Effect of yeast cell product (CitriStim) supplementation on broiler performance and intestinal immune cell parameters during an experimental coccidial infection

Yeast cell wall supplementation affects the Salmonella enteretidis load in the ceca and ovaries of layer pullets

Salmonella enteretidis (SE) has a great propensity to translocate from the cecum into internal organs such as the spleen and liver. However, a major concern is the ability of SE to colonize the ovaries. This study aimed to evaluate the efficacy of cell walls from Saccharomyces cerevisiae to control the Salmonella load in the ceca and ovaries of commercial layer pullets. Ten-week-old layer pullets were divided into 2 groups: one group was fed a control diet with commercial feed without additives, and another group was fed the same diet supplemented with 0.5 kg/metric ton of yeast cell walls (YCWs). At 16 wk of age, the birds in both groups were challenged with 3.0 × 109 CFU/mL SE by oral gavage. The birds were euthanized on d 7 and 14 postchallenge to collect the ceca and ovaries for Salmonella load determination. The results demonstrated that there were no statistical differences in ovary SE infection rates. The trend in the prevalence of SE positivity in the ovaries was similar at 14 d, with 2.1% (YCW pullets) to 4.2% positive for the ovaries of the nontreated pullets. There was also no significant difference in the SE log10 MPN/gram between the YCW and the control groups. In the ceca, the high level of SE (3.0 × 109 cfu/pullet), which results in ovarian transmission, causes high intestinal tract inflammation. There was a significant difference in the prevalence of SE in the ceca at 7 d postchallenge but not at 14 d postchallenge. In conclusion, the reduction in Salmonella load observed in the ceca on d 7 in this study shows the potential of YCW supplementation for reducing Salmonella colonization in poultry.

The effects of arginine and branched-chain amino acid supplementation to reduced-protein diet on intestinal health, cecal short-chain fatty acid profiles, and immune response in broiler chickens challenged with Eimeria spp

We investigated the effects of supplementing arginine (Arg) and branched-chain amino acids (BCAA) in broilers fed reduced-protein diets and challenged with Eimeria spp. All birds were fed the same starter diet meeting Cobb 500 nutrient specifications from d 1 to 9. Four grower diets: positive control (PC) with 20.0% crude protein (CP); reduced-protein negative control (NC) with 17.5% CP; or NC supplemented with Arg or BCAA at 50% above recommendations (ARG or BCAA) were fed to the birds from d 9 to 28. Birds were allocated in a 2 × 4 factorial arrangement (4 diets, each with or without challenge), with 8 replicates per treatment. On d 14, the challenge groups were orally gavaged with mixed Eimeria spp. Intestinal permeability was higher (P < 0.05) in NC than PC, whereas the permeability of ARG and BCAA groups did not differ significantly from PC. On d 28, a significant interaction (P < 0.01) was observed in CD8⁺: CD4⁺ ratios in cecal tonsils (CT), Eimeria challenge increased the ratios in all groups except for the ARG group. On d 21, a significant interaction was found for CD4⁺CD25⁺ percentages in CT (P < 0.01) that Eimeria challenge increased the percentages only in PC and NC groups. On d 21 and 28, significant interactions (P < 0.01) were found for macrophage nitric oxide (NO) production. In nonchallenged birds, NO was higher in the ARG group than other groups, but in challenged birds, NO was higher in both ARG and BCAA groups. On d 21, a significant interaction was found for bile anticoccidial IgA concentrations (P < 0.05) that Eimeria challenge increased IgA only in NC and ARG groups. The results suggest that a reduced-protein diet exacerbates the impact of the Eimeria challenge on intestinal integrity, but this could be mitigated by Arg and BCAA supplementations. Arginine and BCAA supplementations in reduced-protein diets could be beneficial for broilers against Eimeria infection by enhancing the immune responses. The beneficial effects of Arg supplementation tended to be more pronounced compared to BCAA supplementation.

Growth performance, nutrient digestibility, intestinal morphology, cecal mucosal cytokines and serum antioxidant responses of broiler chickens to dietary enzymatically treated yeast and coccidia challenge

BACKGROUND

There is a growing search for natural feed additives to alleviate the deleterious effects of coccidia infection in poultry production. This study aimed to investigate the effect of enzymatically treated yeast (ETY) on the growth performance, nutrient digestibility, intestinal morphology, antioxidative status, and cecal mucosa cytokines of coccidia-challenged broiler chickens.

METHODS

From d 1 to 14 post hatching, 480 broiler chickens were allocated to 3 corn-soybean meal-based experimental diets with increasing concentrations of ETY (0, 1, or 2 g/kg). The experiment was designed as a randomized complete block design with body weight (BW) used as a blocking factor. On d 14 post hatching, the birds were re-randomized within each of the 3 experimental diets. Each of the 3 diet groups was split into a challenge or no-challenge group. This resulted in a 3 × 2 factorial arrangement of treatments. The coccidia challenge was administered on d 15 by an oral gavage.

RESULTS

Dietary ETY improved (P < 0.05) the G:F of birds on d 21 regardless of the challenge state and linearly increased (P < 0.01) the apparent ileal digestibility of dry matter (DM), nitrogen, and gross energy (GE). The coccidia challenge decreased (P < 0.05) BW gain and feed intake of broiler chickens and reduced (P < 0.01) the total tract retention of DM, GE, and nitrogen. The coccidia challenge increased (P < 0.01) the mRNA gene expression of TNFα, IL-1β, IL-10, and IL-6 in the cecal mucosa. There was a tendency (P = 0.08) for ETY to linearly reduce IL-1β expression. Additionally, ETY supplementation increased (P < 0.05) the gene expression of OCLN. Serum catalase increased (P < 0.05) with dietary ETY in broiler chickens on d 21. Dietary ETY linearly increased (P < 0.05) the ileal villus height to crypt depth ratio, and ileal goblet cell density in broiler chickens. The ileal and excreta oocyst counts decreased (P < 0.01) with increasing supplementation of dietary ETY in coccidia-challenged broiler chickens on d 21.

CONCLUSIONS

Dietary ETY enhanced nutrient utilization and augmented intestinal development in broiler chickens. However, dietary ETY did not completely attenuate the adverse effects of a coccidia challenge in broiler chickens.

Kinetics of the Cellular and Transcriptomic Response to Eimeria maxima in Relatively Resistant and Susceptible Chicken Lines

Eimeria maxima is a common cause of coccidiosis in chickens, a disease that has a huge economic impact on poultry production. Knowledge of immunity to E. maxima and the specific mechanisms that contribute to differing levels of resistance observed between chicken breeds and between congenic lines derived from a single breed of chickens is required. This study aimed to define differences in the kinetics of the immune response of two inbred lines of White Leghorn chickens that exhibit differential resistance (line C.B12) or susceptibility (line 15I) to infection by E. maxima. Line C.B12 and 15I chickens were infected with E. maxima and transcriptome analysis of jejunal tissue was performed at 2, 4, 6 and 8 days post-infection (dpi). RNA-Seq analysis revealed differences in the rapidity and magnitude of cytokine transcription responses post-infection between the two lines. In particular, IFN-γ and IL-10 transcript expression increased in the jejunum earlier in line C.B12 (at 4 dpi) compared to line 15I (at 6 dpi). Line C.B12 chickens exhibited increases of IFNG and IL10 mRNA in the jejunum at 4 dpi, whereas in line 15I transcription was delayed but increased to a greater extent. RT-qPCR and ELISAs confirmed the results of the transcriptomic study. Higher serum IL-10 correlated strongly with higher E. maxima replication in line 15I compared to line C.B12 chickens. Overall, the findings suggest early induction of the IFN-γ and IL-10 responses, as well as immune-related genes including IL21 at 4 dpi identified by RNA-Seq, may be key to resistance to E. maxima.

Effects of methylsulfonylmethane and neutralizing anti-IL-10 antibody supplementation during a mild Eimeria challenge infection in broiler chickens

A 28-day experiment was conducted in broilers to study the effects of feeding methylsulfonylmethane (MSM) and IL-10-neutralizing antibody from dried egg product (DEP) on the growth performance, immune responsivity, oxidative stress parameters, and gut health outcomes during a mild infection with mixed species of Eimeria. A total of 500 male Ross 308 chicks were allocated to five treatments: sham-inoculated (uninfected) chickens fed control diet (UCON), Eimeria-infected chickens fed control diet (ICON), and Eimeria-infected chickens fed control diet supplemented with 287 U/tonne of DEP (I-DEP), 0.4% MSM, or their combination (I-DEP-MSM), with 10 replicate cages of 10 birds per treatment. All infected groups received 1 mL of an oral inoculum containing Eimeria acervulina (10,000 oocysts), Eimeria maxima (5,000 oocysts), and Eimeria tenella (5,000 oocysts) on study days 7 and 14. Data were analyzed as a two-way ANOVA for all treatments including Eimeria-infected groups, in addition to a single degree of freedom contrast to compare uninfected and infected groups receiving the control diet. Mild Eimeria infection did not influence the growth performance in ICON compared with UCON at any time points. Overall (day 0-28) growth performance parameters were not influenced by either infection or dietary supplementation of MSM or DEP. However, birds in I-DEP-MSM showed improved ADG during study day 7 to 14 (i.e., 7 d after primary inoculation) indicating a beneficial effect immediately after Eimeria infection. Although MSM supplementation reduced thiobarbituric acid reactive substances (day 21 and 28), both MSM and DEP improved the total antioxidant capacity (day 21) in the plasma of infected birds. Histopathological outcomes were not influenced by treatments, and fecal oocyst output was higher in MSM- and DEP-supplemented groups than with ICON, indicating no beneficial effects. Similarly, expression of cecal inflammatory cytokines (IL-10, IL-1β, and interferon-γ) was not affected by MSM, DEP, or their combination. Overall, the current results suggest that both MSM and DEP supplementation may benefit birds during a mild Eimeria infection as indicated by improvements in ADG and oxidative stress outcomes.

Dietary supplementation with anti-IL-10 antibody during a severe Eimeria challenge in broiler chickens

Attenuation of host IL-10 activity during Eimeria infection may elicit a robust Th1 response to eliminate the parasite from the gut epithelium. An experiment was conducted to study the effects of feeding IL-10 neutralizing antibody delivered via a dried egg product (DEP) on growth performance, immune responsivity, and gut health outcomes during a severe challenge with either Eimeria acervulina (study 1) or Eimeria tenella (study 2) following FDA CVM #217 protocol to test anticoccidial products. A total of 720 male Ross 308 chicks were used in each study, with 15 replicate cages of 12 birds and the following 4 treatments: sham-inoculated (uninfected) control diet (UCON), Eimeria-infected control diet (ICON), and Eimeria-infected control diet supplemented with DEP at 2 levels (165 [I-165] or 287 [I-287] U/tonne in study 1 and 143 [I-143] or 287 [I-287] U/tonne in study 2). Individual birds assigned to infected treatment groups received a single oral dose of either 200,000 E. acervulina (study 1) or 80,000 E. tenella (study 2) oocysts at 12 d of age (i.e., d post inoculation [DPI] 0), whereas uninfected birds were sham-inoculated with tap water. A one-way ANOVA was performed on outcomes including growth performance, hematology, serum chemistry profiles, immunophenotyping profiles, and intestinal lesion scores. In both studies, DPI 0 to 7 weight gain, feed intake, and feed conversion ratio were worse (P < 0.05) in all infected groups compared with the UCON group. Compared with ICON, DEP supplementation elicited no differences on overall growth performance. Histopathology and lesion scores revealed severe damage to the gut epithelium owing to the Eimeria challenge, yet DEP supplementation did not improve these outcomes or oocyst shedding, hematological measurements, or serum chemistry. However, DEP supplementation improved (P < 0.05) the percentage of circulating CD3⁺ cells at 6 DPI in study 2. These results indicate that DEP does not appear to elicit a coccidiostatic effect during a severe infection with E. acervulina or E. tenella.

Effect of Carotenoids, Oligosaccharides and Anthocyanins on Growth Performance, Immunological Parameters and Intestinal Morphology in Broiler Chickens Challenged with Escherichia coli Lipopolysaccharide

This study was conducted to investigate the effect of carotenoid, oligosaccharide and anthocyanin supplementation in broiler diets under Escherichia coli lipopolysaccharide (LPS) challenge. Ross 308 chickens were fed 5 diets: basal diet (control diet), diet supplemented with β-glucan in 0.05% (positive control) and diets with 0.5% carotenoid-, oligosaccharide- or anthocyanin contents. On the 26th days of age, chickens were challenged intraperitoneally 2 mg LPS per kg of body weight. 12 h after injection, birds were euthanized, then spleen and ileum samples were collected. LPS induced increased relative mRNA expression of splenic (p = 0.0445) and ileal (p = 0.0435) interleukin-1β (IL-1β), which was lower in the spleen in carotenoid (p = 0.0114), oligosaccharide (p = 0.0497) and anthocyanin (p = 0.0303)-treated chickens compared to LPS-injected control birds. Dietary supplementation of carotenoids also decreased relative gene expression of splenic interleukin-6 (IL-6) (p = 0.0325). In the ileum, β-glucan supplementation showed lower relative mRNA expression of toll-like receptor 5 (TLR-5) (p = 0.0387) compared to anthocyanin treatment. Gene expression of both splenic and ileal interferon-α (IFN-α), interferon-γ (IFN-γ), toll-like receptor 4 (TLR-4) and toll-like receptor 5 (TLR-5) were not influenced by dietary supplements. In conclusion, carotenoids, oligosaccharides and anthocyanins could partially mitigate the immune stress caused by LPS challenge. All of the compounds impacted longer villus height (p < 0.0001), villus height:crypt depth ratios were higher after β-glucan (p < 0.0001) and anthocyanin (p = 0.0063) supplementations and thickened mucosa was observed in β-glucan (p < 0.0001), oligosaccharide (p < 0.0001) and anthocyanin (p = 0.048) treatments. All of these findings could represent a more effective absorption of nutrients.

The effects of coarse corn and refined functional carbohydrates on the live performance and cecal Salmonella prevalence in coccidiosis-vaccinated broilers1

The interaction between corn particle size and feed additives as it pertains to broiler live performance has been overlooked. This study evaluated the effects of corn particle size and refined-functional carbohydrates (RFC; 100 g/MT) on live performance and Salmonella prevalence in coccidiosis-vaccinated broilers. The following treatments were applied: fine corn (FC), coarse corn (CC), FC+RFC, CC+RFC, and CC+SAL (salinomycin). A natural, non-experimental necrotic enteritis (NE) outbreak began at 12 D of age, and mortality was impacted by dietary treatments. The use of RFC was observed to increase NE-associated mortality compared to broilers fed CC+SAL (P ≤ 0.10). At 19 D, greater than 50% of all broilers were found to be Salmonella-positive; however, at 48 D the use of RFC was shown to decrease cecal Salmonella prevalence. Although differences in early mortality were observed, coccidiosis-vaccinated broilers fed CC or CC+RFC exhibited similar BW and FCR as broilers fed CC+SAL at 48 D (P ≤ 0.05). These data suggested that CC use after 10 D may provide value in a production system free of antibiotic growth promoters and coccidiostats by ameliorating live performance losses associated with coccidiosis vaccination. Further research is warranted to determine how RFC and CC specifically affect Eimeria cycling and the immune response following coccidiosis vaccination and an NE challenge.

Utility of Feed Enzymes and Yeast Derivatives in Ameliorating Deleterious Effects of Coccidiosis on Intestinal Health and Function in Broiler Chickens

Coccidiosis induced necrotic lesions impair digestive capacity and barrier function in concurrence with increased risks for secondary bacterial infections. The industry has been successful in controlling coccidiosis with anticoccidials and vaccination. However, concerns over Eimeria species resistant to anticoccidials, gaps in vaccination and restriction on antibiotics is stimulating research and application of alternative and/or complimentary strategies for coccidiosis control. The aim of this paper is to appraise literature on the utility of feed enzymes and yeast derivatives in modulating coccidiosis. Feed enzymes can complement endogenous enzymes (protease, amylase, and lipase) that may become insufficient in coccidiosis afflicted birds. Coccidiosis in the upper small intestine creates conditions that enhances efficacy of phytase and there are reports indicating supplemental phytase can mitigate the negative impact of coccidiosis on bone quality. Increase in intestinal short chain fatty acids due supplemental fiber degrading enzymes has been linked with reduced survivability of Eimeria. There is evidence whole yeast (live or dead) and derivatives can modulate coccidiosis. Immunomudulation properties of the yeast derivatives have been shown to enhance cellular and humoral immunity in Eimeria challenge models which is critical for effectiveness of coccidial vaccination. Moreover, yeast nucleotides have been shown to be beneficial in stimulating healing of intestinal mucosal surface. Other novel work has shown that certain yeast cells can produce derivatives with anticoccidial compounds effective in attenuating oocysts shedding. Yeast cell surface has also been shown to be an effective oral Eimeria vaccine delivery vehicle. Overall, while further refinement research is warranted to address inconsistencies in responses and commercial application, there is evidence feed enzymes and yeast derivatives could complement strategies for maintaining intestinal function to bolster growth performance in broilers compromised with coccidiosis. However, broilers receive diets containing several feed additives with distinct mode of actions and yet there is dearth of empirical data on the expected responses.Future evaluations should consider combinations of additives to document animal responses and potential synergies.

Effects of dietary yeast extract supplementation on growth, body composition, non-specific immunity, and antioxidant status of Chinese mitten crab (Eriocheir sinensis)

This study was conducted to evaluate the effects of dietary supplementation with yeast extract on growth, body composition, non-specific immunity, and antioxidant status of Chinese mitten crab (Eriocheir sinensis). A total of 432 crabs (initial average weight, 4.62 ± 0.11 g) were randomly distributed into four treatment groups with six replicates of 18 crabs. The crabs were fed a basal diet or the same diet supplemented with 2.5, 5, and 10 g/kg yeast extract for 8 weeks. The results showed that dietary yeast extract inclusion enhanced the edible viscera index (linear, P < 0.001), edible viscera crude protein (CP) content (linear, P = 0.025) and serum phenoloxidase (ProPO) activity (quadratic, P = 0.023) at 56 day, increased the total superoxide dismutase (T-SOD) activity at 28 day (quadratic, P = 0.037) and catelase (CAT) activity at 56 day (quadratic, P = 0.034) of edible viscera, and muscular T-SOD activity (quadratic, P = 0.020) at 56 day in Chinese mitten crab. Compared with the control group, the inclusion of 5 g/kg yeast extract in the diet increased the edible viscera index, enhanced the CAT activity of edible viscera at 56 day in Chinese mitten crab (P < 0.05). Dietary 10 g/kg yeast extract inclusion enhanced the edible viscera index at 56 day in Chinese mitten crab than that of the control group (P < 0.05). These results implied that dietary yeast extract inclusion improved the edible viscera index and crude protein content of edible viscera, enhanced serum immunity, and increased the antioxidant status of edible viscera and muscle in Chinese mitten crab, especially when it is supplemented at 5 g/kg yeast extract in the diet.

Assessing effects of yeast cell wall supplementation on threonine requirements in broilers as measured by performance and intestinal morphology

The objective of this study was to evaluate whether or not the use of a prebiotic yeast cell wall (YCW) affects threonine requirements in starter broilers. Two hundred and forty 1-d-old Ross 308 broiler chickens were distributed among 2 Petersime battery brooder units (48 pens; 5 birds per pen). Different threonine to lysine ratios (0.60, 0.65, and 0.70 to 1.0) with 1.22% available lysine with and without YCW at 250 ppm was fed to the chickens in order to evaluate performance and intestinal morphology over a 21-d trial. A basal diet with 22% protein and 2,980 kcal/kg ME was prepared to create the 6 dietary treatments. The calculated lysine concentration was 1.34%, whereas threonine was 0.81, 0.88, and 0.94%, respectively. Pen weights and feed consumption were recorded at d 1, 7, 14, and 21 of the experiment. Jejunal and ileal samples were collected on d 21 for histology analysis to evaluate villi height (VH), crypt depth, villi width (VW), and muscularis thickness. A threonine to lysine ratio of 0.7:1.0 resulted in significant improvement of performance variables with increased jejunum VW and ileum VH compared with the other threonine to lysine ratios. Adding YCW to starter broiler did not affect the requirement for threonine.

The impact of β-glucans on performance and response of broiler chickens during a coccidiosis challenge

Coccidiosis is a costly parasitic disease to the poultry industry with multiple prevention methods being explored to control its impact. This study evaluated the feeding effects of β-glucans on performance and responses of chickens during a coccidiosis challenge. Cobb 500 male broilers (n = 1280) were assigned to 1 of 8 treatment groups (8 replicate pens; 20 birds/pen) in a 2 × 4 factorial arrangement, including non-infected and Eimeria-infected birds fed for 28 d a control diet, control + BG (150 g/MT Algamune 50), control + BGZn (100 g/MT Algamune 50 Zn), and control + 0.01% Salinomycin (Sal). On d15, birds in the challenge groups received a mixed Eimeria inoculum. Birds and feed were weighed weekly on a per pen basis to evaluate body weight gain (BWG), feed intake (FI), and feed conversion ratios (FCR). Lesion scores were assessed 6 d post infection (d21) on 3 birds per pen. Performance data were subjected to ANOVA and differences were established using the LS-MEANS statement with significance reported at P ≤ 0.05. There were minor differences in lesion scores among the dietary treatments in the infected groups with reduced duodenal and cecal scores in the Sal group compared to the BGZn and BG groups, respectively. The coccidiosis challenge main effect resulted in a significant reduction in 0-28 d BW and FI. Dietary treatment resulted in non-significant effect on BWG, but Sal addition resulted in increased FI. A significant diet X challenge interaction resulted in higher FCR in the Eimeria-challenged birds supplemented with Sal and BGZn in comparison to the other challenged groups, likely due to reduced mortality in the challenged Sal and BGZn groups. Body composition analysis at d28 revealed that the Eimeria challenge reduced both fat and lean tissue contents, where the β-glucans and Sal birds had lower fat percent than control birds.

Effects of yeast cell wall on growth performance, immune responses and intestinal short chain fatty acid concentrations of broilers in an experimental necrotic enteritis model

Subclinical necrotic enteritis (NE) causes devastating economic losses in the broiler chicken industry, especially in birds raised free of in-feed antibiotics. Prebiotics are potential alternatives to in-feed antibiotics. Yeast cell wall extract (YCW) derived from Saccharomyces cerevisiae is a prebiotic with known immune modulating effects. This study examined the effects of YCW and antibiotics (AB) during subclinical NE on broiler growth performance, intestinal lesions, humoral immune response and gut microflora metabolites. The study employed a 2 × 3 factorial arrangement of treatments. Factors were: NE challenge (yes or no) and feed additive (control, AB, or YCW). Each treatment was replicated in 8 floor pens with 15 birds per pen. Challenged birds had higher feed conversion ratio (FCR) than unchallenged birds on d 35 (P < 0.05). Dietary inclusion of AB decreased FCR regardless of challenge (P < 0.05) on d 24 and 35. Inclusion of YCW reduced serum interleukin-1 (IL-1) concentration in NE challenged birds (P < 0.01) and increased immunoglobulin (Ig) G (P < 0.05) and Ig M (P < 0.05) levels compared to other dietary treatments regardless of challenge. Yeast cell wall extract increased formic acid concentration in cecal contents during challenge and increased butyric acid concentration in unchallenged birds on d 16. This study indicates YCW suppressed inflammatory response, promoted generation of immunoglobulin and increased short chain fatty acid production suggesting potential benefits to bird health.

Changes of cecal microflora in chickens following Eimeria tenella challenge and regulating effect of coated sodium butyrate

Eimeria tenella, one of the most important parasitic protozoa in the genus Eimeria, is responsible for chicken caecal coccidiosis resulting in huge economic losses to poultry industry. The present study investigated the changes in caecal microflora of E. tenella-infected chickens and the regulating effect of coated sodium butyrate, a potential alternative to antibiotics. Using high-throughput sequencing of 16S rRNA V3-V4 region of bacteria we found significant changes in caecal microflora of E. tenella-infected chickens indicated by an increase of Firmicutes (mainly Ruminococcaceae, Lachnospiraceae and vadin BB60) and Proteobacteria (mainly Enterobacteriaceae) and a decrease of Bacteroidetes (predominantly Bacteroidaceae). Inclusion of coated sodium butyrate in the diet of chickens per se had no significant effect on caecal microflora of normal healthy chickens but significantly prevented the increase in Firmicute abundance and decrease of Bacteroidetes abundance in E. tenella-infected birds. No significant changes to caecal microflora were observed at the phylum level between control and E. tenella-infected birds given coated sodium butyrate. In conclusion, our results show that coated sodium butyrate can balance the disorders of cecal microflora caused by E. tenella; thus, it can be a useful supplement for the control of avian coccidiosis.

Oral antibody to interleukin-10 reduces growth rate depression due to Eimeria spp. infection in broiler chickens

Eimeria spp. must be controlled in floor-reared poultry to prevent the onset of coccidiosis. Here we use an oral antibody to chicken IL-10 to prevent growth depression due to Eimeria spp. infection. Egg antibody directed against an antigenic peptide of IL-10 was produced in laying hens and measured using an ELISA. In the first experiment, egg yolk powder containing antibody to chicken IL-10 (vlpramqt conjugate) (anti-IL-10 yolk powder) was fed at 3.4 g/kg feed to determine growth response following mixed Eimeria spp. challenge. Chicks were fed either anti-IL-10 antibodies or control antibodies and challenged (d3) with either sterile saline or a 10× attenuated Eimeria spp. vaccine. Control-fed and Eimeria-challenged chicks grew 8.8% slower than those challenged with saline (P < 0.04), whereas anti-IL-10-fed Eimeria challenged chicks were not different from untreated controls. In the second trial a dose response was performed with doses of either 0 (control antibody), 0.34-, or 3.4-g anti-IL-10 yolk powder/kg feed. Control-fed, Eimeria-challenged chicks grew 10.6% slower than control saline-challenged chicks (P < 0.05); however, anti-IL-10-fed chicks fed either dose of anti-IL-10 were not different from saline-challenged chicks. Finally, the effect of anti-IL-10 on acquired immunity was investigated. Chicks were fed control or anti-IL-10 yolk powder and vaccinated with a 1× dose of Eimeria vaccine at d 3. After 14 d, antibody was removed from the diet. Chicks were either saline or 10× Eimeria challenged at d 17. We found that the anti-IL-10-fed chickens did not show a reduction in growth due to challenge; hence anti-IL-10 does not appear to affect adaptive immunity during the primary immunization. Overall, use of an antibody to IL-10 is a novel method in preventing adverse effects of Eimeria spp. infection in poultry.

Impact of Meyerozyma guilliermondii isolated from chickens against Eimeria sp. protozoan, an in vitro analysis

Background

Avian coccidiosis is a disease caused worldwide by several species of parasite Eimeria that causes significant economic losses. This disease affects chickens development and production, that most of times is controlled with anticoccidial drugs. Although efforts have been made to address this disease, they have been made to control Eimeria sporozoites, although enteric stages are often vulnerable, however; the parasite oocyst remains a problem that must be controlled, as it has a resistant structure that facilitates dispersion. Despite some commercial products based on chemical compounds have been developed as disinfectants that destroy oocysts, the solution of the problem remains to be solved.

Results

In this work, we assessed in vitro anticoccidial activity of a compound(s) secreted by yeast isolated in oocysts suspension from infected chickens. The yeast was molecularly identified as Meyerozyma guilliermondii, and its anticoccidial activity against Eimeria tenella oocysts was assessed. Here, we report the damage to oocysts walls caused by M. guilliermondii culture, supernatant, supernatant extract and intracellular proteins. In all cases, a significant decreased of oocysts was observed.

Conclusions

The yeast Meyerozyma guilliermondii secretes a compound with anticoccidial activity and also has a compound of protein nature that damages the resistant structure of oocyst, showing the potential of this yeast and its products as a feasible method of coccidiosis control.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-015-0589-0) contains supplementary material, which is available to authorized users.

Selection for pro-inflammatory mediators produces chickens more resistant to Eimeria tenella

We recently developed a novel selection method based on identification and selection of chickens with an inherently high and low phenotype of pro-inflammatory mediators, including interleukin (IL)-6, CXCLi2, and CCLi2. The resultant high line of chickens is more resistant to Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) compared to the low line. In the current study, we sought to determine if the high line birds were also more resistant to the protozoan parasite Eimeria tenella. In three separate experiments, 14-day-old chickens from the high and low lines were challenged orally with 10×10(3) to 45×10(3) E. tenella oocysts. Birds were sacrificed 6 d postchallenge and the caeca was removed and scored for lesions and body weight gain compared to mock-infected controls. The high line birds were more resistant to intestinal pathology as demonstrated by lower lesion scores (P≤0.04) compared to the low line. There were no differences in body weight gain between the lines. The results from this study showed that in addition to enhanced resistance against Salmonella Enteritidis, high line chickens are also more resistant to the pathology associated with coccidial infections compared to the low line birds. Taken together with our initial study utilizing the high and low lines, selection based on increased pro-inflammatory mediator expression produces chickens that are more resistant to both foodborne and poultry pathogens, including cecal pathology associated with costly coccidial infections.

Towards the control of necrotic enteritis in broiler chickens with in-feed antibiotics phasing-out worldwide

Poultry production has undergone a substantial increase compared to the livestock industries since 1970. However, the industry worldwide is now facing challenges with the removal of in-feed antibiotics completely or gradually, as the once well-controlled poultry diseases have re-emerged to cause tremendous loss of production. Necrotic enteritis (NE) is one of the most important diseases which costs the industry over two billion dollars annually. In this paper, we review the progress on the etiology of NE and its control through dietary modifications, pre- and probiotics, short chain fatty acids, and vaccination. The other likely measures resulted in the most advances in the toxin characterization are also discussed. Vaccine strategies may have greater potential for the control of NE mainly due to clearer etiology of NE having been elucidated in recent years with the identification of necrotic enteritis toxin B-like (NetB) toxin. Therefore, the use of alternatives to in-feed antibiotics with a better understanding of the relationship between nutrition and NE, and limiting exposure to infectious agents through biosecurity and vaccination, might be a tool to reduce the incidence of NE and to improve gut health in the absence of in-feed antibiotics. More importantly, the combinations of different measures may achieve greater protection of birds against the disease. Among all the alternatives investigated, prebiotics, organic acids and vaccination have shown improved gastrointestinal health and thus, have potential for the control of NE.

Use of yeast cell wall extract as a tool to reduce the impact of necrotic enteritis in broilers

The use of a yeast cell wall extract derived from Saccharomyces cerevisiae (Actigen(®)) has been proposed as an alternative to in-feed antibiotics. This experiment was conducted to investigate the efficacy of yeast cell extract as an alternative to zinc bacitracin or salinomycin using a necrotic enteritis challenge model. A feeding study was conducted using 480-day-old male Ross 308 chicks assigned to 48 floor pens. A 2 × 4 factorial arrangement of treatments was employed. The factors were: challenge (- or +) and feed additive (control, zinc bacitracin at 100/50 mg/kg, yeast cell wall extract at 400/800/200 mg/kg, or salinomycin at 60 mg/kg in starter, grower, and finisher, respectively). Diets based on wheat, sorghum, soybean meal, meat and bone meal, and canola meal were formulated according to the Ross 308 nutrient specifications. Birds were challenged using a previously established protocol (attenuated Eimeria spp oocysts) on d 9 and 10(8) to 10(9) Clostridium perfringens (type A strain EHE-NE18) on d 14 and 15). Challenged and unchallenged birds were partitioned to avoid cross contamination. Challenged birds had lower weight gain, feed intake and livability compared to unchallenged birds on d 24 and d 35 (P < 0.05). Birds given zinc bacitracin, yeast cell wall extract, or salinomycin had improved weight gain and livability when compared to control birds given no additives. Challenge × additive interactions were observed for feed intake and weight gain on d 24 and d 35 (P < 0.01). The additives all had a greater positive impact on feed intake, weight gain, and livability in challenged than unchallenged birds. All challenged birds showed higher necrotic enteritis lesion scores in the small intestine sections when compared to unchallenged birds (P < 0.01). Birds fed yeast cell wall extract exhibited increased villus height, decreased crypt depth, and increased villus:crypt ratio when challenged. Yeast cell wall extract, zinc bacitracin, and salinomycin were effective in preventing performance decline from necrotic enteritis in the current study. This study indicates that yeast cell wall extract has promise as a tool for controlling necrotic enteritis.

Control of avian coccidiosis: future and present natural alternatives

Numerous efforts to date have been implemented in the control of avian coccidiosis caused by the Eimeria parasite. Since the appearance of anticoccidial chemical compounds, the search for new alternatives continues. Today, no product is available to cope with the disease; however, the number of products commercially available is constantly increasing. In this review, we focus on natural products and their anticoccidial activity. This group comprises fatty acids, antioxidants, fungal and herbal extracts, and immune response modulators with proven anticoccidial activity, many of which exist as dietary supplements. Additionally, we offer an overview of the poultry industry and the economic cost of coccidiosis as well as the classical strategies used to control the disease.

Effect of butyrate, clopidol and their combination on the performance of broilers infected with Eimeria maxima

1. The effect of butyric acid glycerides (BAGs) with and without clopidol (CLP) on Eimeria maxima on growth and associated biochemical variables was investigated in broiler chickens. 2. One-day-old chicks were divided into 6 equal groups (Gps) of 30 chicks each; each group was subdivided into 6 equal subgroups. Gp 1 was not infected and not treated. Chicks in Gp 2 were not infected and fed on a ration mixed with 4 g BAGs/kg for 6 successive weeks. Chicks of the other groups were directly inoculated intra-crop with 1 × 10(4) sporulated oocysts of E. maxima at 14 d of age. Gp 3 was infected and not treated. Chicks in the remaining three groups were given diets mixed with the tested drugs for 6 successive weeks. Gp 4 was fed on a diet mixed with CLP (125 g/kg). Gp 5 was given a diet mixed with BAGs (4 g/kg diet). Gp 6 was fed on a diet mixed with both BAGs (4 g/kg diet) and CLP (125 g/kg). 3. Birds in Gps 5 and 6 showed a reduction in the mean oocyst count, lesion scores and developmental stages in the lamina propria and improved growth and biochemical variables. BAG supplementation enhanced growth and production of healthy broilers. 4. It was concluded that BAGs were a useful supplement in broiler diets as an alternative to growth promoters and antimicrobial drugs.

Development and characterization of mouse monoclonal antibodies reactive with chicken IL-1β

Interleukin-1β proteins from chicken, duck, goose, turkey, and pigeon share 77 to 99% amino acid sequence similarity among themselves, and only 31 to 35% sequence similarity is shared between avian and mammalian IL-1β. There have been no antibodies that specifically detect avian IL-1β, and the current study was conducted to develop mouse monoclonal antibodies (mAb) against chicken IL-1β (chIL-1β) to further define its biochemical and immunological properties. In this study, 2 mouse mAb that are specific for chIL-1β were produced and characterized. Both mAb identified a 66.0 kDa recombinant chIL-1β protein expressed in Escherichia coli by Western blot analysis that corresponded to the expected molecular weight of a recombinant fusion protein containing the full-length 23.0 kDa chIL-1β protein and a 43.0 kDa maltose binding protein tag. Immunohistochemical analysis identified cells producing endogenous chIL-1β in the cecal tonsils, bursa of Fabricius, and spleen. Purified recombinant chIL-1β dose-dependently stimulated the proliferation and nitric oxide production by thymocytes, and both activities were inhibited by co-incubation with the 2 chIL-1β mAb described in this paper. These mAb will be important immune reagents for basic and applied poultry research of IL-1β in poultry.

Effect of yeast cell product supplementation on broiler cecal microflora species and immune responses during an experimental coccidial infection

This experiment was conducted to study the effects of whole yeast (Pichia guilliermondii; CitriStim, ADM, Quincy, IL) cell product supplementation on cecal microflora population and intestinal immune parameters in broilers. In the first experiment, birds were fed 0, 0.1, or 0.2% yeast cell wall product for 42 d. Feeding yeast cell wall products decreased (P = 0.03) the proportion of Escherichia coli in the ceca by 31% compared with the control group. The group fed 0.2% yeast cell wall product had a 20% decrease (P = 0.23) in Salmonella population compared with the control group. In the second experiment, birds were fed yeast cell wall product for 21 d and challenged or not challenged with coccidial oocysts, thus resulting in a 2 (0 and 0.2% whole yeast product) × 2 (coccidial challenge and no coccidial challenge) factorial model. Supplementing whole yeast cell wall product prevented a coccidial infection-induced decrease in the Lactobacillus population (P = 0.09) at 12 d postchallenge. Supplementing yeast cell wall product prevented a coccidial infection-induced increase in the Salmonella population (P = 0.08) and E. coli (P = 0.12) at 12 d postchallenge. At 5 d (P < 0.01) and 12 d (P < 0.01) postcoccidial infection, yeast cell wall product supplementation or coccidial infection increased the regulatory T cell (Treg) percentage in the cecal tonsils, whereas yeast cell wall product supplementation in the coccidial-infected group decreased the increase in Treg percentage. At 5 d postcoccidial infection, coccidial infection increased (P = 0.01) the relative amounts of cecal interferon (IFN)γ mRNA. In addition, the yeast cell wall product supplementation in the coccidial-infected groups further increased (P = 0.15) the IFNγ mRNA. It could be concluded that yeast cell wall product supplementation decreased coccidial-infection-induced increase in E. coli and Salmonella colonization and improved IFNγ mRNA amounts after coccidial infection.