Reduced Campylobacter jejuni colonization in poultry gut with bioactive phenolics

This study was designed to determine the effects of bioactive phenolics (BPE) extracted from blackberry ( Rubus fruticosus ) and blueberry ( Vaccinium corymbosum ) byproducts/pomaces on Campylobacter jejuni colonization in broiler cecum. We raised a total of 120 Cobb-500 broiler chicks in duplicate trials up to 3 weeks to determine the effect of BPE on the reduction of colonization using a C. jejuni RM1221 marker strain in broiler cecum. We observed that, as a water supplement, 1.0 g Gallic Acid Equivalent (GAE)/L of BPE reduced C. jejuni colonization level by 1 log in three weeks old broiler cecum compared to the control group. 1 g GAE/L of BPE also resulted a complete inhibition of the C. jejuni marker strain in drinking water with a potential for reduced horizontal transfer in poultry flocks. In a separate experiment, we also raised a total of 200 Cobb-500 broilers in duplicate trials up to 6 weeks to investigate natural colonization of Campylobacter in presence of BPE and observed that 1.0 g GAE/L of BPE reduced natural colonization level of Campylobacter by 2 logs in broiler cecum as a water supplement. Relative expression of several C. jejuni stress response genes, including rod shape determining protein ( mreB ) were down-regulated in the presence of sub-lethal concentration of BPE. Prolonged exposure of C. jejuni to BPE resulted the minimum inhibitory concentration (MIC) of BPE to increase from 0.5 to 1.0 mg GAE/mL; however, after single sub-culture in BPE-free broth, the MIC value revived to 0.5 mg GAE/mL. Findings from this study reveal the high potential of berry phenolics as green antimicrobials against enteric pathogen Campylobacter and application in the reduction of pre-harvest colonization level of Campylobacter in poultry gut.