Microarchitecture and Spatial Relationship Between Bacteria and Ileal, Cecal, and Colonic Epithelium in Chicks Fed a Direct-Fed Microbial, PrimaLac, and Salinomycin

Probiotic consortium from poultry strains for supporting gut immunity against pathogens

Multi-strain probiotics have gained increasing attention for their ability to enhance host health by modulating the gut microbiota, immune responses, and resistance to pathogens. This study investigated the probiotic efficacy of KMK3, a novel three-strain consortium comprising Lactobacillus brevis (TN9), Ligilactobacillus salivarius (F9/2), and Ligilactobacillus salivarius (TL4/1), in broiler chickens, with a specific focus on pathogen resistance and immune modulation. Growth kinetics revealed that L. brevis (TN9) had the shortest lag phase (2 h) and the highest maximum optical density (OD600 ≈ 1.8), suggesting superior adaptation and growth compared to L. salivarius strains (lag phases: 6 and 4 h; OD600: 1.5 and 1.6, respectively). KMK3 administration significantly enhanced growth performance, with a 13 % higher body weight gain and an improved Feed Conversion Ratio (FCR: 1.50) compared to the control group (FCR: 1.75). The consortium also modulated immune responses, increasing serum antibody titers against Salmonella enterica lipopolysaccharides (4.5 ± 0.2 log10) and upregulating anti-inflammatory cytokine IL-10 while suppressing pro-inflammatory cytokines (IL-1β, TNF-α). Additionally, KMK3-treated chickens exhibited improved gut histopathology, including higher villus height and reduced immune cell infiltration, even under S. enterica challenge conditions. These findings highlight the ability of KMK3 to promote pathogen resistance, modulate immune mechanisms, and enhance gut health, offering insights into the molecular and functional interactions of probiotics in mitigating infectious challenges. This study highlights the therapeutic potential of multi-strain probiotics in advancing poultry health and productivity by targeting host-pathogen interactions and immune regulation.

The Prophylactic Protection of Salmonella Typhimurium Infection by Lentilactobacillus buchneri GX0328-6 in Mice

Salmonellosis is a disease caused by non-typhoid Salmonella, and although some lactic acid bacteria strains have been shown previously to relieve Salmonellosis symptoms, little has been studied about the preventive mechanism of Lentilactobacillus buchneri (L. buchneri) against Salmonella infection in vivo. Therefore, the L. buchneri was fed to C57BL/6 mice for 10 days to build a protective system of mice to study its prevention and possible mechanisms. The results showed that L. buchneri GX0328-6 alleviated symptoms caused by Salmonella typhimurium infection among C57BL/6 mice, including low survival rate, weight loss, increase in immune organ index and hepatosplenomegaly, and modulated serum immunoglobulin levels and intrinsic immunity. Importantly, the L. buchneri GX0328-6 enhanced the mucosal barrier of the mouse jejunum by upregulating the expression of tight junction proteins such as ZO-1, occludins, and claudins-4 and improved absorptive capacity by increasing the length of mouse jejunal villus and the ratio of villus length to crypt depth and decreasing the crypt depth. L. buchneri GX0328-6 reduced the intestinal proliferation and invasion of Salmonella typhimurium by modulating the expression of antimicrobial peptides in the intestinal tract of mice, and reduced intestinal inflammation and systemic spread in mice by downregulating the expression of IL-6 and promoting the expression of IL-10. Furthermore, L. buchneri GX0328-6 increased the relative abundance of beneficial bacteria colonies and decreased the relative abundance of harmful bacteria in the cecum microflora by modulating the microflora in the cecum contents.

A Two Bacteriocinogenic Ligilactobacillus Strain Association Inhibits Growth, Adhesion, and Invasion of Salmonella in a Simulated Chicken Gut Environment

In this study, we aimed to develop a protective probiotic coculture to inhibit the growth of Salmonella enterica serovar Typhimurium in the simulated chicken gut environment. Bacterial strains were isolated from the digestive mucosa of broilers and screened in vitro against Salmonella Typhimurium ATCC 14028. A biocompatibility coculture test was performed, which identified two biocompatible strains, Ligilactobacillus salivarius UO.C109 and Ligilactobacillus saerimneri UO.C121 with high inhibitory activity against Salmonella. The cell-free supernatant (CFS) of the selected isolates exhibited dose-dependent effects, and the inhibitory agents were confirmed to be proteinaceous by enzymatic and thermal treatments. Proteome and genome analyses revealed the presence of known bacteriocins in the CFS of L. salivarius UO.C109, but unknown for L. saerimneri UO.C121. The addition of these selected probiotic candidates altered the bacterial community structure, increased the diversity of the chicken gut microbiota challenged with Salmonella, and significantly reduced the abundances of Enterobacteriaceae, Parasutterlla, Phascolarctobacterium, Enterococcus, and Megamonas. It also modulated microbiome production of short-chain fatty acids (SCFAs) with increased levels of acetic and propionic acids after 12 and 24 h of incubation compared to the microbiome challenged with S. Typhimurium. Furthermore, the selected probiotic candidates reduced the adhesion and invasion of Salmonella to Caco-2 cells by 37-39% and 51%, respectively, after 3 h of incubation, compared to the control. These results suggest that the developed coculture probiotic strains has protective activity and could be an effective strategy to control Salmonella infections in poultry.

Interplay of poultry-microbiome interactions - influencing factors and microbes in poultry infections and metabolic disorders

1. The poultry microbiome and its stability at every point in time, either free range or reared under different farming systems, is affected by several environmental and innate factors. The interaction of the poultry birds with their microbiome, as well as several inherent and extraneous factors contribute to the microbiome dynamics. A poor understanding of this could worsen poultry heath and result in disease/metabolic disorders.2. Many diseased states associated with poultry have been linked to dysbiosis state, where the microbiome experiences some perturbation. Dysbiosis itself is too often downplayed; however, it is considered a disease which could lead to more serious conditions in poultry. The management of interconnected factors by conventional and emerging technologies (sequencing, nanotechnology, robotics, 3D mini-guts) could prove to be indispensable in ensuring poultry health and welfare.3. Findings showed that high-throughput technological advancements enhanced scientific insights into emerging trends surrounding the poultry gut microbiome and ecosystem, the dysbiotic condition, and the dynamic roles of intrinsic and exogenous factors in determining poultry health. Yet, a combination of conventional, -omics based and other techniques further enhance characterisation of key poultry microbiome actors, their mechanisms of action, and roles in maintaining gut homoeostasis and health, in a bid to avert metabolic disorders and infections.4. In conclusion, there is an important interplay of innate, environmental, abiotic and biotic factors impacting on poultry gut microbiome homoeostasis, dysbiosis, and overall health. Associated infections and metabolic disorders can result from the interconnected nature of these factors. Emerging concepts (interkingdom or network signalling and neurotransmitter), and future technologies (mini-gut models, cobots) need to include these interactions to ensure accurate control and outcomes.

Plasma activated water effects on behavior, performance, carcass quality, biochemical changes, and histopathological alterations in quail

BACKGROUND

Plasma-activated water (PAW) is an innovative promising technology which could be applied to improve poultry health. The current study investigated the effects of drinking water supply with PAW on quail behaviour, performance, biochemical parameters, carcass quality, intestinal microbial populations, and internal organs histopathology. A total of 54 twenty-one-day-old Japanese quail chicks were randomly allotted to three treatments provided with PAW at doses 0, 1 ml (PAW-1), and 2 ml (PAW-2) per one litter drinking water. Each treatment contained 6 replicates (3 birds/ cage; one male and two females).

RESULTS

The results clarified that there were no significant (P > 0.05) changes in behaviour, and performance. For the biochemical indicators, the PAW-1 group showed significantly higher serum H2O2, total protein and globulin levels compared with the other groups (P = 0.015, < 0.001, and 0.019; respectively). PAW groups had significantly lower serum creatinine and urea levels than the control (P = 0.003). For the carcass quality, the internal organs relative weight between different treatments was not changed. In contrast, there was a significant increase in the meat colour, taste, and overall acceptance scores in PAW groups compared with the control one (P = 0.013, 0.001, and < 0.001; respectively). For the intestinal microbial population, lactobacilli count was significantly higher in PAW-2 compared with the control group (P = 0.014), while there were no changes in the total bacterial count between different treatment groups. Moreover, mild histological changes were recorded in the intestine, liver, and spleen of PAW groups especially PAW-2 compared with the control one.

CONCLUSIONS

PAW offered benefits, such as reducing creatine and urea levels, improving meat characteristics, and increasing lactobacilli count, all of which are crucial for sustainable quail farming. Therefore, further research is needed.

Sequencing approaches to identify distal jejunum microbial community composition and function in broiler chickens fed anti-interleukin-10 during coccidiosis and necrotic enteritis challenge

Strategies to counteract interleukin (IL)-10-mediated immune evasion by Eimeria spp. during coccidiosis- like anti-IL-10 antibodies- may protect broiler chicken health and reduce incidence of secondary necrotic enteritis (Clostridium perfringens) via undetermined mechanisms. Objectives were to use sequencing techniques to evaluate jejunal microbial community composition and function in anti-IL-10-fed broilers during coccidiosis and necrotic enteritis. On d0, Ross 308 chicks were placed in 32 cages (15 chicks/ cage) for a 25-d study and randomly assigned to diets ± 0.03% anti-IL-10. Six chicks/ diet were euthanized for distal jejunum content and tissue collection on d 14 (baseline) before inoculating the remainder with saline or 15,000 E. maxima oocysts (M6 strain). Half the chicks challenged with E. maxima were challenged with C. perfringens (1×108 colony forming units) on d 18 and 19. Follow-up samples (6 chicks/treatment) were collected at 7 and 11 d postinoculation (pi) for the E. maxima-only group, or 3 and 7 dpi for the E. maxima + C. perfringens group with 3/7 dpi being designated as peak and 7/11dpi as postpeak challenge. DNA was extracted from digesta for microbiota composition analysis (16S rRNA gene sequencing) while RNA was extracted from tissue to evaluate the metatranscriptome (RNA sequencing). Alpha diversity and genus relative abundances were analyzed using the diet or challenge main effects with associated interactions (SAS 9.4; P ≤ 0.05). No baseline microbial changes were associated with dietary anti-IL-10. At peak challenge, a diet main effect reduced observed species 36.7% in chicks fed anti-IL-10 vs. control; however, the challenge effect reduced observed species and Shannon diversity 51.2-58.3% and 33.0 to 35.5%, respectively, in chicks challenged with E. maxima ± C. perfringens compared to their unchallenged counterparts (P ≤ 0.05). Low sequencing depth limited metatranscriptomic analysis of jejunal microbial function via RNA sequencing. This study demonstrates that challenge impacted the broiler distal jejunum microbiota more than anti-IL-10 while future research to characterize the microbial metatranscriptome may benefit from investigating other intestinal compartments.

Effects of a novel, non-invasive pre-hatch application of probiotic for broilers on development of cecum microbiota and production performance

BACKGROUND

Probiotics are used in the broiler industry to increase production performance. Most often a probiotic is applied by mixing it in the feed, but studies have shown that earlier application may be advantageous. Therefore, in ovo application where the probiotic is administrated into the egg before hatch has been investigated as an alternative application method. However, in ovo application may impact hatchability negatively and may not be feasible at all hatcheries. The purpose of this study was to investigate the effect of a novel non-invasive method for mass application before hatch. The probiotic (E. faecium 669) was applied as a single dose by spray on the unhatched eggs and production performance and development of the cecal microbiota until slaughter was compared with a control flock. Through 16S rRNA sequencing of cecal samples from 25 broilers at day 7, 21 and 37 we compared the microbiota composition and richness for each group. The study was repeated for additional recording of production performance and re-isolation of the probiotic E. faecium from the intestine.

RESULTS

In both trials the probiotic E. faecium could be re-isolated from the yolk sac and intestine at hatch and at day 7. Broilers in the probiotic treated groups had a higher performance in terms of bodyweight at day 34 and European production efficiency factor. Finally, a significant reduction of first-week and overall mortality was observed in the probiotic group in the first trial. Based on 16S rRNA profiling, significant differences in alpha diversity were found exclusively at day 37. Estimation of beta diversities, however, identified significant differences in microbiota composition between the control and probiotic group at day 7, 21 and 37.

CONCLUSION

The probiotic E. faecium strain successfully colonized broilers before/during hatch after a single spray application at day 18 of incubation. Positive effects of the probiotic were observed in multiple production parameters, including reduced mortality in trial 1, and microbiota analyses indicate significantly different microbiota compositions throughout the experimental phase. Taken together, the novel low-tech mass administration of E. faecium (669) may be considered a feasible strategy for improvements of production parameters in broiler production.

Effects of bacteriophage on Salmonella Enteritidis infection in broilers

Bacteriophages (BP) are viruses that can infect bacteria. The present study evaluated the effect of BP on Salmonella infected broilers. A number of 150 day-old broilers were used in a completely randomized design with five treatments that included: (1) basal diet from day 0 to 28; (2) basal diet + 0.3 g/kg of colistin from day 0 to 28; (3) basal diet from day 1 to 13, and basal diet + 0.4 g/kg of colistin from day 14 to 28; (4) basal diet + 1 g/kg of BP from day 0 to 28; (5) basal diet + 1.5 g/kg of BP from day 0 to 28. On day 13, 15 chickens from each treatment were challenged by Salmonella Enteritidis (SE), while fifteen from each treatment were not; instead, they were kept in the same cage with the challenged chickens (exposed chickens). At 7 and 14 days post-challenge, the number of SE and coliform bacteria in the cecum and liver of colistin and BP-fed birds was lower than the control treatment. In exposed and challenged chickens, the height and surface area of villus were greater in the BP and colistin-supplemented groups. Serum concentrations of aspartate aminotransferase and alanine transaminase were greater, while serum albumin and triglycerides concentrations were lower in the control treatment. The liver of the challenged chickens had more pathological lesions than exposed birds. BP significantly decreased PPARγ gene expression in exposed chickens. In the challenged and exposed chickens, TLR4 gene expression was lower in BP and colistin-treated birds as compared to the control. In conclusion, adding BP to the diet from the day of age prevents the spread of Salmonella.

Effect of Probiotic E. coli Nissle 1917 Supplementation on the Growth Performance, Immune Responses, Intestinal Morphology, and Gut Microbes of Campylobacter jejuni Infected Chickens

Campylobacter jejuni is the most common cause of bacterial foodborne gastroenteritis and holds significant public health importance. The continuing increase of antibiotic-resistant Campylobacter necessitates the development of antibiotic-alternative approaches to control infections in poultry and in humans. Here, we assessed the ability of E. coli Nissle 1917 (EcN; free and chitosan-alginate microencapsulated) to reduce C. jejuni colonization in chickens and measured the effect of EcN on the immune responses, intestinal morphology, and gut microbes of chickens. Our results showed that the supplementation of 3-week-old chickens daily with free EcN in drinking water resulted in a 2.0 log reduction of C. jejuni colonization in the cecum, whereas supplementing EcN orally three times a week, either free or microencapsulated, resulted in 2.0 and 2.5 log reductions of C. jejuni colonization, respectively. Gavaged free and microencapsulated EcN did not have an impact on the evenness or the richness of the cecal microbiota, but it did increase the villous height (VH), crypt depth (CD), and VH:CD ratio in the jejunum and ileum of chickens. Further, the supplementation of EcN (all types) increased C. jejuni-specific and total IgA and IgY antibodies in chicken’s serum. Microencapsulated EcN induced the expression of several cytokines and chemokines (1.6 to 4.3-fold), which activate the Th1, Th2, and Th17 pathways. Overall, microencapsulated EcN displayed promising effects as a potential nonantibiotic strategy to control C. jejuni colonization in chickens. Future studies on testing microencapsulated EcN in the feed and water of chickens raised on built-up floor litter would facilitate the development of EcN for industrial applications to control Campylobacter infections in poultry.

Effects of bacteriophage supplement on the growth performance, microbial population, and PGC-1α and TLR4 gene expressions of broiler chickens

Bacteriophages (BP) are viruses that invade bacteria and propagate inside them, leading to the lysis of the bacterial cells. The aim of this study was to investigate the effect of adding BP to the broiler's diet and its effect on the performance, morphology and bacterial population of the gut, some immune responses and expression of some intestinal genes. Accordingly, dietary treatments were as follows: basal diet (control), and control + 0.3 g/kg colistin or 0.5, 1 and 1.5 g BP/kg of diet. BP increased the body weight gain and reduced the feed conversion ratio (FCR), as compared to the colistin treatment, in the finisher and overall period (P < 0.05). European efficiency factor was significantly higher in 1.5 g BP-fed birds, as compared to the control and colistin treatments. meanwhile, bacteriophage and colistin-fed birds had higher Lactobacillus and lowered coliform bacteria counts, as compared to the control treatment (P < 0.05). Cecal concentrations of propionate in the 1.5 g BP-fed birds were higher than those in the control treatment (P < 0.05). BP-fed birds had a significantly increased villus height to crypt depth ratio, as compared to the control treatment. BP increased the serum concentrations of the total antibody, immunoglobulin (Ig) M, and IgG, as compared to the control treatment (P < 0.05). In the ileum, the expression of the Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) gene was decreased by dietary BP supplementation (P < 0.05). Furthermore, Toll-like receptor 4 (TLR4) gene expression was down-regulated in the BP-fed birds, whereas Interleukin 10 (IL-10) gene expression was up-regulated (P < 0.05). Overall, the use of BP may be a promising alternative to growth-promoting antibiotics in broilers by altering the gastrointestinal tract microbiota, enhancing immunological responses and improving the gut's morphology.

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.

Microbiomics Revealed the Disturbance of Intestinal Balance in Rabbits with Diarrhea Caused by Stopping the Use of an Antibiotic Diet

The harmful effects of diarrhea on the growth performance of rabbits have been well documented, but the details of the potential mechanism of intestinal diarrhea when antibiotics are stopped are still unclear. Here, PacBio sequencing technology was used to sequence the full length 16S rRNA gene of the microbiota of intestinal content samples, in order to characterize the bacterial communities in the small intestine (duodenum and jejunum) and large intestine (colon and cecum) in normal Hyplus rabbits and those with diarrhea. The histopathological examination showed that intestinal necrosis occurred in different degrees in the diarrhea group, and that the mucosal epithelium was shed and necrotic, forming erosion, and the clinical manifestation was necrosis. However, the intestinal tissue structure of the normal group was normal. The results revealed that there were significant differences in bacterial communities and structure between the diarrhea and normal groups of four intestinal segments (p < 0.05). In general, 16 bacterial phyla, 144 bacterial genera and 22 metabolic pathways were identified in the two groups. Tax4Fun functional prediction analysis showed that KEGG related to amino acid metabolism and energy metabolism was enriched in the large intestines of rabbits with diarrhea, whereas lipid metabolism was more abundant in the small intestine of rabbits with diarrhea. In conclusion, the change in the relative abundance of the identified dominant microbiota, which could deplete key anti-inflammatory metabolites and lead to bacterial imbalance and diarrhea, resulted in diarrhea in Hyplus rabbits that stopped using antibiotics.

Evaluation of Selected Bacteria and Yeast for Probiotic Potential in Poultry Production

Performance and efficiency of feed utilization in poultry is highly influenced by gut health, which is dependent on intestinal microbial balance. Probiotics are live microbial feed supplements or viable microorganisms that beneficially affect the host animal by improving its gastrointestinal tract (GIT) microbial balance. However, their mode of action and suitable GIT environment favoring their colonization of the GIT is obscure. The probiotic properties of Lactobacillus plantarum, Bifidobacterium longum, and Saccharomyces boulardii were evaluated. These microbes were tested in vitro against gastrointestinal conditions for survivability and their ability to attach to the intestinal mucosa. The ability of the microbes to tolerate and survive varying pH levels and bile concentrations was assessed. The microbes were challenged with a pH of 2 to 7 for 5 h and bile concentrations of 1 to 3% for 6 hrs. The microbes were sampled hourly to evaluate growth or decline in colony-forming units (CFU). B. longum, L. Plantarum, and S. boulardii exhibited significantly higher CFU (p < 0.05) at a pH range of 5 to 7, 4 to 7, and 2 to 7, respectively, when compared with other pH levels. L. plantarum had much higher colony-forming units per mL within each pH level, except at pH 2 where S. boulardii was the only microbe to survive over time. While L. plantarum and S. boulardii were able to tolerate the various bile concentrations, B. longum and L. plantarum showed remarkable ability to attach to the intestinal mucosa and to inhibit pathogenic microbes.

Influence of microbial probiotics on ruminant health and nutrition: sources, mode of action and implications

Globally, ruminant production contributes immensely to the supply of the highest quality and quantity of proteins for human consumption, sustenance of livelihoods, and attainment of food security. Nevertheless, the phasing out of antibiotics in animal production has posed a myriad of challenges, including poor growth, performance and nutrient utilization, pathogen colonization, dysbiosis, and food safety issues in ruminants. Probiotics (direct-fed microbials), comprising live microbial strains that confer health and nutritional benefits to the host when administered in appropriate quantities, are emerging as a viable, safe, natural and sustainable alternative to antibiotics. Although the mechanisms of action exerted by probiotics on ruminants are not well elucidated, dietary probiotic dosage to ruminants enhances development and maturation, growth and performance, milk production and composition, nutrient digestibility, feed efficiency, pathogen reduction, and mitigation of gastrointestinal diseases. However, the beneficial response to probiotic supplementation in ruminants is not consistent, being dependent on the microbial strain selected, combination of strains, dose, time and frequency of supplementation, diet, animal breed, physiological stage, husbandry practice, and farm management. Nonetheless, several studies have recently reported beneficial effects of probiotics on ruminant performance, health and production. This review conclusively re-iterates the need for probiotics inclusion for the sustainability of ruminant production. Considering the role that ruminants play in food production and employment, global acceptance of sustainable ruminant production through supplementation with probiotics will undoubtedly ensure food security and food safety for the world. © 2021 Society of Chemical Industry.

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.

Necrotic enteritis in broiler chickens: disease characteristics and prevention using organic antibiotic alternatives – a comprehensive review

In line with the substantial increase in the broiler industry worldwide, Clostridium perfringens-induced necrotic enteritis (NE) became a continuous challenge leading to high economic losses, especially after banning antimicrobial growth promoters in feeds by many countries. The disease is distributed worldwide in either clinical or subclinical form, causing a reduction in body weight or body weight gain and the feed conversion ratio, impairing the European Broiler Index or European Production Efficiency Factor. There are several predisposing factors in the development of NE. Clinical signs varied from inapparent signs in case of subclinical infection (clostridiosis) to obvious enteric signs (morbidity), followed by an increase in mortality level (clostridiosis or clinical infection). Clinical and laboratory diagnoses are based on case history, clinical signs, gross and histopathological lesions, pathogenic agent identification, serological testing, and molecular identification. Drinking water treatment is the most common route for the administration of several antibiotics, such as penicillin, bacitracin, and lincomycin. Strict hygienic management practices in the farm, careful selection of feed ingredients for ration formulation, and use of alternative antibiotic feed additives are all important in maintaining broiler efficiency and help increase the profitability of broiler production. The current review highlights NE caused by C. perfringens and explains the advances in the understanding of C. perfringens virulence factors involved in the pathogenesis of NE with special emphasis on the use of available antibiotic alternatives such as herbal extracts and essential oils as well as vaccines for the control and prevention of NE in broiler chickens.

Novel mono- and multi-strain probiotics supplementation modulates growth, intestinal microflora composition and haemato-biochemical parameters in broiler chickens

Background

The reduction of antimicrobial usage in food‐producing animals necessitates the intense search for novel alternatives, including new probiotic strains with more effective properties in improving growth performance and curtailing diseases in animals.

Objective

This study evaluated the effects of novel mono‐ and multi‐strain probiotics on the growth performance, intestinal microbiota and haemato‐biochemical parameters of broilers.

Methods

A total of 160 one‐day‐old Cobb 500 broilers were divided into eight treatment groups with two replicates consisting of (1) basal diet (negative control), (2) basal diet with antibiotic, colistin sulphate, (3) basal diet with commercial probiotic, PROMAX® (positive control), (4) basal diet with Pediococcus acidilactici I5, (5) basal diet with P. pentosaceus I13, (6) basal diet with Enterococcus faecium C14, (7) basal diet with Lactobacillus plantarum C16 and (8) basal diet with the combination of all the four probiotic strains. Birds were kept for 35 days and through oral gavage, 1 ml of 108 study probiotic strains administered on days 3–6, 14 and 18.

Results

Supplementation with P. pentosaceus I13, L. plantarum C16 or multi‐strain probiotics significantly (p < 0.05) improved the body weight gain and feed conversion ratio with decrease in feed intake and intestinal Enterobacteria counts. There was a significant (p < 0.05) increase in haemoglobin, mean corpuscular volume, total white blood cells, platelets counts and a lowered (p < 0.05) total cholesterol and glucose levels in multi‐strains probiotic supplemented birds.

Conclusion

The supplementation with novel multi‐strain probiotics improved growth, intestinal health and haemato‐biochemical parameters in broilers and could be used as suitable antibiotic alternatives.

Use of Tannin-Containing Plants as Antimicrobials Influencing the Animal Health

The antimicrobial effects of diverse tannin-containing plants, particularly condensed tannins (CTs) produced from various plants, are the subject of this study. CT components can be determined using CT-specific procedures such the HCl-Butanol Acetone assay, Thiolysis reaction, and HPLC/MS analysis. These methods indicate CT contents, including mean degree of polymerization, the procyanidins and prodelphinidins ratio (PC/PD%), the isomers of trans- and cis-, and CT concentration. Tannin-containing plants possess antibacterial action, which can be attributed to their protein linkage technique, and tannin-type variations, particularly CTs extract and their PC/PD%. The effects of CT components on the development of Gram-positive and Gram-negative bacteria have been documented for their relative PC/PD%; this is regarded to be a key predictor of tannin characteristics in terms of antimicrobials. In conclusion, tannins, more specific CT compositions, have significant impacts on in vivo trials of animal productions and utilization of metabolites and fermentation in vitro experiments. These findings need further investigations to fully understand how CT-types act on animal feeding in terms of enhanced nutritional quality of animal diets, which may have implications for human and animal health.

Positive Influence of a Probiotic Mixture on the Intestinal Morphology and Microbiota of Farmed Guinea Fowls (Numida meleagris)

To understand the effectiveness of a probiotic mixture on intestinal morphology, mucus layer composition, and cecal microbiota diversity, 40 10-day-old Guinea fowls (Numida meleagris) were assigned to two groups: the control group (C), receiving drinking water, and the treated group (P), receiving water plus a commercial multi-strain probiotic (Slab51®, 2 × 10¹¹ CFU/L). Birds were slaughtered after 4 months, and the intestines were collected. Samples from the duodenum, ileum, and cecum were processed for morphological and morphometric studies, and conventional glycohistochemistry. Cecal samples were also used to assess the microbiota by 16S metataxonomic approach. Group P showed significant increase in the villus height (p < 0.001 in the duodenum and p < 0.05 in the ileum and cecum), villus width (p < 0.05 in all investigated tracts), depth of crypts (p < 0.001 in the duodenum and cecum; p < 0.05 in the ileum), and goblet cells per villus (p < 0.001 in all investigated tracts) compared with group C. Cecal microbiota of the birds varied considerably and comparing the relative abundance of the main observational taxonomic units (OTUs), a positive enrichment of several beneficial taxa, such as Oscillospira, Eubacterium, Prevotella, and members of the Ruminococcaceae, was observed. The enrichment of those taxa can improve microbiota stability and resilience facing environmental stresses, enhancing its resistance against invading pathogens. Ruminococcaceae, which represent the most important taxon in both groups, and Prevotella have a key role in the gut physiology due to the production of short-chain fatty acids (SCFAs), which are a vital energy source for enterocytes, improve glucose metabolism, and exert an overall anti-inflammatory effect. Probiotic administration enriches the presence of Coprococcus, Oscillospira, and Eubacterium taxa that produce butyrate, which exerts a beneficial effect on growth performance, structure of villi, and pathogen control and has anti-inflammatory properties too. This study indicates that Slab51® supplementation positively affects the morphology and microbiota diversity of the guinea fowl intestine.

Effect of in Ovo Inoculation of Bifidobacterium spp. on Growth Performance, Thyroid Activity, Ileum Histomorphometry, and Microbial Enumeration of Broilers

Early colonization by beneficial bacteria stimulates the function and development of the digestive tract, on which the performance and vitality of broilers rely. This experiment evaluated the effects of in ovo injection of bifidobacteria on the performance, thyroid activity, bacterial enumeration, and ileal histomorphometry of broiler chickens. A total of 360 fertile eggs were inoculated into the yolk sac, on day 17 of embryogenesis, and allocated to six experimental groups: negative control (not injected, G1), positive control (injected with sterilized distilled water, G2), and groups inoculated with 2 × 10⁸ CFU of Bifidobacterium bifidum, G3; B. animalis, G4; B. longum, G5; or B. infantis, G6. The results revealed an increase (P < 0.01) in body weight and weight gain in all treated groups increases of at least 5.38 and 8.27%, respectively, compared with the control. Feed consumption was not affected during all experimental periods, while the feed conversion ratio (FCR) was enhanced (P < 0.01) only for the overall experimental period (1-28 days of age). The G3 birds recorded the lowest FCR (1.38), while the highest was observed in G1 birds (1.57). Serum concentrations of thyroxin and triiodothyronine were elevated (P < 0.05) with probiotic inoculation. The antioxidant status and immune response of bifidobacteria injected birds were improved; the serum contents of superoxide dismutase and immunoglobulins Y, M, and A were increased (P < 0.05 and P < 0.01), while the malondialdehyde content was decreased (P < 0.01). Ileal architecture was improved in the bifidobacteria treated groups; the highest values of villus height and the villus height/crypt depth ratio were recorded in G3 (936.6 and 11.80) compared with those of G1 (537.1 and 6.93). Moreover, ileal lactic acid bacteria and Bifidobacterium spp. counts increased by at least 10.64 and 51.75%, while total coliform and bacterial counts reduced by at least 15.46 and 15.18%, respectively, compared with those of the control. In conclusion, all tested strains of bifidobacteria enhanced broiler growth performance, ileal function, and thyroid hormone metabolism without obvious differences among them.

Assessment of In Ovo Administration of Bifidobacterium bifidum and Bifidobacterium longum on Performance, Ileal Histomorphometry, Blood Hematological, and Biochemical Parameters of Broilers

Bifidobacterium is one of the most promising probiotics which was recently used as an alternative growth promoter in poultry. This trial was considered to evaluate the potential effects of in ovo administration of Bifidobacterium bifidum and Bifidobacterium longum on growth performance and biochemical parameters of broilers. Three hundred broiler breeder eggs were incubated and candled individually at day 17 of embryogenesis; then, eggs that had live embryos were randomly divided into six groups. The first and second groups were of intact (without injection) and vehicle-injected (sterile distilled water) control groups, respectively. Other groups were in ovo injected with 1 × 10⁹ and 1 × 10⁷ CFU B. bifidum, and 1 × 10⁹ and 1 × 10⁷ CFU B. longum, respectively. Hatchability was significantly (P < 0.001) affected by in ovo inoculation of bifidobacteria strains. Body weight gain and feed conversion ratio were significantly improved (P = 0.014 and 0.019, respectively) in all treatment groups. Protein fractions, aspartate aminotransferase, and alanine aminotransferase activities were not significantly altered by bifidobacteria strains in ovo injection. Regarding ileal histomorphometry parameters, a significant elevation in villus height and villus height/crypt depth ratio values were recorded while crypt depth was insignificantly affected by in ovo treatments. It could be concluded that the tested manual method of in-yolk sac injection at day 17 of incubation is more favorable in easier delivering of bifidobacteria strains which improve broiler growth performance and ileal development without any undesirable effects on blood indices and liver and renal functions.

The potential mechanistic insights and future implications for the effect of prebiotics on poultry performance, gut microbiome, and intestinal morphology

Prebiotics may modify the biological processes in the chickens' gastrointestinal tract to improve poultry performance and health. Prebiotics are natural feed additives that offer many economic advantages by decreasing mortality rates, increasing growth rates, and improving birds' feed efficiency. Prebiotic action potentially affects the degradation of indigestible dietary compounds, the synthesis of nitrogen components and vitamins, and simplifies the removal of undesirable elements in the diet. Prebiotics could also induce desirable gut microbiome modifications and affect host metabolism and immune health. It is worth mentioning that gut bacteria metabolize the prebiotic compounds into organic compounds that the host can subsequently use. It is important to limit the concept of prebiotics to compounds that influence the metabolism of resident microorganisms. Any medicinal component or feed ingredient beneficial to the intestinal microecosystem can be considered a prebiotic. In this review, the impacts of prebiotics on the gut microbiome and physiological structure are discussed, emphasizing the poultry's growth performance. The current review will highlight the knowledge gaps in this area and future research directions.

Effect of Selenium Sources on Laying Performance, Egg Quality Characteristics, Intestinal Morphology, Microbial Population and Digesta Volatile Fatty Acids in Laying Hens

The use of toxic and less bioavailable inorganic selenium can now be supplemented with an alternative organic source from bacterial species in nutrition for human and animal benefit. This study investigated the effects of selenium sources on laying performance, egg quality characteristics, intestinal morphology, caecum microbial population, and digesta volatile fatty acids in laying hens. One hundred and forty-four Lohman Brown Classic laying hens, at 23 weeks of age, were divided into four experimental groups (36 hens in each), differing in form of Se supplementation: no Se supplementation (Con), 0.3 mg/kg of inorganic Se in the form of sodium selenite (Na2SeO3), 0.3 mg/kg of organic Se from selenium yeast (Se-Yeast), and 0.3 mg/kg of organic Se from Stenotrophomonas maltophilia (bacterial organic Se, ADS18). The results showed that different dietary Se sources significantly affected laying rate, average egg weight, daily egg mass, feed conversion ratio (FCR), and live bodyweight (LBW) (p < 0.05). However, average daily feed intake and shell-less and broken eggs were unaffected (p > 0.05) among the treatment groups. The findings revealed that selenium sources had no (p > 0.05) effect on egg quality (external and internal) parameters. However, eggshell breaking strength and Haugh unit were significantly (p < 0.05) improved with organic (ADS18 or Se-yeast) Se-fed hens compared to the control group. In addition, egg yolk and breast tissue Se concentrations were higher (p < 0.05) in the dietary Se supplemented group compared to the control. Intestinal histomorphology revealed that hens fed ADS18 or Se-Yeast groups had significantly (p < 0.05) higher villi height in the duodenum and jejunum compared to those fed Na2SeO3 or a basal diet. However, when compared to organic Se fed (ADS18 or Se-Yeast) hens, the ileum villus height was higher (p < 0.05) in the basal diet group; with the lowest in the SS among the treatment groups. A significant increase (p < 0.05) of Lactobacilli spp. and Bifidobacteria spp., and a decrease of Escherichia coli and Salmonella spp. population were observed in the organic (ADS18 or Se-yeast) compared to inorganic supplemented and control hens. The individual digesta volatile fatty acid (VFA) was significantly different, but with no total VFA differences. Thus, bacterial selenoprotein or Se-yeast improved the performance index, egg quality characteristics, egg yolk and tissue Se contents, and intestinal villus height in laying hens. Moreover, caecum beneficial microbes increased with a decrease in the harmful microbe population and affected individual cecal volatile fatty acids without affecting the total VFA of the laying hens digesta.

Bacteriocinogenic probiotics as an integrated alternative to antibiotics in chicken production - why and how?

The misuse of antibiotics in the livestock industry has played an important role in the spread of resistant superbugs with severe health implications for humans. With the recent ban on the use of antibiotics in poultry and poultry feed in Canada and the USA, poultry farmers will have to rely on the use of alternatives to antibiotics (such as feed acidifiers, antibodies, bacteriophages, antimicrobial peptides, prebiotics, and probiotics) to maintain the same productivity and health of their livestock. Of particular interest are bacteriocinogenic probiotics, that is, bacterial strains capable of producing bacteriocins that confer health benefits on the host. These bacterial strains have multiple promising features, such as the ability to attach to the host mucosa, colonize, proliferate, and produce advantageous products such as bacteriocins and short-chain fatty acids. These not only affect pathogenic colonization but improve poultry phenotype as well. Bacteriocins are antimicrobial peptides with multiple promising features such as being non-harmful for human and animal consumption, non-disruptive to the host microbiota eubiosis, non-cytotoxic, and non-carcinogenic. Therefore, bacteriocinogenic probiotics are at the forefront to be excellent candidates for effective replacements to antibiotics. While evidence of their safety and effectiveness is accumulating in vitro and in vivo in inhibiting pathogens while promoting animal health, their safety and history of use in livestock remains unclear and requires additional investigations. In the present paper, we review the safety assessment regulations and commercialization policies on existing and novel bacteriocinogenic and bacteriocin products intended to be used in poultry feed as an alternative to antibiotics.

The Use of Probiotics in the Reduction of Campylobacter spp. Prevalence in Poultry

Campylobacter spp. are widely distributed microorganisms, many of which are commensals of gastrointestinal tract in multiple animal species, including poultry. Most commonly detected are C. jejuni and C. coli. Although infections are usually asymptomatic in poultry, poultry meat and products represent main sources of infection with these bacteria to humans. According to recent EFSA report, campylobacteriosis is the most commonly reported zoonotic disease. In 2018, EFSA Panel on Biological Hazards indicated that use of feed and water additives is the second most likely strategy that can be successful in minimizing Campylobacter spp. colonization rate in broiler chickens. One of those feed and water additives are probiotics. From numerous research papers it can be concluded that probiotics exhibit plenty of mechanisms of anti-Campylobacter activity, which were evaluated under in vitro conditions. These results, to some extent, can explain the efficacy of probiotics in in vivo studies, although different outcome can be observed under these two laboratory conditions. Probiotics are capable of reducing Campylobacter spp. population count in poultry gastrointestinal tract and they can reduce carcass contamination. Potential modes of anti-Campylobacter activity of probiotics, results of in vivo studies and studies performed at a farm level are widely discussed in the paper.

Effect of Lactobacillus Species Probiotics on Growth Performance of Dual-Purpose Chicken

Introduction

In-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry due to the ever-growing strict prohibitions on antibiotic growth promoters (AGP) in animal production.

Methods

The study was conducted to investigate the effects of Lactobacillus paracaseis sparacasei and Lactobacillus rhamnosus on the growth performance of 120 day-olds randomly selected Sasso dual-purpose chicken. They were divided into four groups with two replicates per group and 15 chicks per replicate. The treatments were T₁ (control), T₂ (supplement diet with 4g probiotic), T₃ (supplement diet with 2g probiotic), T₄ (supplement diet with 1g probiotic). The experimental feeding trials were conducted after two weeks adaptation period.

Results

The present findings revealed that the chickens supplemented with Lactobacillus species probiotics during the first week of age have shown higher body weight than control (p < 0.05). The feed intake of week one of T₂ and T₃ were significantly higher (p< 0.05) than the T₁ (control). However, there was no significant difference (p> 0.05) in feed intake in the 2^nd, 3^rd, 4^th, and 5^{t h} weeks of all treatment groups. The present result showed that there was a significant body weight gain (p< 0.05) in all probiotic fed groups than the control group. The highest body weight gain was observed in chickens found in the T4 treatment group. Whereas the body weight gains significantly higher and improved the feed conversion (p<0.05) in the T₂ and T₄ than the T₁ (control). However, the feed conversion ratio was significantly influenced by probiotic inclusion in T₃ as compared to the control group.

Conclusion

Overall, the results suggest that Lactobacillus paracaseis sparacasei and Lactobacillus rhamnosus have a positive effect on the growth performance of broilers.

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

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

Effect of fermentation bed on bacterial growth in the fermentation mattress material and cecum of ducks

The composition of microorganisms in the gastrointestinal tract is closely related to the intestinal microenvironments and the exterior growth environments of host. In this study, 16S rDNA sequencing technology was adopted to investigate the influence of fermentation bed on the cecum microorganisms of ducks. Two feeding density treatment groups were set up, including group A (n = 4brids/m²) and group B (n = 6brids/m²). Samples were collected from the intermediate core fermentation layer (10-20 cm) of the fermented mattress materials and from the intestinal contents of ducks at 4, 6 and 8 weeks, respectively. Results showed that Bacteroidetes (20.12-27.17%) and Ruminococcaceae UCG-014 (2.97-10.1%) were the predominant microorganisms in duck cecum, while the Truepera (5.08-6.29%), Pricia (4.44-5.44%) and Luteimonas (3.62-4.99%) were the dominant microorganisms in fermentation mattress material. The cecum bacteria exhibited great difference among different growth periods of the ducks. Increasing the stocking density of ducks had a negative effect on the beneficial bacteria in the cecum. The microbial populations in fermentation mattress material were very different from that in the cecal. In summary, our findings can provide a scientific data for the rational use of fermentation bed feeding mode in poultry production.

Probiotics (Direct-Fed Microbials) in Poultry Nutrition and Their Effects on Nutrient Utilization, Growth and Laying Performance, and Gut Health: A Systematic Review

Simple Summary

Probiotics are live bacteria, fungi, or yeasts that supplement the gastrointestinal flora and help to maintain a healthy digestive system, thereby promoting the growth performance and overall health of poultry. Probiotics are increasingly being included in poultry diets as an alternative to antibiotics. This systematic review provides a summary of the use of probiotics in poultry production and the potential role of probiotics in the nutrient utilization, growth and laying performance, and gut health of poultry.

Abstract

Probiotics are live microorganisms which, when administered in adequate amounts, confer health benefits to the host. The use of probiotics in poultry has increased steadily over the years due to higher demand for antibiotic-free poultry. The objective of this systematic review is to present and evaluate the effects of probiotics on the nutrient utilization, growth and laying performance, gut histomorphology, immunity, and gut microbiota of poultry. An electronic search was conducted using relevant keywords to include papers pertinent to the topic. Seventeen commonly used probiotic species were critically assessed for their roles in the performance and gut health of poultry under existing commercial production conditions. The results showed that probiotic supplementation could have the following effects: (1) modification of the intestinal microbiota, (2) stimulation of the immune system, (3) reduction in inflammatory reactions, (4) prevention of pathogen colonization, (5) enhancement of growth performance, (6) alteration of the ileal digestibility and total tract apparent digestibility coefficient, and (7) decrease in ammonia and urea excretion. Thus, probiotics can serve as a potential alternative to antibiotic growth promoters in poultry production. However, factors such as the intestinal health condition of birds, the probiotic inclusion level; and the incubation conditions, feedstuff, and water quality offered to birds may affect the outcome. This systematic review provides a summary of the use of probiotics in poultry production, as well as the potential role of probiotics in the nutrient utilization, growth and laying performance, and gut health of poultry.

Effect of Antibiotic, Phytobiotic and Probiotic Supplementation on Growth, Blood Indices and Intestine Health in Broiler Chicks Challenged with Clostridium perfringens

Simple Summary

Necrotic enteritis is one of the most important economic issues in the poultry industry, associated with sudden death rates of up to 50%. However, there is limited information on the role of probiotics and/or phytobiotic compounds on the treatment and prevention of Clostridium perfringens infections in broiler chicks. This study aimed to assess the effects of probiotic compounds (Maxus, CloStat, Sangrovit Extra, CloStat + Sangrovit Extra and Gallipro Tech) on the growth performance, blood biochemistry and intestinal health of broiler chicks in vivo. The results demonstrated that the inclusion of probiotic and/or phytobiotic compounds has a positive effect on performance, blood constituents, liver histopathology, intestinal morphology and histopathology. Furthermore, a notable reduction in both lesion scores was observed when probiotics and phytobiotics alone or in combination were included in the diets.

Abstract

This study evaluated the effects of feed additives on the growth, blood biochemistry and intestinal health of broiler chicks. A total of 378 of broiler chicks (Ross 308) were randomly allotted to seven groups. Chicks were fed a basal diet with 0.0 (control negative), 0.0 (control positive), 0.1, 0.5, 0.12, 0.5 + 0.12 and 0.2 g Kg⁻¹ of Maxus, CloStat, Sangrovit Extra, CloStat + Sangrovit Extra and Gallipro Tech, respectively for 35 days. After 15 days, the chicks were inoculated with Clostridium perfringens. All feed additives were found to enhance growth performance and feed efficiency. The best feed conversion ratio was found in the Negative Control, CloStat + Sangrovit Extra and Gallipro Tect groups, respectively. A notable increase in villus length, total villus area, small intestine weight, ilium weight and total lesion score was found in chicks supplemented with Bacillus subtilis. Besides, the dietary inclusion of phytobiotic compounds showed potential in reducing the serum Alanine aminotransferase (ALT) concentration and increasing the glucose levels. All intestine and liver histopathological signs were reduced in chicks fed a probiotic-supplemented diet. Our findings indicate that supplementation with probiotics and phytobiotics alone or in combined form can be used to enhance performance, intestine health and blood constituents against C. perfringens infection in broiler chicks.

The association between microbial community and ileal gene expression on intestinal wall thickness alterations in chickens

The dynamic development of the animal intestine with a concurrent succession of microbiota and changes in microbial community and metabolite spectrum can exert far-reaching effects on host physiology. However, the precise mechanism of mutual response between microbiota and the gut is yet to be fully elucidated. Broilers with varying developmental degrees of intestinal wall thickness were selected, and they were divided into the thick group (H type) and the thin group (B type), using multiomics data integration analysis to reveal the fundamental regulatory mechanisms of gut–microbiota interplay. Our data showed, in broilers with similar body weight, the intestinal morphological parameters were improved in H type and the diversity of microbial communities is distinguishable from each other. The beneficial bacteria such as Bifidobacterium breve was increased whereas avian endogenous retrovirus EAV-HP was decreased in the H type compared with the B type. Furthermore, microbial metabolic potentials were more active, especially the biosynthesis of folate was improved in the H type. Similarly, the consolidation of absorption, immunity, metabolism, and development was noticed in the thick group. Correlation analysis indicated that the expression levels of material transport and immunomodulatory-related genes were positively correlated with the relative abundance of several probiotics such as B. breve, Lactobacillus saerimneri, and Butyricicoccus pullicaecorum. Our findings suggest that the chickens with well-developed ileal thickness own exclusive microbial composition and metabolic potential, which is closely related to small intestinal morphogenesis and homeostasis.

The effectiveness of a dietary direct-fed microbial and mannan oligosaccharide on ultrastructural changes of intestinal mucosa of turkey poults infected with Salmonella and Campylobacter

Salmonella and Campylobacter are considered major public health burdens worldwide, and poultry are known to be one of the main reservoirs for these zoonotic pathogens. This study was conducted to evaluate the effect of a commercial probiotic or direct-fed microbial (DFM) Calsporin (CSP), and prebiotic or mannan oligosaccharide (MOS) (IMW50) on ultrastructural changes and the villous integrity of intestinal mucosa in turkey poults challenged with Salmonella and Campylobacter. A 21-day battery cage study was conducted using 4 dietary treatments including a basal diet (corn and soybean-based) nonsupplemented and uninfected as a negative control (NC); basal diet supplemented with 0.05% DFM (CSP); basal diet supplemented with 0.05% MOS (IMW50); and basal diet supplemented with 0.05% mixture of DFM and MOS at equal proportions. Female large white turkey poults aged 336 days were obtained from a local commercial hatchery and randomly distributed in electrically heated battery cages with 12 treatments of 4 replicates per treatment containing 7 poults per pen. The first 16 pens were not infected with bacteria, poults in pens 17-32 were orally challenged at day 7 with 105 cfu Salmonella Heidelberg, and the poults in pens 33-48 were orally challenged at day 7 with 105 cfu Campylobacter jejuni. Feed and water were provided ad libitum throughout the study. At day 21, ileal tissue samples from 1 bird per cage were collected for intestinal integrity and ultrastructural examination by scanning and electron microscopy. DFM and MOS supplementation was effective in both challenged and nonchallenged (not infected with Salmonella and Campylobacter) birds. Goblet cells and mucus were increased, with the presence of large numbers of segmented filamentous bacteria in DFM- and MOS-supplemented groups compared with birds in control treatments. The number and size of villi were reduced in poults exposed to Salmonella and Campylobacter. Results show that CSP and IMW50 provide protection of ileal mucosal integrity in poults exposed to Salmonella or Campylobacter.

Lactobacillus casei DBN023 protects against jejunal mucosal injury in chicks infected with Salmonella pullorum CMCC-533

Pullorum disease is one of the most serious poultry diseases. Antibiotic prophylaxis is commonly applied in actual production, but the emergence of drug-resistant strains and drug residues threatens the health of animals and humans. The use of probiotics has become a potential solution for the aforementioned problem. In this study, we investigated the effects of Lactobacillus casei DBN023 (CGMCC-16146) on the intestinal tissue structure and immune functions of the jejunal epithelium in chicks infected with Salmonella pullorum CMCC-533 using histomorphological and immunological methods. A total of 450 newborn chicks were randomly divided into the control group and experimental groups. We used hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and an enzyme-linked immunosorbent assay (ELISA) to observe the structure of the jejunal mucosa and analyze changes in cytokine and secretory immunoglobulin A (sIgA) levels. The results showed that prophylactic feeding of L. casei DBN023 to chicks significantly increased their jejunum villar height, villar height-to-crypt-depth (V/C) ratio, and muscle thickness; reduced intestinal-crypt depth; and increased the proliferating cell nuclear antigen (PCNA) level compared with S. pullorum infection. L. casei DBN023 enhances intestinal mucosal immunity, regulates cytokine balance, enhances intestinal immune function, and effectively reduces intestinal inflammation. Thus, it protects intestinal tissues and reduces S. pullorum CMCC-533 damage to the intestinal tract.

Effects of protease and phytase supplements on small intestinal microbiota and amino acid digestibility in broiler chickens

The objective of this study was to determine the effects of protease origin and dosage on the prececal (pc) amino acid (AA) digestibility and the influence on composition of the microbial community in the small intestine. In addition, the effects of phytase supplementation were investigated. A total of 8 dietary treatments were included. The basal diet contained mainly corn and soybean meal. Three protease products were added to the basal diet, each at the level recommended by the supplier and at an 8-fold level. Phytase was supplemented in another dietary treatment. Each dietary treatment was allocated to 8 replicates of 15 birds each. The experimental diets were offered from day 15 to 21 for ad libitum consumption. The effect of protease supplementation on the pc AA digestibility depended on the protease product type and the amount supplemented. The pc AA digestibility was significantly increased by 1 protease product when supplemented at high level and when phytase was supplemented. In all the other treatments, protease supplementation had no significant influence or it decreased pc AA digestibility, when compared with the treatment with no enzymes added. In general, Firmicutes was the most abundant phylum among the ileal microbiota across all the treatments. Significant effects on microbiota composition were observed at the genus level for some but not all protease treatments and phytase supplementation. The genera Streptococcus, Lactobacillus, and uncultured Clostridiaceae were responsible for these differences. Furthermore, microbial networks established for each diet showed either high or low number of intergeneric interactions, but without a consistent enzyme effect. We conclude that enzyme supplementation effects were evident in the terminal small intestine microbiota composition, and to a lesser extent, in pc AA digestibility. However, the changes in microbiota composition and pc AA digestibility could not be correlated, indicating absence of a causal relationship.

Effects of dietary Enterococcus faecium NCIMB 11181 supplementation on growth performance and cellular and humoral immune responses in broiler chickens

This study evaluated the effects of dietary Enterococcus faecium NCIMB 11181 on growth performance and immune response in broiler chickens. A total of 360 1-day-old Arbor Acres male birds were randomly assigned to 4 treatments that administered different dosages of E. faecium (0, 5 × 107, 1 × 108, and 2 × 108 CFU E. faecium/kg diet). The results revealed that average daily gain (ADG) changed quadratically, while feed conversion rate (FCR) increased linearly from day 22 to 35 and day 1 to 35 (P < 0.05). Supplementation of E. faecium at 5 × 107CFU/kg diet resulted in increased ADG (P < 0.05) compared with the other groups. Birds fed with 2 × 108 CFU/kg E. faecium exhibited increased peripheral blood lymphocyte proliferation in response to concanavalin A (Con A) (P < 0.05) at day 35 and enhanced skin responses following phytohemagglutinin (PHA) injection (P < 0.05) at 12 h. Serum lysozyme activity at day 21 increased linearly with dietary E. faecium concentration (P < 0.05), the highest activity was observed in the 1 × 108 and the 2 × 108 CFU E. faecium groups (P < 0.01). Serum levels of proinflammatory cytokines IL-1β, IL-2, IL-6, IFN-γ, and anti-inflammatory IL-4, IL-10 changed linearly or quadratically both at the initial and final phases (P < 0.05). In addition, BSA antibody titers were significantly increased following both primary and secondary inoculation when birds were fed with 1 × 108 or 2 × 108 CFU/kg E. faecium (P < 0.05). In comparison with other groups, birds received 5 × 107 CFU E. faecium exhibited the highest levels of serum IgG (P < 0.05) at day 35. Together, our results revealed that broiler diet supplemented with 5 × 107 CFU/kg E. faecium NCIMB 11181 was appropriate in relation to growth performance under normal conditions. Upon administration with higher dosages of E. faecium NCIMB 11181, obvious immune-stimulatory effects were observed following both cell-mediated and humoral immunity.

Dietary Lactobacillus acidophilus positively influences growth performance, gut morphology, and gut microbiology in rurally reared chickens

In a market undergoing constant evolution, the production of chicken meat that consumers would perceive as “natural” and “animal friendly” is crucial. The use of probiotics in rurally reared chickens could represent a major opportunity to achieve mutual benefit for both the industry and consumers. A total of 264 male Kabir chicks were randomly distributed to one of 2 dietary treatments: the L group received a commercial feed supplemented with 2.0 g/100 kg of Lactobacillus acidophilus D2/CSL, while the C group received the same basal diet without the additive. To assess the effects of probiotic supplementation in the chickens’ diet, productive performance was evaluated at d 21 and 42, whereas microbiological analyses of the intestinal content and intestinal histology and morphometry were performed at the end of the trial (d 42). At d 21 and 42, L birds showed better (P < 0.001) performance in terms of body weight, average daily gain, and feed conversion ratio. Enterococci, staphylococci, and Escherichia coli populations were not influenced by dietary treatment. On the contrary, Lactobacillus population increased (P = 0.032) in the L group. Furthermore, a tendency (P = 0.069) was observed for the coliforms to be influenced by diet, with lower values in the L group in comparison to the C group. Histological techniques revealed that the number of goblet cell containing neutral mucins was lower in the C group. Morphometric evaluations demonstrated that the probiotic supplementation increased the height of the mucosal layer by improving (P = 0.040) villus height, while crypt depth was unaffected. In conclusion, the results obtained in this study demonstrate that it is possible to use Lactobacillus acidophilus D2/CSL (CECT 4529) in rurally reared chicken breeds with positive effects on performance and gut health.

Effect of synbiotic supplementation on layer production and cecal Salmonella load during a Salmonella challenge

This study analyzed the inhibitory effects of a synbiotic product (PoultryStar® me) on production parameters, intestinal microflora profile, and immune parameters in laying hens with and without a Salmonella challenge. The synbiotic product contained 4 probiotic bacterial strains (Lactobacillus reuteri, Enterococcus faecium, Bifidobacterium animalis, and Pediococcus acidilactici) and a prebiotic fructooligosaccharide. Layers were supplemented with the synbiotic from d of hatch to 28 wk of age. At 16 wk of age, birds were either vaccinated with Salmonella enterica Enteritidis (SE) vaccine or left unvaccinated. At 24 wk of age, a portion of the birds was challenged with 1 × 109 CFU of SE or left unchallenged, resulting in a 3 (vaccinated, challenged, or both vaccinated and challenged) X 2 (control and synbiotics) factorial arrangement of treatments. At 18 and 20 wk of age, birds fed synbiotics in both vaccinated and unvaccinated groups had increased (P < 0.05) BW more than those in the un-supplemented groups. Birds fed synbiotics had 0.7, 17.8, 21.7, 3, and 4.2% higher (P < 0.05) hen d egg production (HDEP) at 19, 20, 21, 22, and 23 wk of age, compared to the birds without supplementation, respectively. After administering the SE challenge, supplemented birds had 3, 6.7, 4.3, 12.5, and 14.4% higher (P < 0.05) HDEP at 24, 25, 26, 27, and 28 wk of age, compared to the birds not supplemented, respectively. Irrespective of the vaccination status, birds fed synbiotics and challenged with SE had a lower (P < 0.05) SE cecal load compared to the un-supplemented groups. At 22 d post Salmonella challenge, birds supplemented, vaccinated, and challenged had the highest bile IgA content. It can be concluded that supplementation of the synbiotic product could be beneficial to layer diets as a growth promoter, performance enhancer, and for protection against SE infection.

The influence of probiotic supplementation in broiler chickens on population and carcass contamination with Campylobacter spp. - Field study

Campylobacter spp. is a food-borne pathogen occurring all over the world. According to European Food Safety Authority, in Europe, in 2015 the number of recorded and confirmed cases of Campylobacter spp. infections in humans has reached approximately 230,000. Poultry and poultry meat are considered to be the main sources of human infection, which triggers the discussion about the possibility of imposing obligatory control of Campylobacter spp. population at the level of primary poultry production. Recently, the use of probiotics in poultry is considered as a very promising alternative that could reduce infection rate in broiler chickens with Campylobacter spp. Although, there were some approaches made in vivo, up to date, there were no studies that would evaluate those issues under field conditions. A study was carried out in order to determine the feasibility of reducing infection rate in broiler chickens with Campylobacter spp. raised at a commercial farm, by the addition of multispecies probiotic (Lavipan, JHJ, Poland) that composed of Lactococcus lactis, Carnobacterium divergens, Lactobacillus casei, Lactobacillus plantarum and Saccharomyces cerevisae to the feed. Results of our study indicate that probiotic (Lavipan) added to a feed for broiler chickens was capable to reduce the extent of Campylobacter spp. invasion in the gastrointestinal tract of birds and, resultantly, to diminish contamination level in bird environment, which eventually contributed to the improved hygienic parameters of analyzed poultry carcasses. Additionally, this probiotic displayed promising immunomodulatory properties that may improve the effectiveness of the specific prophylaxis program applied in a flock of broiler chickens.

Global restriction of using antibiotic growth promoters and alternative strategies in poultry production

A growing global concern of antibiotic use in poultry diets due to its potential adverse effects on birds and human health, food safety and the environment has led to a complete ban or restricted use in some countries, and, at the same time, expanding options for the use of alternative feed additives. Multiple, rather than a single additive may replace antibiotic growth promoters (AGPs) in poultry. Blending of feeding additives and hygienic farm management, vaccination and biosecurity may help achieve good intestinal health, stabilise enteric ecosystems and result in sustainable and cost effective production performance of birds. Moreover, controlling unsolicited ingredients at the production level must have the support of different markets responsible for the supply of safe and quality poultry products for consumers. This requires the further increase and diversification of value added poultry products and the expansion of their markets through strategic planning and gradual limitation of live bird markets. More research is warranted in order to explore suitable, reliable and cost effective alternatives to AGPs for commercial use, and strategic poultry value chain development.

Effect of probiotics on the basis of Bacillus subtilis and Bifidobacterium longum on the biochemical parameters of the animal organism

For the purpose of safe modulation of the intestinal microflora, probiotics have been increasingly used in recent years. In the present work, the effect of the probiotic sporobacterin (Bacillus subtilis 534) (I group) and soybean-bifidum (Bifidobacterium longum) (II group) on male rats of the Wistar line was evaluated. In assessing nonspecific immunity in vitro, there was an increase in the level of baseline level in the first and second groups (by 8.3 and 12.2% more control). The influence of probiotic preparations on the intestinal normoflora was assessed using PCR. Bifidumbacterin increased the normal microflora, in particular, Escherichia coli 1.55 times, Lactobacillus 1.26 times, Enterococcus 1.3 times as much control; the level of conditionally pathogenic microflora, in particular, Proteus spp. decreased by 1.3 times in comparison with the control. Sporobacterin also contributed to an increase in the amount of E. coli (1.55 times) and Lactobacillus (0.9 times). When a culture of Bifidobacterium longum was introduced, a selective reduction in the loss of chemical elements was observed against the background of the diet used. At the end of the experiment, the content of calcium in the body tissues of animals of group II exceeded this indicator in group I by 3.9%, phosphorus by 17.6%, copper by 28.5%, and zinc by 15.2%. The totality of the results obtained by us indicates that inclusion of Bifidumbacterium longum in the diet of animals makes the use of this preparation in the correction of mineral imbalance and improves the microflora of the intestines of animals by reducing the number of representatives of opportunistic microflora against the background of an increase in the number of basic representatives of normal microbiocenosis. Also, the use of probiotic drugs as additives leads to a slight increase in the level of nonspecific immunity, which increases the natural resistance of the organism.

Safety assessment of antibiotic and probiotic feed additives for Gallus gallus domesticus

Antibiotics in feed select for resistant strains and is thus a threat to human health. In this study, the effect of a multi-strain probiotic and antibiotics on the growth and health of broilers was studied. Equal numbers of broilers received on a daily basis either a multi-strain probiotic or a combination of sulphadiazine, colistin and trimethoprim, whereas the control group received standard feed. The villi of immature broilers (19 days old) administered antibiotics had a larger surface area and their lymphocyte and basophil counts were higher compared to broilers from the probiotic and control groups. The cecal microbiomes of mature broilers (29 days old) that received probiotics had higher levels of Enterobacteriaceae, but lower numbers of Clostridiales, Brucellaceae, Synergistaceae, Erysipelotrichaceae and Coriobacteriaceae compared to the antibiotic-treated group. A decline in the bioluminescence of Listeria monocytogenes observed for broilers on probiotics suggested that the probiotic may be used to control bacterial infections. No significant differences in total red blood cell, haemoglobin and haematocrit content, and mean values for corpuscular volume, corpuscular haemoglobin and corpuscular haemoglobin numbers were recorded amongst broilers from the different treatment groups. This study provides valuable information on the health and performance of broilers when administered probiotics and antibiotics as additives.