Inclusion of trans-cinnamaldehyde and caprylic acid in feed results in detectable concentrations in the chicken gut and reduces foodborne pathogen carriage

Authors: Lyte, Joshua - Josh; Arsi, Komala; Caputi, Valentina; LIYANAGE, ROHANA - University Of Arkansas; ASSUMPCAO, ANNA - University Of Arkansas; Jesudhasan, Palmy; Donoghue, Ann - Annie

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2023
Publication Date: 12/28/2023
Citation: Lyte, J.M., Arsi, K., Caputi, V., Liyanage, R., Assumpcao, A., Jesudhasan, P., Donoghue, A.M. 2023. Inclusion of trans-cinnamaldehyde and caprylic acid in feed results in detectable concentrations in the chicken gut and reduces foodborne pathogen carriage. Poultry Science. 103(2). Article 103368. https://doi.org/10.1016/j.psj.2023.103368.
DOI: https://doi.org/10.1016/j.psj.2023.103368

Interpretive Summary: Phytochemicals are natural compounds obtained from plants. Select phytochemicals are often used in agricultural and food production to improve food safety, quality, and other important measures. In poultry production, phytochemicals are often included in bird feed as a 'generally recognized as safe' (GRAS) component that effectively reduces foodborne pathogen carriage in the chicken gastrointestinal tract; thereby increasing the food safety of poultry products. Several foodborne pathogens are typically acquired by chickens from the production environment. Little is known, however, whether the phytochemicals when consumed in feed reach the gastrointestinal sites where foodborne pathogens are found in the bird, and reduce the natural routes of foodborne pathogen infection in broiler chickens. This is a critically important question considering different phytochemicals have varying ability in reducing different types of foodborne pathogen bacteria. No study to date has investigated whether two widely used phytochemicals, namely trans-cinnamaldehyde (originally obtained from cinnamon tree bark) and caprylic acid (found naturally in coconut oil and other foods), when provided in feed are subsequently detectable in the gastrointestinal tract of chickens and whether this coincides with a reduction in foodborne pathogen carriage. The results of this study demonstrate that when added to feed, trans-cinnamaldehyde and caprylic acid are detectable in the gastrointestinal tract of broiler chickens. Notably, we found these two phytochemicals are efficacious in preventing natural routes of foodborne pathogen acquisition by broiler chickens yet have distinct distributions in the gastrointestinal tract. This study provides poultry producers and scientists critical information regarding the fate of in-feed phytochemicals and their effect on curbing natural routes of foodborne pathogen acquisition, thereby providing a platform for precision targeting of the broiler chicken gastrointestinal tract to improve food safety.

Technical Abstract: Poultry act as a major reservoir host for Salmonella and Campylobacter spp., the two leading causes of foodborne illnesses globally and in the United States. Pre-harvest stage interventions to reduce foodborne pathogen carriage in poultry are increasingly informed by consumer preference for antibiotic-free poultry production. The in-feed inclusion of plant-derived antimicrobial compounds is a promising antibiotic alternative strategy to reduce foodborne pathogen load in the broiler chicken gut. Yet, the fate of these phytochemicals through the broiler chicken gastrointestinal tract is unknown. Likewise, while in-feed phytochemicals have been widely demonstrated in challenge models to reduce foodborne pathogen carriage, little is known regarding efficacy to curb natural routes of infection. As such, the aim of the present study was two-fold. We sought to determine the concentrations of two phytochemicals, trans-cinnamaldehyde and caprylic acid, in each region of the chicken gastrointestinal tract following their in-feed inclusion over a six-week production period. In addition, we investigated how the in-feed provision of these phytochemicals may protect against environmental acquisition of Campylobacter jejuni and Salmonella spp. Trans-cinnamaldehyde and caprylic acid were detected in crop, gizzard, duodenal, jejunal, and ileal contents. Crop and gizzard concentrations were not significantly (P > 0.05) different. A significant (P < 0.05) decrease in phytochemical concentration was observed in intestinal regions compared to crop and gizzard. Trans-cinnamaldehyde was consistently identified in cecal and colon contents, while caprylic acid was not detectable in these regions. Trans-cinnamaldehyde and caprylic acid were found to reduce (P < 0.05) Salmonella load. Together, our data establish that the in-feed addition of trans-cinnamaldehyde and caprylic acid, two phytochemicals that have previously been shown to exert antimicrobial activity against poultry-associated foodborne pathogens, results in detectable concentrations in the broiler chicken gastrointestinal tract. By providing researchers with a gastrointestinal region-by-region map of phytochemical concentrations, the present study is expected to inform the choice of in-feed phytochemicals targeting foodborne pathogen carriage in the broiler chicken gastrointestinal tract.