Avian Coccidiosis Research Articles

Coccidiose aviária: impactos e características da doença

An excellent poultry production in the current national and international commercial scenario is directly related to an adequate sanitary control, since, in situations of incorrect management, adult chicks and chickens can be affected by several diseases, such as avian eimeriosis, caused by the obligate intracellular apicomplex protist Eimeria spp. which generates numerous losses to agribusiness. Among the main species that cause economic impact on poultry farming, the species E. acervulina, E. maxima, and E. tenella stand out, especially due to their high capacity for dissemination and the severity of the disease presentation. Sanitary measures to control coccidiosis, such as rigorous cleaning of sheds and bedding, as well as the responsible use of anticoccidial drugs, require extensive planning and commitment on the part of producers. The objective of this study was to carry out a literature review on avian coccidiosis in order to better understand the characteristics of the agent and to relate the pathogenesis to the methods of diagnosis, control and prevention of this disease, since the impact of the disease is masterful.

Use of Metallic Nanoparticles Against Eimeria-the Coccidiosis-Causing Agents: A Comprehensive Review.

Coccidiosis is a protozoan disease caused by Eimeria species and is a major threat to the poultry industry. Different anti-coccidial drugs (diclazuril, amprolium, halofuginone, ionophores, sulphaquinoxaline, clopidol, and ethopabate) and vaccines have been used for their control. Still, due to the development of resistance, their efficacy has been limited. It is continuously damaging the economy of the poultry industry because under its control, almost $14 billion is spent, globally. Recent research has been introducing better and more effective control of coccidiosis by using metallic and metallic oxide nanoparticles. Zinc, zinc oxide, copper, copper oxide, silver, iron, and iron oxide are commonly used because of their drug delivery mechanism. These nanoparticles combined with other drugs enhance the effect of these drugs and give their better results. Moreover, by using nanotechnology, the resistance issue is also solved because by using several mechanisms at a time, protozoa cannot evolve and thus resistance cannot develop. Green nanotechnology has been giving better results due to its less toxic effects. Utilization of metallic and metallic oxide nanoparticles may present a new, profitable, and economical method of controlling chicken coccidiosis, thus by changing established treatment approaches and improving the health and production of chickens. Thus, the objective of this review is to discuss about economic burden of avian coccidiosis, zinc, zinc oxide, iron, iron oxide, copper, copper oxide, silver nanoparticles use in the treatment of coccidiosis, their benefits, and toxicity.

The anticoccidial effects of probiotics and prebiotics on the live coccidia vaccine and the subsequent influence on poultry performance post-challenge with mixed Eimeria species

Live vaccines containing Eimeria oocysts are commercially available to protect against avian coccidiosis. Additionally, probiotics (PRO) and prebiotics (PRE) improve the poultry productivity and health and can be used as anticoccidial substitutes. However, the impact of PRO and PRE on reproductive potential, lesion score, intestinal health, and immunization outcomes of the live coccidia vaccines has not received adequate attention. Five groups of unsexed 1-day-old broiler chicks were used as follows: negative control (NC); challenged control (CC); vaccinated and challenged (VC); vaccinated, PRO-treated, and challenged (V-PRO); and vaccinated, PRE-treated, and challenged (V-PRE). At 21 d post-vaccination (pv), the vaccine increased the count of cecal anaerobes (P ≤ 0.05) and coliforms (P > 0.05) as well as harmed body weight gain (WG) (P ≤ 0.05), cecal lactic acid bacteria (P ≤ 0.05), and plasma carotenoid level (P > 0.05). None of the additives decreased oocyst shedding after vaccination, although they lowered the middle intestine and cecal lesion scores (P > 0.05). Compared to VC (2.68 ± 0.12) and V-PRE (2.66 ± 0.05), the V-PRO group showed an improved carotenoid level pv (2.96 ± 0.05) (P ≤ 0.05). V-PRE exhibited higher WG (822.95 ± 18.25) (P > 0.05) and FI (1153.01 ± 10.02) (P ≤ 0.05) than VC (781.86 ± 25.16 and 1109.85 ± 33.68) and V-PRO pv (787.61 ± 19.92 and 1077.43 ± 15.99). Following the homologous coccidia challenge, coccidia-vaccinated broilers adminstered the PRO or PRE continued to exhibit protection levels comparable to those received the vaccine alone. During 2 weeks post-challenge, VC, V-PRO and V-PRE improved bird performance and reduced oocyst shedding and lesion scores compared to CC. Ultimately, PRO and PRE treatments did not significantly reverse the reduction in growth performance in broiler chickens vaccinated against coccidia during the 1st three weeks of age.

Metabolomic analysis reveals altered amino acid metabolism and mechanisms underlying Eimeria infection in laying hens

Avian coccidiosis, caused by Eimeria spp, is a devastating disease in laying hens. Previous studies have suggested that amino acids may be involved in Eimeria infection of broiler chickens. However, their metabolic features in laying hens, as well as the effect of multiple Eimeria species challenges on poultry hosts have not been elucidated yet. Here, a targeted metabolomics approach was employed to identify altered amino acid metabolism and mechanisms in laying hens with multiple Eimeria species challenges. Laying hens, Hy-Line W-36 aged 25 wk, were randomly assigned to a control group and groups inoculated with varying levels of mixed Eimeria species (E. maxima, E. tenella, and E. acervulina). Serum samples from each group were collected at 6 d and 14 d of postinoculation (6 and 14 DPI) for metabolite profiling. Metabolomic analysis revealed notable metabolic variations between control and infected groups, especially at 6 DPI stage. Varying levels of Eimeria dosages did not show a significant metabolic difference, and metabolites were sensitive to low-level infection. With statistical analysis, differentially expressed compounds (3-methylhistidine, alanine, aspartate, lysine, asparagine, methionine, ornithine, and tryptophan) were selected, and their metabolic network was identified by pathway enrichment analysis. In the network, the lysine biosynthesis pathway was upregulated, while the arginine and proline metabolic pathway was downregulated under infection. Other pathways showed complex patterns of metabolic relationships. Based on the results, biological implications of metabolic changes were elucidated and discussed. Last, the results were further confirmed with our previous study (phenotype and gene expression results) using the same set of samples. Our finding provides in-depth information on altered amino acid metabolism and mechanisms in laying hens upon multiple Eimeria species infection.

Efeito do gás amônia em cama aviária contaminada com Eimeria spp.

Avian coccidiosis is a common disease that affects poultry worldwide. The practices used to control this pathology in poultry are based mainly on the use of antimicrobials, which have generated increased resistance of Eimeria and other microorganisms. Research is therefore needed to devise new control models and strategies. The objective of our research was to evaluate the effect of different concentrations of ammonia gas on poultry litter artificially contaminated with unsporulated Eimeria spp. oocysts. Samples of sterilized poultry litter were placed in containers artificially contaminated with unsporulated Eimeria spp. oocysts. Samples were placed in plastic bags and ammonia gas was injected in concentrations of 0.2%, 0.4%, 0.8%, 1% and 1.2%. The tested dosages of ammonia gas inhibited the sporulation of oocysts in poultry litter by 100%. Our study indicates that ammonia gas is efficient in eliminating Eimeria spp. in poultry litter at concentrations equal to or higher than 0.2% after one hour of exposure. These results are promising because, through the use of the bedding disinfection method (shallow fermentation with ammonia injection) it will be possible to eliminate field oocysts, improving the result of coccidiosis vaccines.

Development of a TaqMan polymerase chain reaction detection method for the precise identification and quantification of an attenuated Eimeria maxima vaccine strain in poultry.

Avian coccidiosis, a parasitic disease prevalent in poultry, is caused by Eimeria species and leads to significant economic losses. The use of attenuated live oocyst vaccines has been adopted as an alternative to the use of anticoccidial drugs. However, the accurate detection and differentiation of vaccine strains from virulent ones remain challenging. Therefore, this study presents a novel TaqMan polymerase chain reaction (PCR) detection method that offers enhanced sensitivity, specificity, and reproducibility compared with traditional PCR techniques. Through whole-genome resequencing and bioinformatics analysis, we identified a molecular marker gene, Em_marker6, with a unique 21-base pair deletion specific to the Eimeria maxima attenuated vaccine strain. Optimized primers and probes targeting this marker enabled rapid quantification cycle value achievement and high fluorescence intensity. The standard curve's slope of -3.540 and correlation coefficient of 0.9971 confirmed precise quantification capabilities. The TaqMan PCR method detected as few as 30 plasmid DNA copies and 50 oocysts per reaction, outperforming traditional PCR techniques by an order of magnitude. No cross-reactivity was observed with other E. maxima wide-type strains or common intestinal pathogens, ensuring the exclusive detection of the E. maxima EMPY vaccine strain. Weekly testing over 3 weeks demonstrated minimal variability, indicating robust consistency in the method's application. Testing on 61 clinical samples revealed a 57.38% positivity rate for E. maxima species and 13.11% for the vaccine strain. The Em_marker6 gene exhibited genetic stability across multiple generations, confirming the detection method's robust stability for the attenuated E. maxima vaccine strain. This study significantly advances the field of avian coccidiosis research and control by providing a valuable tool for monitoring vaccine purity and preventing inadvertent infections in vaccinated flocks, aligning with global efforts to curb antibiotic use in animal feed.

Prevalence of Avian coccidiosis in India: a review.

Coccidiosis stands as a highly significant and economically impactful parasitic ailment in poultry, attributed to the intracellular parasite belonging to the genus Eimeria. This affliction poses considerable financial challenges to the poultry industry and is prevalent in most tropical and subtropical regions globally. The primary mode of transmission is through the fecal-oral route, predominantly affecting young chicks and chickens within intensive rearing systems. There are nine distinct Eimeria species that affect poultry, manifesting primarily in caecal and intestinal forms. Diagnosis typically relies on examining fecal samples for oocysts and post-mortem lesions. Molecular techniques are employed for both diagnosis and control of poultry coccidiosis. To combat the disease, anticoccidials are consistently incorporated into feed and water, but this practice may contribute to the emergence of resistant strains. Various vaccines, including live or live attenuated options, are currently in use for coccidiosis prevention.

Evaluation of the anticoccidial effect of jataí bee (Tetragonisca angustula) propolis extract against Eimeria spp. oocysts in broiler

The use of anticoccidial compounds is the primary strategy for controlling avian coccidiosis. The emergence of drug resistance, regulatory restrictions, and societal demands for meat production without the use of antimicrobials have increased the need for natural alternatives to control this disease. Propolis is known for its antimicrobial effects and may be an alternative. In this context, this study aimed to evaluate the anticoccidial activity of jataí bee (Tetragonisca angustula) propolis against the sporulation of Eimeria spp. oocysts in broiler chicken feces. Propolis ethanolic extracts were tested at 10, 15, and 20% against Eimeria oocyst sporulation. Direct use of the extract on oocysts completely inhibited sporulation. When applied to feces, the extract significantly reduced the number of sporulated oocysts. Thus, the jatai bee propolis extract is a promising alternative to commercial anticoccidial agents.

Global profiling of protein S-palmitoylation in the second-generation merozoites of Eimeria tenella.

The intracellular protozoan Eimeria tenella is responsible for avian coccidiosis which is characterized by host intestinal damage. During developmental cycle, E. tenella undergoes versatile transitional stages such as oocyst, sporozoites, merozoites, and gametocytes. These developmental transitions involve changes in cell shape and cell size requiring cytoskeletal remodeling and changes in membrane proteins, which may require transcriptional and translational regulations as well as post-translational modification of proteins. Palmitoylation is a post-translational modification (PTM) of protein that orchestrates protein targeting, folding, stability, regulated enzymatic activity and even epigenetic regulation of gene expression. Previous research revealed that protein palmitoylation play essential role in Toxoplasma gondii, Trypanosoma cruzi, Trichomonas vaginalis, and several Plasmodium parasites. Until now, there is little information on the enzymes related to palmitoylation and role of protein acylation or palmitoylation in E. tenella. Therefore, palmitome of the second-generation merozoite of E. tenella was investigated. We identified a total of 2569 palmitoyl-sites that were assigned to 2145 palmitoyl-peptides belonging to 1561 protein-groups that participated in biological processes including parasite morphology, motility and host cell invasion. In addition, RNA biosynthesis, protein biosynthesis, folding, proteasome-ubiquitin degradation, and enzymes involved in PTMs, carbohydrate metabolism, glycan biosynthesis, and mitochondrial respiratory chain as well as vesicle trafficking were identified. The study allowed us to decipher the broad influence of palmitoylation in E. tenella biology, and its potential roles in the pathobiology of E. tenella infection. Raw data are publicly available at iProX with the dataset identifier PXD045061.

Coccidiosis in Egg-Laying Hens and Potential Nutritional Strategies to Modulate Performance, Gut Health, and Immune Response.

Avian coccidiosis, despite advancements in management, nutrition, genetics, and immunology, still remains the most impactful disease, imposing substantial economic losses to the poultry industry. Coccidiosis may strike any avian species, and it may be mild to severe, depending on the pathogenicity of Eimeria spp. and the number of oocysts ingested by the bird. Unlike broilers, low emphasis has been given to laying hens. Coccidiosis in laying hens damages the gastrointestinal tract and causes physiological changes, including oxidative stress, immunosuppression, and inflammatory changes, leading to reduced feed intake and a drastic drop in egg production. Several countries around the world have large numbers of hens raised in cage-free/free-range facilities, and coccidiosis has already become one of the many problems that producers have to face in the future. However, limited research has been conducted on egg-laying hens, and our understanding of the physiological changes following coccidiosis in hens relies heavily on studies conducted on broilers. The aim of this review is to summarize the effect of coccidiosis in laying hens to an extent and correlate it with the physiological changes that occur in broilers following coccidiosis. Additionally, this review tries to explore the nutritional strategies successfully used in broilers to mitigate the negative effects of coccidiosis in improving the gut health and performance of broilers and if they can be used in laying hens.

Bioefficacy of dietary inclusion of Nannochloropsis oculata on Eimeria spp. challenged chicks: clinical approaches, meat quality, and molecular docking

ABSTRACT Although anticoccidial drugs have been used to treat avian coccidiosis for nearly a century, resistance, bird harm, and food residues have caused health concerns. Thus, Nannochloropsis oculata was investigated as a possible coccidiosis treatment for broilers. A total of 150 1-day-old male Cobb broiler chicks were treated as follows: G1-Ng: fed a basal diet; G2-Ps: challenged with Eimeria spp. oocysts and fed basal diet; G3-Clo: challenged and fed basal diet with clopidol; G4-NOa: challenged and fed 0.1% N. oculata in diet, and G5-NOb: challenged and fed 0.2% N. oculata. Compared to G2-Ps, N. oculata in the diet significantly (P < 0.05) decreased dropping scores, lesion scores, and oocyst shedding. Without affecting breast meat colour metrics, N. oculata improved meat quality characters. At 28 days of age, birds received 0.2% N. oculata had significantly (P < 0.05) higher serum levels of MDA, T-SOD, HDL, and LDL cholesterol compared to G2-Ps. Serum AST, ALT, and urea levels were all decreased when N. oculata (0.2%) was used as opposed to G2-Ps. Histopathological alterations and the number of developmental and degenerative stages of Eimeria spp. in the intestinal epithelium were dramatically reduced by 0.2% N. oculata compared to G2-Ps. Molecular docking revealed a higher binding affinity of N. oculata for E. tenella aldolase, EtAMA1, and EtMIC3, which hindered glucose metabolism, host cell adhesion, and invasion of Eimeria. Finally, N. oculata (0.2%) can be used in broiler diets to mitigate the deleterious effects of coccidiosis.

Cloning, expression, and functional identification of aquaporin genes from Eimeria tenella

Avian coccidiosis, caused by Eimeria spp., is one of the major parasitic diseases in chicken. Aquaporins (AQP) are essential mediators of water regulation and nutritional intake in parasites, and it may be a suitable molecule for chemotherapeutic target and vaccine candidate. We identified two aquaporin genes in Eimeria tenella (EtAQP1 and EtAQP2) with their full sequence, and the expression profiles were analyzed across different stages of E. tenella life cycle. The expression of EtAQP1 and EtAQP2 in Xenopus oocytes renders them highly permeable for both water and glycerol. Sugar alcohols up to five carbons and urea pass the pore. The immunohistochemical analysis confirms the restriction of antiserum staining to the surface of transfected Xenopus oocytes. Like other AQP family, EtAQPs are transmembrane proteins that are likely important molecules that facilitate solute uptake for parasite intracellular growth and therapeutic targets.

Integrated application of transcriptomics and metabolomics provides insight into the mechanism of Eimeria tenella resistance to maduramycin

Avian coccidiosis, caused by Eimeria parasites, continues to devastate the poultry industry and results in significant economic losses. Ionophore coccidiostats, such as maduramycin and monensin, are widely used for prophylaxis of coccidiosis in poultry. Nevertheless, their efficacy has been challenged by widespread drug resistance. However, the underlying mechanisms have not been revealed. Understanding the targets and resistance mechanisms to anticoccidials is critical to combat this major parasitic disease. In the present study, maduramycin-resistant (MRR) and drug-sensitive (DS) sporozoites of Eimeria tenella were purified for transcriptomic and metabolomic analysis. The transcriptome analysis revealed 5016 differentially expressed genes (DEGs) in MRR compared to DS, and KEGG pathway enrichment analysis indicated that DEGs were involved in spliceosome, carbon metabolism, glycolysis, and biosynthesis of amino acids. In the untargeted metabolomics assay, 297 differentially expressed metabolites (DEMs) were identified in MRR compared to DS, and KEGG pathway enrichment analysis indicated that these DEMs were involved in 10 pathways, including fructose and mannose metabolism, cysteine and methionine metabolism, arginine and proline metabolism, and glutathione metabolism. Targeted metabolomic analysis revealed 14 DEMs in MRR compared to DS, and KEGG pathway analysis indicated that these DEMs were involved in 20 pathways, including fructose and mannose metabolism, glycolysis/gluconeogenesis, and carbon metabolism. Compared to DS, energy homeostasis and amino acid metabolism were differentially regulated in MRR. Our results provide gene and metabolite expression landscapes of E. tenella following maduramycin induction. This study is the first work involving integrated transcriptomic and metabolomic analyses to identify the key pathways to understand the molecular and metabolic mechanisms underlying drug resistance to polyether ionophores in coccidia.

Prevalence of Eimeria Species, Detected by ITS1-PCR Immobilized on FTA Cards, in Future Laying Hens and Breeding Hens in Six Provinces in Northeastern Algeria.

Avian coccidiosis is an important and widely distributed disease that affects global agricultural economies through losses. In Algeria, there is limited epidemiological and ecological knowledge about this disease and this hinders implementation of control strategies. A recent study, in Algeria, demonstrated a high prevalence and diversity of Eimeria species in broiler chickens. However, very little is known about the Eimeria species that exist on chicken farms raised on the floor and older than broiler chickens (for example, future laying hens and breeding hens) in Algeria. Samples were collected from 32 poultry farms located in 6 northeastern Algerian provinces (Algiers, Batna, Bejaia, Bordj Bou Arréridj, Jijel, Mila). These included 22 pre-laying pullet farms, with hens aged between 11 and 17 weeks, and 10 breeding hen farms with older hens (over 20 weeks). FTA cards were used to capture DNA and internal transcribed Spacer 1 PCR (ITS1-PCR) was used to determine the prevalence and composition of Eimeria species in the chickens. This showed the presence of six species of Eimeria with a diverse prevalence range. Eimeria necatrix (63%) was the most common species, followed by E. maxima (53%), E. tenella (31%), E. brunetti (19%), E. acervulina and E. mitis (both 0.3%). Eimeria praecox was absent. Eimeria infection affected all farms studied where co-infections by different Eimeria species (63%) were more frequent than single infections (38%). The number of oocyts, per ml of enriched oocyst suspension was higher in breeding hen farms compared to pre-laying pullet farms. This study, taken alongside a previous study involving broiler farms, demonstrated that the infection with this parasite is a significant problem in Algeria.

Mycotoxins and coccidiosis in poultry - co-occurrence, interaction, and effects.

Avian coccidiosis, a common disease caused by Eimeria species, results in significant losses in global poultry production. Mycotoxins are low-molecular-weight natural products (i.e., small molecules) produced as secondary metabolites by filamentous fungi and they have the potential to economically and significantly affect global poultry production. Little is known about the relationship between mycotoxins and avian coccidiosis, although they often co-occur in the field. This comprehensive review examines the intricate relationship between mycotoxins and avian coccidiosis, in particular how mycotoxins, including aflatoxins, ochratoxins, trichothecenes as well as Fusarium mycotoxins, compromise the health of the poultry flock and open the door to Eimeria parasites in the gut. In addition, this review sheds light on the immunosuppressive effects of mycotoxins, their disruption of cellular signaling pathways, and the consequent exacerbation of coccidiosis infections. The mechanisms of mycotoxin toxicity are also reviewed, emphasizing direct damage to intestinal epithelial cells, impaired nutrient absorption, inflammation, oxidative stress, and changes in the gut microbiota. Finally, the consequences for the prevention and treatment of coccidiosis when mycotoxins are present in the feed are discussed. This review emphasizes the need for effective management strategies to mitigate the combined risks of mycotoxins and coccidiosis and highlights the complexity of diagnosing and controlling these interrelated problems in poultry. The review advocates a holistic approach that includes strict feed management, disease prevention measures and regular monitoring to maintain the health and productivity of poultry against these significant challenges.

Gut Health in Avian Coccidiosis and its Prevention using Probiotics

Gut Health in Avian Coccidiosis and its Prevention using Probiotics

Role of Probiotics in Prevention of Avian Coccidiosis

Role of Probiotics in Prevention of Avian Coccidiosis

Effects of prebiotic (lactoferrin) and diclazuril on broiler chickens experimentally infected with Eimeria tenella.

Avian coccidiosis presents a significant challenge to the poultry industry in Egypt, highlighting the urgent need for validating new drug targets offering promising prospects for the development of advanced anticoccidials. Although numerous reports highlight the activity of lactoferrin (LF) against various microorganisms, its potential against Eimeria has not been explored. The present study evaluated the potential anticoccidial effect of LF and diclazuril in broiler chickens experimentally infected with Eimeria tenella. A total of 100 one-day-old broiler chicks were divided into five equal groups (20 each) as follows: Group 1 (G1) served as the normal healthy control group, Group 2 (G2) consisted of chickens infected with 1 × 105 sporulated E. tenella oocysts at 14 days of age, Group 3 (G3) comprised infected chickens treated with diclazuril (0.5 mL/L in drinking water) for 3 days successively, Group 4 (G4) included infected chickens treated with LF (at a dose of 250 mg/kg of diet) from one day of age until the end of the study, and Group 5 (G5) comprised infected chickens treated with both LF and diclazuril. The positive control group (G2) experienced significant reductions in body weight (BW), BW gain, serum glucose, lipase, amylase, total antioxidant capacity, several hematological indices, and total proteins, along with alterations in various antioxidant enzymes. Conversely, serum levels of aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Alkaline phosphatases (ALP), urea, creatinine, nitric oxide, mean corpuscular volume (MCV), White blood cells (WBCs), heterophils, alpha 2, beta 1, and liver contents of malondialdehyde were elevated in this group. Moreover, higher oocyst counts and lesion scores, along with histopathological alterations, were observed in G2. Remarkably, treatment with diclazuril and/or LF demonstrated potent antioxidant and anticoccidial effects, resulting in reduced shedding of oocysts, lesion scores, and lymphocytic infiltrates in the cecum. Additionally, these treatments improved the antioxidant and immune systems in chickens and restored all histopathological changes reported in the infected non-treated group (G2). This study offers novel perspectives on the potential anticoccidial effects of the combination of LF and diclazuril in broiler chickens infected with E. tenella, highlighting the potential synergistic actions of LF in treating poultry coccidiosis.

Immunological studies on the effects of toltrazuril and neem extract in broiler chickens suffering from coccidiosis.

The prevalence of avian coccidiosis in the poultry industry has grown, resulting in substantial financial losses from high mortality, stunted growth, reduced productivity, and expensive medical expenses. The purpose of the current study was to assess the immunological effects of neem leaf extract and toltrazuril on broilers that had contracted coccidiosis. In this investigation, 100 one-day-old Cobb broiler chicks without sexes were employed. The chicks were divided into five equal groups, with 20 birds in each. On the 14th day of life, the birds in groups 2, 3, 4, and 5 received an oral inoculation with 1 × 105 sporulated oocysts of Eimeria tenella (E. tenella) (field isolate). The first group (Gp), which consists of 20 healthy broilers, served as a negative control. Gp (2) contains experimentally infected broilers and nontreated (served as a positive control). Gp (3) contains experimentally infected broilers treated with toltrazuril (1 ml/l drinking water) for two consecutive days. Gp (4) contains experimentally infected broilers treated with neem leaf extract 4% (50 ml/l drinking water) for 5 successive days, and Gp (5) contains experimentally infected broilers treated with toltrazuril (1 ml/l drinking water) and a half dose of neem leaves extract 4% (25 ml/l drinking water) for 5 successive days. For the purpose of estimating body weight growth and feed conversion ratio, each broiler was weighed separately at the start of the trial and again on the 1st and 10th day after treatment. In addition to obtaining intestinal samples for immunohistochemistry, blood samples were also obtained for immunological examination. As compared to the negative control group, the experimentally infested broilers with E. tenella showed significant decreases in serum nitric oxide, lysosome, phagocytic percent, and phagocytic index, along with significant increases in white blood cells (WBCs), lymphocyte, heterophilis, eosinophilis, basophilis, monocyte, serum total protein, γ globulin, fibrinogen, and haptoglobin. When compared to the control positive group, experimentally infested broilers treated with either neem or toltrazuril alone or in combination demonstrated significant increases in serum total protein, nitric oxide, lysozyme, phagocytic percent, and phagocytic index, but significant decreases in WBCs, lymphocytes, heterophile, eosinophile, basophile, and monocyte. The intestinal peroxidase stain of broilers infected with E. tenella exhibited a significant positive expression for CD4, but the infected broilers treated with toltrazuril and half a dosage of neem displayed a negative expression for CD4, identical to the negative control. The broiler chickens infested with E. tenella may have a variety of negative impacts on their immune systems and immunohistopathological findings. Nonetheless, toltrazuril and neem extract, either separately or in combination, function as anticoccidial medications that may enhance the broiler chicks' immune state.

Protective Efficacy Induced by the Common Eimeria Antigen Elongation Factor 2 against Challenge with Three Eimeria Species in Chickens.

Avian coccidiosis arises from co-infection involving multiple Eimeria species, which could give rise to substantial economic losses in the global poultry industry. As a result, multivalent anticoccidial vaccines containing common Eimeria antigens offer considerable promise for controlling co-infection in clinical practice. In our previous study, Elongation factor 2 (EF2) was deemed as an immunogenic common antigen across various Eimeria species. This current investigation aimed to further assess the immunogenicity and protective efficacy of EF2 in recombinant subunit vaccine format against three Eimeria species. The EF2 gene cloned from Eimeria maxima (E. maxima) cDNA was designated as EF2 of E. maxima (EmEF2). The immunogenicity of the recombinant protein EmEF2 (rEmEF2) was assessed through Western blot analysis. The evaluation of the vaccine-induced immune response encompassed the determination of T lymphocyte subset proportions, cytokine mRNA transcription levels, and specific IgY concentrations in rEmEF2-vaccinated chickens using flow cytometry, quantitative real-time PCR (qPCR), and indirect enzyme-linked immunosorbent assay (ELISA). Subsequently, the protective efficacy of rEmEF2 was evaluated through vaccination and challenge experiments. The findings demonstrated that rEmEF2 was effectively recognized by the His-tag monoclonal antibody and E. maxima chicken antiserum. Vaccination with rEmEF2 increased the proportions of CD4+ and CD8+ T lymphocytes, elevated IL-4 and IFN-γ mRNA transcription levels, and enhanced IgY antibody levels compared to the control groups. Moreover, compared to the control groups, vaccination with rEmEF2 led to decreased weight loss, reduced oocyst outputs, and alleviated enteric lesions. Furthermore, in the rEmEF2-immunized groups, challenges with E. maxima and E. acervulina resulted in anticoccidial index (ACI) scores of 166.35 and 185.08, showing moderate-to-excellent protective efficacy. Nevertheless, challenges with E. tenella and mixed Eimeria resulted in ACI scores of 144.01 and 127.94, showing low protective efficacy. In conclusion, EmEF2, a common antigen across Eimeria species, demonstrated the capacity to induce a significant cellular and humoral immune response, as well as partial protection against E. maxima, E. acervulina, and E. tenella. These results highlight EmEF2 as a promising candidate antigen for the development of multivalent vaccines targeting mixed infections by Eimeria species.