Enhanced mucosal immunity against Eimeria acervulina in broilers fed a Lactobacillus-based probiotic

Comparison of the effect of anticoccidial drug, probiotic, synbiotic, phytochemicals and vaccine in prevention and control of coccidiosis in broiler chickens challenged with Eimeria spp

The objective of this study was to investigate the effects of an anti-coccidiosis drug, vaccine, probiotic, symbiotic, and phytochemicals in the prevention and control of coccidia infection in broilers. A total of 525 one-day-old Ross 308 chicks were randomly allocated to 7 experimental diets with 5 replicates of 15 birds each in a completely randomized design. Experimental diets consisted of negative control (NC) without any additives and not challenged. The other 6 groups were challenged with mixed Eimeria and fed the basal diet with no additives (Positive Control, PC) or supplemented with Coxidine 100 (1 g / 1 kg), probiotic, synbiotic, Livacox T vaccine and phytobiotic additives based on the manufacturer's recommended dose. Body weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) were recorded weekly. Oocysts per gram of excreta (OPG) were determined on d 25 to 33 and 42. One bird per cage was euthanized to analyze lesion score and jejunum and ileum inflammatory genes expression. Coccidial challenge reduced WG (P < 0.05) during 15 to 28 d and vaccine treatment was more effective in improving WG and FCR on d 29 to 42 and 1 to 42 (P < 0.05) than other treatments. Birds in the PC group had higher (P < 0.05) OPG than NC group for all days and the vaccine treatment resulted in the lowest rate of OPG compared to other treatments (P < 0.05) at 27, 28, 29, 30, 32, and 33 d of age and overall average. Relative mRNA levels of IFN-γ, IL-1β and IL-10 were significantly upregulated among treatments under coccidiosis challenge in jejunum and ileum except for IL-1β expression in the ileum. In conclusion, based on the results of this study the individual characteristics of feed additives for the prevention of coccidiosis can be different depending on the type and source of feed additives, duration, and amount used, levels of oocyst inoculation and Eimeria types.

Probiotics: an alternative anti-parasite therapy

This paper review about probiotic effects and mechanism of action against the gut and non-gut helminths and protozoan parasites. Gastrointestinal parasitic infections are considered a serious health problem and are widely distributed globally. The disease process which emanates from this parasite infection provides some of the many public and veterinary health problems in the tropical and sub-tropical countries. Prevention and control of the parasite disease is through antihelmintic and anti-protozoan drugs, but, due to the increasing emergence of such drug resistance, eradication of parasite infestation in human and livestock still lingers a challenge, which requires the development of new alternative strategies. The use of beneficial microorganisms i.e. probiotics is becoming interesting due to their prophylactic application against several diseases including parasite infections. Recent studies on the interactions between probiotics, parasites and host immune cells using animal models and in vitro culture systems has increased considerably and draw much attention, yet the mechanisms of actions mediating the positive effects of these beneficial microorganisms on the hosts remain unexplored. Therefore, the aim of the present review is to summarize the latest findings on the probiotic research against the gut and non-gut parasites of significance.

Effect of supplementation with Glycyrrhiza uralensis extract and Lactobacillus acidophilus on growth performance and intestinal health in broiler chickens

Intestinal microbiota community is an important factor affecting the nutritional and health status of poultry, and its balance is crucial for improving the overall health of poultry. The study aimed to investigate the effect of dietary supplementation with Glycyrrhiza uralensis extract (GUE), Lactobacillus acidophilus (Lac) and their combination (GL) on growth performance and intestinal health in broilers in an 84-day feeding experiment. Supplementary 0.1% GUE and 4.5×107 CFU/g Lac significantly increased average daily gain (ADG), and GL (0.1% GUE and 4.5×107 CFU/g Lac) increased ADG and average daily feed intake (ADFI), and decreased feed conversion rate (FCR) in broilers aged 29 to 84 d and 1 to 84 d. Dietary GUE, Lac and GL increased the superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activity and decreased Malondialdehyde (MDA) content in the jejunum mucosa of broilers, and increased secretory IgA (sIgA) content in broilers at 84 d. Moreover, GUE, Lac and GL increased cecal microbial richness and diversity, and modulated microbial community composition. Both GUE and Lac reduced the harmful bacteria Epsilonbacteraeota, Helicobacter, and H. pullorum at 28 d and Proteobacteria, Escherichia, and E. coli at 84 d, while Lac and GL increased beneficial bacteria Lactobacillus and L. gallinarum at 28 d. Compared with individual supplementation, GL markedly increased the SOD activity and the sIgA content, and reduced Helicobacter and Helicobacter pullorum. In conclusion, GUE and Lactobacillus acidophilus as feed additives benefit growth performance and intestinal health, and their combined use shows an even more positive effect in broilers.

Efficacy of liver free and Chitosan against Eimeria tenella in chickens

Eimeria spp. are the pathogen that causes coccidiosis, a significant disease that affects intensively reared livestock, especially poultry. Anticoccidial feed additives, chemicals, and ionophores have routinely been employed to reduce Eimeria infections in broiler production. Therefore, the shift to antibiotic-free and organic farming necessitates novel coccidiosis preventive strategies. The present study evaluated the effects of potential feed additives, liver free and chitosan, against Eimeria tenella infection in White Leghorn broiler female chickens. One hundred sixty-five 1-day-old White Leghorn broiler female chicks were divided into 11 groups (15 female chicks per group), including the positive control group (G1), the negative control group (G2), a chitosan-treated group (G3), a chitosan-treated-infected group (G4), the liver free-treated group (G5), the liver free-treated-infected group (G6), the liver free-and-chitosan-treated group (G7), the liver free-and-chitosan-infected group (G8), the therapeutic liver free-and-chitosan-treated-infected group (G9), the sulfaquinoxaline-treated group (G10), and the sulfaquinoxaline-treated-infected group (G11). Chitosan was fed to the chicks in G3 and G4 as a preventative measure at a dose of 250 mg/kg. The G5 and G6 groups received 1.5 mg/kg of Liverfree. The G7 and G8 groups received chitosan and Liverfree. The G10 and G11 groups were administered 2 g/L of sulfaquinoxaline. From the moment the chicks arrived at Foshan University (one-day-old chicks) until the completion of the experiment, all medications were given to them as a preventative measure. G8 did; however, receive chitosan and liver free as therapeutic supplements at 7 dpi. The current study showed that the combination of liver free and chitosan can achieve better prophylactic and therapeutic effects than either alone. In E. tenella challenged chickens, G8 and G9 chickens showed reduced oocyst shedding and lesion score, improved growth performance (body weight, body weight gain, feed intake, feed conversion ratio, and mortality rate), and cecal histology. The current study demonstrates that combining liver free and chitosan has superior preventive and therapeutic benefits than either alone, and they could also be used as alternative anticoccidial agents.

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

Introduction

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.

Methods

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.

Results

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).

Conclusion

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.

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.

Biophysiology of in ovo administered bioactive substances to improve gastrointestinal tract development, mucosal immunity, and microbiota in broiler chicks

Early embryonic exogenous feeding of bioactive substances is a topic of interest in poultry production, potentially improving gastrointestinal tract (GIT) development, stimulating immunization, and maximizing the protection capability of newly hatched chicks. However, the biophysiological actions and effects of in ovo administered bioactive substances are inconsistent or not fully understood. Thus, this paper summarizes the functional effects of bioactive substances and their interaction merits to augment GIT development, the immune system, and microbial homeostasis in newly hatched chicks. Prebiotics, probiotics, and synbiotics are potential bioactive substances that have been administered in embryonic eggs. Their biological effects are enhanced by a variety of mechanisms, including the production of antimicrobial peptides and antibiotic responses, regulation of T lymphocyte numbers and immune-related genes in either up- or downregulation fashion, and enhancement of macrophage phagocytic capacity. These actions occur directly through the interaction with immune cell receptors, stimulation of endocytosis, and phagocytosis. The underlying mechanisms of bioactive substance activity are multifaceted, enhancing GIT development, and improving both the innate and adaptive immune systems. Thus summarizing these modes of action of prebiotics, probiotics and synbiotics can result in more informed decisions and also provides baseline for further research.

Effect of fenugreek seeds and Bacillus-based direct-fed microbials on the growth performance, blood biochemicals, and intestinal histomorphology of broiler chickens

BACKGROUND

The objective of the present study was to evaluate the potential synergistic impact of the combination of fenugreek seeds (FS) and Bacillus-based direct-fed microbials (DFM) on growth performance, intestinal health, and hematological parameters of broiler chickens.

METHODS

A total of 160 one-day-old (Ross 308) broiler chicks were randomly assigned to a 2 × 2 factorial arrangement, with two levels of FS (0 and 5 g/kg) and two levels of Bacillus-DFM (0 and 0.1 g/kg), with five replicates of 8 birds each.

RESULTS

The result showed that dietary supplementation of FS at 5 g/kg did not improve the growth performance of broilers but impaired the early growth performance by reducing body weight gain and increasing feed conversion ratio, which was recovered during finisher phase. Dietary supplementation of Bacillus-based DFM at 0.1 g/kg did not affect the performance variables but increased the feed conversion ratio. The interaction of fenugreek seeds and Bacillus-based DFM showed synergistic effects on growth performance during the later stages of production. However, antagonistic effects were observed on the blood parameters and the gut morphology.

CONCLUSION

This study demonstrated that FS and DFM had different effects on the broiler health and production depending on the phase of production. The interaction between FS and DFM revealed synergistic effects on growth performance during the finisher phase, but antagonistic effects on blood parameters and gut morphology. Further studies are needed to elucidate the underlying mechanisms and optimize the dosage and combination of FS and DFM for broiler health and production.

Monocyte-Derived Chicken Macrophages Exposed to Eimeria tenella Sporozoites Display Reduced Susceptibility to Invasion by Toxoplasma gondii Tachyzoite

Both Eimeria tenella and Toxoplasma gondii are common apicomplexan parasites in chickens. Host cell invasion by both protozoans includes gliding motility, host cell attachment and active penetration. Chicken macrophages as phagocytic cells participate in the innate host immune response against these two parasites. In this study, primary chicken monocyte-derived macrophages (MM) were infected with both pathogens to investigate mutual and host-parasite interactions. MM cultures were assigned to groups that were infected with E. tenella, T. gondii or both. In co-infected cultures, MM were first exposed to E. tenella sporozoites for 2 h. Afterwards, T. gondii tachyzoite infection was performed. Live-cell imaging was carried out to observe cell invasion and survival of T. gondii by single parasite tracking over a period of 20 h post infection (hpi). Quantitative analysis for parasite replication was performed by real-time quantitative PCR (qPCR) at 2, 6, 12 and 24 hpi. Overall, the ability of T. gondii to penetrate the cell membrane of the potential host cell was reduced, although high motility was displayed. We found that T. gondii tachyzoites adhered for more than 4 h to macrophages during early co-infection. qPCR results confirmed that significantly less T. gondii entered in E. tenella-activated MM at 2 hpi, and a reduced proportion of intracellular T. gondii survived and replicated in these cells at 24 hpi. We conclude that E. tenella modulates host cell responses to another apicomplexan agent, T. gondii, reducing active invasion and multiplication in chicken primary macrophages.

Nutritional supplements for the control of avian coccidiosis

Coccidiosis is acclaimed as the most prevalent enteric parasitic ailment of poultry. It is caused by an apicomplexan protozoon of the genus Eimeria, which resides in chicken intestinal epithelium leading to intestinal damage. As a result, bloody droppings are there, feed efficiency is reduced, the growth rate is impaired, and egg production is temporarily decreased. Treatment and prevention of coccidiosis are primarily accomplished by inoculating live vaccines and administering anticoccidial drugs. Due to anticoccidials’ continuous and excessive use, the mounting issue is drug resistant Eimeria strains. The poultry industry has managed resistance-related issues by suggesting shuttle and rotation schemes. Furthermore, new drugs have also been developed and introduced, but it takes a long time and causes cost inflation in the poultry industry. Moreover, government disallows growth promoters and drugs at sub-therapeutic doses in poultry due to increased concerns about the drug residues in poultry products. These constraints have motivated scientists to work on alternative ways to control coccidiosis effectively, safely, and sustainably. Using nutritional supplements is a novel way to solve the constraints mentioned above. The intriguing aspects of using dietary supplements against coccidiosis are that they reduce the risk of drug-resistant pathogen strains, ensure healthy, nutritious poultry products, have less reliance on synthetic drugs, and are typically considered environmentally safe. Furthermore, they improve productivity, enhance nonspecific immunity, preventing oxidation of fats (acting as antioxidants) and inflammation (acting as an anti-inflammatory). The present manuscript focuses on the efficacy, possible mechanism of action, applications, and different facets of nutrition supplements (such as organic acids, minerals, vitamins, probiotics, essential oils, amino acids, dietary nucleotides, feed enzymes, and yeast derivatives) as feed additive for treating poultry coccidiosis.

Growth performance, nutrient digestibility, antioxidant state, ileal histomorphometry, and cecal ecology of broilers fed on fermented canola meal with and without exogenous enzymes

This study was conducted to evaluate the effects of supplementation of exogenous enzymes in broiler diets that includes fermented canola meal on performance, nutrient digestibility, biochemical indication, antioxidative capacity, digestive enzyme activity, immune responses, and gut health. Five hundred 1-day-old Ross 308 broiler chicks were randomly allocated into five experimental groups (5 replicate/group), the first group: a control (CON) contained a basal diet, and the second to the fifth groups were fed diets as follows: containing 20% canola meal (CM), contains 20% fermented canola meal (FCM), contains 20% canola meal and exogenous enzymes at 0.02%/kg feed (ECM), and contains 20% fermented canola meal and exogenous enzymes at 0.02%/kg feed (EFC), respectively. At the finisher phase, the best body weight gain, feed conversion ratio, and nutrient utilization were associated with chickens fed EFC compared to other groups (P < 0.05). Total protein, albumin, alanine aminotransferase, and superoxide dismutase levels increased (P < 0.05), while cholesterol and malondialdehyde levels decreased in chickens fed on EFC. Likewise, there was a significant increase in the relative weight of the bursa of Fabricius and antibody titer against Newcastle disease, whereas the weight of abdominal fat decreased in the EFC group compared to other groups. Furthermore, there was a significant improvement in the activity of lipase and amylase enzymes (P < 0.05) in the EFC group. Fermented canola meal addition improved gut health (decreased Escherichia coli, increased Lactobacillus, and the highest values of villus height). Overall, these results confirmed that supplementing a fermented canola meal diet with exogenous enzymes improved growth performance through enhancing nutrient digestibility, immunity, antioxidant capacity, and gut health. Thus, adding enzymes to a diet containing fermented canola meal can be recommended as an alternative protein source that could be safely used to replace up to 20% soybean meal in broiler diets.

Effects of a Dietary Multi-Strain Probiotic and Vaccination with a Live Anticoccidial Vaccine on Growth Performance and Haematological, Biochemical and Redox Status Indicators of Broiler Chickens

A total of 256 male Ross 308 chickens were assigned to four treatments in a 2 × 2 factorial design with two levels of the anticoccidial vaccine (ACV) Livacox T (none or 1 × dose) with or without dietary supplementation with the probiotic Protexin^® (P). The growth performance parameters for the test periods (1-21, 22-42, and 1-42 d) and oocyst per gram (OPG) at weekly intervals were analysed. Blood samples were collected at 16 post-vaccination (pv) days to measure selected haematological, biochemical, redox, and immunological parameters. ACV administration worsened the performance parameters of the chickens for 1-21 d pv, while supplementation with P reduced this negative effect with a significant improvement in 1-21 d body weight gain and feed conversion ratio. ACV administration increased % phagocytic cells (%PC), phagocytic index (PI), respiratory burst activity, proportion of monocytes, and activities of aspartate aminotransferase (AST) and lactate dehydrogenase, while it decreased the catalase activity and concentration of malondialdehyde and peroxides. The dietary administration of P significantly increased counts of red blood cells and white blood cells and increased %PC and PI, while it decreased the heterophil proportion, heterophil/lymphocyte ratio (p = 0.059), and alanine aminotransferase and AST activities. The oocyst counts were comparable in all sampling periods, except on 14 d pv, as supplementation with P significantly decreased 14 d OPG, thus indicating a positive influence of P on immunity development. In conclusion, dietary supplementation with P led to improved performance, better immunity, and benefits in health status in broilers vaccinated with the ACV, without interfering with the circulating vaccine strains.

An updated review on probiotics as an alternative of antibiotics in poultry - A review

Antibiotics used to be supplemented to animal feeds as growth promoter and as an effective strategy to reduce the burden of pathogenic bacteria present in the gastro-intestinal tract. However, in-feed antibiotics also kill bacteria that may be beneficial to the animal. Secondly, unrestricted use of antibiotics enhanced the antibiotic resistance in pathogenic bacteria. To overcome above problems, scientists are taking a great deal of measures to develop alternatives of antibiotics. There is convincing evidence that probiotics could replace in-feed antibiotics in poultry production. Because they have beneficial effects on growth performance, meat quality, bone health and eggshell quality in poultry. Better immune responses, healthier intestinal microflora and morphology which help the birds to resist against disease attack were also identified with the supplementation of probiotics. Probiotics establish cross-feeding between different bacterial strains of gut ecosystem and reduce the blood cholesterol level via bile salt hydrolase activity. The action mode of probiotics was also updated according to recently published literatures, i.e antimicrobial substances generation or toxin reduction. This comprehensive review of probiotics is aimed to highlight the beneficial effects of probiotics as a potential alternative strategy to replace the antibiotics in poultry.

The influence of nutrition on intestinal disease with emphasis on coccidiosis

Ever since the poultry industry began to intensify early last century, coccidiosis has been a significant problem with which it has had to contend. Losses due to mortality and morbidity can be significant and before the advent of control agents there were several practices, some of which were nutritional, which were implemented to limit these losses. The development of coccidiostats reduced these problems considerably and as a result some of the more extreme intervention measures were no longer necessary. Modern day interpretation of what may have been happening with some of these early interventions provide interesting insights into what may be possible today should cocciodiostats be removed. More recent research has also indicated that the diet has a significant influence on the ability of poultry to resist and resolve an infection through direct and indirect effects on the pathogen, the immune system and on the litter. This paper reviews the role of dietary ingredients and nutrients on the pathogen to establish and the host to resist such an infection. There is clearly no panacea, but the combination of a few practices may reduce the overall challenge experienced by the poultry producer.

Comparison of Therapeutic Antibiotics, Probiotics, and Synthetic CpG-ODNs for Protective Efficacy Against Escherichia coli Lethal Infection and Impact on the Immune System in Neonatal Broiler Chickens

The poultry industry needs alternatives to antibiotics, as there are growing public concerns about the emergence of antimicrobial resistance owing to antimicrobial use in animal production. We have reported that the administration of neonatal chicks with synthetic DNA oligodeoxynucleotides containing unmethylated cytosine guanine dinucleotide (CpG) motifs (CpG-ODN) can protect against bacterial pathogens in chickens. The objective of this study was to compare the immunoprotective effects of CpG-ODN and probiotics against Escherichia coli infection vs. commonly used therapeutic antibiotics. Day-old broiler chicks were divided into five groups (n = 35/group; 30 for the challenge experiment and 5 for the flow cytometry analysis). The chicks in Group 1 received a single dose of CpG-ODN by the intramuscular route on day 4 (D4) posthatch (PH), and Group 2 received drinking water (DW) with a probiotic product (D1-D15 PH, DW). The Group 3 chicks received tetracycline antibiotics during D9-D13 in DW; the Group 4 chicks got sodium sulfamethazine on D9, D10, and D15 PH in DW; and the Group 5 chicks were administered intramuscular (IM) saline D4 PH, DW. We challenged all the groups (n = 30/group) with E. coli (1 × 10⁵ or 1 × 10⁶ colony-forming units/bird) on D8 PH through the subcutaneous route. Our data demonstrated that the CpG-ODNs, but not the probiotics, could protect neonatal broiler chickens against lethal E. coli septicemia, as would the tetracycline or sodium sulfamethazine. The flow cytometry analysis (n = 5/group) revealed enrichment of immune cells in the CpG-ODN group and a marked decrease in macrophages and T-cell numbers in antibiotics-treated groups, indicating immunosuppressive effects. Our data showed that, like therapeutic antibiotics, CpG-ODNs reduced clinical signs, decreased bacterial loads, and induced protection in chicks against E. coli septicemia. Unlike therapeutic antibiotics-induced immunosuppressive effects, CpG-ODN caused immune enrichment by increasing chicken immune cells recruitment. Furthermore, this study highlights that, although therapeutic antibiotics can treat bacterial infections, the ensuing immunosuppressive effects may negatively impact the overall chicken health.

Eimeria infections in domestic and wild ruminants with reference to control options in domestic ruminants

Eimeria infections are commonly seen in a variety of mammalian hosts. This genus of unicellular sporozoan parasites causes significant disease (coccidiosis) in different livestock species leading to economic losses for agricultural producers. Especially the production of cattle, sheep, and goat is strongly dependent on efficient coccidiosis control. However, many other livestock hosts like, e.g., camelids, bison, rabbits, and guinea pigs may benefit from reduced parasite transmission and targeted control measures as well. Besides livestock, also wildlife and pet animals may be affected by Eimeria infections resulting in clinical or subclinical coccidiosis. Wildlife herd health is crucial to conservation efforts, and Eimeria species are a prevalent pathogen in multiple mammalian wildlife species. This review aims to highlight the epidemiology of mammalian Eimeria infections in both wild and domestic ruminants, including host specificity, transmission, survival of environmental oocysts, occurrence, and risk factors for infection. Understanding general drivers of Eimeria infection may support adequate livestock and wildlife management. Furthermore, control options for livestock with reference to management factors, drug application, and alternative approaches are discussed. The goal of Eimeria control should be to reduce pathogen transmission in different host species and to improve sustainable livestock production. Controlling Eimeria infections in livestock is important considering both their animal welfare impact and their high economic relevance.

Impact of Probiotics on Dairy Production Efficiency

There has been growing interest on probiotics to enhance weight gain and disease resistance in young calves and to improve the milk yield in lactating animals by reducing the negative energy balance during the peak lactation period. While it has been well established that probiotics modulate the microbial community composition in the gastrointestinal tract, and a probiotic-mediated homeostasis in the rumen could improve feed conversation competence, volatile fatty acid production and nitrogen flow that enhances the milk composition as well as milk production, detailed changes on the molecular and metabolic level prompted by probiotic feed additives are still not understood. Moreover, as living biotherapeutic agents, probiotics have the potential to directly change the gene expression profile of animals by activating the signalling cascade in the host cells. Various direct and indirect components of probiotic approaches to improve the productivity of dairy animals are discussed in this review.

Comparative effect of dietary supplements on the performance and severity of experimental Eimeria tenella infection in broiler chickens

The effect of the dietary supplements, sugarcane molasses (prebiotic), Antox® (probiotic) and Enflorax® (synbiotic), on gut health, performance and severity of infection with Eimeria tenella in broiler chickens was evaluated in this study. Ninety-day-old broiler chicks were divided into six groups (A, B, C, D, E and F). Groups B to F were challenged with Eimeria tenella (2.0 × 10⁴ oocysts/chick). Groups C, D and E were supplemented from day old with prebiotic, probiotic and synbiotic, respectively, while F was administered amprolium. Groups A and B served as negative and positive controls, respectively. Feed intake and performance parameters were assessed weekly for each group. After infection clinical signs, morbidity and mortality rates were monitored alongside oocyst output, gross and microscopic caecal lesions. Infected chickens exhibited clinical signs 4 days post infection (dpi) with 100% morbidity in all infected groups. Infected groups showed significant (P < 0.05) drop in feed intake and weight gain from 3 to 5 weeks of age. Feed conversion ratio was highest in B but lower in the supplemented groups. Oocyst output in faeces were significantly lower (P < 0.05) in the supplemented groups compared with B. Macroscopic lesion scores 7 dpi were significantly lower in the supplemented groups compared with B, though group F had the lowest mean score. Histopathological examination of caeca tissues showed milder lesions in the supplemented groups. In conclusion, the supplements prebiotic, probiotic and synbiotic ameliorated the consequences of caecal coccidiosis in broiler chickens and therefore recommended for use in broiler production.

Current trends in the development of soy-based foods containing probiotics and paving the path for soy-synbiotics

In the world of highly processed foods, special attention is drawn to the nutrient composition and safety of consumed food products. Foods fortified with probiotic bacteria confer beneficial effects on human health and are categorized as functional foods. The salubrious activities of probiotics include the synthesis of vital bioactives, prevention of inflammatory diseases, anticancerous, hypocholesterolemic, and antidiarrheal effects. Soy foods are exemplary delivery vehicles for probiotics and prebiotics and there are diverse strategies to enhance their functionality like employing mixed culture fermentation, engineering probiotics, and incorporating prebiotics in fermented soy foods. High potential is ascribed to the concurrent use of probiotics and prebiotics in one product, termed as "synbiotics," which implicates synergy, in which a prebiotic ingredient particularly favors the growth and activity of a probiotic micro-organism. The insights on emended bioactive profile, metabolic role, and potential health benefits of advanced soy-based probiotic and synbiotic hold a promise which can be profitably implemented to meet consumer needs. This article reviews the available knowledge about strategies to enhance the nutraceutical potential, mechanisms, and health-promoting effects of advanced soy-based probiotics. Traditional fermentation merged with diverse strategies to improve the efficiency and health benefits of probiotics considered vital, are also discussed.

Alternatives to antibiotics for organic poultry production: types, modes of action and impacts on bird's health and production

The poultry industry contributes significantly to bridging the nutritional gap in many countries because of its meat and eggs products rich in protein and valuable nutrients at a cost less than other animal meat sources. The natural antibiotics alternatives including probiotics, prebiotics, symbiotics, organic acids, essential oils, enzymes, immunostimulants, and phytogenic (phytobiotic) including herbs, botanicals, essential oils, and oleoresins are the most common feed additives that acquire popularity in poultry industry following the ban of antibiotic growth promoters (AGPs). They are commonly used worldwide because of their unique properties and positive impact on poultry production. They can be easily mixed with other feed ingredients, have no tissue residues, improve feed intake, feed gain, feed conversion rate, improve bird immunity, improve digestion, increase nutrients availability as well as absorbability, have antimicrobial effects, do not affect carcass characters, decrease the usage of antibiotics, acts as antioxidants, anti-inflammatory, compete for stress factors and provide healthy organic products for human consumption. Therefore, the current review focuses on a comprehensive description of different natural antibiotic growth promoters' alternatives, the mode of their action, and their impacts on poultry production.

Avian Cell Culture Models to Study Immunomodulatory Properties of Bioactive Products

Antimicrobial resistance is becoming a greater danger to both human and animal health, reducing the capacity to treat bacterial infections and increasing the risk of morbidity and mortality from resistant bacteria. Antimicrobial efficacy in the treatment of bacterial infections is still a major concern in both veterinary and human medicine. Antimicrobials can be replaced with bioactive products. Only a small number of plant species have been studied in respect to their bioactive compounds. More research is needed to characterize and evaluate the therapeutic properties of the plant extracts. Due to the more and more common phenomenon of antimicrobial resistance, poultry farming requires the use of natural alternatives to veterinary antibiotics that have an immunomodulatory effect. These include a variety of bioactive products, such as plant extracts, essential oils, probiotics, prebiotics, and synbiotics. This article presents several studies on bioactive products and their immunomodulatory effects tested in vitro and ex vivo using various avian cell culture models. Primary cell cultures that have been established to study the immune response in chickens include peripheral blood mononuclear cells (PBMCs), intestinal epithelial cells (IEC), and bone marrow-derived dendritic cells (BMDCs). Chicken lymphatic lines that can be used to study immune responses are mainly: chicken B cells infected with avian leukemia RAV-1 virus (DT40), macrophage-like cell line (HD11), and a spleen-derived macrophage cell line (MQ-NCSU). Ex vivo organ cultures combine in vitro and in vivo studies, as this model is based on fragments of organs or tissues grown in vitro. As such, it mimics the natural reactions of organisms, but under controlled conditions. Most ex vivo organ cultures of chickens are derived from the ileum and are used to model the interaction between the gastrointestinal tract and the microbiota. In conclusion, the use of in vitro and ex vivo models allows for numerous experimental replications in a short period, with little or no ethical constraints and limited confounding factors.

Coccidiosis: Recent Progress in Host Immunity and Alternatives to Antibiotic Strategies

Coccidiosis is an avian intestinal disease caused by several distinct species of Eimeria parasites that damage the host’s intestinal system, resulting in poor nutrition absorption, reduced growth, and often death. Increasing evidence from recent studies indicates that immune-based strategies such as the use of recombinant vaccines and various dietary immunomodulating feed additives can improve host defense against intracellular parasitism and reduce intestinal damage due to inflammatory responses induced by parasites. Therefore, a comprehensive understanding of the complex interactions between the host immune system, gut microbiota, enteroendocrine system, and parasites that contribute to the outcome of coccidiosis is necessary to develop logical strategies to control coccidiosis in the post-antibiotic era. Most important for vaccine development is the need to understand the protective role of the local intestinal immune response and the identification of various effector molecules which mediate anti-coccidial activity against intracellular parasites. This review summarizes the current understanding of the host immune response to coccidiosis in poultry and discusses various non-antibiotic strategies which are being developed for coccidiosis control. A better understanding of the basic immunobiology of pertinent host–parasite interactions in avian coccidiosis will facilitate the development of effective anti-Eimeria strategies to mitigate the negative effects of coccidiosis.

Immunomodulatory and ameliorative effects of probiotic in combination with diclazuril on broilers under coccidia infection

AIM

This study aimed to determine the potential prophylactic efficacy of probiotic individually and/or in combination with anti-coccidial drug on the performance and immunity of broilers under an induced coccidial infection over a 28-day of experimental trial.

METHODS

One hundred and eighty 1-day-old Cobb broiler chicks were randomly divided into five groups, included control group (CG), control positive group (CPG), probiotic-treated group (Prob), diclazuril-treated group (Dic), and probiotic + diclazuril-treated group (Prob + Dic). On day 21 of age, all birds, except group CG, were orally inoculated with 1 ml of tap water containing 25,000 Eimeria tenella sporulated oocysts.

RESULTS

Our results showed that the probiotic treatment did not influence pre-challenge body weight, feed intake and feed conversion ratio (FCR). During the post-challenge period, chickens in groups probiotic and diclazuril individually and in combination exhibited higher body weight and lower (better) FCR, reduced oocyst shedding (throughout the day four, five, six and seven post-infection), cecal lesions and mortality compared with control positive chickens. Moreover, Compared to CPG group, Prob + Dic group showed increased (p < 0.05) serum levels of interleukin-10 (IL-10) and immunoglobulin M (IgM) and decreased the concentrations of interferon gamma (IFN-γ). On the other hand, individual treatment with probiotic exhibited highest serum levels of IL-10 and IgM, while diclazuril alone increased the blood concentrations of IL-10 and decreased the levels of IFN-γ compared to control positive group; however, there was no significant effect of Prob on IFN-γ, Dic on IgM and all groups on interleukin-17.

CONCLUSION

In conclusion, supplementation of probiotic, with and/or without anti-coccidial drug, enhances immunity and inhibits the negative effects of Eimeria infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study reveals the anti-coccidial mechanisms of probiotic in the presence and absence of anti-coccidial drug in preventing the coccidia infection.

Bacitracin, Bacillus subtilis, and Eimeria spp. challenge exacerbates woody breast incidence and severity in broilers

Woody breast (WB) is a myopathy that is related to the increasing growth rate. Understanding the influence of management factors on WB formation and development is important to minimize WB. This study was conducted to define how management factors affect broiler growth performance, processing yield, and WB incidence. Ross × Ross 708 chicks were randomly assigned to a 3 (diet) × 2 (cocci challenge) × 2 (sex) factorial arrangement of treatments. The 3 dietary treatments were: control diet (corn-soybean meal basal diet), antibiotic diet (basal diet + 6.075 mg bacitracin /kg feed), and probiotic diet (basal diet + 2.2 × 10⁸ CFU Bacillus subtilis PB6/kg feed). Birds in cocci challenge treatments received 20 × live cocci vaccine on d 14. The hardness of breast muscle in live birds was determined by palpation and grouped into Normal, Slight, Moderate, and Severe categories. Across diet and sex treatments, the cocci challenge resulted in decreases in body weight (BW) on d 29 and 35 (P < 0.0001 and = 0.032) in body weight gain (BWG) from d 14 to 29 (P < 0.0001). However, an increase of BW occurred on d 35 (P = 0.032) and an increase of BWG occurred from d 29 to 35 and d 35 to 43 (P = 0.0001 and 0.002), and the cocci challenge increased WB incidence on d 29 (P = 0.043) and d 43 (P = 0.013). Across challenge and sex treatments, birds fed the antibiotic diet exhibited a higher growth rate (GR) than those fed the control or probiotic diet from d 0 to 14 (P = 0.016), but not after d 14 (P > 0.05). Across sex, the antibiotic and probiotic diets increased WB incidence for those birds that did not receive a cocci challenge on d 43 (P = 0.040). Across challenge and diet treatments, males exhibited a higher BW, BWG, and GR throughout all growth phases, and males showed a higher WB incidence on d 29, 35, and 43 (P = 0.002, P < 0.0001, and P = 0.0002, respectively). In conclusion, bacitracin and Eimeria spp. increased WB incidence, BW, and GR. However, Bacillus subtilis increased WB incidence in male broilers without affecting BW and GR.

Controlling the causative agents of coccidiosis in domestic chickens; an eye on the past and considerations for the future

Coccidiosis is a potentially severe enteritis caused by species of obligate intracellular parasites of the genus Eimeria. These parasites cause significant economic losses to the poultry industry, predominantly due to compromised efficiency of production as well as the cost of control. These losses were recently estimated to cost chicken producers approximately £10.4 billion worldwide annually. High levels of Eimeria infection cause clinical coccidiosis which is a significant threat to poultry welfare, and a pre-disposing contributory factor for necrotic enteritis. Control of Eimeria parasites and coccidiosis is therefore an important endeavour; multiple approaches have been developed and these are often deployed together. This review summarises current trends in strategies for control of Eimeria, focusing on three main areas: good husbandry, chemoprophylaxis and vaccination. There is currently no "perfect solution" and there are advantages and limitations to all existing methods. Therefore, the aim of this review is to present current control strategies and suggest how these may develop in the future.

Exogenous Enzymes Influenced Eimeria-Induced Changes in Cecal Fermentation Profile and Gene Expression of Nutrient Transporters in Broiler Chickens

Two 21-day experiments were conducted to investigate the effects of exogenous enzymes on growth performance, tight junctions, and nutrient transporters, jejunal oligosaccharides and cecal short-chain fatty acids (SCFA) of broiler chickens challenged with mixed Eimeria. Two different basal diets: high fiber-adequate protein (HFAP; Expt. 1) or low fiber-low protein (LFLP; Expt. 2) were used in the two experiments. In each experiment, birds were allocated to four treatments in a 2 × 2 factorial arrangement (with or without protease and xylanase combination; with or without Eimeria challenge). In Expt. 1, with HFAP diets, Eimeria upregulated (p < 0.05) the expression of claudin-1, but downregulated (p < 0.05) glucose transporters GLUT2/GLUT5. On the contrary, enzymes downregulated (p < 0.05) claudin-1 and alleviated the Eimeria-depressed GLUT2/GLUT5 expression. In both experiments, Eimeria decreased (p < 0.05) cecal saccharolytic SCFA and increased (p < 0.05) cecal branched-chain fatty acids. The challenge × enzyme interaction (p < 0.05) showed that enzymes reversed the Eimeria effects on fermentation pattern shift. In conclusion, Eimeria altered tight junctions and nutrient transporters expression promoted cecal proteolytic fermentation and inhibited saccharolytic fermentation. Exogenous enzymes showed the potential of alleviating the Eimeria-induced intestinal gene expression changes and reversing the unfavorable cecal fermentation pattern.

Protective Effect of Lactobacillus plantarum P8 on Growth Performance, Intestinal Health, and Microbiota in Eimeria-Infected Broilers

Coccidiosis is one of the major parasitic diseases in the commercial broiler industry. Probiotics can protect poultry against Eimeria infection. However, the mechanisms are not fully known. Therefore, Lactobacillus plantarum P8 (P8) was used to investigate its anti-coccidial property and mechanism. Five hundred broilers were allocated to five treatments: control diet (NC), control diet + Eimeria infection (IC), control diet containing 1 × 10⁷ cfu/g P8 + Eimeria infection (P8L), control diet containing 1 × 10⁸ cfu/g P8 + Eimeria infection (P8H), and control diet + Eimeria infection + Diclazuril (DIC). At day 14, all treatments except NC were inoculated with sporulated oocysts. Results indicated that Eimeria infection increased the mortality and oocysts shedding, and declined the growth performance as well as the intestinal barrier in Eimeria-treated broilers. On the contrary, dietary supplementation of low level P8, high level P8 and DIC decreased the mortality and oocysts shedding, but improved the growth performance and intestinal barrier. The impaired intestinal morphology in the IC group was also improved by P8H and DIC treatments. Besides, the elevated oxidative stress and pro-inflammation in Eimeria-infected broilers were reduced by P8L, P8H, and DIC treatments. Metagenomic analysis indicated P8 altered the structure of the gut microbiota, and the alteration was more obvious at day 21 than day 42. Notably, IC also increased the abundances of Eimeriidae, Eimeria and Eimeria tenella at day 21, while P8L and DIC decreased the abundances. Correlation analysis revealed that bacteria in Eimeria-treated broilers positively correlated with the intestinal permeability, oxidative stress and inflammation, while bacteria in broilers receiving P8L and DIC negatively correlated with the aforementioned pathological indices. Functional prediction demonstrated that the metagenomes of Eimeria-infected broilers were involved in several diseases. But the metagenomes of P8L-treated broilers were involved in energy metabolism and replication repair. In conclusion, dietary P8 supplementation inhibited oocyst shedding and improved the growth performance as well as the intestinal health of broilers infected with Eimeria, which was closely related to the regulation of gut microbiota. Moreover, the effects of P8 may be more effective in the early infection of coccidia.

Probiotics-Live Biotherapeutics: a Story of Success, Limitations, and Future Prospects-Not Only for Humans

In livestock production, lactic acid bacteria (LAB) represent the most widespread microorganisms used as probiotics. For such critical use, these bacteria must be correctly identified and characterized to ensure their safety and efficiency. Recently, probiotics have become highly recognized as supplements for humans and in particular for animals because of their beneficial outcome on health improvement and well-being maintenance. Various factors, encompassing dietary and management constraints, have been demonstrated to tremendously influence the structure, composition, and activities of gut microbial communities in farm animals. Previous investigations reported the potential of probiotics in animal diets and nutrition. But a high rate of inconsistency in the efficiency of probiotics has been reported. This may be due, in a major part, to the dynamics of the gastrointestinal microbial communities. Under stressing surroundings, the direct-fed microbials may play a key role as the salient limiting factor of the severity of the dysbiosis caused by disruption of the normal intestinal balance. Probiotics are live microorganisms, which confer health benefits on the host by positively modifying the intestinal microflora. Thus, the aim of this review is to summarize and to highlight the positive influence of probiotics and potential probiotic microbe supplementation in animal feed with mention of several limitations.

Single or Combined Applications of Zinc and Multi-strain Probiotic on Intestinal Histomorphology of Broilers Under Cyclic Heat Stress

Two-hundred-eighty-day-old broiler chicks were divided into seven groups. The groups were designated as T1, thermoneutral zone; T2, heat stressed (HS); T3, HS + zinc (Zn) supplementation (30 mg/kg); T4, HS + Zn (60 mg/kg); T5, HS + probiotic (0.1 g/kg); T6, HS + probiotic (0.1 g/kg) + Zn (30 mg/kg); and T7, HS + Zn (60 mg/kg) + probiotic (0.1 g/kg). Significant decrease (p < 0.05) was observed in villus height (VH), VH to crypt depth ratio, and villus surface area of all intestinal segments in the T2 group when compared with the T1 group. The same parameters had significantly higher (p < 0.05) values in the jejunum and ileum of the Zn- and probiotic-supplemented groups (alone + combination) when compared with the T2 group. The birds exposed to HS showed fewer (p < 0.05) intraepithelial lymphocytes (IELs) in the jejunum and ileum than the T1 group, while their count increased in the jejunum and ileum with dietary treatments. In conclusion, Zn and probiotic positively modulated the intestinal microstructures of broilers kept under high environmental temperature.

Effects of Gasterophilus pecorum infestation on the intestinal microbiota of the rewilded Przewalski's horses in China

Horse botflies have been a threat to the Przewalski’s horses in the Kalamaili Nature Reserve in Xinjiang of China since their reintroduction to the original range. As larvae of these parasites could infest the intestine of a horse for months, they could interact with and alter the structure and composition of its intestinal microbiota, affecting adversely its health. Nonetheless, there are no such studies on the rewilded Przewalski’s horses yet. For the first time, this study characterizes the composition of the intestinal microbiota of 7 rewilded Przewalski’s horses infected severely by Gasterophilus pecorum following and prior to their anthelmintic treatment. Bioinformatics analyses of the sequence data obtained by amplicon high throughput sequencing of bacterial 16S rRNA genes showed that G. pecorum infestation significantly increased the richness of the intestinal microbial community but not its diversity. Firmicutes and Bacteroidetes were found the dominant phyla as in other animals, and the parasitic infestation decreased the F/B ratio largely by over 50%. Large reduction in relative abundances of the two genera Streptococcus and Lactobacillus observed with G. pecorum infestation suggested possible changes in colic and digestion related conditions of the infected horses. Variations on the relative abundance of the genus groups known to be pathogenic or symbiotic showed that adverse impact of the G. pecorum infestation could be associated with reduction of the symbiotic genera Lactobacillus and Bifidobacterium that are probiotics and able to promote immunity against parasitic infection.

Effect of Fermented Products Produced by Bacillus licheniformis on the Growth Performance and Cecal Microbial Community of Broilers under Coccidial Challenge

This study investigated the effects of fermented products produced by Bacillus licheniformis (fermented products) on the growth performance and cecal microbial community in broilers exposed to coccidial challenge. A total of 108 one-day-old male broiler chicks (Ross 308) were randomly allotted to one of three treatments. Each treatment was distributed into six replicate cages with six birds each. The treatments consisted of a basal diet without treatment (NC), basal diet plus coccidial challenge (PC), and basal diet plus the coccidial challenge and 1 g/kg of fermented products (FP). The results indicated that FP increased the average daily gain of broilers at 21 to 35 days of age compared with the PC group (p < 0.05). The anti-coccidia index in the FP group was elevated compared with the PC group (p < 0.05). Principal coordinate analysis showed significant segregation in bacterial community composition in the cecal digesta among the groups. The genus Lactobacillus was more abundant in the cecal digesta of the FP group compared with the PC group (p < 0.05). There was a positive correlation between the abundance of the genus Lactobacillus in the cecal digesta and growth performance (body weight, average daily gain, and average feed intake). Furthermore, the abundance of the genus Lactobacillus in the cecal digesta was positively associated with the cecal short-chain fatty acid levels (formic acid, acetic acid, propionic acid, butyric acid, and isobutyric acid). These findings suggest that fermented products produced by B. licheniformis can ameliorate the average daily gain of broilers exposed to coccidial challenge. B. licheniformis-fermented product supplementation increases anti-coccidial activity and modulates gut microbiota composition by increasing beneficial microbes and decreasing harmful microbes in broilers under coccidial challenge.

Ways to minimize bacterial infections, with special reference to Escherichia coli, to cope with the first-week mortality in chicks: an updated overview

On the commercial level, the poultry industry strives to find new techniques to combat bird's infection. During the first week, mortality rate increases in birds because of several bacterial infections of about ten bacterial species, especially colisepticemia. This affects the flock production, uniformity, and suitability for slaughter because of chronic infections. Escherichia coli (E. coli) causes various disease syndromes in poultry, including yolk sac infection (omphalitis), respiratory tract infection, and septicemia. The E. coli infections in the neonatal poultry are being characterized by septicemia. The acute septicemia may cause death, while the subacute form could be characterized through pericarditis, airsacculitis, and perihepatitis. Many E. coli isolates are commonly isolated from commercial broiler chickens as serogroups O₁, O₂, and O₇₈. Although prophylactic antibiotics were used to control mortality associated with bacterial infections of neonatal poultry in the past, the commercial poultry industry is searching for alternatives. This is because of the consumer's demand for reduced antibiotic-resistant bacteria. Despite the vast and rapid development in vaccine technologies against common chicken infectious diseases, no antibiotic alternatives are commercially available to prevent bacterial infections of neonatal chicks. Recent research confirmed the utility of probiotics to improve the health of neonatal poultry. However, probiotics were not efficacious to minimize death and clinical signs associated with neonatal chicks' bacterial infections. This review focuses on the causes of the increased mortality in broiler chicks during the first week of age and the methods used to minimize death.

Anticoccidial effect of Fructus Meliae toosendan extract against Eimeria tenella

CONTEXT

Fructus Meliae toosendan extracts (FMTE) have a good therapeutic effect on coccidiosis, but there is no relevant research on its prophylactic effect on coccidiosis.

OBJECTIVE

This study comprehensively evaluates the anticoccidial effect of FMTE.

MATERIALS AND METHODS

In vitro, the unsporulated oocysts were treated with serial dilutions of FMTE and incubated for 7 d, and the sporulated oocysts were counted for calculating the median lethal concentration (LC₅₀) of FMTE. In vivo, 180 10-day-old broiler chickens free of coccidiosis were weighted and randomly distributed into six groups: normal group, untreated group, 4 protective groups (positive group and three FMTE groups). From day 10 to day 21, chickens in the three FMTE groups were pre-treated with FMTE at the dosage of 2.5, 5 and 10 g/kg/d, respectively, and chickens in the positive group were pre-treated with qiuliling (10 g/kg/d). On day 14, chickens in all groups except the normal group were orally infected with 1.5 × 10⁴ sporulated oocysts. The clinical symptoms were observed from day 10 to day 21, the anticoccidial index (ACI), tissue lesions, and intestinal microflora were determined on day 21.

RESULTS

FMTE showed anti-sporulation effect against E. tenella and the LC₅₀ value was 245.83 µg/mL in vitro. In vivo, FMTE at the dosage of 10 g/kg/d was effective against E. tenella infection, and its ACI value was 162.56, which was higher than the value of positive drug qiuliling (128.81). Discussion and conclusions: FMTE have potent anticoccidial effects, and it presents an alternative anticoccidial agent for avian coccidiosis control.

Adaptive response to a future life challenge: consequences of early-life environmental complexity in dual-purpose chicks

Conditions in early life play profound and long-lasting effects on the welfare and adaptability to stress of chickens. This study aimed to explore the hypothesis that the provision of environmental complexity in early life improves birds' adaptive plasticity and ability to cope with a challenge later in life. It also tried to investigate the effect of the gut-brain axis by measuring behavior, stress hormone, gene expression, and gut microbiota. One-day-old chicks were split into 3 groups: (1) a barren environment (without enrichment items) group (BG, n = 40), (2) a litter materials group (LG, n = 40), and (3) a perches with litter materials group (PLG, n = 40). Then, enrichment items were removed and simulated as an environmental challenge at 31 to 53 d of age. Birds were subjected to a predator test at 42 d of age. In the environmental challenge, when compared with LG, PLG birds were characterized by decreased fearfulness, lower plasma corticosterone, improved gut microbial functions, lower relative mRNA expression of GR, and elevated mRNA expressions of stress-related genes CRH, BDNF, and NR2A in the hypothalamus (all P < 0.05). Unexpectedly, the opposite was true for the LG birds when compared with the BG (P < 0.05). Decreased plasma corticosterone and fearfulness were accompanied by altered hypothalamic gene mRNA expressions of BDNF, NR2A, GR, and CRH through the HPA axis in response to altered gut microbial compositions and functions. The findings suggest that gut microbiota may integrate fearfulness, plasma corticosterone, and gene expression in the hypothalamus to provide an insight into the gut-brain axis in chicks. In conclusion, having access to both perches and litter materials in early life allowed birds to cope better with a future challenge. Birds in perches and litter materials environment may have optimal development and adaptive plasticity through the gut-brain axis.

Probiotics in poultry feed: A comprehensive review

The use of antibiotics to maintain animal well-being, promote growth and improve efficiency has been practised for more than 50 years. However, as early as the 1950s, researchers identified concern on the development of resistant bacteria for the antibiotics streptomycin and tetracycline used in turkeys and broilers respectively. These findings laid the groundwork for agricultural officials to impose stricter regulatory parameters on the use of antibiotics in poultry feeds. Probiotics are live micro-organisms included in the diet of animals as feed additives or supplements. Commonly known as a direct-fed microbial, probiotics provide beneficial properties to the host, primarily through action in the gastrointestinal tract (GIT) of the animal. Supplementation of probiotics in the diet can improve animal health and performance, through contributions to gut health and nutrient use. For instance, supplementation of probiotics has been demonstrated to benefit farm animals in immune modulation, structural modulation and increased cytokine production, which positively affect the intestinal mucosal lining against pathogens. Bacillus subtilis has been a popular bacterium used within the industry and was shown to improve intestinal villus height. Increasing the villus height and structure of the crypts in the GIT allows for the improvement of nutrient digestion and absorption. Tight junctions maintain important defences against pathogenic bacteria and cellular homeostasis. Heat stress can be a major environmental challenge in the poultry industry. Heat stress causes the bird to fluctuate its internal core temperature beyond their comfort zone. To overcome such challenges, poultry will attempt to balance its heat production and dissipation through behavioural and physiological adaptation mechanisms.

Modulation of the intestinal microbiota of broilers supplemented with monensin or functional oils in response to challenge by Eimeria spp

The objective of this study was to evaluate the effect of supplementation with 100ppm sodium monensin or 0.15% of a blend of functional oils (cashew nut oil + castor oil) on the intestinal microbiota of broilers challenged with three different Eimeria spp. The challenge was accomplished by inoculating broiler chicks with sporulated oocysts of Eimeria tenella, Eimeria acervulina, and Eimeria maxima via oral gavage. A total of 864, day-old male broiler chicks (Cobb) were randomly assigned to six treatments (eight pens/treatment; 18 broilers/pen) in a 3 × 2 factorial arrangement, composed of three additives (control, monensin or blend), with or without Eimeria challenge. Intestinal contents was collected at 28 days of age for microbiota analysis by sequencing 16s rRNA in V3 and V4 regions using the Illumina MiSeq platform. Taxonomy was assigned through the SILVA database version 132, using the QIIME 2 software version 2019.1. No treatment effects (p > 0.05) were observed in the microbial richness at the family level estimated by Chao1 and the biodiversity assessed by Simpson’s index, except for Shannon's index (p < 0.05). The intestinal microbiota was dominated by members of the order Clostridiales and Lactobacillales, followed by the families Ruminococcaceae, Bacteroidaceae, and Lactobacillaceae, regardless of treatment. When the controls were compared, in the challenged control group there was an increase in Erysipelotrichaceae, Lactobacillaceae, Bacteroidaceae, Streptococcaceae, and Peptostreptococcaceae, and a decrease in Ruminococcaceae. Similar results were found for a challenged group that received monensin, while the blend partially mitigated this variation. Therefore, the blend alleviated the impact of coccidiosis challenge on the microbiome of broilers compared to monensin.

Effects of in ovo Inoculation of Multi-Strain Lactobacilli on Cytokine Gene Expression and Antibody-Mediated Immune Responses in Chickens

This study was conducted to investigate the effects of various doses of a multi-strain lactobacilli mixture (Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus crispatus, and Lactobacillus johnsonii) on the innate and adaptive immune responses in broiler chickens. At embryonic day eighteen, 200 eggs were injected with PBS, or three different doses of a multi-strain lactobacilli mixture (1 × 105, 1 × 106, and 1 × 107 CFU/egg, P1, P2, and P3 respectively) along with a group of negative control. On days 5 and 10 post-hatch, cecal tonsil, bursa of fabricius, and spleen were collected for gene expression and cellular analysis. On days 14 and 21 post-hatch, birds were immunized intramuscularly with both sheep red blood cells (SRBC) and keyhole limpet hemocyanin (KLH). Serum samples were collected on days 0, 7, 14, and 21 after primary immunization. The results demonstrated that lactobacilli inoculation increased the splenic expression of cytokines, including interferon (IFN) - α, IFN-β, IFN-γ, interleukin (IL)-8, and IL-12 on day 5 post-hatch compared to the control group (PBS). However, in cecal tonsils, lactobacilli treatment downregulated the expression of IL-6 on day 5 post-hatch and IL-2 and IL-8 on day 10 post-hatch. No significant differences were observed in the expression of cytokine genes in the bursa except for IL-13 which was upregulated in lactobacilli-treated groups P2 and P3 on days 5 and 10 post-hatch. Flow cytometry analysis showed that the percentage of KUL01, CD4+ and CD8+ splenocytes was not affected by treatments. In addition, no significant differences were observed for antibody titers against SRBC. However, lactobacilli treatment (P1, P2, and P3) was found to increase IgM titers on day 21 post-primary immunization compared to controls. Furthermore, in ovo injection of the highest dose of probiotics (1 × 107, P3) increased serum IgG titers against KLH on day 7 post-primary immunization. In conclusion, this study demonstrated that that in ovo administration of lactobacilli can improve antibody-mediated immune responses and differentially modulate cytokine expression in mucosal and systemic lymphoid tissues of chickens.

Dissection of the cecal microbial community in chickens after Eimeria tenella infection

Background

Eimeria spp. are responsible for chicken coccidiosis which is the most important enteric protozoan disease resulting in tremendous economic losses in the poultry industry. Understanding the interaction between the avian cecal microbiota and coccidia is of interest in the development of alternative treatments that do not rely on chemotherapeutics and do not lead to drug resistance.

Methods

We utilized 16S rRNA gene sequencing to detect the dynamics of the cecal microbial community in AA broilers challenged with Eimeria tenella. Histopathological analysis of the cecum was also conducted.

Results

We found that microbial shifts occur during the infection. Lactobacillus, Faecalibacterium, Ruminococcaceae UCG-013, Romboutsia and Shuttleworthia decreased in abundance. However, the opportunistic pathogens Enterococcus and Streptococcus increased in abundance over time in response to the infection.

Conclusions

Eimeria tenella disrupts the integrity of the cecal microbiota and could promote the establishment and growth of potentially pathogenic bacteria. Defining bacterial populations affected by coccidial infection might help identify bacterial markers for intestinal disease as well as populations or species that could be beneficial in maintaining and restoring gut homeostasis during and after infection with E. tenella.

Research Note: Evaluating fecal shedding of oocysts in relation to body weight gain and lesion scores during Eimeria infection

Coccidiosis has been a pervasive disease within the poultry industry, with test parameters used to measure effectiveness of treatment strategies often being subjective or influenced by non-disease-related activity. Four experiments were completed, which examined several test parameters of coccidiosis, including body weight gain (BWG), lesion scores, and oocysts per gram of feces (OPG). Each experiment included at least 2 parameters for measuring coccidial infection in chickens and turkeys. In experiment 1, an inoculated control was measured against 3 anticoccidial groups, whereas in experiments 2 to 4, noninoculated and inoculated controls were compared via BWG and OPG. Lesion scores were also included in experiments 1, 3, and 4. Experiment 4 resulted in high correlation, via Pearson correlation coefficient, between BWG and OPG (r = -0.69), very high correlation between OPG and lesion score (r = 0.86), and moderate correlation between BWG and lesion score (r = -0.49). Lesion scores proved to be effective in confirming Eimeria infection, although they did not correlate well with BWG or OPG. Each parameter tended to provide more useful information when lined up with the Eimeria life cycle. Incorporation of OPG, with BWG and lesion scores, as test parameters to measure coccidiosis intervention strategies, provides a global description of disease that may not otherwise be observed with the 2 latter measurements alone.

Effects of Probiotics as Antibiotics Substitutes on Growth Performance, Serum Biochemical Parameters, Intestinal Morphology, and Barrier Function of Broilers

The aim of this study was to investigate the effects of the combination of probiotics replacing antibiotics on growth performance, serum biochemical parameters, intestinal morphology, and expression of tight junction proteins in intestinal mucosa of broilers. A total of 168 Arbor Acres broilers (45.04 ± 0.92 g) were randomly divided into three treatments, with seven replicates per treatment, and eight broilers per replicate. The experiment included phases 1 (d 0 to 21) and 2 (d 21 to 42). The dietary treatments contained a corn soybean meal-based diet (control group; CON); an antibiotic group (basal diet + 75 mg/kg chlortetracycline; CTC), and a probiotics group (basal diet + probiotics (500 mg/kg in phase 1 and 300 mg/kg in phase 2; Bacillus subtilis 5 × 109 CFU/g, Bacillus licheniformis 2.5 × 1010 CFU/g and Saccharomyces cerevisiae 1 × 109 CFU/g; PB). The results showed broilers fed PB had improved (p < 0.05) feed conversion ratio (FCR) in phase 1 and increased (p < 0.05) average daily gain (ADG) in phase 2, as well as improved (p < 0.05) ADG and FCR overall (d 0 to 42). The apparent total tract digestibility (ATTD) of dry matter, organic matter, gross energy, and crude protein was increased (p < 0.05) in broilers fed PB, while the ATTD of dry matter and organic matter was enhanced in broilers fed CTC compared with CON. Broilers fed PB showed increased (p < 0.05) serum total antioxidant capacity concentrations and tended to have higher (p = 0.06) level of serum immunoglobulin M in phase 1 compared with CON. These broilers also had increased (p < 0.05) level of serum immunoglobulin A in phase 2 in comparison with CON and CTC. Moreover, broilers fed CTC and PB showed increased (p = 0.05) villus height to crypt depth ratio in duodenum, as well as higher (p < 0.05) mRNA expression of zonula occludens-1 in jejunum compared with CON. In conclusion, dietary supplementation with PB as chlortetracycline substitute could improve the growth performance, nutrient digestibility, serum antioxidant capacity, jejunal mucosal barrier function, and intestinal morphology of broilers.

Bacillus subtilis B21 and Bacillus licheniformis B26 improve intestinal health and performance of broiler chickens with Clostridium perfringens-induced necrotic enteritis

This study investigated the influence of Bacillus-based probiotics on performance and intestinal health in broiler challenged with Clostridium perfringens-induced necrotic enteritis. One-day-old Arbor Acre (n = 480) were randomly assigned to four treatments with 10 cages of 12 birds: (a) basal diet negative control (NC), with no probiotics nor antibiotics formulated to contain 2,930 and 3,060 kcal/kg with 24.07 and 15.98% CP, for starter and finisher diet, respectively, (b) basal diet + enramycin (5 mg/kg), an antibiotic growth promoter (AGP); (c) basal diet + Bacillus subtilis B21 at 2 × 10⁹ CFU per g (BS); (d) basal diet + Bacillus licheniformis B26 at 2 × 10⁹ CFU per g (BL); growth performance, intestinal morphology, intestinal lesion scores, short-chain fatty acids (SCFAs) and mucosal barrier tight junction's (TJ) mRNA expression were assessed. NC- and BL-fed groups showed higher (p = 0.005) average daily feed intake from d1 to d21 than AGP and BS, whereas BS- and AGP-fed groups showed higher average daily weight gain from d22 to d42 and d1 to d42 of age. Higher mortality rate of (12.5%) and lower of (5.5%) were recorded in AGP and NC fed-groups respectively, lesion score was higher in BS and BL than in AGP, while no lesion was observed in NC group, results revealed higher duodenum and jejunum villus height to crypt depth (VH:CD) compared with NC and BS. Probiotics-fed groups showed higher total (SCFAs), acetic and butyric acid concentrations at d21 post-challenge (PC) than other groups. The expression of claudin-1 was upregulated in duodenum (d7) PC and in jejunum (d7) and (d21) PC in BL group, while at d21 PC, the expression of occludens was higher in jejunum and ileum by AGP and BL. The present study indicated both BS and BL have some similarity with AGP in preventing or partially preventing NE effect in broilers.