No abstract

The purpose of this study was to 1) identify microbial compositional changes on chicken carcasses during processing, 2) determine the antimicrobial efficacy of peracetic acid (PAA) and Amplon (blend of sulfuric acid and sodium sulfate) at a poultry processing pilot plant scale, and 3) compare microbial communities between chicken carcass rinsates and recovered bacteria from media. Birds were collected from each processing step and rinsates were applied to estimate aerobic plate count (APC) and Campylobacter as well as Salmonella prevalence. Microbiome sequencing was utilized to identify microbial population changes over processing and antimicrobial treatments. Only the PAA treatment exhibited significant reduction of APC at the post chilling step while both Amplon and PAA yielded detectable Campylobacter reductions at all steps. Based on microbiome sequencing, Firmicutes were the predominant bacterial group at the phyla level with over 50% frequency in all steps while the relative abundance of Proteobacteria decreased as processing progressed. Overall microbiota between rinsate and APC plate microbial populations revealed generally similar patterns at the phyla level but they were different at the genus level. Both antimicrobials appeared to be effective on reducing problematic bacteria and microbiome can be utilized to identify optimal indicator microorganisms for enhancing product quality.

Feed additives that can modulate the poultry gastrointestinal tract and provide benefit to bird performance and health have recently received more interest for commercial applications. Such feed supplements offer an economic advantage because they may directly benefit poultry producers by either decreasing mortality rates of farm animals, increasing bird growth rates, or improve feed efficieny. They can also limit foodborne pathogen establishment in bird flocks by modifying the gastrointestinal microbial population. Prebiotics are known as non-digestible carbohydrates that selectively stimulate the growth of beneficial bacteria, thus improving the overall health of the host. Once prebiotics are introduced to the host, 2 major modes of action can potentially occur. Initially, the corresponding prebiotic reaches the intestine of the chicken without being digested in the upper part of the gastrointestinal tract but are selectively utilized by certain bacteria considered beneficial to the host. Secondly, other gut activities occur due to the presence of the prebiotic, including generation of short-chain fatty acids and lactic acid as microbial fermentation products, a decreased rate of pathogen colonization, and potential bird health benefits. In the current review, the effect of prebiotics on the gastrointestinal tract microbiome will be discussed as well as future directions for further research.

Fermentation metabolites of Diamond V Original XPC™ (XPC), a biological product derived from yeast fermentation, were evaluated for their ability to reduce the Salmonella Typhimurium population using an in vitro mixed anaerobic culture system containing cecal microbiota to simulate chicken hindgut conditions. Four different samples were prepared: anaerobic mixed culture containing (1) feed only, (2) cecal only (ceca were harvested from 42 days old broiler chickens), (3) feed and cecal contents, and (4) feed, cecal contents, and 1% XPC. Two experimental conditions were investigated: Group 1, in which the cecal content was added at the same time as a S. Typhimurium marker strain and Group 2, in which the cecal content was preincubated for 24 h prior to the inoculation with the S. Typhimurium marker strain. The mixed cultures were incubated anaerobically at 37°C, and the S. Typhimurium marker strain was enumerated at 0, 24, and 48 h. Analysis of short chain fatty acids was also conducted for 24 h. In the Group 1 experiment, adding XPC did not exhibit significant reduction of S. Typhimurium. However, the presence of XPC resulted in rapid reduction of S. Typhimurium in Group 2. S. Typhimurium was reduced from 6.81 log10 CFU/ml (0 h) to 3.73 log10 CFU/ml and 1.19 log10 CFU/ml after 24 and 48 h, respectively. These levels were also 2.47 log10 and 2.72 log10 lower than the S. Typhimurium level recovered from the control culture with feed and cecal contents, but without XPC. Based on these results, it appears that the ability of XPC to reduce S. Typhimurium requires the presence of the cecal microbiota. Short chain fatty acid analysis indicated that acetate and butyrate concentrations of cultures containing XPC were twofold greater than the control cultures by 24 h of anaerobic growth. Results from the present study suggest that dietary inclusion of XPC may influence cecal microbiota fermentation and has the potential to reduce Salmonella in the cecum. Implications of these findings suggest that XPC may decrease preharvest levels of Salmonella in broilers and layers.

Campylobacter as an inhabitant of the poultry gastrointestinal tract has proven to be difficult to reduce with most feed additives. In-feed antibiotics have been taken out of poultry diets due to the negative reactions of consumers along with concerns regarding the generation of antibiotic resistant bacteria. Consequently, interest in alternative feed supplements to antibiotics has grown. One of these alternatives, prebiotics, has been examined as a potential animal and poultry feed additive. Prebiotics are non-digestible ingredients by host enzymes that enhance growth of indigenous gastrointestinal bacteria that elicit metabolic characteristics considered beneficial to the host and depending on the type of metabolite, antagonistic to establishment of pathogens. There are several carbohydrate polymers that qualify as prebiotics and have been fed to poultry. These include mannan-oligosaccharides and fructooligosaccharides as the most common ones marketed commercially that have been used as feed supplements in poultry. More recently, several other non-digestible oligosaccharides have also been identified as possessing prebiotic properties when implemented as feed supplements. While there is evidence that prebiotics may be effective in poultry and limit establishment of foodborne pathogens such as Salmonella in the gastrointestinal tract, less is known about their impact on Campylobacter. This review will focus on the potential of prebiotics to limit establishment of Campylobacter in the poultry gastrointestinal tract and future research directions.