Special Issue "Poultry Microbiology and Immunology"

A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Veterinary Clinical Studies".

Deadline for manuscript submissions: closed (31 December 2020).

Special Issue Editor

Prof. Morgan B. Farnell
E-Mail Website
Guest Editor
Department of Poultry Science, Texas A and M University, Texas TX. USA
Interests: Animal Production; Antimicrobials; Immunology; Avian Gut Health; Poultry Diseases; Poultry Diseases

Special Issue Information

Dear Colleagues,

Modern poultry are thrifty and remarkable animals. They can convert feed to animal protein extremely efficiently, when provided an optimal rearing environment. A broiler chicken has a short grow out period and can reach a marketable size of 5 to 10 pounds at only 5 to 9 weeks of age. A layer hen may be economically viable for 1–2 years, laying an average of 259 eggs per year. However, animals bred for improved performance and feed conversion may also have been inadvertently selected for a diminished immune response.

Poultry are known carriers of foodborne pathogens such as the Salmonella and Campylobacter species. Testing methodologies have become more sensitive and regulations for the reduction of these pathogens have increased. Unfortunately, many of these enteric pathogens are considered as commensals by the bird and are difficult to eradicate as tolerance develops in the gut. Respiratory and enteric diseases continue to negatively affect the industry due to decreased nutrient absorption, morbidity and mortalities. Enhanced biosecurity, surveillance and vaccination strategies have helped, but improvements are still needed.

Maintaining the health and welfare of these animals has become more difficult, as consumer preferences and concerns from the medical community have resulted in restrictions of antibiotic usage in food-producing animals. Producers are attempting to improve avian health by utilizing vaccines and antibiotic alternatives such as probiotics, prebiotics, immune-modulators, botanicals, nutraceuticals, and bacteriophages to combat these pathogens and potentially modulate the avian immune response.

The poultry industry has been successful in producing a wholesome and inexpensive source of animal protein for human consumption, but it is also faced with significant challenges concerning improving bird health and welfare with more restrictions and less available tools. We invite original research papers that address improving avian health by refining our understanding of pathogenesis and developing new strategies to ameliorate disease.

Prof. Morgan B. Farnell
Guest Editor

Manuscript Submission Information

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Keywords

  • poultry
  • chicken
  • avian
  • antibiotic alternatives
  • immune modulators
  • vaccine
  • gut health
  • food safety
  • microbiology
  • immunology

Published Papers (9 papers)

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Research

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Article
Prevalence and Molecular Characterization of Salmonella Isolated from Broiler Farms at the Tolima Region—Colombia
Animals 2021, 11(4), 970; https://doi.org/10.3390/ani11040970 - 31 Mar 2021
Viewed by 455
Abstract
Salmonella is an important animal and human pathogen responsible for Salmonellosis, and it is frequently associated with the consumption of contaminated poultry products. The aim of this study was to estimate the prevalence of Salmonella in the poultry farms and to determine the [...] Read more.
Salmonella is an important animal and human pathogen responsible for Salmonellosis, and it is frequently associated with the consumption of contaminated poultry products. The aim of this study was to estimate the prevalence of Salmonella in the poultry farms and to determine the genetic relationship. A total of 135 samples collected from fifteen broiler farms, including cloacal, feed, water, environmental and farm operator faeces samples were subjected to microbiological isolation. Molecular confirmation of Salmonella isolates was carried out by amplification of the invA gene, discrimination of d-tartrate-fermenting Salmonella isolates using multiplex PCR, and subsequently analysed by pulsed-field gel electrophoresis (PFGE). A survey questionnaire was conducted to identify potential risk factors for Salmonella presence in broiler farms. The prevalence of Salmonella at the farm level was 26.67%, and Salmonella isolates were serotyped as S. Paratyphi B and all isolates were d-tartrate-fermenting (dT+). PFGE showed three highly similar clusters and one significantly different Salmonella isolate. S. Paratyphi B continued to be present in different links of the poultry chain in the Tolima region, and identification of its main source is necessary to control its dissemination. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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Article
The Modulating Effect of Dietary Beta-Glucan Supplementation on Expression of Immune Response Genes of Broilers during a Coccidiosis Challenge
Animals 2021, 11(1), 159; https://doi.org/10.3390/ani11010159 - 12 Jan 2021
Cited by 1 | Viewed by 513
Abstract
This study investigated the effects of a yeast-derived β-glucan (Auxoferm YGT) supplementation on mRNA expression of immune response genes in the spleen, thymus, and bursa of broiler chickens during a mixed Eimeria infection. Day (d)-old chicks (n = 1440) were fed diets [...] Read more.
This study investigated the effects of a yeast-derived β-glucan (Auxoferm YGT) supplementation on mRNA expression of immune response genes in the spleen, thymus, and bursa of broiler chickens during a mixed Eimeria infection. Day (d)-old chicks (n = 1440) were fed diets containing 0% or 0.1% YGT. On d 8 post-hatch, half the replicate pens (n = 8) were challenged with a mixed inoculum of E. acervulina, E. maxima, and E. tenella. On d 10 and d 14 post-hatch, the spleen, thymus, and bursa were collected to evaluate mRNA abundance by quantitative real-time PCR. Data were analyzed using PROC GLIMMIX model (2-way interaction) and differences were established by LS-MEANS with significance reported at p ≤ 0.05. In spleen tissues at d 10, expression of interleukin (IL)-10 and inducible nitric oxide synthase (iNOS) were elevated in both 0.1% YGT-fed challenged and non-challenged birds. In thymus tissues at d 14, expression of IL-10, IL-17F, interferon (IFN)-γ, iNOS, and macrophage migration inhibitory factor (MIF) were elevated in challenged birds fed 0.1% YGT. In bursal tissues at d 10 and d 14, expression of IL-10, IFN-γ, iNOS (d 10 only), and MIF were elevated in 0.1% YGT-fed challenged and non-challenged birds. Dietary β-glucan supplementation to chicken diets modulated their immune response to the Eimeria challenge. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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Article
Immunomodulatory Effects of Dietary Phosphorus and Calcium in Two Strains of Laying Hens
Animals 2021, 11(1), 129; https://doi.org/10.3390/ani11010129 - 08 Jan 2021
Viewed by 678
Abstract
Insufficient nutrient supply can impair the immune system, which is important for animal health and welfare. Since chicken can partly hydrolyze phytate, which is the primary phosphorus storage in plant seeds, a reduction of mineral phosphorus in the diets could be an option [...] Read more.
Insufficient nutrient supply can impair the immune system, which is important for animal health and welfare. Since chicken can partly hydrolyze phytate, which is the primary phosphorus storage in plant seeds, a reduction of mineral phosphorus in the diets could be an option for more sustainable egg production. Laying hens require high concentrations of calcium that might inhibit the function of endogenous enzymes for phytate hydrolyzation. The objective of this study was to characterize the impact of standard and reduced dietary phosphorus and calcium concentrations on the number and functionality of immune cells in the peripheral and gut-associated immune system in a white and brown laying hen strain. Reduced mineral phosphorus enhanced several immune parameters such as B cells in blood and IgA concentrations in bile in both strains, and peripheral monocytes and T cells in cecal tonsils in brown hens. Reduced calcium levels resulted in lower numbers of T cells in blood and cecal tonsils in both strains, suggesting negative effects on adaptive immunity. Differences between the two strains were found in almost all immune parameters. Results suggest a potentially beneficial effect of reduced dietary mineral phosphorus on the immune system that is dependent on the genetic background. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
Article
Detection of Plasmid-Mediated Colistin Resistant mcr-1 Gene in Escherichia coli Isolated from Infected Chicken Livers in Nepal
Animals 2020, 10(11), 2060; https://doi.org/10.3390/ani10112060 - 07 Nov 2020
Cited by 1 | Viewed by 937
Abstract
Background: Plasmid-mediated resistance to the colistin in poultry is considered as an emerging problem worldwide. While poultry constitutes the major industry in Nepal, there is a paucity of evidence on colistin resistance in Escherichia coli isolates causing natural infections in poultry. This study [...] Read more.
Background: Plasmid-mediated resistance to the colistin in poultry is considered as an emerging problem worldwide. While poultry constitutes the major industry in Nepal, there is a paucity of evidence on colistin resistance in Escherichia coli isolates causing natural infections in poultry. This study aimed to explore the prevalence of plasmid-mediated colistin resistance gene, mcr-1 in E. coli isolated from liver samples of dead poultry suspected of E. coli infections. Methods: A total of two hundred and seventy liver samples (227 broilers and 43 layers) from dead poultry suspected of colibacillosis were collected from post-mortem in the Central Veterinary Laboratory (CVL), Kathmandu, between 1 February and 31 July 2019. The specimens were processed to isolate and identify E. coli; an antimicrobial susceptibility test (AST) using disk diffusion method was performed with 12 different antibiotics: Amikacin (30 µg), ampicillin (10 µg), ciprofloxacin (5 µg), chloramphenicol (30 µg), cefoxitin (30 µg), ceftazidime (30 µg), ceftriaxone (30 µg), cotrimoxazole (25 µg), gentamicin (10 µg), imipenem (10 µg), levofloxacin (5 µg) and tetracycline (30 µg). Colistin resistance was determined by agar dilution method and colistin-resistant strains were further screened for plasmid-mediated mcr-1 gene, using conventional polymerase chain reaction (PCR). Results: Out of 270 liver samples, 53.3% (144/270) showed growth of E. coli. The highest number (54%; 109/202) of E. coli isolates was obtained in the liver samples from poultry birds (of both types) aged less than forty days. In AST, 95.1% (137/144) and 82.6% (119/144) of E. coli isolates were resistant against tetracycline and ciprofloxacin, respectively, while 13.2% (19/144) and 25.7% (37/144) isolates were resistant to cefoxitin and imipenem, respectively. In the same assay, 76.4% (110/144) E. coli isolates were multi-drug resistant (MDR). The phenotypic prevalence of colistin resistance was 28.5% (41/144). In the PCR assay, 43.9% (18/41) of colistin-resistant isolates were screened positive for plasmid-mediated mcr-1. Conclusion: The high prevalence of mcr-1 in colistin-resistant E. coli isolates in our study is a cause of concern for the probable coming emergence of colistin resistance in human pathogens, due to horizontal transfer of resistant genes from poultry to human isolates. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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Article
Effect of a Synbiotic Mix on Lymphoid Organs of Broilers Infected with Salmonella typhimurium and Clostridium perfringens
Animals 2020, 10(5), 886; https://doi.org/10.3390/ani10050886 - 19 May 2020
Cited by 3 | Viewed by 1258
Abstract
Synbiotic consumption can modulate immune response. This work involves studying the effect of a synbiotic on lymphoid organs and IgA of broilers infected with Salmonella typhimurium and Clostridium perfringens. A total of 258 one-day-old male broilers (Gallus gallus domesticus), line [...] Read more.
Synbiotic consumption can modulate immune response. This work involves studying the effect of a synbiotic on lymphoid organs and IgA of broilers infected with Salmonella typhimurium and Clostridium perfringens. A total of 258 one-day-old male broilers (Gallus gallus domesticus), line COBBAvian48 (free of growth-promoting antibiotics), were distributed into eight treatment groups. A symbiotic mix comprising Lactobacillus rhamnosus HN001 and Pediococcus acidilactici MA18/5 M as probiotics and 4.5% (0.045 g g−1) of Agave tequilana fructans as prebiotic per dose (one milliliter) was administered through drinking water the first day of life. Bursa, spleen and thymus were analyzed. Broilers treated with the synbiotic, whether or not infected with pathogens, had bigger bursa follicles than the non-treated (p < 0.05), and the ones from the synbiotic group had more lymphocytes than the control group (p < 0.05). Thymus follicles of the synbiotic group were bigger than the control group (p < 0.05). Lesions associated with Salmonella infection were found in the bursa, however, in the broilers treated with the synbiotic, the lesions were less intense and were not present after 32 days of life. The synbiotic mix can stimulate the bursa, increasing the size of their follicles and promoting the ability to resist infections caused by S. typhimurium in broilers. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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Article
Establishing a Model for Evaluating Chicken Coccidiosis Resistance Based on Principal Component Analysis
Animals 2019, 9(11), 926; https://doi.org/10.3390/ani9110926 - 06 Nov 2019
Cited by 1 | Viewed by 701
Abstract
To establish a coccidiosis resistance evaluation model for chicken selection, the different parameters were compared between infected and control Jinghai yellow chickens. Validation parameters were selected for principal component analysis (PCA), and an optimal comprehensive evaluation model was selected based on the significance [...] Read more.
To establish a coccidiosis resistance evaluation model for chicken selection, the different parameters were compared between infected and control Jinghai yellow chickens. Validation parameters were selected for principal component analysis (PCA), and an optimal comprehensive evaluation model was selected based on the significance of a correlation coefficient between coccidiosis resistance parameters and principal component functions. The following six different parameters were identified: body weight gain 3–5 days post infection and catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA) and γ-interferon (IFN-γ) concentrations on the eight day post inoculation. Six principal components and one accumulated contribution of up to 80% of the evaluation models were established by PCA. The results showed that the first model was significantly or highly significantly related to nine resistance parameters (p < 0.01 or p < 0.05), especially to cecal lesions (p < 0.01). The remaining models were related to only 2–3 parameters (p < 0.01 or p < 0.05) and not to cecal lesions (p > 0.05). The values calculated by the optimal model (first model) were significantly negatively correlated with cecal lesion performance; the larger the value, the more resistant to coccidiosis. The model fi1 = −0.636 zxi1 + 0.311 zxi2 + 0.801 zxi3 − 0.046 zxi4 − 0.076 zxi5 + 0.588 zxi6 might be the best comprehensive selection index model for chicken coccidiosis resistance selection. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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Article
Effect of a Synbiotic Mix on Intestinal Structural Changes, and Salmonella Typhimurium and Clostridium Perfringens Colonization in Broiler Chickens
Animals 2019, 9(10), 777; https://doi.org/10.3390/ani9100777 - 10 Oct 2019
Cited by 10 | Viewed by 1627
Abstract
Synbiotics can prevent gastrointestinal infections in broilers. This work studies the effect of a Synbiotic on broilers. One-day-old male broilers were divided into groups: Control; Synbiotic; Synbiotic + S. Typhimurium; Synbiotic + C. perfringens; Synbiotic + S. Typhimurium + C. [...] Read more.
Synbiotics can prevent gastrointestinal infections in broilers. This work studies the effect of a Synbiotic on broilers. One-day-old male broilers were divided into groups: Control; Synbiotic; Synbiotic + S. Typhimurium; Synbiotic + C. perfringens; Synbiotic + S. Typhimurium + C. perfringens; S. Typhimurium; C. perfringens; and S. Typhimurium + C. perfringens. Histopathological analysis revealed that the Synbiotic promoted longer villi, less deep crypts, and better villi-crypt ratio. Broilers treated with the Synbiotic, infected with pathogens or not, had healthier mucosa. In groups infected with pathogens, the frequency and intensity of histopathologic lesions were lessened often in groups treated with the Synbiotic. The Synbiotic group had higher lactic acid bacteria counts than the Control group on day 39, and the isolation frequency of S. Typhimurium was lower (p < 0.05) in the Synbiotic-treated groups. On day 18, mucosa, villi, villi-crypt ratio, crypt, and feed intake were influenced by Enterobacteriaceae. However, on day 39 (end of the trial), those parameters were influenced by lactic acid bacteria. The Synbiotic influenced morphological modifications in the duodenal mucosa, which in turn gave the broilers the ability to resist infections caused by S. Typhimurium and C. perfringens, by inhibiting their growth and decreasing the intensity and frequency of histopathological injuries. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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Review

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Review
Impact of Housing Environment on the Immune System in Chickens: A Review
Animals 2020, 10(7), 1138; https://doi.org/10.3390/ani10071138 - 05 Jul 2020
Cited by 8 | Viewed by 1397
Abstract
During their lifespan, chickens are confronted with a wide range of acute and chronic stressors in their housing environment that may threaten their welfare and health by modulating the immune system. Especially chronic stressful conditions can exceed the individual’s allostatic load, with negative [...] Read more.
During their lifespan, chickens are confronted with a wide range of acute and chronic stressors in their housing environment that may threaten their welfare and health by modulating the immune system. Especially chronic stressful conditions can exceed the individual’s allostatic load, with negative consequences for immunity. A fully functional immune system is mandatory for health and welfare and, consequently, also for high productivity and safe animal products. This review provides a comprehensive overview of the impact of housing form, light regime as well as aerial ammonia and hydrogen sulfide concentrations on the immune system in chickens. Certain housing conditions are clearly associated with immunological alterations which potentially impair the success of vaccinations or affect disease susceptibility. Such poor conditions counteract sustainable poultry production. This review also outlines current knowledge gaps and provides recommendations for future research. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
Review
Immunomodulation of Avian Dendritic Cells under the Induction of Prebiotics
Animals 2020, 10(4), 698; https://doi.org/10.3390/ani10040698 - 17 Apr 2020
Cited by 1 | Viewed by 941
Abstract
Although the immunomodulatory properties of prebiotics were demonstrated many years ago in poultry, not all mechanisms of action are yet clear. Dendritic cells (DCs) are the main antigen-presenting cells orchestrating the immune response in the chicken gastrointestinal tract, and they are the first [...] Read more.
Although the immunomodulatory properties of prebiotics were demonstrated many years ago in poultry, not all mechanisms of action are yet clear. Dendritic cells (DCs) are the main antigen-presenting cells orchestrating the immune response in the chicken gastrointestinal tract, and they are the first line of defense in the immune response. Despite the crucial role of DCs in prebiotic immunomodulatory properties, information is lacking about interaction between prebiotics and DCs in an avian model. Mannan-oligosaccharides, β-glucans, fructooligosaccharides, and chitosan-oligosaccharides are the main groups of prebiotics having immunomodulatory properties. Because pathogen-associated molecular patterns on these prebiotics are recognized by many receptors of DCs, prebiotics can mimic activation of DCs by pathogens. Short-chain fatty acids are products of prebiotic fermentation by microbiota, and their anti-inflammatory properties have also been demonstrated in DCs. This review summarizes current knowledge about avian DCs in the gastrointestinal tract, and for the first-time, their role in the immunomodulatory properties of prebiotics within an avian model. Full article
(This article belongs to the Special Issue Poultry Microbiology and Immunology)
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