Potential for Development of an Escherichia coli—Based Biosensor for Assessing Bioavailable Methionine: A Review

Methionine is an essential amino acid for animals and is typically considered one of the first limiting amino acids in animal feed formulations. Methionine deficiency or excess in animal diets can lead to sub-optimal animal performance and increased environmental pollution, which necessitates its accurate quantification and proper dosage in animal rations. Animal bioassays are the current industry standard to quantify methionine bioavailability. However, animal-based assays are not only time consuming, but expensive and are becoming more scrutinized by governmental regulations. In addition, a variety of artifacts can hinder the variability and time efficacy of these assays. Microbiological assays, which are based on a microbial response to external supplementation of a particular nutrient such as methionine, appear to be attractive potential alternatives to the already established standards. They are rapid and inexpensive in vitro assays which are characterized with relatively accurate and consistent estimation of digestible methionine in feeds and feed ingredients. The current review discusses the potential to develop Escherichia coli-based microbial biosensors for methionine bioavailability quantification. Methionine biosynthesis and regulation pathways are overviewed in relation to genetic manipulation required for the generation of a respective methionine auxotroph that could be practical for a routine bioassay. A prospective utilization of Escherichia coli methionine biosensor would allow for inexpensive and rapid methionine quantification and ultimately enable timely assessment of nutritional profiles of feedstuffs

Establishment of \u3ci\u3eListeria monocytogenes\u3c/i\u3e in the Gastrointestinal Tract

Listeria monocytogenes is a Gram positive foodborne pathogen that can colonize the gastrointestinal tract of a number of hosts, including humans. These environments contain numerous stressors such as bile, low oxygen and acidic pH, which may impact the level of colonization and persistence of this organism within the GI tract. The ability of L. monocytogenes to establish infections and colonize the gastrointestinal tract is directly related to its ability to overcome these stressors, which is mediated by the efficient expression of several stress response mechanisms during its passage. This review will focus upon how and when this occurs and how this impacts the outcome of foodborne disease

TruncTrimmer: A First Step Towards Automating Standard Bioinformatic Analysis

Bioinformatic analysis is a time-consuming process for labs performing research on various microbiomes. Researchers use tools like Qiime2 to help standardize the bioinformatic analysis methods, but even large, extensible platforms like Qiime2 have drawbacks due to the attention required by researchers. In this project, we propose to automate additional standard lab bioinformatic procedures by eliminating the existing manual process of determining the trim and truncate locations for paired end 2 sequences. We introduce a new Qiime2 plugin called TruncTrimmer to automate the process that usually requires the researcher to make a decision on where to trim and truncate manually after importing and demultiplexing sequences in the Qiime2 pipeline. By automating this process and removing the need for manual interaction by the researcher, this plugin provides another opportunity to automate another standard bioinformatic analysis procedure

Source of Water and Potential Sanitizers and Biological Antimicrobials for Alternative Poultry Processing Food Safety Applications

The landscape of commercial poultry production is changing due to increasing trends in consumer preference for organic sources of poultry products. This is in part due to perceptions regarding food safety and environmental issues, along with concerns for livestock animal welfare. Consequently, alternative poultry production systems such as small-scale farming and mobile poultry processing units (MPPUs) have achieved a certain level of popularity. However, these alternative production systems, like conventional poultry processing systems, face food safety concerns, due to potential of Campylobacter and Salmonella prevalence. Unlike stationary processing systems, MPPUs may have limited access to sanitation products as they often attempt to comply with organic processing regulations. They may also have limited access to a consistent, high quality water supply which may pose additional food safety and microbial contamination concerns. Due to these food safety concerns and potential limitations on traditional sanitizers, botanicals, organic acids, dry acids, bacteriocins, and phages may offer alternative potential solutions to ensure poultry product safety. The objective of this review is to discuss food safety concerns within alternative poultry processing systems, particularly MPPUs, and describe potential sanitizer strategies

Organic Acids and Potential for Modifying the Avian Gastrointestinal Tract and Reducing Pathogens and Disease

Recently, antibiotics have been withdrawn from some poultry diets; leaving the birds at risk for increased incidence of dysbacteriosis and disease. Furthermore, mortalities occurring from disease contribute between 10 to 20% of production cost in developed countries. Currently, numerous feed supplements are being proposed as effective antibiotic alternatives in poultry diets, such as prebiotics, probiotics, acidic compounds, competitive exclusion products, herbs, essential oils, and bacteriophages. However, acidic compounds consisting of organic acids show promise as antibiotic alternatives. Organic acids have demonstrated the capability to enhance poultry performance by altering the pH of the gastrointestinal tract (GIT) and consequently changing the composition of the microbiome. In addition, organic acids, by altering the composition of the microbiome, protect poultry from pH-sensitive pathogens. Protection is further provided to poultry by the ability of organic acids to potentially enhance the morphology and physiology of the GIT and the immune system. Thus, the objective of the current review is to provide an understanding of the effects organic acids have on the microbiome of poultry and the effect those changes have on the prevalence of pathogens and diseases in poultry. From data reviewed, it can be concluded that the efficacy of organic acids on shifting microbiome composition is limited to the time of administration, the composition of the organic acid product, and the current health conditions of poultry

Applications of Microbiome Analyses in Alternative Poultry Broiler Production Systems

While most of the focus on poultry microbiome research has been directed toward conventional poultry production, there is increasing interest in characterizing microbial populations originating from alternative or non-conventional poultry production. This is in part due to the growing general popularity in locally produced foods and more specifically the attractiveness of free-range or pasture raised poultry. Most of the focus of microbiome characterization in pasture flock birds has been on live bird production, primarily on the gastrointestinal tract. Interest in environmental impacts on production responses and management strategies have been key factors for comparative microbiome studies. This has important ramifications since these birds are not only raised under different conditions, but the grower cycle can be longer and in some cases slower growing breeds used. The impact of different feed additives is also of interest with some microbiome-based studies having examined the effect of feeding these additives to birds grown under pasture flock conditions. In the future, microbiome research approaches offer unique opportunities to develop better live bird management strategies and design optimal feed additive approaches for pasture flock poultry production systems

A Review of Prebiotics Against Salmonella in Poultry: Current and Future Potential for Microbiome Research Applications

Prebiotics are typically fermentable feed additives that can directly or indirectly support a healthy intestinal microbiota. Prebiotics have gained increasing attention in the poultry industry as wariness toward antibiotic use has grown in the face of foodborne pathogen drug resistance. Their potential as feed additives to improve growth, promote beneficial gastrointestinal microbiota, and reduce human-associated pathogens, has been well documented. However, their mechanisms remain relatively unknown. Prebiotics increasing short chain fatty acid (SCFA) production in the cecum have long since been considered a potential source for pathogen reduction. It has been previously concluded that prebiotics can improve the safety of poultry products by promoting the overall health and well-being of the bird as well as provide for an intestinal environment that is unfavorable for foodborne pathogens such as Salmonella. To better understand the precise benefit conferred by several prebiotics, “omic” technologies have been suggested and utilized. The data acquired from emerging technologies of microbiomics and metabolomics may be able to generate a more comprehensive detailed understanding of the microbiota and metabolome in the poultry gastrointestinal tract. This understanding, in turn, may allow for improved administration and optimization of prebiotics to prevent foodborne illness as well as elucidate unknown mechanisms of prebiotic actions. This review explores the use of prebiotics in poultry, their impact on gut Salmonella populations, and how utilization of next-generation technologies can elucidate the underlying mechanisms of prebiotics as feed additives

Essential Oils as an Intervention Strategy to Reduce Campylobacter in Poultry Production: A Review

Campylobacter is a major foodborne pathogen and can be acquired through consumption of poultry products. With 1.3 million United States cases a year, the high prevalence of Campylobacter within the poultry gastrointestinal tract is a public health concern and thus a target for the development of intervention strategies. Increasing demand for antibiotic-free products has led to the promotion of various alternative pathogen control measures both at the farm and processing level. One such measure includes utilizing essential oils in both pre- and post-harvest settings. Essential oils are derived from plant-based extracts, and there are currently over 300 commercially available compounds. They have been proposed to control Campylobacter in the gastrointestinal tract of broilers. When used in concentrations low enough to not influence sensory characteristics, essential oils have also been proposed to decrease bacterial contamination of the poultry product during processing. This review explores the use of essential oils, particularly thymol, carvacrol, and cinnamaldehyde, and their role in reducing Campylobacter concentrations both pre- and post-harvest. This review also details the suggested mechanisms of action of essential oils on Campylobacter

Antiviral activity of a novel mixture of natural antimicrobials, in vitro, and in a chicken infection model in vivo.

The aim of this study was to test in vitro the ability of a mixture of citrus extract, maltodextrin, sodium chloride, lactic acid and citric acid (AuraShield L) to inhibit the virulence of infectious bronchitis, Newcastle disease, avian influenza, porcine reproductive and respiratory syndrome (PRRS) and bovine coronavirus viruses. Secondly, in vivo, we have investigated its efficacy against infectious bronchitis using a broiler infection model. In vitro, these antimicrobials had expressed antiviral activity against all five viruses through all phases of the infection process of the host cells. In vivo, the antimicrobial mixture reduced the virus load in the tracheal and lung tissue and significantly reduced the clinical signs of infection and the mortality rate in the experimental group E2 receiving AuraShield L. All these effects were accompanied by a significant reduction in the levels of pro-inflammatory cytokines and an increase in IgA levels and short chain fatty acids (SCFAs) in both trachea and lungs. Our study demonstrated that mixtures of natural antimicrobials, such AuraShield L, can prevent in vitro viral infection of cell cultures. Secondly, in vivo, the efficiency of vaccination was improved by preventing secondary viral infections through a mechanism involving significant increases in SCFA production and increased IgA levels. As a consequence the clinical signs of secondary infections were significantly reduced resulting in recovered production performance and lower mortality rates in the experimental group E2

Listeria Occurrence and Potential Control Strategies in Alternative and Conventional Poultry Processing and Retail

Listeria monocytogenes is a psychrotrophic Gram positive organism that is considered one of the more critical foodborne pathogens of public health concern. To prevent illness the USDA and FDA enforce a zero-tolerance policy for Listeria on ready-to-eat foods such as delicatessen meats and poultry. Regardless, L. monocytogenes can still be isolated from food production facilities and retail products, indicating that current sanitation methods are not always sufficient. Both conventional and alternative poultry production and processing systems have also been identified as potential sources of Listeria spp. Concerns associated with alternative poultry production and processing can be further exacerbated by limitations on sanitation and available antimicrobials for usage in organic and natural poultry products. Furthermore, mobile poultry processing units often process organic and small-scale poultry farms that are not able to be processed by conventional standing facilities. These alternative production facilities and their products are often exempt from federal inspection, due to processing a relatively low number of carcasses. Due to these exemptions, it is unknown if sufficient sanitation is applied in these alternative processing facilities to prevent L. monocytogenes contamination. Organic processing restrictions may also impact which sanitizers and antimicrobials can be utilized. This review describes variations between conventional and mobile poultry processing units in conjunction with how L. monocytogenes may persist in the processing environment and on retail products. This review will also examine alternative antimicrobials proven to be effective against Listeria spp. and potentially be acceptable for use in alternative poultry production systems