Investigating the Prophylactic Efficacy of Linalool to Control Campylobacter jejuni in Broiler Chickens

Campylobacter jejuni (CJ) is a major foodborne pathogen with chickens serving as the reservoir host. This study investigated the efficacy of linalool, a Generally Recognized as Safe (GRAS) phytochemical, as an in-feed intervention to reduce CJ colonization in broiler chickens. Three independent trials were conducted using 212-day-old Cornish Cross chicks per trial. Of these, 192 birds were randomly allocated to eight treatment groups (n = 24/group): negative control, linalool-only controls (1.0%, 1.5%, and 1.8%), positive control (CJ only), and CJ-challenged birds supplemented with linalool at 1.0%, 1.5%, or 1.8%. Linalool supplementation commenced on day 0, and birds were orally challenged with approximately 9 log10 CFU of CJ on day 7. Cecal CJ populations were enumerated on days 14, 24, and 34. Positive control birds harbored approximately 6–7 log CFU/g of CJ in the ceca, whereas linalool supplementation significantly reduced CJ colonization (p < 0.05) by 2–3 log on day 14 and by 3–5 log on days 24 and 34. No adverse effects of linalool were observed on body weight, feed intake, or feed conversion ratio. Additionally, RT-qPCR analysis demonstrated downregulation (p < 0.0001) of key CJ virulence and colonization-associated genes. These findings suggest that dietary linalool is a potential strategy to reduce CJ colonization in broiler chickens; however, large-scale studies under field conditions are warranted.