Antimicrobial Bacillus: Metabolites and Their Mode of Action

The agricultural industry utilizes antibiotic growth promoters to promote livestock growth and health. However, the World Health Organization has raised concerns over the ongoing spread of antibiotic resistance transmission in the populace, leading to its subsequent ban in several countries, especially in the European Union. These restrictions have translated into an increase in pathogenic outbreaks in the agricultural industry, highlighting the need for an economically viable, non-toxic, and renewable alternative to antibiotics in livestock. Probiotics inhibit pathogen growth, promote a beneficial microbiota, regulate the immune response of its host, enhance feed conversion to nutrients, and form biofilms that block further infection. Commonly used lactic acid bacteria probiotics are vulnerable to the harsh conditions of the upper gastrointestinal system, leading to novel research using spore-forming bacteria from the genus Bacillus. However, the exact mechanisms behind Bacillus probiotics remain unexplored. This review tackles this issue, by reporting antimicrobial compounds produced from Bacillus strains, their proposed mechanisms of action, and any gaps in the mechanism studies of these compounds. Lastly, this paper explores omics approaches to clarify the mechanisms behind Bacillus probiotics.

Performance of distinct microbial based solutions in a Campylobacter infection challenge model in poultry

Background Antibiotic growth promoters (AGPs) are commonly used within poultry production to improve feed conversion, bird growth, and reduce morbidity and mortality from clinical and subclinical diseases. Due to the association between AGP usage and rising antimicrobial resistance, the industry has explored new strategies including the use of probiotics and other microbial-based interventions to promote the development of a healthy microbiome in birds and mitigate against infections associated with food safety and food security. While previous studies have largely focused on the ability of probiotics to protect against Clostridium perfringens and Salmonella enterica, much less is known concerning their impact on Campylobacter jejuni, a near commensal of the chicken gut microbiome that nevertheless is a major cause of food poisoning in humans. Results Here we compare the efficacy of four microbial interventions (two single strain probiotics, the bacterium—Pediococcus acidilactici, and the yeast—Saccharomyces cerevisiae boulardii; and two complex, competitive exclusion, consortia—Aviguard and CEL) to bacitracin, a commonly used AGP, to modulate chicken gut microbiota and subsequently impact C. jejuni infection in poultry. Cecal samples were harvested at 30- and 39-days post hatch to assess Campylobacter burden and examine their impact on the gut microbiota. While the different treatments did not significantly decrease C. jejuni burden relative to the untreated controls, both complex consortia resulted in significant decreases relative to treatment with bacitracin. Analysis of 16S rDNA profiles revealed a distinct microbial signature associated with each microbial intervention. For example, treatment with Aviguard and CEL increased the relative abundance of Bacteroidaceae and Rikenellaceae respectively. Furthermore, Aviguard promoted a less complex microbial community compared to other treatments. Conclusions Depending upon the individual needs of the producer, our results illustrate the potential of each microbial interventions to serve flock-specific requirements.

Phytogenic Feed Additives as An Alternative to Antibiotic Growth Promoters in Poultry Nutrition

Phytoadditives in animal nutrition have attracted a lot of attention for their potential role as alternatives to antibiotic growth promoters. Phytoadditives are feed additives originated from plants or botanicals that are used in poultry nutrition. This chapter provides an overview about the potency of alternative additive from plants as a basis for exploring it as a phytoadditive for poultry. These substances are derived from herbs, spices, and other plants and their extracts. They are natural, less toxic, residue free and ideal feed additives for poultry when compared to synthetic antibiotics. There efficacy of phytogenic applications in poultry nutrition depends on several factors, such as composition and feed inclusion level of phytogenic preparations, bird genetics, and overall diet composition. Addition of 100 mg/kg feed essential oils consist of carvacrol, thymol and limonene in matrix encapsulation improved performance and apparent ideal digestibility of nutrients of broiler chickens. Besides enhancing performance, phytogenic also has antioxidant, the effects of which are associated with essential oils (EOs) and their components. Administration of eucalyptus and peppermint oil blends by oral (0.25 ml/L drinking water) and spray route (0.1 ml/20 ml water) reduced Newcastle disease infection in broilers. Phytoadditives have antimicrobial, antifungal, antiviral, antitoxigenic, antiparasitic and insecticidal properties. The benefits of using phytoadditives in poultry nutrition are increased feed intake, stimulation of digestion, increased growth performance, reduced incidence of disease, improved reproductive parameters, feed efficiency, profitability. Based on the latest scientific findings presented in this chapter, the following main conclusions have been drawn that phytomolecule and that bioactives have potential to be developed as an alternative additive for poultry, and that promote health.

Glycerol Monolaurate Attenuated Immunological Stress and Intestinal Mucosal Injury by Regulating the Gut Microbiota and AMPK/NF-κB/Nrf2 Signaling Pathway in Lipopolysaccharide-Challenged Broilers

Background Antibiotic residues and resistance issues have led to the ban on antibiotic growth promoters in the poultry industry. Targeted dietary supplementation such as glycerol monolaurate (GML) has been found to ameliorate the negative effects of restriction on the use of antibiotic growth promoters by modulating the animal immune system and intestinal health. However, the mechanism by which GML contributes to the health and growth of broilers is indistinct. This study was conducted to investigate the effects of GML on immunity, intestinal barrier function, and cecal microbiota profiles in lipopolysaccharide (LPS)-challenged broilers. Results The results revealed that dietary GML intake augmented serum immunoglobulin A and G levels in LPS-challenged broilers. GML supplementation normalized LPS-induced variations in serum interleukin-6, interferon-γ, and LPS levels; jejunal villus height; and gene expression of interleukin-6, macrophage inflammatory protein-3α, toll-like receptor 4, nuclear factor kappa-B (NF-κB), caspase-1, tight junction proteins, adenosine monophosphate-activated protein kinase α1, nuclear factor-erythroid 2-related factor 2, and superoxide dismutase-1. GML administration ameliorated LPS-induced peroxidation by reducing malondialdehyde content and increasing antioxidant enzyme activity. Dietary GML intake enhanced the abundances of cecal probiotics such as Blautia, Lactobacillus, and Coprobacter in challenged broilers. The LPS-induced reduction in Anaerostipes, Pseudoflavonifractor, and Gordonibacter abundances in the cecum was inhibited by GML supplementation. Dietary GML intake was positively correlated with alterations in antioxidant enzyme activities and adenosine monophosphate-activated protein kinase (AMPK) α1, nuclear factor-erythroid 2-related factor 2 (Nrf2), and zonula occludens-1 levels. The genera Anaerostipes, Lachnospira, Gordonibacter, Lachnospira, Marvinbryantia, Peptococcus, and Pseudoflavonifractor were linked to attenuated inflammation and improved immunity and antioxidant capacity of LPS-challenged broilers. Conclusion Dietary GML intake alleviated LPS-induced immunological stress and intestinal injury in broilers. This beneficial effect of GML supplementation was attributed to the suppression of inflammation and oxidative stress by regulation of cecal microbiota and the AMPK/NF-κB/Nrf2 signaling pathway in LPS-challenged broilers.

Analysis of broiler farming business systems without Antibiotic Growth Promoters (AGP) in traditional farms

The broiler farming industry cannot be separated from the use of Antibiotic Growth Promoter (AGP) in feed ingredients, but the negative impact of the utilization of AGP has led to a ban which has been in effect since January 2018. This study aims to analyze various factors and their relationship in broiler farming, so that it can be seen how the broiler farming business system runs after the ban of AGP. The research was conducted using a survey method on broiler farmers in one of the partner companies. Data analysis was carried out qualitatively using Causal Loop Diagram modeling. The results showed that the use of AGP was not the only factor that influenced the success of broiler farming. Other factors that affect broiler farming include maintenance management, cage quality and farmer quality. In addition to the regulation and arrangement of the broiler marketing trade system, efforts or strategies to improve broiler farming business include setting production standards based on the quality of the SAPRONAK used, upgrading open house cages to semi closed houses and improving the quality of farmers, especially motivation and education.

Dietary inulin supplementation modulates the composition and activities of carbohydrate-metabolizing organisms in the cecal microbiota of broiler chickens

Inulin is a highly effective prebiotic and an attractive alternative to antibiotic growth promoters for increasing production and maintaining health in chickens. However, how inulin elicits its effects on members of the intestinal microbiota is unknown, even though their importance for energy metabolism and the health of chickens is well documented. A combination of 16S rRNA Illumina sequencing and transcriptomic analysis was used to investigate the effects of supplementing a corn-based basal diet with 1, 2, or 4% inulin or 400 ppm bacitracin on the composition, diversity and activities of carbohydrate-metabolizing organisms (CMOs) in the cecal microbiota of broiler chickens. We found that members of Bacteroides were the most abundant non-starch degrading CMOs, contributing 43.6–52.1% of total glycoside hydrolase genes and 34.6–47.1% activity to the meta-transcriptomes of chickens in the different dietary groups, although members of Parabacteroides, Prevotella, Alistipes, Clostridium, Barnesiella, Blastocystis, Faecalibacterium and others were also actively involved. Inulin and bacitracin inclusion in the basal diet did not change significantly the composition or diversity of these CMOs. Inulin supplementation at three levels promoted the activities of Bacteroides, Prevotella and Bifidobacterium, and 2% level appears to be the most optimal dosage for bifidobacterial activity.