Dietary modulation of gut microflora in broiler chickens: a review of the role of six kinds of alternatives to in-feed antibiotics

In-ovo injection of Bacillus subtilis, raffinose, and their combinations enhances hatchability, gut health, nutrient transport- and intestinal function-related genes, and early development of broiler chicks

An experiment was conducted to assess the response of chicks to in-ovo injection of Bacillus subtilis (probiotic), raffinose (prebiotic), and their combinations. The study used 1,500 embryonated eggs allotted to 10 groups/ 6 replicates (150 eggs/group). The experimental treatments were: 1) un-injected control (NC); 2) sham (sterile distilled water) (PC); 3) probiotic 4 × 105CFU/egg (LBS); 4) probiotic 4 × 106CFU/egg (HBS); 5) prebiotic 2 mg/egg (LR); (6 prebiotic 3 mg/egg (HR); 7) probiotic 4 × 105CFU + prebiotic 2 mg/egg (LBS+LR); 8) probiotic 4 × 105CFU + prebiotic 3 mg/egg (LBS+HR); 9) probiotic 4 × 106CFU + prebiotic 2 mg/egg (HBS+LR); and 10) probiotic 4 × 106CFU + prebiotic 3 mg/egg (HBS+HR). Results showed that in-ovo inclusion of Bacillus subtilis, prebiotic, and their combinations improved hatchability, yolk-free chick weight, and chick weight compared to the control group. Moreover, the in-ovo treatment reduced residual yolk weight on the day of hatch compared to the control group. Different levels of in-ovo B. subtilis alone or combined with raffinose significantly (P ≤ 0.001) reduced total bacterial count and total yeast and mold count compared to the negative control group. Total coliform and E. coli decreased significantly (P ≤ 0.001) in groups treated with probiotics, prebiotics, and synbiotics with different doses during incubation compared to those in the control. Clostridium spp. was not detected in the groups injected with B. subtilis alone or combined with raffinose. In-ovo probiotics and synbiotics (LBS+LR & LBS+HR) significantly (P ≤ 0.001) increased ileal villus length compared to other groups. In-ovo treatment increased mRNA expression of JAM-2 compared to the control group. The fold change significantly increased in group LBS+HR for genes MUC-2, OCLN, VEGF, SGLT-1, and EAAT-3 compared to the negative control. In conclusion, in-ovo injection of a low dose of B. subtilis plus a high or low dose of raffinose can positively affect hatching traits, cecal microbial populations, intestinal histomorphometry, nutrient transport- and intestinal function-related genes, and chick quality of newly hatched broiler chicks.

Mannan oligosaccharides as a prebiotic for laying hens: effects on fertility, hatchability, productive performance, and immunity

This experiment examined how adding mannan-oligosaccharides (MOS) to the diet affected fertility, hatching rates, egg production, carcass characteristics, cost-effectiveness, and immune function in laying hens. One hundred and twenty Mandarah chickens (30 hens and 3 roosters per group) were randomly chosen between 34 and 50 wk old and divided into four groups. The first group was the control group, which was given just the basal diet. The basal diet was given to the second, third, and fourth experimental groups along with three different levels of MOS (0.1, 0.2, and 0.5 g/kg diet, respectively). Results found that hens fed MOS at various levels laid eggs at a significantly higher rate, enhanced egg number, egg mass and feed conversion ratio than the control group (P < 0.05). MOS seemed to improve carcass quality. The best results for egg quality (Haugh unit) and testosterone levels were seen with a dose of 0.5 g/kg of MOS compared to the control birds (P < 0.05). All MOS levels led to higher estradiol-17β (E2) levels and better economic efficiency (EE). MOS also improved the hens' immune systems as compared to the control group. Hens-fed MOS had significantly greater levels of antibodies against Influenza viruses (H9N2) and Infectious Bronchitis Virus (P < 0.05). Also, the spleen and thymus gland, both crucial immune system components, were slightly larger (P < 0.05). It's important to note that fertility rates, hatchability, and embryo mortality rates remained similar across all groups. So, our findings suggest that incorporating MOS into the birds' diet enhances their productivity, strengthens their immune system, improves EE, and contributes to the overall health of the hens.

Mechanisms of medicinal, pharmaceutical, and immunomodulatory action of probiotics bacteria and their secondary metabolites against disease management: an overview

Probiotics or bacteriotherapy is today's hot issue for public entities (Food and Agriculture Organization, and World Health Organization) as well as health and food industries since Metchnikoff and his colleagues hypothesized the correlation between probiotic consumption and human's health. They contribute to the newest and highly efficient arena of promising biotherapeutics. These are usually attractive in biomedical applications such as gut-related diseases like irritable bowel disease, diarrhea, gastrointestinal disorders, fungal infections, various allergies, parasitic and bacterial infections, viral diseases, and intestinal inflammation, and are also worth immunomodulation. The useful impact of probiotics is not limited to gut-related diseases alone. Still, these have proven benefits in various acute and chronic infectious diseases, like cancer, human immunodeficiency virus (HIV) diseases, and high serum cholesterol. Recently, different researchers have paid special attention to investigating biomedical applications of probiotics, but consolidated data regarding bacteriotherapy with a detailed mechanistically applied approach is scarce and controversial. The present article reviews the bio-interface of probiotic strains, mainly (i) why the demand for probiotics?, (ii) the current status of probiotics, (iii) an alternative to antibiotics, (iv) the potential applications towards disease management, (v) probiotics and industrialization, and (vi) futuristic approach.

A Meta-Analysis of the Effects of Dietary Yeast Mannan-Rich Fraction on Broiler Performance and the Implication for Greenhouse Gas Emissions from Chicken Production

Dietary supplementation of yeast-derived mannan-rich fraction (MRF) could improve the gastrointestinal health and production efficiency of broilers, and, consequently, lower the environmental impacts of chicken production. The objective of this meta-analysis was to quantify the retrospective effects of feeding MRF (Actigen®, Alltech Inc., Nicholasville, KY) on the production performance of broilers. The meta-analysis database included 27 studies and consisted of 66 comparisons of MRF-supplemented diets vs. basal (i.e., negative control) and antibiotic-supplemented (i.e., positive control) diets. A total of 34,596 broilers were involved in the comparisons and the average final age of the birds was 35 days. Additionally, the impact of feeding MRF on the carbon footprint (feed and total emission intensities) of chicken production was evaluated using the meta-analysis results of broiler performance (MRF vs. basal diets) to develop a scenario simulation that was analyzed by a life cycle assessment (LCA) model. A database of all trials (MRF vs. basal and antibiotic diets) indicated that feeding MRF increased (p < 0.01) average daily feed intake (ADFI; +3.7%), final body weight (FBW; +3.5%), and average daily gain (ADG; 4.1%) and improved (p < 0.01) feed conversion ratio (FCR; -1.7%) without affecting (p > 0.05) mortality. A subdatabase of MRF vs. basal diets indicated that dietary MRF increased ADFI (+4.5%), FBW (+4.7%), and ADG (+6.3%) and improved FCR (-2.2%) and mortality (-21.1%). For the subdatabase of MRF vs. antibiotic diets, both treatments exhibited equivalent effects (p > 0.05) on broiler performance parameters, suggesting that MRF could be an effective alternative to in-feed antibiotics. Subgroup analysis revealed that different study factors (year of study, breed/strain, production challenges, and MRF feeding duration) influenced the effect of dietary MRF on broiler performance. Simulated life cycle analysis (LCA) indicated that feeding MRF decreased feed and total emission intensities, on average, by -2.4% and -2.1%, respectively. In conclusion, these results demonstrate that dietary MRF is an effective nutritional solution for improving broiler performance, an effective alternative to in-feed antibiotic growth promoters, and reduces the environmental impact of poultry meat production.

Assessing the potential of phytogenic feed additives: A comprehensive review on their effectiveness as a potent dietary enhancement for nonruminant in swine and poultry

Phytogenic feed additives (PFAs) often referred to as phytobiotics or botanical feed additives, are natural compounds derived from various plants, herbs, spices and other botanical sources. These feed additives are intended to serve a variety of purposes, including an immune system regulator, an antimicrobial, an antimutagenic, an antioxidant and a growth promoter. They are composed of bioactive compounds extracted from plants, including essential oils, polyphenols, terpenoids and flavonoids. They are mostly utilized as substitute antibiotic growth promoters in nonruminant (swine and poultry) livestock production, owing to the prohibition of antibiotic usage in the feed industry. It has been thoroughly examined to ascertain their impact on intestinal health and activity, correlation with animals' effective health and well-being, productivity, food security and environmental impact. The potential uses of these feed additives depend on the properties of herbs, the comprehension of their principal and secondary components, knowledge of their mechanisms of action, the safety of animals and the products they produce. They are gaining recognition as effective and sustainable tools for promoting animal health and performance while reducing the reliance on antibiotics in nonruminant nutrition. Their natural origins, multifaceted benefits and alignment with consumer preferences make them a valuable addition to modern animal farming process. However, because of their inconsistent effects and inadequate knowledge of the mechanisms of action, their usage as a feed additive has been limited. This review offers a comprehensive assessment of the applications of PFAs as an effective feed supplement in swine and poultry nutrition. In summary, this comprehensive review provides current knowledge, identifies gaps in research and emphasizes the potential of phytogenic additives to foster sustainable and healthier livestock production systems while addressing the global concerns associated with antibiotic use in livestock farming.

Influence of using synbiotics by various routes on Mandarah male chicks: intestinal bacterial counts, gut morphology and histological status

This experiment investigated the influence of different synbiotic processing methods on the intestinal bacterial count, morphology and histological status of developed male Mandarah chicks. Two hundred and ten male Mandarah line chicks aged 1 d were randomized to receive one of 7 chicks. The method and dose for 1-time synbiotics administration to the day-old chicks were as follows: G1: chicks on basal diet received no treatment (control); G2: 0.25 mL synbiotics sprayed; G3: 0.50 mL synbiotics sprayed; G4: 0.25 mL of synbiotics are added to drinking water; G5: 0.50 mL of synbiotics are added to drinking water; G6: 0.25 mL of synbiotics dripped into the mouth; and G7: 0.50 mL of synbiotics dripped into mouth drops. Lactic acid bacteria(LAB) were significantly increased (P<0.0001) compared to the control group and other treated groups and had the maximum values after the use of synbiotics via drinking water (0.25 or 0.50 mL). Furthermore, when comparing the treated birds (G4, G5) with the control birds, the Escherichia coli concentration in the drinking water containing synbiotics was significantly lower. In addition, treated chickens at (G7) showed a higher duodenum, ileum villus height (VH), and VH. - Ileum crypt depth (CD) ratio compared to other groups. In addition, birds treated with 0.50 mL of synbiotics in drinking water (G5) performed better in duodenum, ileum, CD and VH. - CD ratio than the other groups. Meanwhile, intestinal tract length and visceral pH did not differ significantly between groups. It can be concluded that the use of 0.25 mL of synbiotics in drinking water can improve the overall health of birds.

Organ growth and fermentation profiles of broilers differing in body growth rate

This study sought to determine the relationship among broiler performance, organ development, and indicators of microbiota colonization. A total of 1,200 two-day-old male Ross 308 broiler chicks, divided among 3 cohorts of equal size, were housed in battery cages, and allotted based on body weight. On study d 11, birds were weighed, and birds with BW gain within the 10th and 90th percentiles were assigned to the Slow and Fast groups, respectively. Birds (n = 30 for each group) selected on d 11 were provided water and a corn-soybean meal-based diet ad libitum while maintained individually through study d 25 (i.e., a 14-d growth period). Parameters regarding growth performance, organ and intestine weights and lengths, and intestinal volatile fatty acid concentrations were measured. All data were analyzed by one-way ANOVA using the Mixed procedure of SAS. Fast birds exhibited greater (P < 0.001) BW gain and feed intake than slow birds, but feed conversion ratio (FCR) did not differ (P = 0.19). Additionally, Slow birds had higher (P < 0.05) relative weights (% of BW) for nearly all organs on d 11 and 25, most notably the gizzard, proventriculus, pancreas, and liver. Conversely, intestinal sections were longer (P < 0.05) in the Fast birds. Measurement of gut histomorphology did not show any notable differences between growth rate groups in terms of villi height, crypt depth, or their ratio for either time-point (P > 0.05). In terms of volatile fatty acid concentrations of luminal contents, acetate concentrations were 10.2% higher (P < 0.001) in the ileum of the Slow birds compared with Fast birds on d 25. Overall, the findings suggest that total BW gain is influenced by the development of metabolically active organs, as supported by lower weight gain in Slow birds with relatively larger organ weights and shorter intestinal lengths than their Fast counterparts. The general lack of differences in fermentation end-product concentrations in luminal contents does not rule out influence of the microbiota on growth rate of broilers, which warrants further investigation.

Expression of chicken epidermal growth factor (cEGF) in Escherichia coli regulates the microflora structure of the duodenum to improve growth performance and intestinal morphogenesis in broilers

1. A study used gene synthesis to obtain the functional domains of chicken epidermal growth factor (cEGF) and examined their impact on broiler growth performance, small intestinal morphology, digestive enzyme activities in the intestinal contents and the structure of duodenal microflora.2. The pET-32a-cEGF recombinant expression vector was constructed. The specific band at 26 KDa was shown by SDS-PAGE analysis and WB results. The purified protein content was shown to be 1687 μg/ml by assay.3. A total of 180 healthy, one-day-old Arbor Acres male, white-feathered broilers were randomly divided into three dietary treatment groups (six replicate pens, 10 birds per replicate): A control diet (ND); cEGF diet (cEGF), control supplemented with 250 mg/kg cEGF and the control diet (CD) supplemented with 250 mg/kg chlortetracycline.4. The results showed that feeding the cEGF and CD diet reduced FCR of broilers aged 1-21 d, average daily feed intake (ADFI) at 22-42 d, and the FCR in the whole period (1-42 d; p < 0.05). Compared with the ND group, the cEGF diet increased duodenal α-amylase and alkaline phosphatase activities in the 1-21 d, duodenal lipase, alkaline phosphatase, and ileal alkaline phosphatase activities in the post-period and increased villus height in the duodenum and ileum (p < 0.05). In addition, the ACE and Chao1 index for the birds fed cEGF were higher than the ND group (p < 0.05). At the phyla level, Firmicutes and Proteobacteria were dominant in all groups. At the genus level, the dominant genus was Lactobacillus. The LEfSe analysis showed that the cEGF group was enriched by 11 species including Brevibacillus, Eisenbergiella, Cloacibacterium, Butyricoccus spp.5. The addition of 250 mg/kg cEGF to the diet can increase growth performance by improving intestinal development and digestive enzyme activity, which may be related to the duodenal intestinal microflora. Therefore, cEGF is an effective alternative to antibiotics in broiler farming.

The Interactive Impacts of Corn Particle Size and Conditioning Temperature on Performance, Carcass Traits, and Intestinal Morphology of Broiler Chickens

This study aimed to investigate the interactions between corn particle size (PS) and conditioning temperature (CT) on the performance, carcass traits, intestinal morphology, and immune responses in broilers fed a corn-soybean meal-based diet. A total of 360 one-day-old male broiler chicks (Ross 308) were randomly allocated into six dietary treatments in a 2 × 3 factorial arrangement, consisting of two corn PS (finely ground with geometric mean diameter (GMD) of 357 µm (PSF) vs. coarsely ground corn with GMD of 737 µm (PSC), and three CT [unconditioned (CTU), conditioned at 75 °C (CT75) and 90 °C (CT90)]. Birds were accommodated in 30 pens with five replicates and 12 chicks per each pen. There was no interaction between corn PS and CT on the growth performance and immune response of broilers at any growth phases. However, during the starter (0-10 days) period, the average daily weight gain (ADWG) and feed conversion ratio (FCR) of PSF-fed birds were significantly improved compared to those fed PSC (p < 0.05). During the starter (0-10 days) and grower (11-24 days) periods, increasing the conditioning temperature of corn increased the ADWG, while in the starter phase only the CT75 caused a lower FCR (p < 0.05). Broilers fed PSF corn showed the lowest FCR during the finisher (25-42 days) period compared to those fed PSC (p < 0.05). Conditioning corn at 75 °C reduced FCR during the finisher (25-42 days) period compared to the birds fed CTU and CT90 corn (p < 0.05). In whole experimental periods (1-42 days), PSF and CT75 treatment increased the ADWG compared to the PSC and CTU (p < 0.05). The CT75 treatment improved primary total anti-sheep red blood cell (SRBCs) titer (IgT) and IgM and secondary IgT and IgG responses compared to the other experimental groups (CTU and CT90) (p < 0.05). No significant PS × CT interaction was found on the Newcastle disease (ND) antibody titer of broiler chickens (p > 0.05). Feeding CT75 corn reduced duodenum and jejunum relative lengths compared to the birds fed diets containing CTU corn. Significant PS × CT interactions (p < 0.05) were observed for villus height, villus height to crypt depth, crypt depth, muscle thickness, and absorption surface area of the jejunum. The highest carcass yield was observed in the PSF-CT75 group (p < 0.05). In conclusion, the use of finely ground corn (PSF) conditioned at 75 °C (CT75) was beneficial to growth performance, development of the digestive tract, jejunum histomorphometry and the immune responses of broilers.

Phage cocktail administration to reduce Salmonella load in broilers

Salmonella is a serious foodborne pathogen that can cause gastrointestinal disease through the consumption of contaminated foods; including poultry meat. Salmonella is commonly present in the intestinal tract of poultry and farm environments, posing a potential risk of contamination during the processing of poultry meat. This study was a continuation in evaluating the effects of our previously developed phage cocktail targeting Salmonella at large-scale trials in commercial broiler farms, in which this cocktail considerably lowered Salmonella colonization in the gut of broilers. The phage cocktail given to broilers showed resistance to temperatures of up to 65 °C (> 60% survivability), pH ranging from 2 to 12 (> 96% survivability), 0.5 to 15% (w/v) NaCl (> 98% survivability), chlorine up to 0.5% (v/v) (53% survivability), and chlorine neutralizer (100% survivability). In the animal challenge study, phage treatments, designed as "prevention" and "exclusion" programs, could control Salmonella on day 20 and 32 of the experiment, respectively; as indicated by the absence of Salmonella detection in cloacal swabs from broilers (0% prevalence). In the commercial-scale trial I, Salmonella was not detected in the phage-treated group from cloacal swabs, boot cover swabs, and bedding material samples after 16 days (0% prevalence) of phage administration. In the commercial-scale trial II, phage treatment extended the Salmonella control period in broilers during a 40-day growout period. In summary, a phage cocktail demonstrated high efficiency in controlling various serovars of Salmonella historically linked to contamination on these broiler farms. Phage cocktail application offers an effective, alternative to enhance food safety within the poultry value chain, protecting consumers and as well as the economic sustainability of the poultry sector.

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

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

Potential Effects of Garlic (Allium sativum L.) on the Performance, Immunity, Gut Health, Anti-Oxidant Status, Blood Parameters, and Intestinal Microbiota of Poultry: An Updated Comprehensive Review

The use of antibiotics as growth promoters or for the prevention of some poultry diseases has faced global concern and serious criticism. Their addition to poultry feed has shown hazardous effects, including the development of antimicrobial resistance and a potentially harmful effect on human health. To eliminate these threats, there is increasing interest in natural alternatives. Plant derivatives such as garlic (Allium sativum L.) and its derivatives are presently extensively used in the poultry production system. The dietary supplementation of broilers and layers with garlic induced improvement in the production parameters, carcass quality, and intestinal integrity. The modulation of the immune response against some important viral diseases has resulted from the supplementation of poultry with garlic. Moreover, garlic has been shown to modulate gut health through antibacterial and antiparasitic activities. Treatment with garlic can also mitigate oxidative stress and reduce free-radical production. The reduction of cholesterol levels and improvement of some liver and blood parameters were also reported following the dietary inoculation of garlic. This review was designed to investigate the influence of garlic as a dietary additive on the performance, immunity, gut health, anti-oxidant status, blood parameters, and intestinal microbiota of poultry.

Evaluation of Natural Antimicrobial Substances Blend as a Replacement for Antibiotic Growth Promoters in Broiler Chickens: Enhancing Growth and Managing Intestinal Bacterial Diseases

In recent years, commercial use of antibiotic growth promoter (AGP) has restrictions due to drug resistance against intestinal pathogenic bacteria: Escherichia coli, Salmonella, and Clostridium perfringens. Currently there is no single non-antibiotic treatment approach that is effective against intestinal illnesses in broiler chicken. Hence, present study aimed to analyze efficacy of blend of natural antimicrobial substances (probiotics, prebiotics, organic acids, and essential oils blend named as AGPR) as replacers of AGPs (BMD and CTC) for promoting growth and controlling bacterial diseases in aforementioned three microbes challenged broiler chickens. Effects of treatments (5) and microbes (3) on growth and health performances in experimental birds were analyzed using two factorial ANOVA. Health performance like pathogen loads, morbidity and mortality was considerably reduced by AGPR. Similarly small intestine villi morphometry, nutrition utilization, serum immune response, and carcass yield, was improved significantly by AGPR equivalent to AGPs. Further, growth performance like body weight gain, feed efficiency was also improved by AGPR compared to control but, non-significantly. Among three microbes, E. coli infections had higher morbidity and mortality rates. It was concluded that AGPR blend could be used to improve growth and control the intestinal bacterial infections in broiler chickens as an alternative for AGPs.

The effects of peppermint (Mentha piperita L.) and chicory (Cichorium intybus L.) in comparison with a prebiotic on productive performance, blood constituents, immunity and intestinal microflora in broiler chickens

A total of 320 one-day-old broiler chickens were used in a 42-day feeding trial to evaluate the effects of peppermint (Mentha piperita L.) and chicory (Cichorium intybus L.) in comparison with a prebiotic on-growth performance, blood constitutes, immunity and intestinal microflora. The dietary treatments were as follows: basal diet (control); control + prebiotic (Fermacto™); control + 0.1% peppermint; control + 0.1% chicory, respectively. A significant (p < 0.05) body weight gain and feed intake was found at 21 and 42 days of growth period in broilers fed diet supplemented with 0.1% chicory compared with other groups. Feeding of prebiotic or chicory led to higher (p < 0.05) feed intake. Chickens fed control diet had higher (p < 0.05) abdominal fat compared with the other groups. Serum blood constituents indicated that broilers fed prebiotic or supplemented with peppermint or chicory had reduced (p < 0.05) levels of cholesterol, triglycerides and low-density lipoprotein than control group. Immunity-related parameters showed that chicken fed chicory had lower (p < 0.05) heterophil-to-lymphocyte ratio compared with the other groups. Intestinal microflora revealed that chickens fed prebiotic or herbals had higher count of Lactobacillus and lower E. coli than control. Thus, it can be concluded that broiler dietary supplementation with prebiotic or chicory can improve performance supporting positively health status.

Dietary supplementation with different alternative to in-feed antibiotic improves growth performance of broilers during specific phases

The effects of substituting Bacillus subtilis, Astragalus membranaceus, and enzymes for aureomycin to improve the growth performance of broilers during specific phases were studied to develop alternatives to in-feed antibiotics and decrease drug residues in meat food and antibiotic resistance. Six hundred one-day-old broilers were randomly assigned to 5 groups. Broilers in the control group were supplied with basal diets (CT), and those in the remaining 4 groups were supplied with feed containing aureomycin premix (AU), B. subtilis powder (BS), A. membranaceus root powder (AM), and enzyme compound powder (EN), respectively. Compared to the control group, broilers in the other groups exhibited better growth performance during different phases. Microbial analysis of cecal contents suggested that treatment with BS or EN significantly increased the abundance of Lactobacillus or Bifidobacteria but inhibited Escherichia coli or Clostridium welchii; however, these bacteria were suppressed by AU treatment except C. welchii. The digestibility of the feed in vitro was significantly enhanced by adding BS or EN to the feed, consistent with findings for growth performance. In conclusion, dietary supplementation with 3 additives could improve the growth performance of broilers during specific phases. Future studies should focus on designing suitable schedules to partially replace in-feed antibiotics.

Potential Implication of in ovo Feeding of Phytogenics in Poultry Production

Hatchery's goals include maximizing revenue by achieving high hatchability with day-old birds of excellent quality. The advancement of technology has benefited the poultry sector since breeding and genetics technology have increased the rates of meat maturation in developing birds in a short period of time. Excessive use of in-feed antibiotics has been shown in studies to increase the chance of resistance to human infections. Bacterial resistance and antibiotic residues in animal products raised concerns about using antibiotics as growth promoters, eventually leading to a prohibition on using in-feed antibiotics in most industrialized nations. In ovo technology is a novel method for delivering bioactive chemicals to developing avian embryos. In ovo feeding technologies may provide additional nutrients to the embryos before hatching. The introduction of bioactive compounds has the potential to assist in decreasing and eventually eliminating the problems associated with traditional antibiotic delivery in chicken production. Phytobiotics were advocated as an alternative by researchers and dietitians. So far, several studies have been conducted on the use of phytogenic feed additives in poultry and swine feeding. They have primarily demonstrated that phytobiotics possess antibacterial, antioxidant, anti-inflammatory, and growth-stimulating properties. The antioxidant effect of phytobiotics can improve the stability of animal feed and increase the quality and storage duration of animal products. In general, the existing documentation indicates that phytobiotics improve poultry performance. To effectively and efficiently use the in ovo technique in poultry production and advance research in this area, it is important to have a thorough understanding of its potential as a means of nutrient delivery during the critical stage of incubation, its effects on hatching events and posthatch performance, and the challenges associated with its use. Overall, this review suggests that in ovo feeding of phytobiotics has the potential to improve the antioxidant status and performance of chickens.

Intestinal colonization with Campylobacter jejuni affects broiler gut microbiota composition but is not inhibited by daily intake of Lactiplantibacillus plantarum

Introduction

Lactobacilli may prevent broilers from colonization with Campylobacter spp. and other gram-negative zoonotic bacteria through lactic acid production and modulation of the intestinal microbiota. This study evaluated the effects of daily intake of Lactiplantibacillus plantarum 256 (LP256) on Campylobacter jejuni (C. jejuni) loads in ceca and feces of C. jejuni challenged broilers, together with the changes in the gut microbiota.

Methods

Two experiments were conducted using the broilers Ross 308 (R-308; Experiment 1) for 42 days and Rowan Ranger broilers (RR; Experiment 2) for 63 days. The LP256 strain was administered either via silage inoculated with LP256 or direct supplementation in the drinking water. Concurrently, haylage as a forage similar to silage but without any inoculum was tested. C. jejuni loads in fecal matter and cecal content were determined by plate counts and qPCR, respectively. The cecal microbiota, in response to treatments and the challenge, were assessed by 16S rRNA sequencing.

Results and Discussion

Culturing results displayed a significant reduction in C. jejuni colonization (2.01 log) in the silage treatment in comparison to the control at 1 dpi (day post-infection) in Experiment 1. However, no treatment effect on C. jejuni was observed at the end of the experiment. In Experiment 2, no treatment effects on C. jejuni colonization were found to be statistically significant. Colonization load comparison at the peak of infection (3 dpi) to that at the end of the trial (32 dpi) revealed a significant reduction in C. jejuni in all groups, regardless of treatment. Colonization dynamics of C. jejuni in the cecal samples analyzed by qPCR showed no difference between any of the treatments in Experiment 1 or 2. In both experiments, no treatment effects on the cecal microbiota were observed. However, proportional changes in the bacterial composition were observed after the C. jejuni challenge, suggesting that colonization affected the gut microbiota. Overall, the daily intake of LP256 was not effective in reducing C. jejuni colonization in either broiler type at the end of the rearing period and did not cause any significant changes in the birds' cecal microbiota composition.

Nutrigenomic profiling of reduced specification diets and phytogenic inclusion effects on critical toll-like receptor signaling, mitogen-activated protein kinase-apoptosis, and PI3K-Akt-mTOR gene components along the broiler gut

The effects of concurrent reduction of dietary metabolizable energy (ME) and crude protein (CP) levels combined or not with the dietary inclusion of a phytogenic feed additive (PFA) were studied using a nutrigenomics approach. In particular, the expression of 26 critical genes relevant for inflammation control (TLR pathway), cellular apoptosis (MAPK pathway) cell growth and nutrient metabolism (PI3K-Akt-mTOR pathway) was profiled along the broiler intestine. Two dietary types (L and H) differing in metabolizable energy and crude protein levels (L: 95% and H: 100% of optimal Cobb 500 recommendations for ME and CP requirements) supplemented or not with PFA (- or +) and their interactions (L-, L+, H-, H+) were evaluated. There were only 3 total interactions (mTOR, IL8, and HRAS P < 0.05) between diet type and PFA inclusion indicating limited concurrent effects. Diet type, L upregulated genes related with inflammation mainly in the jejunum, ileum, and cecum (P < 0.05) and MAPK pathway in the ileum and cecum (P < 0.05). Moreover, diet type L negatively affected the expression of genes related to PI3K-Akt-mTOR pathway mainly in duodenum and cecum (P < 0.05). On the other hand, PFA inclusion downregulated (P < 0.05) genes related with TLR signaling pathway (TLR2B, MyD88, TLR3, IL8, LITAF) along the intestine and MAPK pathway genes (APO1, FOS) in jejunum (P < 0.05). Finally, PFA supplementation regulated nutrient sensing and metabolism in the cecum in a manner perceived as beneficial for growth. In conclusion, the study results highlight that the reduced ME and CP specifications, especially in the absence of PFA, regulate inflammation, apoptosis and nutrient metabolism processes at homeostatic control levels that hinder maximizing the availability of dietary energy and nutrients for growth purposes. Inclusion of PFA helped to adjust the respective homeostatic responses and control to levels supporting broiler performance, especially at reduced specification diets.

Immunomodulatory Effects of Natural Feed Additives for Meat Chickens

Broiler chickens are increasingly kept in large numbers in intensive housing conditions that are stressful, potentially depleting the immune system. With the prohibition of the use of antibiotics in poultry feed spreading worldwide, it is necessary to consider the role of natural feed additives and antibiotic alternatives to stimulate the chickens' immune systems. We review the literature to describe phytogenic feed additives that have immunomodulatory benefits in broilers. We initially review the major active ingredients from plants, particularly flavonoids, resveratrol and humic acid, and then describe the major herbs, spices, and other plants and their byproducts that have immunomodulatory effects. The research reviewed demonstrates the effectiveness of many natural feed additives in improving the avian immune system and therefore broiler health. However, some, and perhaps all, additives have the potential to reduce immunocompetence if given in excessive amounts. Sometimes additives are more effective when given in combination. There is an urgent need to determine tolerance levels and optimum doses for additives deemed most suitable to replace antibiotics in the diet of broiler chickens. Effective replacement is most likely with readily available additives, such as olive oil byproducts, olive leaves and alfalfa. It is concluded that effective replacement of antibiotic function with plant-derived additives will be possible, but that further research is necessary to determine optimum doses.

Yeast Extract: Characteristics, Production, Applications and Future Perspectives

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

An evaluation of the thermoregulatory potential of in ovo delivered bioactive substances (probiotic, folic acid, and essential oil) in broiler chickens

Mitigating the negative effects of heat stress (HS) is a critical challenge for the global poultry industry. This study evaluated the thermoregulatory potential of 3 in ovo delivered bioactive substances using selected gut health parameters. Eggs were incubated and allotted to 5 groups, and respective bioactive substances delivered. These groups included-the noninjected, in ovo saline, in ovo folic acid (FA), in ovo probiotics (P), and in ovo essential oil (EO). At hatch, chicks were assigned to 5 new posthatch treatment combinations, including A) Negative control (NC)-noninjected eggs offered a basal corn-wheat-soybean diet, B) Antibiotics-NC + 0.05% bacitracin methylene disalicylate, C) In ovo FA-eggs injected with FA + NC diet, D) In ovo probiotics-eggs injected with probiotics + NC diet, E) In ovo + in-water EO-eggs injected with EO and supplied EO via drinking water + NC diet. Birds were raised for 28 d in 8 replicate cages/treatment (6 birds/cage) and exposed to either a thermoneutral (24°C ± 0.2) or HS challenge (31°C) condition from d 21 to d 28. The in ovo delivered FA and EO treatments reduced (P < 0.001) hatchability by at least 26% compared to NC. Induced HS reduced (P < 0.001) total plasma protein, total antioxidant capacity, and villus width in the duodenum and jejunum. Independent of HS and compared to NC, the in ovo + in-water EO treatment resulted in (P < 0.05) at least a 15% increase in villus height: crypt depth across the 3 gut sections. The in ovo + in-water EO treatment also increased the relative mRNA expression of intestinal barrier-related genes (Claudin1,3,4, Occludin, Zona occludens-2, and Mucin 2). Under HS, the in ovo + in-water EO treatment recorded a 3.5-fold upregulation of amino acid transporter gene (SLC1A1), compared to NC. Subject to further hatchability optimization, the in ovo + in-water delivery of EO show potential to afford broiler chicken thermotolerance.

The effect of Bacillus subtilis and its delivery route on hatch and growth performance, blood biochemistry, immune status, gut morphology, and microbiota of broiler chickens

This study evaluated the effect of probiotics (Bacillus subtilis fermentation extract) and its delivery route (in-feed or in ovo) on hatch and growth performance, blood biochemistry, immune status, gut morphology, and microbiota of broiler chickens. Hatching eggs were incubated for 21 d. On d 12, viable eggs were randomly allotted to 4 groups: the noninjected, in ovo saline (S), in ovo Bacillus subtilis 1 (P1), and in ovo Bacillus subtilis 2 (P2). On d 18, S, P1, and P2 groups received 0.2 mL saline diluent, 10 × 10⁶, and 20 × 10⁶ CFU of the bacterium via the amnion, respectively. At hatch, chicks were re-allotted to 5 new treatment groups: P1, P2, 0.005% in-feed Bacillus subtilis extract (P3), 0.05% in-feed bacitracin methylene disalicylate (BMD,), and corn-wheat-soybean diet negative control (NC) in 9 replicate pens (22 birds/pen) and raised for 35 d. Hatch parameters were assessed on d 0, and growth performance indices measured weekly. On d 25, 1 bird/cage was euthanized, and samples collected for further analysis. Data were analyzed by generalized linear model. Treatments S and P2 recorded higher (P = 0.01) chick BW/ Egg Weight values compared to the non-injected eggs. P3 and P2 reduced (P = 0.02) FI at week 5 compared to the NC treatment. However, no change in average body weight gain (ABG) and feed conversion ratio (FCR) were observed during the same period. At d 35, while BMD treatment showed a tendency (P = 0.09) to increase FI compared to the NC treatment, ABG and FCR were similar for all treatments. Blood sodium and chloride levels were increased (P < 0.05) by the BMD treatment compared to the NC treatment. Compared to other treatments, BMD and P3 treatments increased (P < 0.001) jejunal and ileal villus height to crypt depth ratios, respectively. However, P1 and P2 increased (P < 0.001) villus height to crypt depth ratio in the duodenum compared to NC treatment. Treatments did not affect gut microbial diversity; however, BMD treatment increased (P < 0.05) the proportion of bacteria in the genus Enterococcus in the ileum and reduced (P < 0.05) the proportion of bacteria in the genus Streptococcus in the ceca. All probiotics treatments (irrespective of route and dose) reduced (P < 0.001) the levels of serum IgG compared to the NC treatment. However, P1 and P2 had the lowest numerical decrease in serum IgG concentrations, suggesting that Bacillus subtilis (especially in ovo delivered) might provide broiler chickens with better immunological protection by neutralizing pathogenic organisms that could result in the production of natural antibodies.

Compound probiotics can improve intestinal health by affecting the gut microbiota of broilers

Probiotics, as a widely used additive, have played a unique advantage in replacing antibiotic products. As a result, the probiotic effects on broiler development, intestinal flora, intestinal barrier, and immunity were assessed by this investigation. Four hundred and eighty 1-day-old Arbor Acres broilers were randomly allotted to 4 groups of 5 replicates with 24 broilers each. The control was fed only a basal corn-soybean meal diet. Probiotics I, probiotics II, and probiotics III were fed basal diet and 1, 5, and 10 g/kg compound probiotics (Lactobacillus casei: Lactobacillus acidophilus: Bifidobacterium = 1:1:2), respectively. We found that broilers in the compound probiotic group exhibited better growth performance and carcass characteristics compared with control, especially among probiotics III group. The intestinal barrier-related genes relative expression of Claudin, Occludin, MUC2, and ZO-1 mRNA in the probiotic group increased at 21 and 42 d compared with control, especially among probiotics III group (P < 0.05). The early gut immune-related genes (TLR2, TLR4, IL-1β, and IL-2) mRNA increased compared with control, while the trend at 42 d was completely opposite to that in the earlier stage (P < 0.05). Among them, probiotics III group showed the most significant changes compared to probiotics II group and probiotics I group. Select probiotics III group and control group for 16S rDNA amplicon sequencing analysis. The 16S rDNA amplicon sequencing results demonstrated that probiotics increased the relative abundance of beneficial microbes such as o_Bacteroidales, f_Rikenellaceae, and g_Alistipes and improved the cecum's gut microbiota of 42-day-old broilers. Additionally, adding the probiotics decreased the relative abundance of harmful microbes such as Proteobacteria. PICRUSt2 functional analysis revealed that most proteins were enriched in DNA replication, transcription, and glycolysis processes. Therefore, this study can provide theoretical reference value for probiotics to improve production performance, improve intestinal barrier, immunity, intestinal flora of broilers, and the application of probiotics.

Effects of cumin (Cuminum cyminum L.) essential oil and chronic heat stress on growth performance, carcass characteristics, serum biochemistry, antioxidant enzyme activity, and intestinal microbiology in broiler chickens

This study was conducted on 600 one-day-old male broiler chicks, using a 2 × 6 factorial design (ambient temperature, A x feed additive, F), for a period of 42 days. The chicks assigned to different groups were exposed to thermoneutral (TN, 24 ± 1 °C) and constant heat stress (HT, 36 ± 1 °C) conditions, and were only fed on a basal diet, and a basal diet supplemented with either 100 mg/kg chloramphenicol, 50 IU/kg α-tocopherol, or 200, 400, and 600 mg/kg of cumin essential oil (CEO). The results showed that heat stress adversely affected performance and carcass characteristics, and increased both the mortality rate and footpad lesions. Moreover, constant chronic heat stress showed negative effects on serum biochemistry and the intestinal microbiota, increased antioxidant activity in both the plasma and breast meat, and increased counts of the pathogenic microorganisms in the small intestine. On the other hand, dietary CEO supplementation positively affected these parameters. CEO had a slight effect on performance, carcass characteristics, mortality rate and the incidence of footpad lesions. When compared to the control group, it was determined that CEO generally had a positive effect on lipid peroxidation in the plasma and tissues and decreased antioxidant enzyme activity. Furthermore, CEO positively affected serum biochemistry and counts of beneficial microorganisms in the small intestine.

Aloe vera: A Sustainable Green Alternative to Exclude Antibiotics in Modern Poultry Production

Over the past 50 years, there has been a rapid increase in the need for poultry meat on a global scale to meet the rising demand from health, ecology, safety and equity. However, there has been a significant rise in recent years in both public demand and scientific interest for organic poultry farming, particularly when using medicinal herbs due to the rising concern of antibiotic resistance in end users. Ban on the use of antibiotics in the poultry industry has resulted in the demand of herbs as alternatives to antibiotics. Various research efforts have illustrated the nutritional value of Aloe vera in improving growth performance and immune status and acting as an antibacterial and anticoccidial agent in poultry. Aloe vera has been used as a supplement in the form of gel, alcoholic extract, powder, polysaccharide and aqueous extract. Aloe vera contains more than 200 nutrients, bioactive compounds, polysaccharides and saponins. In the current review, we have detailed the effect of Aloe vera as an alternative to antibiotics on growth performance, antimicrobial and antiparasitic activities and blood biochemical alternations in poultry.

Impact of Supplementing Phytobiotics as a Substitute for Antibiotics in Broiler Chicken Feed on Growth Performance, Nutrient Digestibility, and Biochemical Parameters

To determine the level of application and the effectiveness of the use of plant feed additives from sweet chestnut wood extract (Castanea Sativa Mill) in the diet of Cobb-500 cross broiler chickens, four groups were formed via the balanced groups method. The chickens in the experimental groups were supplemented with sweet chestnut wood extract in the main diet rather than a feed antibiotic at an amount of 500 g per ton of compound starter feed and 250 g per ton of grower and finisher in the second experimental group; 650 g per ton of compound starter feed and 325 g per ton of grower and finisher in the third experimental group; and 800 g per ton of compound starter feed and 400 g per ton of grower and finisher in the fourth experimental group. Supplementation with phytobiotics led to an increase in the digestibility of the dry matter in the second and third groups compared to the first experimental group. Furthermore, broiler chickens supplemented with a medium dose of phytobiotics revealed a significant difference in both crude protein and fiber when compared to the second experimental group (91.95% and 12.11% vs. 88.98% and 10.07%, respectively). The preslaughter weight of the birds in the phytobiotics supplemented groups was higher than in those fed with the lowest dosage of phytobiotic by 5.47%, and the difference was significant. There were no significant differences in terms of the blood biochemical parameters between the groups. In summary, the inclusion of plant feed additives from sweet chestnut wood extract as a substitute for an antibacterial drug in the diet of broiler chickens did not deteriorate the blood biochemical parameters and improved the intensity of the nutrient digestion process. As a result, it enhanced the quality indicators of the broiler carcass during the entire growth period.

Role of Bacteriophages for Optimized Health and Production of Poultry

The poultry sector is facing infections from Salmonella, Campylobacter, Listeria and Staphylococcus spp., and Escherichia coli, that have developed multidrug resistance aptitude. Antibiotics cause disturbances in the balance of normal microbiota leading to dysbiosis, immunosuppression, and the development of secondary infections. Bacteriophages have been reported to lower the colonization of Salmonella and Campylobacter in poultry. The specificity of bacteriophages is greater than that of antibiotics and can be used as a cocktail for enhanced antibacterial activity. Specie-specific phages have been prepared, e.g., Staphylophage (used against Staphylococcus bacteria) that specifically eliminate bacterial pathogens. Bacteriophage products, e.g., BacWash^TM and Ecolicide PX have been developed as antiseptics and disinfectants for effective biosecurity and biosafety measures. The success of phage therapy is influenced by time to use, the amount used, the delivery mechanism, and combination therapy with other therapeutics. It is a need of time to build a comprehensive understanding of the use of bacteriophages in poultry production. The current review thus focuses on mechanisms of bacteriophages against poultry pathogens, their applications in various therapeutics, impacts on the economy, and current challenges.

Effects of dietary organic acids and probiotics on laying performance, egg quality, serum antioxidants and expressions of reproductive genes of laying ducks in the late phase of production

Five hundred and forty Cheery Valley ducks were used to investigate the effects of dietary supplementation of acidifier and compound probiotics, individually or in combination, on production performance, egg quality, immune and oxidative status, expression of reproductive, and calcium binding related genes from 42 wk to 48 wk of age. Ducks were randomly allocated to 9 treatment groups with 6 replicates and 10 ducks per replicate for each group. A 3 × 3 factorial arrangement, with 3 dietary inclusion levels of acidifier and probiotics (0, 2, and 3 g/kg acidifier; 0, 1, and 2 g/kg probiotics) were used. The acidifier used was mainly consisted of Benzoic acid, Fumaric acid, phosphoric acid, and formic acid. The main components of the probiotics were Bacillus subtilis and Clostridium butyricum. Dietary supplementation of probiotics improved the daily feed intake, egg production rate, and body weight of ducks (P < 0.05), and diet acidifier also increased the daily feed intake compared to the control (P < 0.01). Egg quality was improved by diet inclusion of probiotics, including Haugh unit, albumen height, egg shape index (P < 0.01), and eggshell hardness (P = 0.05). A significant increase in Haught unit and yolk weight was observed in ducks fed diet added with acidifier (P < 0.05). Acidifier supplementation reduced the total antioxidant capacity (T-AOC), immunoglobulin A (IgA), and IgG content and the catalase (CAT) activity in the serum (P < 0.05), in accompanied with an increased malondialdehyde (MDA) concentration (P < 0.05). Serum total superoxide dismutase (T-SOD) activities were improved by dietary inclusion of probiotics (P < 0.05). There was an interaction effects on serum IgA and IgG contents between acidifier and probiotics (P < 0.05). Diet supplementation of probiotics improved the ovary follicle-stimulating hormone receptor (FSHR) and estrogen receptor (ER) gene expressions (P < 0.01), while dietary acidifier reduced the transcription levels of FSHR and luteinizing hormone receptor (LHR) (P < 0.01) in ovary. In the uterus of the oviduct, expressions of FSHR, and carbonic anhydrase 2 (CA2) were also increased by diet probiotics (P < 0.01), and diet acidifier reduced the gene expressions of calbindin-D28k (CaBP-D28k) and CA2 (P < 0.05). Significant interaction effects between diet acidifier and probiotics were obtained on gene expressions of FSHR, LHR, and ovalbumin (OVAL) in the ovary (P < 0.05), and LHR, CaBP-D28k, and CA2 (P < 0.05) in the uterus. It can be concluded that production performance and egg quality of laying ducks can be improved in the late phase of reproduction by dietary inclusion of probiotics, while the organic acid mixture caused a decline in serum antioxidant and immune capacity of the ducks.

Modulation of growth performance, gut morphometry, and cecal microbiota in broilers by clove (Syzygium aromaticum) and tulsi (Ocimum sanctum) supplementation

In an epoch of the growing risk of antibiotic resistance, there is a dire need to establish an effective novel feeding practice for broiler nutrition as an alternative to antibiotics. Hence, the aim of the current study was to evaluate the impact of clove powder and tulsi extract on the growth performance, gut morphologic and morphometric indices, and cecal microbial status of broiler, as an alternative to antibiotic growth promoters (AGPs). Sixty day-old chicks of Cobb-500 strain were randomly divided into 4 groups, each having 15 birds. Chicks of the control group (T0) were fed commercial broiler feed with no additional supplementation. The treatment groups were offered commercial broiler feed and received clove powder and tulsi extract with drinking water at the rate of 0.5% + 2% (T1), 1% + 3% (T2), and 1.5% + 4% (T3), respectively. Results showed a nonlinear relationship with the dosage of clove and tulsi. All the growth parameters substantially (P < 0.05) improved in T2 while T1 and T3 showed no significant improvement compared to T0. The final body weight was significantly (P < 0.05) higher in T2. Giblet and offal weights showed no noticeable differences except in the intestine and heart where intestine weight markedly (P < 0.05) decreased in T3 and heart weight significantly (P < 0.05) increased in T1 and T2. Clove and tulsi supplementation substantially improved the villus height and villus surface area of the small intestine in T2 while the large intestine remained mostly unaffected by the treatment. Cecal microbial status significantly improved in all the treatment groups having increased (P < 0.05) Lactobacillus spp. count and decreased (P < 0.05) E. coli count compared to T0. Based on the aforementioned findings, it can be concluded that the combination of clove and tulsi can improve the growth performance and gut health of broilers which is largely dose-dependent and might be supplied as a potential alternative to AGPs.

Quantitative Proteomic Analysis Reveals Yeast Cell Wall Products Influence the Serum Proteome Composition of Broiler Chickens

With an ever-growing market and continual financial pressures associated with the prohibition of antibiotic growth promoters, the poultry industry has had to rapidly develop non-antibiotic alternatives to increase production yields. A possible alternative is yeast and its derivatives, such as the yeast cell wall (YCW), which have been proposed to confer selected beneficial effects on the host animal. Here, the effect of YCW supplementation on the broiler chicken was investigated using a quantitative proteomic strategy, whereby serum was obtained from three groups of broilers fed with distinct YCW-based Gut Health Products (GHP) or a control basal diet. Development of a novel reagent enabled application of ProteoMiner™ technology for sample preparation and subsequent comparative quantitative proteomic analysis revealed proteins which showed a significant change in abundance (n = 167 individual proteins; p < 0.05); as well as proteins which were uniquely identified (n = 52) in, or absent (n = 37) from, GHP-fed treatment groups versus controls. An average of 7.1% of proteins showed changes in abundance with GHP supplementation. Several effects of these GHPs including immunostimulation (via elevated complement protein detection), potential alterations in the oxidative status of the animal (e.g., glutathione peroxidase and catalase), stimulation of metabolic processes (e.g., differential abundance of glyceraldehyde-3-phosphate dehydrogenase), as well as evidence of a possible hepatoprotective effect (attenuated levels of serum α-glutathione s-transferase) by one GHP feed supplement, were observed. It is proposed that specific protein detection may be indicative of GHP efficacy to stimulate broiler immune status, i.e., may be biomarkers of GHP efficacy. In summary, this work has developed a novel technology for the preparation of high dynamic range proteomic samples for LC-MS/MS analysis, is part of the growing area of livestock proteomics and, importantly, provides evidential support for beneficial effects that GHP supplementation has on the broiler chicken.

Aspergillus awamori attenuates ochratoxin A-induced renal and cardiac injuries in rabbits by activating the Nrf2/HO-1 signaling pathway and downregulating IL1β, TNFα, and iNOS gene expressions

Ochratoxin A (OTA) is one of the most dangerous and that pollute agricultural products, inducing a variety of toxic effects in humans and animals. The current study explored the protective effect of different concentrations of Aspergillus awamori (A. awamori) against OTA (0.3 mg/kg diet) induced renal and cardiac damage by exploring its mechanism of action in 60 New Zealand white male rabbits. Dietary supplementation of A. awamori at the selected doses of 50, 100, and 150 mg/kg diet, respectively, for 2 months significantly improved the rabbit's growth performance; modulated the suppressed immune response and restored the altered hematological parameters; reduced the elevated levels of renal injury biomarkers such as urea, creatinine, and alkaline phosphatase; and increased serum total proteins concentrations. Moreover, it also declined enzymatic activities of cardiac injury biomarkers, including AST, LDH, and CK-MB. A. awamori alleviated OTA-induced degenerative and necrotic changes in the kidney and heart of rabbits. Interestingly, A. awamori upregulated Nrf2/OH-1 signaling pathway. Therefore enhanced TAC, CAT, and SOD enzyme activities and reduced OTA-induced oxidative and nitrosative stress by declining iNOS gene expression and consequently lowered MDA and NO levels. In addition to attenuating renal and cardiac inflammation via reducing IL-1β, TNF-α gene expressions in a dose-dependent response. In conclusion,this is the first report to pinpoint that dietary incorporation of A. awamori counteracted OTA-induced renal and cardiac damage by potentiating the rabbit's antioxidant defense system through its potent antioxidant, free radical scavenging, and anti-inflammatory properties in a dose-dependent response. Based on our observations, A. awamori could be utilized as a natural protective agent against ochratoxicosis in rabbits.

Oregano Oil Combined with Macleaya Cordata Oral Solution Improves the Growth Performance and Immune Response of Broilers

Simple Summary

Developing safe and effective antibiotic growth promoters (AGPs) substitutes is particularly important to improve animal health and production performance. As an essential plant oil, the oregano oil's main bioactive substance is carvacrol, which has been proven to have antioxidant, anti-inflammatory, antibacterial, and antiviral properties. The sanguinarine from macleaya cordata is the primary bioactive substance. Sanguinarine has anti-tumor, immune-enhancing, antibacterial, and anti-inflammatory effects. However, it has not been reported whether the compatibility of oregano oil and macleaya cordata extract could produce better results. This study is the first to report the effect of oregano oil combined with macleaya cordata oral solution on the growth of broilers. The oregano oil combined with macleaya cordata oral solution significantly improved the growth performance of broilers. At the same time, serum biochemical indices, serum antioxidant indices, serum immune indices, serum cytokines, and intestinal morphology were significantly improved. In summary, our results demonstrated that the mixed solution of oregano oil and macleaya cordata has substantial potential to be an alternative to AGPs for broilers to reduce costs and improve benefits. This study provides basic data and technical support for further research.

Abstract

The abuse of AGPs in animal husbandry has led to severe problems such as drug resistance and ecological, and environmental destruction, which seriously threaten human health and public health security. In recent years, extracts of oregano oil and macleaya cordata have become a hot spot in the research and application of AGP substitutes for their safety and high efficiency. This study is the first to report the effect of oregano oil combined with macleaya cordata oral solution on broiler growth performance. A total of 960 one-day-old broiler chickens were randomly divided into four treatment groups (240 chickens per group). Each treatment group was divided into six replicate groups (40 birds per replicate group). There were four groups in this study: the solvent control group, the oregano essential oil combined with macleaya cordata extract oral solution group (OS group), the oregano essential oil oral solution group (OEO group), and the macleaya cordata extract oral solution group (MCE group). Two chickens from each replicate group were collected and mixed into a composite sample. Six composite samples were obtained for each treatment group. The results showed that the oregano oil combined with macleaya cordata oral solution significantly improved the growth performance of broiler chickens. At the same time, serum biochemical indices, serum antioxidant indices, serum immune indices, serum cytokines, and intestinal morphology were significantly improved by the OS group. This study shows that oregano oil combined with macleaya cordata oral solution has substantial potential to be an alternative to AGPs for broilers.

Ileal profile of non-starch polysaccharides and oligosaccharides in response to exogenous enzymes in broiler chickens offered wheat- or maize-based diets under subclinical necrotic enteritis challenge

The present study evaluated the impacts of fibre-degrading enzymes on the profiles of non-starch polysaccharides (NSP) and oligosaccharides (OS) in the ileum of broiler chickens offered wheat- or maize-based diets under subclinical necrotic enteritis (NE) challenge. A 2 × 2 × 4 factorial arrangement of treatments was used. Factors were the following: NE challenge, no or yes; diet type, wheat- or maize-based; and supplemental enzymes, control (no enzyme), family 10 xylanase (XYN10), family 11 xylanase (XYN11) or β-mannanase (MAN). Birds in the challenged group were inoculated with Eimeria on d 9 and Clostridium perfringens on d 14 and 15. A 3-way interaction (P = 0.047) occurred on overall (d 0 to 16) weight gain. When NE was present, all the supplemental enzymes increased weight gain in birds fed the wheat-based diet; whereas in those fed the maize-based diet supplemental XYN10 and XYN11 decreased weight gain. When NE was absent, birds fed the wheat-based diet supplemented with XYN10 or MAN presented increased weight gain compared to non-supplemented birds, but no improvements with enzyme addition were observed in birds fed the maize-based diet. A 3-way interaction (P = 0.002) was observed on insoluble NSP level in the ileum. When NE was absent, all the supplemental enzymes reduced the ileal level of insoluble NSP, regardless of diet type. In the challenged birds, supplementing XYN10 and MAN reduced insoluble NSP level in the ileum, but only in birds fed the wheat-based diet. Ileal soluble NSP level was reduced by supplemental XYN11 and MAN, but only in birds fed the wheat-based diet, resulting in a 2-way diet type × enzyme interaction (P < 0.001). Ileal OS arabinose (P = 0.030) level was highest in birds offered the wheat-based diet supplemented with XYN11. Collectively, supplementation of NSP-degrading enzymes to the wheat-based diet enhanced bird performance regardless of NE challenge, with XYN11 significantly increasing oligosaccharide release. However, enzyme addition did not improve growth performance in birds fed maize-based diet, with supplemental XYN10 and XYN11 impeding weight gain when NE was present.

Influence of fermented feed additive on gut morphology, immune status, and microbiota in broilers

BACKGROUND

This study examined the effects of a solid-state fermented feed additive (FFA) on the small intestine histology/morphology, immunity and microbiota of broilers. Two hundred eighty-eight day-old Arbor Acre chicks, were randomly assigned to one of four groups (each group has 6 replicates, with each replicate containing 12 chickens). The negative control (NC; basal diet), the positive control (PC; basal diet +antibiotic 15 ppm), the fermented feed additive low dose (FFL; basal diet + 0.3 kg/t FFA), and the fermented feed additive high dose (FFH; 3 kg/t FFA) with Lactobacillus casei (L.casei).

RESULTS

The study found that the FFH and FFL groups gained more weight (1-21d) and the FFL and PC diets had better feed conversion ratio (P < 0.05) than the NC from 0-42d. The FFH group had higher villus height (P < 0.05) in the duodenum than the PC and villus height to crypt depth ratio VH/CD compared to PC and FFL groups. The FFL chickens had greater (P < 0.05) jejunal and ileal villus height than PC and NC groups respectively. The FFL group had a higher ileal VH/CD ratio (P < 0.05). Jejunum VH/CD was higher in FFL and FFH (P < 0.05) than PC (P < 0.05). FFH had a smaller thymus than NC (P < 0.05). FFA diets also increased IL-10 expression (P < 0.05). While IL-1 and TLR4 mRNA expression decreased (P < 0.05) compared to NC. The microbiota analysis showed that the microorganisms that have pathogenic properties such as phylum Delsulfobacterota and class Desulfovibriona and Negativicutes was also significantly reduced in the group treated with FFH and PC while microorganisms having beneficial properties like Lactobacillaceae family, Lactobacillus aviarus genus and Lactobacillus spp were also tended to increase in the FFH and FFL fermented feed groups compared to the PC and NC groups.

CONCLUSION

These findings suggested that the FFA diet may modulate cecal microbiota by reducing pathogenic microorganisms such as phylum Delsulfobacterota and class Desulfovibriona and Negativicutes improve beneficial microorganisms like Lactobacillaceae family, Lactobacillus aviarus genus and Lactobacillus spp. While FFA diet also affect immunity, and gene expression related to immunity.

Effects of Total Sulfur Amino Acids on Growth Performance, Immunity, and Meat Yield in Broilers Fed Diets With and Without Antibiotics

Two experiments were conducted to evaluate the effects of digestible sulfur amino acids (SAA) on performance, carcass yield, immunity, and amino acid transporters in broilers fed diets with or without an antibiotic growth promoter (AGP). In experiment 1, a total of 250 1-day-old Cobb500 male chicks were assigned to battery cages with two levels of AGP (0 and 0.05% bacitracin) and five levels of SAA (0.7, 0.8, 0.9, 1.0, and 1.1%) for 21 d. In experiment 2, a total of 900 1-day-old Cobb500 male chicks were assigned to floor pens with two levels of AGP and three levels of SAA for the starter (0.7, 0.8, and 0.9%) or finisher phase (0.52, 0.62, and 0.72%) for 42 d. In experiment 1, from 0 to 7 d, the body weight gain (BWG) was the lowest for birds fed 0.7% SAA. The AGP significantly decreased the feed conversion ratio (FCR), and birds fed 0.9 and 1.1% SAA had significantly lower FCR than 0.7% SAA. From 8 to 14 d, for the AGP-fed birds, the lowest BWG was observed in the 0.7% SAA group. In birds not fed AGP, birds fed 0.8% SAA had higher BWG than 0.7 and 1.1% SAA. Birds fed 0.7% SAA diet had lower feed intake (FI) than 0.8% SAA and higher FCR than 0.8, 0.9, and 1.0% SAA. In experiment 2, from 0 to 21 d, the lowest BWG and the highest FCR were observed in birds fed 0.7% SAA, whereas birds fed 0.9% SAA had the highest BWG and lowest FCR. From 22 to 42 d, FCR was lower for birds fed AGP, and for birds fed 0.72%. Interactions between the factors were found for FI and BWG. The whole thigh and wing weights were the highest for 0.62% SAA, and the pectoralis major weight was higher for birds fed 0.62% SAA than those fed 0.52% SAA. There was an interaction between SAA and AGP for Lat1 (large neutral amino acid transporter) expression, and AGP-fed birds had higher expression of ileal interleukin 1β (Il−1β gene). The interleukin 10 (Il-10) expression was upregulated in the ileum. There was an interaction between factors for sodium-dependent neutral amino acid transporter B [0] AT1 (SLC6A19) expression. The results suggested that both AGP and SAA supplementation would affect the growth performance of the broilers.

Effects of coated sodium butyrate on performance, egg quality, nutrient digestibility, and intestinal health of laying hens

This study determined the effects of coated sodium butyrate (CSB) on production performance, egg quality, nutrient digestibility, and intestinal health of laying hens. We divided a total of 800 Lohmann laying hens, aged 51 wk, into 4 treatment groups: 0 (CON), 300 (CSB1), 500 (CSB2), and 800 (CSB3) mg/kg of CSB. Each group comprised 20 birds, with 10 replicates set. A 12-wk monitoring process was conducted for each laying hen. Compared to CON, dietary supplementation of CSB did not affect the average daily feed intake or the egg weight. The CSB3 group demonstrated a linear increase in the production performance (P < 0.05), with decreased feed conversion ratio (P < 0.05). CSB2 and CSB3 exhibited markedly elevated egg mass (P < 0.05). The CSB supplementation markedly enhanced the yolk color (P < 0.05). CSB1 improved the digestibility of dry matter (P = 0.029). No significant differences were observed among dietary treatments in the duodenal morphology (P > 0.05). The three dosages of CSB reduced the crypt depth (P < 0.05) in the jejunum, whereas CSB3 exhibited an increase in the villus height (VH; P = 0.048). The CSB3 group showed a markedly elevated ileal VH (P = 0.011). CSB supplementation significantly increased the butyric acid content in the cecum (P = 0.009). The hens fed on the 800 mg/kg CSB diet showed a significant increase (P = 0.029) in butyric acid content in the ileum. The CSB3 group showed an elevation in microbial diversity (P < 0.05). Additionally, at the phylum level, the CSB3 increased the enrichment of Bacteroidetes, the CSB2 increased Firmicutes, and the abundance of Deferribacteres was increased in CSB2 and CSB3 groups (P < 0.05). An enrichment of Muribaculaceae (family) was observed in the CSB3 group. In conclusion, dietary supplementation of CSB improved production, yolk color, intestinal morphology, butyrate content, and microbial composition in laying hens.

Yeast-Derived Products: The Role of Hydrolyzed Yeast and Yeast Culture in Poultry Nutrition—A Review

Simple Summary

Yeast and yeast-derived products are largely employed in animal nutrition to support animals’ health and to improve their performance. Thanks to their components, including mannans, β-glucans, nucleotides, vitamins, and other compounds, yeasts have numerous beneficial effects. Among yeast-derived products, hydrolyzed yeasts and yeast cultures have received less attention, but, although the results are somewhat conflicting, in most of the cases, the available literature shows improved performance and health in poultry. Thus, the aim of this review is to provide an overview of hydrolyzed-yeast and yeast-culture employment in poultry nutrition, exploring their effects on the production performance, immune response, oxidative status, gut health, and nutrient digestibility. A brief description of the main yeast bioactive compounds is also provided.

Abstract

Yeasts are single-cell eukaryotic microorganisms that are largely employed in animal nutrition for their beneficial effects, which are owed to their cellular components and bioactive compounds, among which are mannans, β-glucans, nucleotides, mannan oligosaccharides, and others. While the employment of live yeast cells as probiotics in poultry nutrition has already been largely reviewed, less information is available on yeast-derived products, such as hydrolyzed yeast (HY) and yeast culture (YC). The aim of this review is to provide the reader with an overview of the available body of literature on HY and YC and their effects on poultry. A brief description of the main components of the yeast cell that is considered to be responsible for the beneficial effects on animals’ health is also provided. HY and YC appear to have beneficial effects on the poultry growth and production performance, as well as on the immune response and gut health. Most of the beneficial effects of HY and YC have been attributed to their ability to modulate the gut microbiota, stimulating the growth of beneficial bacteria and reducing pathogen colonization. However, there are still many areas to be investigated to better understand and disentangle the effects and mechanisms of action of HY and YC.

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.

Structural Modeling of Drosophila melanogaster Gut Cytochrome P450s and Docking Comparison of Fruit Fly Gut and Human Cytochrome P450s

Drosophila melanogaster is a prominent model organism in developmental biology research and in studies related to pathophysiological conditions like cancer and Alzheimer's disease. The fruit fly gut contains several cytochrome P450s (CYP450s) which have central roles in Drosophila development and in the normal physiology of the gut. Since the crystal structures of these proteins have not been deciphered yet, we modeled the structure of 29 different D. melanogaster gut CYP450s using Prime (Schrödinger). The sequences of chosen D. melanogaster gut CYP450s were compared with that of their human counterparts. The common gut (and liver) microsomal CYP450s in humans were chosen for structural comparison to find the homology and identity % of D. melanogaster CYPs with that of their human counterparts. The modeled structures were validated using PROCHECK and the best fit models were used for docking several known human pharmacological agents/drugs to the modeled D. melanogaster gut CYP450s. Based on the binding affinities (ΔG values) of the selected drug molecules with the modeled fly gut CYPs, the plausible differences in metabolism of the prominent drugs in humans and fly were projected. The gut is involved in absorption of oral drugs/pharmacological agents and hence, upregulation of intestinal CYP450 and their reactions with endobiotics and xenobiotics is envisaged. The insights gleaned from this work can validate D. melanogaster as a model organism for studying intestinal drug metabolism, particularly in the context of a) toxicology of pharmacological agents to the gut cells and b) how gut P450 metabolites/products can influence gut homeostasis. This work can help establish a platform for further in vitro investigations on how intestinal CYP450 metabolism can influence gut health. The data from this work can be used for further in silico studies and this work can serve as a platform for future in vitro investigations on intestinal CYP450-mediated metabolism of endo- and xeno-biotics in D. melanogaster.

Out-Look on Worldwide Trends of Related Studies on Citrus Waste as Feed for Livestock Production: A Scientometric Analysis

The present study aimed to reveal the abundant tapestry of research on citrus waste and livestock feed, taking into account the recurring challenges posed by feed shortage and high price of conventional animal feed in livestock farming. In total, 565 articles were retrieved in a BibTeX format for analysis using bibliometric package in R studio. The retrieved data included, but not restricted to authors, citations, keywords, journals, and institutions. Published outputs on citrus waste and animal feed for livestock production obtained from Scopus and web of science (WOS) databases were used in this study. The field of citrus waste and livestock feed research experienced an increase in terms of research outputs with an annual growth of 10.20% during the study period. Based on the country level, Brazil was rated first with an aggregate sum of publications (n = 81), with China having a huge global academic influence with most top article citations (n = 1,338). The topmost authors' keywords commonly used in the studied research area were citrus pulp (n = 48), pectin (n = 26), performance (n = 22), and citrus (n = 33), which created a hint on associated studies on citrus waste and livestock feed. The present study provides a global trend to traverse the intellectual quandary on citrus waste and livestock feed research, and guidance for further studies in this field. It is essential to stress that the present study only dealt with core areas of citrus waste and livestock feed research, hence, it is anticipated that new empirical research and prospective solutions would afford new knowledge insight on citrus waste and livestock feed as new studies evolve.

Performance and environmental impact of egg production in response to dietary supplementation of mannan oligosaccharide in laying hens: a meta-analysis

A meta-analysis was conducted to examine the effect of supplementing mannan oligosaccharide (MOS; Bio-Mos, Alltech Inc., Nicholasville, KY) in the diets of laying hens on the performance and environmental impact of egg production. Data on production performance (feed intake, hen-day production [HDP], feed conversion ratio [FCR], and mortality) and egg quality attributes (egg weight, egg mass, and eggshell thickness) were extracted from 18 studies to build a database of comparisons between nonsupplemented diets (control) and diets supplemented with MOS. A total of 4,664 laying hens were involved in the comparisons and the average MOS dosage and age of hens were 0.97 kg/ton and 44 wk, respectively. The dataset was analyzed using the random-effects model to estimate the effect size of MOS supplementation on production performance and egg quality attributes. The impact of feeding MOS on the carbon footprint (feed and total emission intensities) of egg production was evaluated by using the meta-analysis results of production performance to develop a scenario simulation that was analyzed by a life cycle assessment (LCA) model. Overall pooled effect size (raw mean difference) indicated that MOS supplementation did not affect feed intake. In contrast, HDP increased by +1.76% and, FCR and mortality reduced by -26.64 g feed/kg egg and -2.39%, respectively. Dietary MOS did not influence egg weight while egg mass increased (P < 0.01) by +0.95 g/day/hen and eggshell thickness tended to increase (P = 0.07) by +0.05 mm. Subgroup analysis indicated that dietary MOS exhibited consistent improvement on HDP and FCR under several study factors (age of hens, number of hens, production challenges, MOS dosage, and study duration). Additionally, the simulated LCA revealed that supplementing MOS decreased feed and total emission intensities of egg production by -1.3 and -1.5%, respectively. Overall, dietary supplementation of MOS at 1.0 kg/ton improved the production performance of laying hens and reduced the carbon footprint and, therefore, can enhance the sustainability credentials of egg production.

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.

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.

Antibacterial and Antibiofilm Activity of Selected Medicinal Plant Leaf Extracts Against Pathogens Implicated in Poultry Diseases

Antimicrobial resistant poultry pathogens are responsible for treatment failure and economic losses, and can also be a source of resistant zoonotic infections representing a risk to human health. In 2006 the European Union banned the use of antibiotics as growth promoters in farm animals and other regions are likely to follow suit. Alternative products and strategies are sought to help maintain animal gut health to reduce the prevalence of pathogens in the food chain. The minimum inhibitory concentration (MIC) of organic and aqueous leaf extracts of Alchornea laxiflora, Ficus exasperata, Morinda lucida, Jatropha gossypiifolia, Ocimum gratissimum, and Acalypha wilkesiana were tested against bacterial poultry pathogens including Staphylococcus aureus, Enterococcus faecalis, Salmonella spp., Escherichia coli, Campylobacter spp., and fungal species (Aspergillus fumigatus, Aspergillus flavus, and Candida albicans) using a 2-fold serial microdilution method. Activity of extracts against biofilms of the pathogens was done using a modified crystal violet staining in vitro assay. The safety of extracts was determined against Vero and Caco-2 cells using a tetrazolium-based in vitro assay. Acetone and cold water extracts of M. lucida had the best activity against three bacteria (MIC = 0.05-0.07 mg/ml) and two fungal (MIC = 0.03-0.15 mg/ml) organisms, respectively. The E. coli isolate and A. flavus were the most susceptible bacteria and fungi, respectively. Caco-2 cells generally displayed higher selectivity index (SI) values compared to Vero cells and average SI values against Vero and Caco-2 cells for both bacteria and fungi ranged from 0.01 to 4.48 and 0.005 to 16.41, respectively. All plant extracts had good anti-biofilm activity (>50%) against at least one organism. The disruption of established biofilm growth by the plant samples proved to be more difficult to achieve than efficacy against planktonic forms of bacteria. This study shows that some of the plant species are potential candidates as alternative feed additives in poultry production. In the future, a poultry feed trial to evaluate their in vivo efficacy as herbal feed additives will be conducted.