| Campylobacter is one of the most common causes of bacterial diarrhea in the United States and the rest of the world. Contaminated poultry products are thought to be one of the most significant sources of Campylobacter infection in humans and Campylobacter positive flocks are common. A reduction in intestinal Campylobacter counts in preharvest poultry would reduce the likelihood of producing contaminated poultry products, which could drastically reduce the incidence of human illness caused by this pathogen. Three compounds were evaluated for their ability to reduce enteric cecal Campylobacter in broiler chicks in two studies: sodium octanoate in the first and eugenol and trans-cinnamaldehyde in the second. Sodium octanoate is a water soluble salt of the medium-chain fatty acid caprylic acid, a GRAS (Generally Recognized As Safe) substance. The first trial consisted of 84 birds in six groups (n=12): an untreated Campylobacter-negative control and six other groups, all of which were inoculated with Campylobacter and received 0%, 0.175%, 0.35%, 0.7%, 1.4%, or 2.8% sodium octanoate in water 72 h prior to necropsy on the 14 d of the trial. The second trial consisted of 96 birds in eight groups (n=12): an untreated Campylobacter-negative control and seven other groups, all of which were inoculated with Campylobacter and received 0%, 0.044%, 0.088%, 0.175%, 0.35%, 0.7%, or 1.4%, sodium octanoate for 72 h prior to necropsy on the 14 d of the trial. Chicks were challenged at 72 h with C. jejuni, 2.1x10 7 or 1.2x104 CFU/mL in trial 1 or 2, respectively. In trial 1, only the birds in the 0.175% sodium octanoate treatment group experienced a significant reduction in cecal Campylobacter counts in comparison with the positive control (approximately a 2 log reduction). In trial 2, there was no significant reduction in C. jejuni among any of the groups in comparison with the positive control (0%). The 1.4% sodium octanoate treatment group experienced an average reduction in body weight, feed, and water consumption for the two trials of 25%, 39%, and 36%, respectively. Unlike use of caprylic acid in feed, water treatment with sodium octanoate had an inconsistent effect on intestinal Campylobacter counts. It is probable that the difference between these two applications is a result of either the co-administration of caprylic acid in feed or that the water soluble form of caprylic acid changes the intestinal absorption of this compound, limiting the concentration reaching the lower intestine. Eugenol and trans-cinnamaldehyde are essential oil extracts (from clove and cinnamon, respectively) and have been shown to have an antimicrobial effect in vitro, and so were evaluated for their effect on Campylobacter colonization of broiler chicks when applied prophylactically. In three replicate trials (n=90/trial), day of hatch chicks were allocated into nine treatment groups and received either 0% or 0.1%, 0.2%, 0.4%, 0.8% eugenol or trans-cinnamaldehyde in feed for 14 days prior to necropsy (n=10/group/trial). Chicks were challenged in all trials with C. jejuni 72 h after start of experiment and sacrificed on day 14 to measure cecal Campylobacter counts. Enteric Campylobacter counts were reduced in the 0.1%, 0.2% and 0.4% eugenol or 0.4% trans-cinnamaldehyde treatment groups in 2 of 3 trials when compared to the positive controls. Although these treatments demonstrated some efficacy, they did not consistently reduce cecal Campylobacter in all three trials. It is possible that the essential oil extracts tested were partially digested prior to reaching the ceca, or perhaps reached the ceca but failed to diffuse in adequate concentrations into the ecological niche of Campylobacter; the crypts. |
