Poultry management: a useful tool for the control of necrotic enteritis in poultry

Coated sodium butyrate and vitamin D3 supplementation improve gut health through influencing intestinal immunity, barrier, and microflora in early-stage broilers

BACKGROUND

Intestinal development and function are critical to maintaining sustained broiler growth. The present study aimed to evaluate the effects of coated sodium butyrate (CSB) and vitamin D3 (VD3) on the intestinal immunity, barrier, oxidative stress and microflora in early-stage broilers. In total, 192 one-day-old broilers were assigned to a 2 × 2 factorial design including two dietary supplements at two different levels, in which the main effects were VD3 (3000 or 5000 IU kg-1) and CSB (0 or 1 g kg-1).

RESULTS

The results showed that CSB supplementation increased ileal goblet cells (GCs) numbers, villus height and decreased crypt depth in broilers. CSB increased ileal proliferating cell nuclear antigen expression and high-level VD3 decreased cluster of differentiation 3 expression. CSB reduced serum d-lactate, endotoxin (ET), adrenocorticotropic hormone, corticosterone and malondialdehyde (MDA) concentrations and increased total antioxidant capacity (T-AOC) level. Meanwhile, high-level VD3 decreased serum ET concentration. Furthermore, CSB increased ileal T-AOC, lysozyme (LYZ) and transforming growth factor (TGF)-β and decreased MDA, whereas high-level VD3 decreased ileal MDA and increased secretory immunoglobulin A. CSB up-regulated ileal claudin1, superoxide dismutase 1, TGF-β and LYZ mRNA expression and down-regulated interleukin-1β mRNA expression. CSB combined with high-level VD3 increased ileal Faecalibaculum abundance. Spearman correlation analysis showed that Faecalibaculum was related to the immune and barrier function.

CONCLUSION

Dietary supplementation with CSB and high-level VD3 improved early gut health in broilers by promoting intestinal development, enhancing antioxidant capacity, strengthening barrier function and enhancing the favorable composition of the gut bacterial flora. © 2024 Society of Chemical Industry.

Necrotic enteritis and antibiotic-free production of broiler chickens: Challenges in testing and using alternative products

The global trend towards raising broiler chickens without the use of in-feed antibiotics (IFAs) means that there is an ongoing need to develop alternative treatments capable of delivering the benefits that IFAs previously provided. IFAs supported the productivity performance of chickens and played a key role in maintaining their health. Necrotic enteritis (NE) is an important disease of broilers that affects health, productivity, and welfare, and was previously well controlled by IFAs. However, with the reduction in IFA use, NE is resurgent in some countries. Vaccines and various feed additives, including pre-, pro-, and postbiotics, phytobiotics, fatty acids, and phage therapies have been introduced as alternative methods of NE control. While some of these feed additives have specific activity against the NE pathogen, Clostridium perfringens, most have the more general goal of reinforcing gut health. Extensive reviews of the effects of many of these feed additives on gut health have been published recently. Hence, rather than cover previously well reviewed areas of research this review focuses on the challenges and pitfalls in undertaking experimental assessment of alternative NE treatments and translating laboratory research to real world commercial production settings. The review is based on the author's particular experience, reading, thoughts, and analysis of the available information and inevitably presents a particular understanding that is likely to be at odds with others thinking on these issues. It is put forward to stimulate thinking and discussion on the issues covered.

Synergistic Effects of Essential Oils and Organic Acids against Aspergillus flavus Contamination in Poultry Feed

Organic acids and essential oils are commonly used in the poultry industry as antimicrobials and for their beneficial effects on gut health, growth performance, and meat quality. A common postharvest storage fungal colonist, Aspergillus flavus, contaminates corn, the primary component of poultry feed, with the highly detrimental mycotoxin, aflatoxin. Aflatoxin adversely affects poultry feed intake, feed conversion efficiency, weight gain, egg production, fertility, hatchability, and poultry meat yield. Both organic acids and essential oils have been reported to inhibit the growth of A. flavus. Thus, we evaluated if the inhibitory synergy between combined essential oils (cinnamon, lemongrass, and oregano) and organic acids (acetic, butyric, and propionic) prevents A. flavus growth. The study confirmed that these compounds inhibit the growth of A. flavus and that synergistic interactions do occur between some of them. Overall, cinnamon oil was shown to have the highest synergy with all the organic acids tested, requiring 1000 µL/L air of cinnamon oil and 888 mg/kg of butyric acid to fully suppress A. flavus growth on corn kernels. With the strong synergism demonstrated, combining certain essential oils and organic acids offers a potentially effective natural method for controlling postharvest aflatoxin contamination in poultry feed.

Evaluation of the Immunoprotective Capacity of Five Vaccine Candidate Proteins against Avian Necrotic Enteritis and Impact on the Caecal Microbiota of Vaccinated Birds

Avian necrotic enteritis is an enteric disease of broiler chickens caused by certain pathogenic strains of Clostridium perfringens in combination with predisposing factors. A vaccine offering complete protection against the disease has not yet been commercialized. In a previous study, we produced five recombinant proteins predicted to be surface-exposed and unique to necrotic enteritis-causing C. perfringens and the immunogenicity of these potential vaccine candidates was assessed in broiler chickens. In the current work, the relative contribution of the antibodies raised by these putative antigens to protect broiler chickens was evaluated using an experimental necrotic enteritis induction model. Additionally, the link between the immune response elicited and the gut microbiota profiles in immunized birds subjected to infection with virulent C. perfringens was studied. The ELISA results showed that the IgY antibody titers in vaccinated birds on days 21 and 33 were significantly higher than those on days 7 and 14 and those in birds receiving the adjuvant alone, while the relative contribution of the specific immunity attributed to these antibodies could not be precisely determined using this experimental necrotic enteritis induction model. In addition, 16S rRNA gene amplicon sequencing showed that immunization of birds with recombinant proteins had a low impact on the chicken caecal microbiota.

Characterization of Collagen Binding Activity of Clostridium perfringens Strains Isolated from Broiler Chickens

Clostridium perfringens is the etiological agent for necrotic enteritis (NE) in broiler chickens, which causes a substantial economic loss of an estimated USD 6 billion annually in the global poultry industry. Collagen adhesion is involved in the NE pathogenesis in poultry. In this study, the binding capabilities of chicken C. perfringens isolates of various genetic backgrounds (netB^-tpeL^-, netB⁺tpeL^-, netB⁺tpeL⁺) to collagen types I-V and gelatin were examined, and the putative adhesin protein cnaA gene was investigated at the genomic level. In total, 28 C. perfringens strains from healthy and NE-inflicted sick chickens were examined. The results on collagen adhesin-encoding gene cnaA by the quantitative-PCR results indicated that netB^-tpeL^- isolates had much lower copies of the detectable cnaA gene than netB⁺ isolates (10 netB⁺tpeL^- isolates, 5 netB⁺tpeL⁺ isolates). Most of the virulent C. perfringens isolates demonstrated collagen-binding abilities to types I-II and IV-V, while some strains showed weak or no binding to collagen type III and gelatin. However, the netB⁺tpeL⁺ isolates showed significantly higher binding capabilities to collagen III than netB^-tpeL^- and netB⁺tpeL^- isolates. The data in this study suggest that the collagen-binding capability of clinical C. perfringens isolates correlates well with their NE pathogenicity levels, especially for C. perfringens isolates carrying genes encoding crucial virulence factors and virulence-associated factors such as netB, cnaA, and tpeL. These results indicate that the presence of the cnaA gene may be correlated with C. perfringens virulence (particularly for netB⁺ isolates).

Bioactive compounds, antibiotics and heavy metals: effects on the intestinal structure and microbiome of monogastric animals – a non-systematic review

The intestinal structure and gut microbiota are essential for the animals‘ health. Chemical components taken with food provide the right environment for a specific microbiome which, together with its metabolites and the products of digestion, create an environment, which in turn is affects the population size of specific bacteria. Disturbances in the composition of the gut microbiota can be a reason for the malformation of guts, which has a decisive impact on the animal‘ health. This review aimed to analyse scientific literature, published over the past 20 years, concerning the effect of nutritional factors on gut health, determined by the intestinal structure and microbiota of monogastric animals. Several topics have been investigated: bioactive compounds (probiotics, prebiotics, organic acids, and herbal active substances), antibiotics and heavy metals (essentaial minerals and toxic heavy metals).

Evaluation of Predisposing Factors of Necrotic Enteritis in Experimentally Challenged Broiler Chickens

Simple Summary

The ban of antibiotic growth promoters in animal feed increased the number of cases of necrotic enteritis (NE) in broilers, greatly affecting the poultry industry. The induction of experimental NE faces challenges, as it is a multifactorial disease and the pathogenesis is not fully understood, hampering the development of in vivo studies for disease control and prevention strategies. The literature reports several protocols using different factors to assist in NE induction. This study assessed predisposing factors, such as immunosuppression, infection or both, by Eimeria spp. in broilers (n = 99) fed a wheat-based diet and challenged with three different strains of Clostridium perfringens (CP). Under microscopy, Eimeria spp. had a negative effect on intestinal morphometry and favored the increase of intraepithelial lymphocytes. However, the macroscopic analysis did not show which factor was more effective in potentiating the lesions, suggesting a synergistic effect between the strain of CP used and the predisposing factors. Therefore, each experimental protocol should first be evaluated for the association of the CP strain with the predisposing factors.

Abstract

Clostridium perfringens is the etiological agent of NE, a disease that greatly affects the poultry industry. Experiments on the induction of NE are difficult to carry out, as it is a multifactorial disease, and thus different predisposing factors have been used. This study evaluated the effect of the Gumboro disease vaccine virus vaccine (IBDV-vac) associated or not with infection by Eimeria spp. in broilers, as a predisposing factor for NE. Broilers (n = 99) were divided into groups (11) challenged with IBDV-vac, Eimeria spp. CP type G (CP13, CP14 and CP03) or both. The macroscopic evaluation revealed that the highest average (3.45) of injury occurred for the CP13 + IBDV-vac group. The microscopic analysis showed that Eimeria spp. increased the population of intraepithelial lymphocytes and reduced the villus/crypt ratio in duodenum and jejunum when associated with CP13 or CP14. There was a synergistic effect between the CP strain used and the predisposing factors; nevertheless, it was not clear which was the most effective predisposing factor to potentiate the lesions, suggesting that the association of the strain with the factors should first be evaluated for each experimental protocol.

Effects of dietary fiber on intestinal microbiota in geese evaluated by 16SrRNA gene sequencing

AIMS

The purpose of the research is to study the effects of different fiber types and sources on the intestinal flora of geese.

METHODS AND RESULTS

A total of 48 geese (males 35 days old) were divided into 4 groups, each of which included 3 replicates of 4 geese. Groups 1 to 4 were fed a diet containing 5% corn stover Crude fiber (CF, the LJ group), 8% corn stover CF (the HJ group), 5% alfalfa CF (the LM group), or 8% alfalfa CF (the HM group) respectively. After 42 days of feeding, the intestinal flora of each group was determined by 16SrRNA gene sequencing. In the duodenum, the diet supplemented with corn stover meal increased the relative abundance of Proteobacteria, Actinobacteria and Euryarchaeota, and with alfalfa as fiber source increased the relative abundance of Firmicutes, Bacteroidetes, Tenericutes and Chloroflexi. In the jejunum, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Tenericutes and Spirochetes were significantly more abundant in the corn stover group. There were no significant differences among the results for the other two fiber sources, which were fibre level in their influence where in ileum. Firmicutes, Deferribacteres and Euryarchaeota with corn stover as fiber source in the cecum were higher than the alfalfa group.

CONCLUSIONS

Different fiber sources have significant effects on goose gut microbiota. There were same flora has the same trend of change in different intestinal segments. The relative fiber source in the ileum makes the gut microbiota more sensitive to differences in fiber levels..

SIGNIFICANCE AND IMPACT OF THE STUDY

This study proved that the dietary fibre affects the intestinal flora. At the same time, different groups of dietary fibre may be used to provide the possibility to study functional roles of specific bacteria in host physiology.

Phytogenic Compounds for Enhancing Intestinal Barrier Function in Poultry-A Review

After the European Union ban of antibiotic growth promoters, works on different methods of improving gut health have intensified. The poultry industry is struggling with problems that were previously controlled by antibiotic growth promoters, therefore the search for optimal solutions continues. Simultaneously, there is also increasing social pressure to minimize the use of antibiotics and replace them with alternative feed additives. A variety of available alternatives is considered safe by consumers, among which phytogenics play a significant role. However, there are still some limitations that need to be considered. The most questionable are the issues related to bioavailability, metabolism of plant derivatives in birds, and the difficulty of standardizing commercial products. There is still a need for more evidence-based recommendations for the use of phytogenics in livestock. On the other hand, a positive influence of phytogenic compounds on the health of poultry has been previously described by many researchers and practical application of these compounds has auspicious perspectives in poultry production. Supplementation with phytogenic feed additives has been shown to protect birds from various environmental threats leading to impaired intestinal barrier function. Phytogenic feed additives have the potential to improve the overall structure of intestinal mucosa as well as gut barrier function on a molecular level. Recognition of the phytogenics' effect on the components of the intestinal barrier may enable the selection of the most suitable ones to alleviate negative effects of different agents. This review aims to summarize current knowledge of the influence of various phytogenic constituents on the intestinal barrier and health of poultry.

Necrotic enteritis in chickens: a review of pathogenesis, immune responses and prevention, focusing on probiotics and vaccination

Necrotic enteritis (NE), caused by Clostridium perfringens (CP), is one of the most common of poultry diseases, causing huge economic losses to the poultry industry. This review provides an overview of the pathogenesis of NE in chickens and of the interaction of CP with the host immune system. The roles of management, nutrition, probiotics, and vaccination in reducing the incidence and severity of NE in poultry flocks are also discussed.

Short and Medium Chain Fatty Acids and Their Derivatives as a Natural Strategy in the Control of Necrotic Enteritis and Microbial Homeostasis in Broiler Chickens

The use of antibiotic growth promoters (AGPs) has historically been the most important prophylactic strategy for the control of Necrotic Enteritis (NE) caused by some Clostridium perfringens toxin types in poultry. During the last five decades, AGPs have also been supplemented in feed to improve body weight gain and feed efficiency as well as to modulate the microbiome (consisting of microbes and their genes both beneficial and potentially harmful) and reduce enteric pathogens, among other benefits. New regulatory requirements and consumer preferences have led to strong interest in natural alternatives to the AGPs for the prevention and control of illnesses caused by enteric pathogens. This interest is not just focused on the direct removal or inhibition of the causative microorganisms but also the improvement of intestinal health and homeostasis using a range of feed additives. A group of promising feed additives is short- and medium-chain fatty acids (SCFA and MCFA, respectively) and their derivatives. The use of SCFA and MCFA, including butyric, caproic, caprylic, capric, and lauric acids, has shown strong effects against NE in broilers both at experimental and commercial levels. These fatty acids also benefit intestinal health integrity and homeostasis. Other effects have also been documented, including increases in intestinal angiogenesis and gene expression of tight junctions. Chemical modifications to improve stability and point of release in the intestine have been shown to improve the efficacy of SCFA and MCFA and their derivatives. The aim of this review is to give an overview of SCFA, MCFA and their derivatives, as an alternative to replace AGPs to control the incidence and severity of NE in poultry.

Role of Clostridium perfringens Necrotic Enteritis B-like Toxin in Disease Pathogenesis

Necrotic enteritis (NE) is a devastating enteric disease caused by Clostridium perfringens type A/G that impacts the global poultry industry by compromising the performance, health, and welfare of chickens. Coccidiosis is a major contributing factor to NE. Although NE pathogenesis was believed to be facilitated by α-toxin, a chromosome-encoded phospholipase C enzyme, recent studies have indicated that NE B-like (NetB) toxin, a plasmid-encoded pore-forming heptameric protein, is the primary virulence factor. Since the discovery of NetB toxin, the occurrence of NetB⁺ C. perfringens strains has been increasingly reported in NE-afflicted poultry flocks globally. It is generally accepted that NetB toxin is the primary virulent factor in NE pathogenesis although scientific evidence is emerging that suggests other toxins contribute to NE. Because of the complex nature of the host-pathogen interaction in NE pathogenesis, the interaction of NetB with other potential virulent factors of C. perfringens needs better characterization. This short review will summarize the primary virulence factors involved in NE pathogenesis with an emphasis on NetB toxin, and a new detection method for large-scale field screening of NetB toxin in biological samples from NE-afflicted commercial broiler flocks.

Investigation of Clostridium perfringens in small-scale commercial broiler flocks in Mymensingh district of Bangladesh

Background and Aim

Necrotic enteritis (NE) is one of the most prevalent diseases in broiler poultry caused by Clostridium perfringens connected with significant economic losses. A cross-sectional survey was conducted in Mymensingh district of Bangladesh to assess the prevalence of C. perfringens through toxinotyping molecular assay and confirm the risk factors for NE, including antimicrobial-resistant (AMR) status of the isolates.

Materials and Methods

We included 40 small-scale commercial broiler farms randomly selected from two subdistricts of Mymensingh district of Bangladesh. As an individual sample, 240 cloacal swabs, and as a pooled sample, 40 drinking water, 40 workers' hand washing, 40 litter swab, and 40 feed samples were collected and evaluated by culture, biochemical, and molecular assays. A pretested semi-structured interview questionnaire was employed to capture flock-level data on risk factors from the farm owners. The flock-level data on risk factors were assessed through univariable and multivariable logistic regression analyses with p<0.05 was considered statistically significant.

Results

Overall flock-level prevalence of C. perfringens was estimated to be 10.3% (95% confidence interval [CI] 7.5-13.6%). Litter swab (pooled) was found to be highly contaminated with C. perfringens (25.0%, 95% CI: 12.7-41.2%) followed by the cloacal swab (10.4%, 95% CI: 6.9-15.0%) and feed sample (5.0%, 95% CI: 0.6-16.9%). History of coccidia infection (Adjusted odds ratio =33.01, 95% CI: 2.14-507.59, p=0.01) was significantly associated with flock-level C. perfringens infection status. In this study, 78.1% isolates were found as multidrug-resistant as they demonstrated resistance to 3-5 antimicrobial agents.

Conclusion

Evidence-based control options need to be taken through the uses of prebiotics and probiotics, biosecurity, and hygienic measurement, including control of coccidia infection, is needed to lessen the NE infection and AMR related to this pathogen in small-scale commercial broiler poultry.

Effects of Replacing In-feed Antibiotics with Synergistic Organic Acids on Growth Performance, Health, Carcass, and Immune and Oxidative Statuses of Broiler Chickens Under Clostridium perfringens Type A Challenge

This study was conducted to investigate the effects of replacing in-feed antibiotics with synergistic organic acids on growth performance, health, carcass, and immune and oxidative statuses of broiler chickens under Clostridium perfringens (CP) type A challenge. Two organic acid products were tested: organic acid 1 (OA1), consisting of butyrate, medium-chain fatty acids, organic acids, and phenolics; and organic acid 2 (OA2), consisting of buffered short-chain fatty acids. Six hundred 1-day-old male Arbor Acres broiler chicks were randomly assigned to one of five treatments: Control 1, basal diet, nonchallenged birds; Control 2, basal diet, with CP challenge; antimicrobial growth promoters (AGP), basal diet supplemented with Aureomycin (chlortetracycline), with CP challenge; OA1, basal diet supplemented with OA1, with CP challenge; and OA1OA2, basal diet supplemented with OA1 and OA2, with CP challenge. Each treatment had eight replicate pens of 15 birds. The experiments lasted for 29 days. The disease challenge was performed on days 15-17, with an oral gavage of 0.5 mL of CP culture (2.0 × 108 colony-forming units [CFU]/mL) for each bird. Body weights (BWs), intestinal lesion scores, immune organ indices, and serum malondialdehyde (MDA) concentrations were measured on days 19, 22, and 29, respectively, in three birds per pen. Carcass characteristics were determined on day 29. No treatment-related differences in mortality were noted before (P = 0.28) or after (P = 0.64) challenge or over the whole study period (days 0-28; P = 0.66). On day 19, the BW of Control 2 was lower than other treatments (P < 0.0001). On day 22, AGP, OA1, and OA1OA2 had higher BW than Control 2 (P = 0.001). The breast muscle yield of OA1 and OA1OA2 was higher than AGP (P < 0.05). The abdominal fat yield of OA1OA2 was lower than AGP and Control 2 (P < 0.05). On day 22, the birds fed OA1OA2 showed lower intestinal lesion scores than OA1 (P < 0.05). No treatment-related differences in immune organ (spleen, thymus, and bursa) indices were noted (P > 0.05). On day 29, the MDA concentration of OA1 and OA1OA2 was lower than those of Control 1 and AGP (P < 0.05). In conclusion, the addition of organic acids may protect broiler chickens from severe intestinal lesions and oxidative stress and may help reduce abdominal fat mass deposition. There is potential for organic acid-based products as alternatives for AGP in preventing necrotic enteritis in broilers.

Asymptomatic Carriage of C. botulinum Type D/C in Broiler Flocks as the Source of Contamination of a Massive Botulism Outbreak on a Dairy Cattle Farm

In winter 2018, a massive type D/C cattle botulism outbreak occurred on a mixed dairy and broiler farm in France. An investigation was conducted based on the hypothesis of asymptomatic carriage in poultry. We set out to identify the source of contamination of the dairy cattle and to monitor the contamination of broilers over time, including the hatchery delivering chicks to the farm. Environmental samples were collected on the farm during the cattle outbreak (n = 40), after the outbreak for three successive broiler flocks (n = 128), and once in the hatchery delivering the chicks (n = 58). These samples were analyzed using real-time PCR after an enrichment step to detect Clostridium botulinum type D/C. The results showed contamination in the manure from the broilers raised just before the onset of the cattle outbreak (5 + /5), as well as in some of the components of the cattle ration (3 + /17). This latter contamination is likely due to the use of the same tractor bucket to remove litter from the poultry house and to prepare the cattle ration on the same day. Contamination monitoring over several months revealed continuous asymptomatic carriage in the broilers (4 + /20 and 17 + /20 cloacal swabs in 2 successive flocks), a persistence of C. botulinum type D/C in the ventilation system of the poultry house (8 + /14), and contamination of the equipment coming from the hatchery used for delivering the chicks (3 + /18). Further investigations conducted in the hatchery demonstrated contamination in the hatchery by C. botulinum type D/C (6 + /58). Comparison of samples using a multilocus variable number tandem repeat analysis showed the same profile for samples collected on broilers, cattle and in the hatchery. This study highlighted the crucial role of the implementation of biosecurity measures in mixed farms to avoid cross-contamination between production units given the potential asymptomatic carriage of poultry. This study also revealed the contamination of the poultry hatchery. Further investigations are required to better understand the role of hatcheries in the epidemiology of animal botulism.

Impacts of Microbial based Therapy on Growth Performance, Intestinal Health, Carcass Traits and Economic Efficiency of Clostridium perfringens-Infected Cobb and Arbor Acres Broilers

The poultry farms need a safe and effective alternative for antibiotics that can counteract the negative impacts of necrotic enteritis (NE), which causes severe mortalities and economic losses. The current study was aimed to examine the influence of antibiotic (Flagymox) and the microbial‐based administration on carcass traits in Clostridium(C.)perfringens‐infected Cobb and Arbor Acres broilers. A total number of 360 Cobb and Arbor Acres broiler chicks (180 numbers per breed) were allocated to four groups; negative control group (without any treatments); positive control group (administration of C. perfringens at the rate of 1 × 10⁹cfu/bird via crop gavage twice daily from day 16 to 18 post‐hatch); C. perfringens challenge plus antibiotic (Flagymox^®) group, and Clostridiumperfringens challenge plus microbial‐based treatment (Big‐lactoα^®) group. The results indicated that the Flagymox and Big‐lactoα treated Cobb breed group achieved a significant increase in their body weight (BW) than the positive control group at the third week post‐infection. Also, the Arbor Acres breed gained significantly higher weight compared to the Cobb breed at the third week. Total weight gain (TWG) from 0 to the fifth week in the Cobb and Arbor Acres breeds were higher in the groups treated with Flagymox and Big‐lactoα compared to the birds challenged with C. perfringens without any treatment, thus, increasing the total return (TR) in the treated groups. Economic efficiency showed no significant differences (p < .05) between the treatment groups of both the breeds. Although the treatment cost of Flagymox is higher than the microbial‐based treatment (0.86 versus 0.35 LE), there were no mortalities reported in the microbial‐based groups in both the breeds resulting in significantly low losses compared to the Flagymox treated groups. The groups treated with the microbial‐based products in both breeds were superior in dressing percentage (75.16 and 77.06% for Cobb and Arbor Acres, respectively) compared to that of the other groups. In conclusion, microbial‐based therapy improved the growth rate, carcass traits, survival rate, and economic efficiency in necrotic enteritis induced in Cobb and Arbor Acres broilers.

A chicken DNA methylation clock for the prediction of broiler health

The domestic chicken (Gallus gallus domesticus) is the globally most important source of commercially produced meat. While genetic approaches have played an important role in the development of chicken stocks, little is known about chicken epigenetics. We have systematically analyzed the chicken DNA methylation machinery and DNA methylation landscape. While overall DNA methylation distribution was similar to mammals, sperm DNA appeared hypomethylated, which correlates with the absence of the DNMT3L cofactor in the chicken genome. Additional analysis revealed the presence of low-methylated regions, which are conserved gene regulatory elements that show tissue-specific methylation patterns. We also used whole-genome bisulfite sequencing to generate 56 single-base resolution methylomes from various tissues and developmental time points to establish an LMR-based DNA methylation clock for broiler chicken age prediction. This clock was used to demonstrate epigenetic age acceleration in animals with experimentally induced inflammation. Our study provides detailed insights into the chicken methylome and suggests a novel application of the DNA methylation clock as a marker for livestock health.

Raddatz, Lyko and colleagues use whole-genome bisulfite sequencing data to generate a methylation clock for chicken. This clock was able to detect age acceleration in broiler chickens under experimentally induced inflammation.

Probiotic Bacillus subtilis 29,784 improved weight gain and enhanced gut health status of broilers under necrotic enteritis condition

The study investigated the benefit of a Bacillus subtilis probiotic (Bs 29,784) in necrotic enteritis (NE)-challenged broilers. Four treatments were performed with 312 male day-old Ross 308 reared in floor pens from day 0 to day 35: 2 groups fed control diet without or with NE challenge (CtrlNC and CtrlNE); 2 groups fed probiotic and antibiotic supplements in the control diet with NE challenge (ProNE and AntNE). Necrotic enteritis challenge procedures commenced with inoculation of Eimeria spp 1 mL/bird per os at day 9 and Clostridium perfringens EHE-NE18 (approximately 10⁸ cfu/mL) 1 mL/bird per os at day 14 and day 15. Performance parameters were measured on day 16 and day 35. Lesion, cecal microbiota, and jejunal gene expression were analyzed on day 16. Necrotic enteritis challenge significantly suppressed the performance parameters compared with CtrlNC: 27% weight gain reduction, 11 points feed conversion ratio (FCR) increase at day 16, and 12% weight gain reduction, 5-point FCR increase at day 35. By day 35, ProNE and AntNE treatments enabled significantly higher weight gain (4 and 9%, respectively) than CtrlNE. Compared with CtlrNE and contrary to AntNE, ProNE treatment exhibited upregulation of genes coding for tight junctions proteins (CLDN1, JAM2, TJP1), cytokines (IL12, interferon gamma, TGFβ), and Toll-like receptors (TLR5, TLR21) suggesting enhanced immunity and intestinal integrity. 16S NGS analysis of cecal microbiota at day 16 showed a decreased alpha diversity in challenged groups. Principal component analysis of operational taxonomic unit (OTU) abundance revealed that ProNE and AntNE grouped closely while both distantly from CtrlNC and CtrlNE, which were separately grouped, indicating the similar effects of ProNE and AntNE on the OTU diversity that were however different from both CtrlNC and CtrlNE. Microbiota analysis revealed an increase of genera Faecalibacterium, Oscillospira, and Butyricicoccus; and a decrease of genera Ruminococcus, Lactobacillus, and Bacteroides; and an increase of the Firmicutes-to-Bacteroidetes ratio in ProNE and AntNE groups compared with the CtlrNE group. It is concluded that Bs 29,784 may enable improved health of broiler chickens under NE conditions thus performance implications.

Characterization of a novel bacteriophage φCJ22 and its prophylactic and inhibitory effects on necrotic enteritis and Clostridium perfringens in broilers

High necrotic enteritis (NE) incidence and mortality rates in poultry can be caused by Clostridium perfringens (CP) coinfected with Eimeria spp., a causative agent of coccidiosis. Banning of prophylactic use of antibiotics in feed has been accompanied by increased NE outbreaks, resulting in economically devastating losses to the broiler industry. To determine alternatives for controlling NE, we isolated CP-specific bacteriophages (BP), characterized their properties, evaluated their inhibitory effects on pathogenic CP, selected a highly effective phage (φCJ22), and used φCJ22 as a dietary supplement in experimental NE-afflicted broiler chickens. Male broilers (n = 780) were randomly assigned to 60 pens (n = 13 broilers/pen) and into 5 groups [CP-uninfected negative control (NC), basal diet (BD) without CP and BP; CP-infected positive control (PC), BD + CP; and 3 BP groups receiving low- (LP; BD + CP+10⁵ BP), medium- (MP; BD + CP+10⁶ BP), and high-phage (HP; BD + CP+10⁷ BP plaque-forming units/kg) concentrations]. The results showed that MP and HP groups presented an antimicrobial activity toward clinical CP isolate strains, and the groups decreased NE lesions and mortality rates without changes in chicken performance at the end of the experimental period. After CP-challenge body weight gain and feed efficiency were significantly lower in phage-fed groups than that in the PC group (P < 0.05), and NE-associated mortality was the lowest in the HP group (P < 0.001). Moreover, histopathology revealed lesser gastrointestinal mucosal damage in the NC and BP-treated (LP, MP, and HP) groups than that in the PC group, and MP and HP significantly lowered viable CP number in the cecum content by up to 1.24log10 relative to only CP-infected PC group (P < 0.05). These findings suggest that addition of φCJ22 to chicken feed might effectively ameliorate NE, which is accompanied by reduced CP strains in the gut and compensate the performance of NE-afflicted broilers.

Analysis of miRNA Expression in the Ileum of Broiler Chickens During Bacillus licheniformis H2 Supplementation Against Subclinical Necrotic Enteritis

Subclinical necrotic enteritis (SNE) is one of the serious threats to the poultry industry. Probiotics have been proven to exert beneficial effects in controlling SNE. However, their exact mechanisms have not been fully elucidated. Moreover, few studies have focused on their impact on microRNAs (miRNAs). Therefore, the present study aimed to explore the miRNA expression profiles in the ileum of broiler chickens during probiotic supplementation for controlling SNE. A total of 180 newly hatched male broilers were randomly allocated into three groups, including a negative control group, an SNE infection group, and a Bacillus licheniformis H2 pretreatment group. Illumina high-throughput sequencing was conducted to identify the miRNA expression of the three groups. Results showed that 628 miRNAs, including 582 known miRNAs and 46 novel miRNAs, were detected in the miRNA libraries. The target genes of 57 significantly differentially expressed miRNAs were predicted and annotated. Moreover, they were found to be partly enriched in pathways related to immunity and inflammation such as tumor necrosis factor receptor binding, immune response-regulating signaling pathway, Toll-like receptor 2 signaling pathway, interleukin-15 production, activation of NF-κB-inducing kinase activity, and MAP kinase tyrosine/serine/threonine phosphatase activity. Some of the target genes of 57 miRNAs were related to the MAPK signaling pathway. Furthermore, the expression of several miRNAs, which may be involved in the MAPK signaling pathway, was significantly affected by SNE induction and showed no significant difference in the presence of H2. All these findings provide comprehensive miRNA expression profiles of three different treatment groups. They further suggest that H2 could exert beneficial effects in controlling SNE through immune and inflammatory response associated with altered miRNA expression, such as the MAPK signaling pathway.

Clostridium perfringens as Foodborne Pathogen in Broiler Production: Pathophysiology and Potential Strategies for Controlling Necrotic Enteritis

Clostridium perfringens (Cp.) is the cause of human foodborne desease. Meat and poultry products are identified as the main source of infection for humans. Cp. can be found in poultry litter, feces, soil, dust, and healthy birds' intestinal contents. Cp. strains are known to secrete over 20 identified toxins and enzymes that could potentially be the principal virulence factors, capable of degrading mucin, affecting enterocytes, and the small intestine epithelium, involved in necrotic enteritis (NE) pathophysiology, also leading to immunological responses, microbiota modification and anatomical changes. Different environmental and dietary factors can determine the colonization of this microorganism. It has been observed that the incidence of Cp-associated to NE in broilers has increased in countries that have stopped using antibiotic growth promoters. Since the banning of such antibiotic growth promoters, several strategies for Cp. control have been proposed, including dietary modifications, probiotics, prebiotics, synbiotics, phytogenics, organic acids, and vaccines. However, there are aspects of the pathology that still need to be clarified to establish better actions to control and prevention. This paper reviews the current knowledge about Cp. as foodborne pathogen, the pathophysiology of NE, and recent findings on potential strategies for its control.

Risks and disease aetiologies of compromised performance in commercial broilers kept at lower stocking density and limited antimicrobial use

The health status of broilers raised at lower stocking density and limited antimicrobial use (but routine anticoccidials) was assessed in order to identify prevalent causes of disease, mortality and reduced performance. "Dead-on-farm"(DOF) broilers from 145 commercial flocks were investigated at two different time points (TP1:7-14 and TP2:28-35 days of age); per sampling, 6-10 DOF broilers were selected for post-mortem investigation and gross pathomorphological changes were assessed from 2717 birds in total. Post-mortem findings were substantiated by bacteriological, virological and parasitological investigations. Furthermore, production data of all flocks were collected and used to perform comprehensive statistical analysis. Overall, colibacillosis was found most important with a significant negative impact on flock health, productivity and profitability through all ages of broiler production. At TP1, primary reasons for mortality comprised yolk sac infections, generally found together with fibrinous polyserositis due to E. coli. Furthermore, femoral lesions, which correlated with increased flock mortality, were associated with detection of E. coli. At TP2, ascites was detected frequently in DOF broilers, correlating with increased production losses in the fourth and fifth weeks of life. No aetiological link between the presence of ascites and the detection of the investigated pathogens was observed, instead a positive correlation was noticed with altitude above sea level of the farm, and with the sex of the birds. Disease conditions could not be linked with the housing system. Presence of infectious bronchitis virus, avian reovirus and fowl adenovirus did not correlate with macroscopic lesions or a specific disease. RESEARCH HIGHLIGHTS In young broilers lesions of visceral organs due to bacterial infections dominated. Colibacillosis impacts broiler health, productivity and profitability independent of the age of birds. Disorders of the locomotor system were frequently observed throughout production. Older broilers frequently showed pathologic changes due to metabolic disorders. Overall, a shift from infectious towards metabolic disease conditions was noticed.

Probiotics mitigating subclinical necrotic enteritis (SNE) as potential alternatives to antibiotics in poultry

Subclinical necrotic enteritis (SNE) caused by Clostridium perfringens (CP), is an important disease in chickens, which causes huge economic losses by damaging the intestinal mucosa, decreasing digestion and absorption of nutrients. Use of antibiotics at a sub-therapeutic level as antimicrobial growth promoters in poultry feed prevents the birds from SNE and improves growth. Due to the ban on the use of antibiotics in 2006 as antimicrobial growth promoters have led to the reemergence of the disease. Worldwide numerous studies have been carried out to investigate the alternatives to antibiotics for the prevention of SNE. Possible alternatives to control SNE include probiotics, prebiotics, bacteriophages, essential oils, organic acids, secondary metabolites and other microbial products. Currently, probiotics are most extensively used in poultry production as an alternative to antibiotics. This review summarizes recent insights and experimental evidence on the use of different microorganisms like Bacillus, Lactic acid bacteria, Bifidobacteria, Enterococcus, yeast, etc. as valuable probiotics for prevention of SNE and potential molecular mechanisms responsible for ameliorating effects of probiotics against SNE.

Embryonic Thermal Manipulation Affects the Antioxidant Response to Post-Hatch Thermal Exposure in Broiler Chickens

Simple Summary

The broiler chicken is one of the most important livestock species in the world, as it occupies a major role in the modern human diet. Due to uneven artificial selection pressures, the broiler has increased in size over the past few decades at the expense of its ability to withstand oxidative damage, the latter of which is often a byproduct of thermal stress. In order to attenuate the effects of heat stress, thermal manipulation (TM), which involves changes in incubation temperature at certain points of embryonic development, is increasingly being presented as a way in which to improve broiler thermotolerance. Therefore, the objective of this study was to investigate how TM might affect broiler response to post-hatch thermal stress in the context of the genes that help combat oxidative damage, namely the catalase, NADPH oxidase 4 (NOX4), and superoxide dismutase 2 (SOD2) genes. Expression of all three aforementioned genes differed significantly between TM and control chickens after exposure to cold and heat stress. Conclusively, TM may act as a viable mode of preventative treatment for broilers at risk of thermally induced oxidative stress.

Abstract

Thermal stress is a major source of oxidative damage in the broiler chicken (Gallus gallus domesticus) due to the latter’s impaired metabolic function. While heat stress has been extensively studied in broilers, the effects of cold stress on broiler physiologic and oxidative function are still relatively unknown. The present study aimed to understand how thermal manipulation (TM) might affect a broiler’s oxidative response to post-hatch thermal stress in terms of the mRNA expression of the catalase, NADPH oxidase 4 (NOX4), and superoxide dismutase 2 (SOD2) genes. During embryonic days 10 to 18, TM was carried out by raising the temperature to 39 °C at 65% relative humidity for 18 h/day. To induce heat stress, room temperature was raised from 21 to 35 °C during post-hatch days (PD) 28 to 35, while cold stress was induced during PD 32 to 37 by lowering the room temperature from 21 to 16 °C. At the end of the thermal stress periods, a number of chickens were euthanized to extract hepatic and splenic tissue from the heat-stressed group and cardiac, hepatic, muscular, and splenic tissue from the cold-stressed group. Catalase, NOX4, and SOD2 expression in the heart, liver, and spleen were decreased in TM chickens compared to controls after both cold and heat stress. In contrast, the expression levels of these genes in the breast muscles of the TM group were increased or not affected. Moreover, TM chicks possessed an increased body weight (BW) and decreased cloacal temperature (T^C) compared to controls on PD 37. In addition, TM led to increased BW and lower T^C after both cold and heat stress. Conclusively, our findings suggest that TM has a significant effect on the oxidative function of thermally stressed broilers.

Treatment With Probiotic Bacteria Does Not Diminish the Impact of a Cystoisospora suis Challenge in Suckling Piglets

Colonization of newborn piglets with beneficial and ubiquitous microorganisms in combination with colostral passive immunity is the prerequisite for development of immunity and gut maturation. In this study living strains of Clostridium perfringens type A (CpA) and non-pathogenic Escherichia (E.) coli strains harvested from healthy piglets were administered to piglets prior to first colostrum intake in order to prevent disease caused by pathogenic variants of the same bacterial species by competitive exclusion. In addition, it was investigated whether these potential beneficial colonizers were able to prevent harmful effects of infection with Cystoisospora (C.) suis as a primary invasive pathogen. In a first trial, half of the piglets from four litters were treated with a bacterial cocktail consisting of two E. coli and four CpA strains immediately after birth on two consecutive days, while the other half of the litters served as control group. In a second trial, piglets were treated following the protocol of the first trial, and additionally all piglets were infected 4 h after the end of littering with ~1,000 sporulated oocysts of a C. suis laboratory strain. General health, body weight development, fecal consistency and, in the second trial, oocyst excretion were monitored from birth until weaning. No adverse effects of the cocktail on the health status were observed. Treated piglets of the first trial showed a higher average daily weight gain until weaning. In the second trial, no significant differences were found with respect to average daily weight gain, fecal consistency, amount, and duration of oocyst excretion assessed in daily samples. In treatment group 51.1% and in the control group 38.5% of the fecal samples were positive for oocysts in autofluorescence. The average duration of oocyst excretion was longer in treatment group (7.7 days) than in control group (5.6 days). Application of bacterial cocktail could not effectively minimize disease symptoms caused by C. suis. There was a trend toward an increase in severity of disease symptoms in treated pigs, suggesting that the synergism between CpA and C. suis was independent of the bacterial strains, but is exclusively dominated by the pathogenic effect of C. suis.

Analysis of hepatic transcriptome demonstrates altered lipid metabolism following Lactobacillus johnsonii BS15 prevention in chickens with subclinical necrotic enteritis

Background

Subclinical necrotic enteritis (SNE) widely outbreaks in chickens which inflicted growth-slowing, causing enormous social and economic burdens. To better understand the molecular underpinnings of SNE on lipid metabolism and explore novel preventative strategies against SNE, we studied the regulatory mechanism of a potential probiotic, Lactobacillus johnsonii BS15 on the lipid metabolism pathways involved in chickens with SNE.

Methods

One hundred eighty one-day-old chickens were randomly divided into three groups and arranged with basal diet (control and SNE group). Added with BS15 (1 × 10⁶ cfu/g) or Man Rogosa Sharpe (MRS) liquid medium for 28 days. The hepatic gene expression of each group was then measured using high-throughput analysis methods (RNA-Seq). Quantitative real-time PCR (qRT-PCR) was used to detect the expression changes of the related genes.

Results

The results showed that there are eleven lipid metabolic pathways were found during the prevention of BS15 treatment in SNE chickens by RNA-Seq, including the peroxisome proliferator-activated receptor (PPAR) signaling pathway and arachidonic acid metabolism. BS15 notably facilitated the expressions of fatty acid binding protein 2 (FABP2), acyl-CoA synthetase bubblegum family member 1 (ACSBG1), perilipin 1 (PLIN1) and perilipin 2 (PLIN2), which were involved in PPAR signaling pathway of SNE chickens. Besides, suppression of phospholipase A2 group IVA (PLA2G4A) in arachidonic acid metabolism was observed in SNE chickens after BS15 prevention. The expression patterns of FABP2, ACSBG1, PLIN1, PLIN2 and PLA24G in qRT-PCR validation were consistent with RNA-Seq results.

Conclusions

These findings indicate that SNE may affect the hepatic lipid metabolism of chickens. Meanwhile, BS15 pretreatment may provide a prospective natural prophylaxis strategy against SNE through improving the PPAR signaling pathway and arachidonic acid metabolism.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0741-5) contains supplementary material, which is available to authorized users.

Preventing subclinical necrotic enteritis through Lactobacillus johnsonii BS15 by ameliorating lipid metabolism and intestinal microflora in broiler chickens

Increasing studies have focused on the beneficial effects of Lactobacillus johnsonii in certain diseases. Here, we studied the prevention ability of a probiotic strain, L. johnsonii BS15 on subclinical necrotic enteritis (SNE), and its underlying mechanism. 180 male Cobb 500 chicks were randomly allotted into three groups and administrated with BS15 (1 × 10⁶ cfu/g) or Man Rogosa Sharpe liquid medium throughout a 28-day experimental period. With the exception of the normal group, SNE infection was treated for the remaining experimental period after the chicks were fed with normal diet 14 days. Results showed that BS15 notably suppressed the SNE-induced loss of average daily gain and liver functional abnormality. Additionally, BS15 facilitated lipid metabolism of SNE boilers when the contents of peroxisome proliferator activated receptor γ and adipose triglyceride lipase in adipose tissue and serum high-density lipoprotein cholesterol decreased. BS15 also attenuated the hepatic lipid accumulation of stricken chicks by suppressing the genes expression of acetyl-CoA carboxylase, fatty acid synthase and sterol regulatory element binding protein-1c as well as stimulating the genes expression of peroxisome proliferator activated receptor α and carnitine palmitoyltransferase-1. Moreover, BS15 enhanced the development of SNE gut by improving the intestinal development and digestion as well as adjusting the gut microflora. Therefore, BS15 may provide a promising natural preventative strategy against SNE, which may be contributed to the amelioration of lipid metabolism and intestinal microflora.