strategies to preserve the efficacy of anticoccidial drugs and reduce the emergence of resistance. Tools such as anticoccidial sensitivity tests (ASTs) are ideally used to make rational rotation programs and bring benefits to production. The objective of this study was to evaluate the sensitivity of E. acervulina (EA) and E. maxima (EM) from 3 different regions in Brazil, by using four ASTs. Feces samples weighing 6 to 7 kg were collected in the regions of São Paulo, Paraná, and Minas Gerais. Prevalent oocysts from feces were filtered, identified, and quantified to conduct 2 ASTs with EA and 2 with EM. The same experimental design was used in every AST (4 replicates per treatment, with 6 birds each, for a total of 240 birds). Treatment groups were a nonchallenged and nonmedicated control group (T1), a challenged and nonmedicated control group (T2), and the other groups challenged and treated with the following compounds: lasalocid (90 ppm – T3), maduramycin (6 ppm – T4), decoquinate (30 ppm – T5), nicarbazin+semduramicin (66 ppm – T6), monensin (110 ppm – T7), salinomycin (66 ppm – T8), narasin+nicarbazin (100 ppm – T9), and nicarbazin (125 ppm – T10). At the end of each AST (20 d), the percent change (delta value) between the treated group (T3 to T10) and the control group (T2) was calculated for the following variables: body weight gain, feed conversion ratio, lesion score, and an indicator of percentage of optimal anticoccidial activity (POAA) that included T2. Different sensitivity levels of EA and EM isolates could be identified. As a whole, drugs from T5 and T3 groups showed higher delta values when compared to other compounds, whereas the lowest sensitivity levels of these isolates were observed in groups T4 and T7. Despite some limiting factors, ASTs can be a good tool for strategic selection of anticoccidial drugs in order to maintain efficacy and extend the lifespan of these molecules.

Transcriptome Analysis Revealed Ameliorative Effects of Bacillus Based Probiotic on Immunity, Gut Barrier System, and Metabolism of Chicken under an Experimentally Induced Eimeria tenella Infection

In this study, we performed transcriptome analysis in the cecum tissues of negative control untreated non-challenged (NC), positive control untreated challenged (PC), and Bacillus subtilis (B. subtilis) fed challenged chickens (BS + ET) in order to examine the underlying potential therapeutic mechanisms of Bacillus based probiotic feeding under an experimental Eimeria tenella (E. tenella) infection. Our results for clinical parameters showed that birds in probiotic diet decreased the bloody diarrhea scores, oocyst shedding, and lesion scores compared to positive control birds. RNA-sequencing (RNA-seq) analysis revealed that in total, 2509 up-regulated and 2465 down-regulated differentially expressed genes (DEGs) were detected in the PC group versus NC group comparison. In the comparison of BS + ET group versus PC group, a total of 784 up-regulated and 493 down-regulated DEGs were found. Among them, several DEGs encoding proteins involved in immunity, gut barrier integrity, homeostasis, and metabolism were up-regulated by the treatment of probiotic. Functional analysis of DEGs also revealed that some gene ontology (GO) terms related with immunity, metabolism and cellular development were significantly affected by the exposure of probiotic. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that the DEGs in the cecum of B. subtilis-fed challenged group were mainly participated in the pathways related with immunity and gut barrier integrity, included mitogen-activated protein kinase (MAPK) signaling pathway, toll-like receptor (TLR) signaling pathway, extracellular matrix (ECM)–receptor interaction, tight junction, and so on. Taken together, these results suggest that Bacillus based probiotic modulate the immunity, maintain gut homeostasis as well as barrier system and improve chicken metabolism during E. tenella infection.

Efficacy of Live Attenuated Vaccine and Commercially Available Lectin Against Avian Pathogenic E. coli Infection in Broiler Chickens.

In this study, the protective efficacy of an E. coli live attenuated vaccine was compared to the preventive administration of lectin preparation before the challenge. Two hundred broiler chicks were divided into eight equal groups. The first group was used as a negative control group. Three groups were vaccinated at day 1 with the avian colibacillosis live vaccine of which one group served as a vaccinated nonchallenged group. Another two groups were treated with lectin product (0.5 mL/L drinking water) for three days before the challenge. The last two groups served as challenge control for either E. coli O78 or O125 strains. The challenge was conducted at three weeks of age with either homologous O78 or heterologous O125 E. coli strains, using 0.5 mL/bird of each avian pathogenic E. coli (APEC) strain (~108 colony forming units “CFU”/mL)/subcutaneously. The bodyweight and feed conversion ratios (FCR) were calculated for four weeks. Clinical signs and gross and histopathological lesions were scored at two and seven days post inoculation (dpi). The heart and liver of euthanized chickens at 2 dpi were removed aseptically and homogenized to evaluate pathogenic E. coli colonization. Results showed that live avian colibacillosis vaccine reduced mortalities and APEC colonization in the homologous challenge group but not in the heterologous challenge group. Lectin-treated groups showed 20% and 16% mortality after challenge with E. coli O78 and O125, respectively, and both groups showed performance parameters, clinical signs, and histopathological lesion scores comparable to the negative control group, with variable E. coli colonization of heart and liver. The study demonstrated the efficacy of live attenuated avian colibacillosis vaccine against homologous but not heterologous APEC challenge in broiler chickens. The lectin-containing products can be used as a preventive medication to reduce the clinical impacts of colibacillosis regardless of the challenge strain. Standardization of the evaluation parameters for APEC vaccines is recommended.

The similarity of the effect of carbohydrase or prebiotic supplementation in broilers aged 21 days, fed mixed cereal diets and challenged with coccidiosis infection.

The aim of this study was to investigate the effect on growth performance and nutrient utilisation when supplementing diets deficient in energy and protein with carbohydrase enzymes or xylo-oligosaccharide in broilers challenged with coccidia. 960 Ross 308 broilers were used in this 21-day study. The treatments were arranged into a 2×4 factorial with 2 challenge states (challenged and non-challenged) and 4 different additive types (control, xylanase alone, xylanase and β-glucanase mixture and xylo-oligosaccharide). On day 14, the challenged group received 12× the recommended dose of coccidiosis vaccine while the non-challenged group received a sham treatment of water only. The birds and feed were weighed on days 0, 14 and 21. On day 21, two birds per pen were euthanized, the caeca were removed and the contents collected for short chain fatty acid analysis. Six more birds per pen were euthanized and ileal digesta were collected and pooled per pen for nutrient digestibility analysis. Feed intake was greater (P < 0.05) on days 14 and 21 when xylo-oligosaccharide was included in the diet compared to the xylanase and β-glucanase mixture in birds challenged with coccidiosis. Including xylo-oligosaccharide in the diet improved (P < 0.05) the digestibility of nitrogen and supplementing diets with the xylanase and β-glucanase mixture improved (P < 0.05) the digestibility of several amino acids. The concentration of arabinose and xylose was (P < 0.001) greater when broiler diets were supplemented with carbohydrase enzymes or xylo-oligosaccharide compared to the control. Although there was an increase in short chain fatty acid production due to the addition of carbohydrase enzymes or xylo-oligosaccharide, there was no additive effect on the %G+C profile of caecal bacteria however there was a negative effect of coccidiosis. In conclusion, the similarity in the response to carbohydrase enzymes or xylo-oligosaccharide supplementation illustrates that the hydrolysis products from carbohydrase activity may have prebiotic like effects.

Evaluation of nitro compounds as feed additives in diets of Eimeria-challenged broilers in vitro and in vivo

Coccidiosis is a disease caused by Eimeria spp., resulting in approximately 3 billion US dollar loss in the poultry industry annually. The present study evaluated the effects of potential feed additives, 2-Nitro-1-propanol (NP) and nitroethanol (NE), on control of coccidiosis. An in vitro experiment indicated that both NP and NE inhibited the development of sporozoites in Madin-Darby bovine kidney cells (MDBK). The in vivo study was further conducted to evaluate the effects of NP and NE on growth performance, nitrogen-corrected apparent metabolizable energy (AMEn), and intestinal lesion scores of broilers challenged with Eimeria spps. Six treatments were tested in the study, including the nonchallenged control, challenged control, 100 ppm NP, 200 ppm NP, 100 ppm NE, and 200 ppm NE. Broilers were fed the treatment diets from day 12 until the end of the trial. All birds except the unchallenged control were challenged with Eimeria maxima, Eimeria tenella, and Eimeria acervulina on day 14. The growth performance was calculated, and the intestinal lesion was scored on day 20. The results showed that Eimeria challenge significantly reduced growth performance, increased intestinal lesion scores, and decreased AMEn compared with the nonchallenged control group. Birds fed with 200 ppm of NP had reduced growth performance compared with the nonchallenged control and challenged control. However, the supplementation of NP significantly improved AMEn and reduced cecal damage. Overall, NP and NE reduced sporozoites numbers in the MDBK cells. NP improved dietary digestibility of energy and reduces lesion scores in the ceca but could not maintain growth performance in broiler chickens infected with Eimeria spp.

Effects of Dietary Direct Fed Microbial Supplementation on Performance, Intestinal Morphology and Immune Response of Broiler Chickens Challenged With Coccidiosis.

Poultry coccidiosis is a costly intestinal disease that leads to considerable tissue damage, inefficient nutrient absorption, increased mortality, and predisposition to secondary infections. This study evaluated the effects of a direct feed microbial (DFM) dietary additive on performance, intestinal morphology, and immune response of broilers during a mixed coccidiosis challenge. In total, 840 Cobb500 male broilers were randomly allocated to 3 treatments (7 replicates, 40 birds/pen) including negative control (NC) fed basal diet; positive control (PC) fed basal diet with coccidiosis challenge; and DFM supplemented diet, with coccidiosis challenge. At 15 days of age, all birds except for the NC treatment were orally gavaged with live oocysts of a commercial vaccine. On d 21 (6 days post challenge), 4 birds/pen were randomly selected and euthanized for scoring of coccidia-caused lesions in the duodenum, jejunum, and ceca. Body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were recorded on d 7, 14, 28, and 42. Jejunal and ileal tissue samples were taken for histomorphological assessment from 2 birds/pen on d 21. Ileal samples were also taken for mRNA expression analysis on d 14 and d 21. The DFM birds had significantly greater BWG than PC birds during d 0–21 (P < 0.05). No differences were observed among the treatment groups in terms of FI and FCR. Dietary DFM supplementation significantly reduced lesion scores in the duodenum and jejunum when compared with PC group (P < 0.05). The coccidia challenge significantly reduced (P < 0.05) ileal villus height when compared to the non-challenged group on d 21. Conversely, dietary DFM supplementation alleviated the negative effects of coccidiosis by increasing ileal villus area on d 21 (P < 0.05). The challenged birds had significantly greater expression of IFN-γ and IL-1β in the ileum on d 21. Based on these findings, dietary DFM supplementation may help restore broiler performance during the starter and early grower periods during coccidiosis, likely by maintaining gut integrity via improving intestinal morphology and also by reducing disease severity as manifested by lower lesion scores.

Response of broiler chickens to dietary soybean bioactive peptide and coccidia challenge

Growth performance, nutrient digestibility, jejunal morphology, plasma cytokine, and gene expression responses of broiler chickens (Cobb 500) to graded concentrations of dietary soybean bioactive peptide (SBP) and coccidia challenge (CC) were investigated in 2 experiments. In experiment 1, 384 male broiler chicks were used to investigate the effect of graded dietary concentrations of SBP on growth performance, nutrient digestibility, and intestinal morphology in a randomized complete block design with 8 replicate cages and 6 diets. Corn-soybean meal-based diet was supplemented with 0, 1, 2, 3, 4, and 5g of SBP/kg of diet. There were linear effects (P < 0.05) of graded concentrations of SBP on BW, BW gain, gain:feed, ileal villus height, and jejunal crypt depth at day 22 post hatching. There were linear effects (P < 0.01) of graded SBP concentrations on Ileal DM and energy digestibility. Experiment 2 was conducted to investigate the immune-protective properties of SBP on broiler chickens during a coccidia challenge. A total of 256 male broiler chicks were randomly assigned to 8 replicate cages in a 2 × 2 factorial arrangement of treatments with 2 SBP levels (0 or 4g/kg of diet) and with or without CC. On day 14 post hatching, birds in the challenged group received 20×, which is twice the recommended coccidia vaccine dose of 25 doses/kg BW, whereas the non-challenged group received physiological saline. Dietary SBP ameliorated the CC-induced effect (P = 0.01) on gain: feed. Coccidia challenge reduced (P < 0.05) jejunal villi height, whereas dietary SBP supplementation increased (P < 0.05) jejunal villi height. Dietary SBP attenuated the CC-induced effects (P < 0.05) on the expression of plasma IL-1β, transforming growth factor-β, claudin-1, and occludin genes. In conclusion, dietary SBP improved growth performance, nutrient digestibility, and jejunal morphology. In addition, dietary SBP reduced the impact of coccidia challenge, and may be beneficial in the feed of broiler chickens for alleviation of health-related effects of coccidia infection.

Comparative efficacy of commercial inactivated Newcastle disease virus vaccines against Newcastle disease virus genotype VII in broiler chickens

Newcastle disease is still causing huge economic losses and devastating outbreaks in poultry flocks despite implementation of extensive vaccination programs. Five commercial broiler chicken groups were established as G1 (non-vaccinated, non-challenged group) and G2 (non-vaccinated, challenged group), and 3 vaccinated challenged groups as G3 (vaccinated with heterologous inactivated Newcastle disease virus (NDV) genotype II (NDV II) vaccine), G4 (vaccinated with homologous inactivated NDV genotype VII (NDV VII) vaccine), and G5 (vaccinated with bivalent (heterologous inactivated NDV II plus H5) vaccine) were used. Challenge test was done using a velogenic NDV genotype VII (vNDV VII) at 28-d olds. Respiratory signs, greenish diarrhea, and obvious post-mortem lesions of vNDV VII appeared in all the challenged birds whether vaccinated or not. In addition, the mortality rate decreased from 93.3% in G2 to 46.7%, 53.3%, and 66.7% in G4, G5, and G3, respectively. Overall, 2 wk postchallenge; body weight loss (%) had increased mainly in G2, with some improvement in chickens in G4 followed by G5 and chickens of G3 showed the least improvement. At 28 d (day of challenge), the highest hemagglutination inhibition values were 4.3 and 5.4 log2 in chickens in G4 and G5, respectively, which increased in all groups after the challenge. Cytokine (IL-6 and IFN-γ) levels were significantly higher (P < 0.05) in the vaccinated groups than that in the non-vaccinated group, especially in G5. Viral shedding in the trachea was higher than that in the cloacal swabs in all vaccinated and non-vaccinated challenged groups with peak shedding on the 6th day post challenge for both swabs, and the lowest viral shedding titers were observed in chickens in G5. Therefore, the use of homologous genotype NDV with inactivated vaccine conferred a higher clinical protection in terms of body weight loss and mortality against vNDV VII challenge in broiler chickens; however, the heterologous vaccine used in G5 induced the highest cell-mediated immune response and hemagglutination inhibition titers with the lowest viral shedding titer.

Examination of viraemia and clinical signs after challenge with a heterologous PRRSV strain in PRRS Type 2 MLV vaccinated pigs: A challenge-dose study.

Vaccination with porcine reproductive and respiratory syndrome (PRRS) Type 2 modified-live vaccines (MLVs) has been shown to improve clinical signs and survival rates in PRRS virus (PRRSV)-challenged pigs. This study evaluated the dose of PRRSV challenge needed to cause and maintain viraemia in PRRS Type 2 MLV-vaccinated pigs and assessed clinical responses to various doses of virulent challenge. This controlled, randomised, blinded vaccination-challenge study involved 95 pigs who were either vaccinated with 2 mL of a PRRS Type 2 MLV on Day 0 or left unvaccinated. On Day 28, pigs were challenged intranasally with virulent PRRSV isolate (dose range <1.5 to 4 log10 50% tissue culture infectious dose/mL). Five pigs were left unchallenged and served as environmental controls. Viraemia levels, pyrexia, average daily weight gain and clinical signs were assessed. At all challenge doses, vaccinated groups had reduced viraemia levels and clinical signs, and higher average daily weight gain compared with non-vaccinated groups. Vaccinated groups challenged with ≤2 log had similar viraemia levels and clinical performance (days pyrexic and average daily weight gain) as the non-challenged group. Vaccinated groups had significantly reduced pyrexic days compared with non-vaccinated groups across all challenge doses (P <.05). Vaccinated pigs challenged with <3 log had significantly improved average daily weight gain (P <.05). In vaccinated groups, challenge dose correlated positively with viraemia levels and number of days pyrexic, and negatively with average daily weight gain. This is the first study to use a challenge-dose model to evaluate the efficacy of vaccination against PRRSV. PRRS Type 2 MLV was shown to mitigate the consequences of PRRSV infection at all evaluated PRRSV challenge doses. Lower levels of challenge had minimal impact on health and performance of vaccinated pigs, supporting the benefit of vaccinating swine with PRRS Type 2 MLV.

Protective effect of Lactobacillus reuteri KUB-AC5 against Salmonella Enteritidis challenge in chickens.

Poultry is an important high-quality food and protein source for humans. However, chicken is considered a primary source of foodborne diseases, especially Salmonella Enteritidis infection. Reducing Salmonella contamination in live poultry will thus lower the risk to consumers. Our previous studies reported that Lactobacillus reuteri KUB-AC5 can produce a substance with antimicrobial activity against pathogenic bacteria, especially Salmonella. In vivo testing revealed that this strain greatly influenced the ileal microbiota by improving chicken gastrointestinal health and inhibiting certain pathogenic bacteria. However, its activity against Salmonella in chicken is unknown. This study investigated the effects of the probiotic L. reuteri KUB-AC5 at various concentrations against Salmonella and the microbiota status in the gastrointestinal tract of broiler chickens. Four treatments groups were used: negative-control group (no Salmonella challenge), positive-control group (Salmonella challenge), and 5 or 7 log cfu probiotic supplementation to Salmonella-challenged chickens. The resultant microbial diversities at the growing and finisher stages were not significantly different among the groups (P>0.05). However, a high dosage of KUB-AC5 maintained similar microbial diversity in Salmonella-challenged chickens as observed in the non-challenged group in the early stage. The exposure Salmonella can affect the microbial diversity that consequently contributes to the disease progression in chicken. Low and high dosages of KUB-AC5 eliminated S. Enteritidis from the ileum and caecum at 14, 21 and 35 days of age. A high-dose of KUB-AC5 also enhanced Lactobacillaceae levels in the growing stage in both the ileum and caecum and suppressed Enterobacteriaceae levels in the finisher stage on day 35, whereas these effects were not observed in the low dose of KUB-AC5 or control groups. These results support the potential value of high-dose L. reuteri KUB-AC5 supplementation for three days after hatching in preventing Salmonella infection in chickens.

Immunostimulant activity of standardised extracts of &lt;i&gt;Mangifera indica&lt;/i&gt; leaf and &lt;i&gt;Curcuma domestica&lt;/i&gt; rhizome in mice

Purpose : To investigate the immunomodulating activity of Mangifera indica. (MI) and Curcuma domestica (CD) extracts in mice. Methods : Mice were randomly divided into 4 groups, namely, vehicle, untreated, MI and CD groups (n = 6). They were treated with MI (160 mg/kg) or CD (200 mg/kg) extracts, and vehicle for control group, for 14 days and sacrificed on day 15. In innate immunity test, the mice were challenged with sheep red blood cells (SRBCs) antigen on day 8, while in adaptive immunity test, mice were immunized and challenged on days 7 and 14, respectively, with SRBC. White blood cells count (WBC), spleen index (SI), and haemagglutination (HA) titer, and delayed type hypersensitivity (DTH) responses were determined. Results : For both plant extracts, adaptive immunity groups showed the highest response compared to innate groups. In adaptive immunity, the WBC count of MI and CD treated animals was significantly higher than in the untreated and vehicle treated groups (p < 0.001). Moreover, the SI of mice from MI and CD treated groups differed significantly that of the untreated group (p < 0.01 and p < 0.05, respectively). HA titer in CD (both non-challenged and challenged) groups was significantly higher than in the non-challenged vehicle group (p < 0.001). HA titer in MI group (non-challenged) was significantly lower than in non-challenged CD and challenged groups (p < 0.01 and p < 0.001, respectively). Conclusion : MI and CD extracts, in appropriate doses, exerted immunostimulant effects in mice by enhancing both innate and adaptive immune systems via increase in WBC, SI, HA titer and DTH responses. Keywords : Mangifera indica, Curcuma domestica, Immunostimulant activity, Spleen index, Haemagglutination, Hypersensitivity response

Vaccination Against Lawsonia intracellularis Decreases Shedding of Salmonella enterica serovar Typhimurium in Co-Infected Pigs and Alters the Gut Microbiome

Salmonella enterica serovar Typhimurium continues to be a major cause of foodborne illness worldwide and pork can serve as a source of infection. Co-infection of S. enterica with Lawsonia intracellularis, a common intestinal pathogen of swine, has been found as risk factor for increased S. enterica shedding. The objective of this study was to investigate if vaccination against L. intracellularis could lead to decreased S. Typhimurium shedding. To test this hypothesis, pigs were challenged with either S. Typhimurium or S. Typhimurium and L. intracellularis, with and without L. intracellularis vaccination (n = 9 per group). A non-challenged group served as a negative control. Vaccination decreased the shedding of S. Typhimurium in co-infected animals by 2.12 log10 organisms per gram of feces at 7 days post infection. Analysis of the microbiome showed that vaccination led to changes in the abundance of Clostridium species, including Clostridium butyricum, in addition to other compositional changes that may explain the protection mediated against S. Typhimurium. These results indicate that vaccination against L. intracellularis in co-infected herds may provide a new tool to increase food safety by helping to prevent S. enterica without the need for antibiotics.

Alginate oligosaccharide alleviates enterotoxigenic Escherichia coli-induced intestinal mucosal disruption in weaned pigs.

Alginate oligosaccharide (AOS) is a non-toxic, non-immunogenic, non-carcinogenic and biodegradable product generated by depolymerisation of alginate, and exhibits various salutary properties. The present study was designed to evaluate whether AOS supplementation could attenuate enterotoxigenic Escherichia coli (ETEC)-induced intestinal mucosal injury in weaned pigs. Twenty-four weaned pigs were randomly assigned to three treatments: (1) non-challenged control; (2) ETEC-challenged control; and (3) ETEC challenge + AOS treatment (100 mg kg-1). On day 12, pigs in the non-challenged group were orally infused with sterilised Luria-Bertani culture while pigs in other groups were orally infused with ETEC (2.6 × 1011 colony-forming units). At 3 days after the challenge, all pigs were orally administered d-xylose at 0.1 g per kg body weight and then euthanised 1 h later to obtain serum and intestinal mucosa samples. Our results showed that ETEC infection both reduced (P < 0.05) the villus height and proportion of epithelial cells in the S phase and elevated (P < 0.05) the percentage of total apoptotic epithelial cells in the jejunum and ileum; these deleterious effects caused by ETEC were alleviated (P < 0.05) by supplemental AOS. Meanwhile, AOS ingestion attenuated (P < 0.05) not only the up-regulated tumour necrosis factor receptor 1 (TNFR1), cysteinyl aspartate-specific protease-3 (caspase-3), -8 and -9 transcriptions, as well as the enhanced caspase activities (caspase-3, -8 and -9), but also the down-regulated cyclin E1 and cyclin-dependent kinase 2 (CDK2) transcriptions in jejunal and ileal mucosae, caused by the ETEC challenge. In conclusion, it is possible that the protective effects of AOS against ETEC-induced intestinal mucosal disruption in weaned pigs are associated with the restrained enterocyte death, by reducing both mitochondria-dependent and TNFR1-dependent apoptosis and the accelerated enterocyte proliferation, via enhancing the cyclin E-CDK2 complex formation.

Modulatory effect of different doses of β-1,3/1,6-glucan on the expression of antioxidant, inflammatory, stress and immune-related genes of Oreochromis niloticus challenged with Streptococcus iniae

β-glucans are widely-known immunostimulants that are profusely used in aquaculture industry. The present study was conducted to evaluate the effect of different in-feed doses of β-1,3/1,6-glucans on the expression of antioxidant and stress-related genes (GST, HSP-70, Vtg), inflammation related genes (Il-8, TNFα, CXC-chemokine and CAS) and adaptive immune-related genes (MHC-IIβ, TLR-7, IgM-H, and Mx) of Oreochromis niloticus challenged and non-challenged with Streptococcus iniae. Six experimental groups were established: non-challenged control (non-supplemented diet), challenged control (non-supplemented diet), non-challenged supplemented with 0.1% β-glucan, challenged supplemented with 0.1% β-glucan, non-challenged supplemented with 0.2% β-glucan and challenged supplemented with 0.2% β-glucan. Fish were fed with β-glucan for 21 days prior challenge and then sampled after 1, 3 and 7 days post-challenge. In non-challenged group, variable effects of the two doses of β-Glucans on the expression of the studied genes were observed; 0.1% induced higher expression of HSP70, CXC chemokine, MHC-IIβ and MX genes. Meanwhile, 0.2% induced better effect on the expression of Vtg, TNF-α, CAS and IgM-H, and almost equal effects of both doses on GST and IL8. However, with the challenged group, 0.2% β-Glucans showed better effect than 0.1% at day one post challenge through significant up-regulation of GST, HSP, IL8, TNF-α, CXC, and MHC-IIβ, meanwhile, the effect of 0.1% was only on the expression of HSP70, MHC-IIβ, and TLR7 at day 3 post challenge. No stimulatory role for both doses of β-Glucans on the expression of almost all genes at day 7 post-challenge.We conclude that both doses of β-glucan can modulate the antioxidant, inflammation, stress and immune-related genes in Nile tilapia, moreover, 0.2% β-Glucans showed better protective effect with Streptococcus iniae challange.

Development of a Salmonella Typhimurium challenge model in weaned pigs to evaluate effects of water and feed interventions on fecal shedding and growth performance.

The aim of this study was to develop a Typhimurium (ST) challenge model in weaned pigs suitable to evaluate effects of water and feed interventions on fecal shedding and growth performance. Two studies were performed. In Exp. 1 weaned pigs were fed either a standard diet (CON) or a diet with a high buffer capacity (HB) and challenged for either 3 or 7 consecutive days in a Latin square design with 4 × 8 individually housed pigs. In Exp. 2, the CON 7-d challenge method was chosen for further model development and validation. Thirty-two individually housed weaned pigs were divided over 4 treatments: a nonchallenged control group (NCON), a challenged positive control group (PCON), a challenged intervention group with acidified water (WATER), and a challenged intervention group with acidified feed (FEED). Pigs were orally challenged once daily on d 7 to 9 or d 7 to 13 after weaning (d 0) with 1 ×10 cfu ST. From d 0 to 28, rectal temperature and occurrence of diarrhea were recorded daily, and BW and feed intake were measured weekly. Fecal samples were collected on d 0, 2, 7, 9, 13, 16, 20, 23, and 27 in Exp. 1 and d 0, 2, 7, 8, 9, 13, 15, and 27 in Exp. 2 for quantification. The results of both experiments showed quantifiable fecal shedding (average peak shedding of approximately 3.5 log and 5.5 log cfu/g, respectively), accompanied by a transient 0.5°C increase in rectal temperature and an increase in occurrence of diarrhea. In Exp. 2 during the week of challenge (i.e., d 7 to 14), a reduction in growth performance (ADG: -157 to 200 g/d and G:F: -0.22 to 0.25 g/d; < 0.01) in PCON and FEED was observed compared to NCON, with WATER showing an intermediate response. The WATER treatment also showed a numerically lower peak shedding (difference of -1.3 to 1.4 log cfu/g) compared to PCON and FEED. To conclude, we repeatedly infected weaned pigs successfully with 1 × 10 cfu of ST for 7 consecutive days, resulting in detectable and quantifiable fecal shedding. This ST challenge model may be suitable for evaluation of effects of water and feed interventions on peak fecal shedding and growth performance.

Quantification of the horizontal transmission of Mycoplasma synoviae in non-vaccinated and MS-H-vaccinated layers

ABSTRACTThe number of newly infected birds attributable to one infectious bird per day (= transmission rate β) was assessed in non-vaccinated and MS-H-vaccinated experimental specified pathogen-free White Leghorns after Mycoplasma synoviae challenge. Furthermore, the effect of vaccination on the shedding of the challenge strain was determined. The following groups were made: a negative control group (n = 5), a vaccinated (MS-H vaccine by eye drop (>105.7 colour changing units/bird)) non-challenged group (n = 5), two non-vaccinated challenged groups (n = 18 each) and two vaccinated challenged groups (n = 18 each). In the challenged groups, six seeder birds were intratracheally inoculated with 105.4 colony forming units (CFUs)/bird. Trachea swabs were taken at day (D)2, D3, D4, D5, D7, D9, D11, D14, D17, D21, D25, D28, D32, D35, D42 and D46 after contact with seeders and analyzed with a quantitative PCR able to detect the vaccine and field strain separately. The transmission rate and shedding were estimated using the susceptible exposed infectious transmission model and a linear mixed model, respectively. The mean shedding of the challenge strain was 106.4 CFU equivalents M. synoviae/g trachea mucus in vaccinates shedding MS-H, while in the birds not shedding the vaccine (non-vaccinates and vaccinates not shedding MS-H) it was 106.9 CFU equivalents M. synoviae/g trachea mucus. In vaccinates shedding MS-H, β was 0.0012 (95% C.I.: 0.00048 – 0.0024), while in birds not shedding vaccine (non-vaccinates and vaccinates not shedding MS-H) a significantly higher β of 0.022 (95% C.I.: 0.015 – 0.031) was found.

Meta-analysis of individual and combined effects of mycotoxins on growing pigs

Little is known about the toxicity of concomitantly occurring mycotoxins in pig diets. This study was conducted to evaluate, through meta-analysis, the individual and the combined effects of mycotoxins on pig performance. The meta-analysis followed three sequential analyses (graphical, correlation, and variance-covariance) based on a database composed of 85 published papers, 1,012 treatments and 13,196 animals. Contamination of diets with individual mycotoxins reduced (p < 0.05) feed intake by 14 % and weight gain by 17 %, while combined mycotoxins reduced the same responses by 42 % and 45 %, respectively, in comparison with the non-challenged group. The correlation (p < 0.05) between reduction in weight gain (ΔG) and reduction in feed intake (ΔFI) was 0.67 in individual challenges and 0.93 in combined challenges. The estimated ΔG was –6 % in individual challenges and –7 % in combined challenges when ΔFI was zero, suggesting an increase in the maintenance requirements of challenged animals. Most of ΔG (58 % in individual challenges and 84 % in combined challenges) was attributed to the changes in feed efficiency. The association of mycotoxins enhances individual toxic effects and the ΔFI is important in explaining the deleterious effects on the growth of challenged pigs.

Milk fat globule membrane coating of large lipid droplets in the diet of young mice prevents body fat accumulation in adulthood.

Epidemiological studies have demonstrated protective effects of breast-feeding on childhood obesity. Differences between human milk and infant milk formula (IMF) in dietary lipid structure may contribute to this effect. In our mouse model, feeding a diet containing large lipid droplets coated with phospholipids (PL) (Nuturis®; PL of milk fat globule membrane (MFGM) fraction origin) in early life protected against excessive body fat accumulation following a diet challenge in adult life. We now set out to determine the relevance of increased droplet size and/or MFGM lipid droplet coating to the observed anti-obesogenic effects in adult life. From day 16 to 42, male mouse pups were exposed to diets with small (S) or large (L) lipid droplets (0·3 v. 2·9 µm average mode diameter, respectively), either without MFGM or with MFGM coating around the lipid droplet, resulting in four groups: S (control diet), L, Scoating and Lcoating (Nuturis® IMF diet). Mice were subsequently challenged with a Western-style diet until dissection at postnatal day 98. A non-challenged group served as reference (REF). We repeatedly determined body composition between postnatal day 42 and 98. At day 98 plasma and gene expression measurements were performed. Only the Nuturis® IMF diet (Lcoating) in early life containing MFGM-coated large lipid droplets reduced body fat mass to a level comparable with the REF group. These data support the notion that the structural aspects of lipids in human milk, for example, both lipid droplet size as well as the MFGM coating, may contribute to its reported protective effect against obesity in later life.

Immune responses of a chimaeric protein vaccine containing Mycoplasma hyopneumoniae antigens and LTB against experimental M. hyopneumoniae infection in pigs

A recombinant chimaeric protein containing three Mycoplasma hyopneumoniae antigens (C-terminal portion of P97, heat shock protein P42, and NrdF) fused to an adjuvant, the B subunit of heat-labile enterotoxin of Escherichia coli (LTB), was used to immunize pigs against enzootic pneumonia. The systemic and local immune responses, as well as the efficacy of the chimaeric protein in inducing protection against experimental M. hyopneumoniae infection were evaluated. In total, 60 male piglets, purchased from a M. hyopneumoniae-free herd, at 4 weeks of age were randomly allocated to six different experimental groups of 10 animals each: recombinant chimaeric protein by intramuscular (IM) (1) or intranasal (IN) (2) administration, commercial bacterin by IM administration (3), and the adjuvant LTB by IM (4, control group A) or IN (5, control group B) administration. All groups were immunized at 24 and 38 days of age and challenged at 52 days of age. The sixth group that was not challenged was used as the negative control (IN [n=5] or IM [n=5] administration of the LTB adjuvant). Compared with the non-challenged group, administration of the chimaeric protein induced significant (P<0.05) IgG and IgA responses against all individual antigens present in the chimaera, but it could not confer a significant protection against M. hyopneumoniae infection in pigs. This lack of effectiveness points towards the need for further studies to improve the efficacy of this subunit-based vaccine approach.