Research note: Dose- and time-dependent effects of phytogenic water supplementation on water utilization and Campylobacter control in broilers

This study aimed to evaluate the efficacy of a phytogenic blend (PB) in drinking water at different rearing stages, doses, and administration durations on Campylobacter colonization in broilers. In Experiment 1, a total of 360 one-day-old male broilers were randomly assigned to 30 battery cages (five treatment with six replicates) for 21 days. Treatments included a non-challenged control, and four C. jejuni challenged groups receiving 0, 100, 125, or 150 mg/L PB in drinking water. In Experiment 2, a total of 360 28-day-old broilers were allocated to 24 floor pens (four treatments with six replicates) and challenged with C. jejuni. Treatments comprised a no PB treatment group and three PB groups with PB administration (150 mg/L water) for 2, 3, or 5 days before processing (35-day-old). In Experiment 1, growth performance, water intake, and Campylobacter loads in ceca, digesta, and liver were measured; in Experiment 2, growth performance, carcass yield, and Campylobacter loads in ceca and carcass rinsate. One-way ANOVA followed by Tukey's honest significant difference or Tukey-Kramer test was used for comparing all treatment groups. The orthogonal polynomial contrasts were applied to evaluate PB level in the C. jejuni challenged groups (Experiment 1) or duration effects in PB groups (Experiment 2). In Experiment 1, increasing PB levels dose-dependently improved feed conversion ratio and reduced Campylobacter colonization, with the greatest reduction in cecal Campylobacter loads observed at 150 mg/L. Concurrently, water intake was decreased with an increasing PB level without adverse effects on growth performance (P < 0.05). In Experiment 2, PB supplementation before processing reduced cecal Campylobacter load in a time-dependent manner, with the most substantial effect observed when administered for 5 days (P < 0.05). However, water intake was temporarily reduced on the first day of administration without affecting growth performance (P < 0.05). Overall, PB supplementation in drinking water dose- and time-dependently reduced Campylobacter colonization in broilers, with 150 mg/L administered for 5 days before processing, showing the most significant potential.