Campylobacter spp. are present in organs and tissues of broiler chickens but the dissemination route is unclear. The current study aimed to determine Campylobacter prevalence within circulating blood of commercial broilers.
Broilers were acquired from 19 flocks originating from three commercial poultry processing companies. Using aseptic blood collection techniques, 5 mL of circulating blood was collected from each bird and the sample analyzed for Campylobacter.
From the 248 total birds sampled, 12 percent of the birds had Campylobacter in the blood.
This study documents Campylobacter prevalence in the circulating blood of commercially raised broilers. Campylobacter presence in the circulatory system may indicate the path used by the organism for rapid dissemination to organs and tissue. Campylobacter presence in circulating blood of market-age broilers may increase the likelihood of cross-contamination between birds during slaughter.
Study conducted over 20-month period
A total of 248 commercial market-age broilers were sampled. These broilers were obtained from 19 flocks in three different poultry integrator sources spanning a 20-month period. The broilers from each flock were obtained from the live haul unloading area at each of the poultry companies’ processing plants. Two validated aseptic blood collection techniques were used in the current study, with the first technique performed on 12 flocks and the second technique used on the next seven flocks.
For the first blood collection technique, an assistant held the bird on its side with the wing extended. The feathers were removed from the ventral side of the wing over the humerus and surrounding area. Ethanol (70 percent) was sprayed on the skin and allowed a 30-second contact time. Betadine was then applied to the area and allowed a one-minute contact time before vena-puncture (brachial vein) was performed using a sterile needle. Using sterile 5 mL syringes and 20-guage needles, 5 mL of circulating blood was collected from each broiler. The blood from each bird was immediately added into 50 mL sterile conical centrifuge tubes, which contained 45 mL of modified Bolton enrichment broth (broth without the addition of lysed horse blood or supplements). The ceca from each euthanatized bird was aseptically removed and placed into individual sterile stomacher bags. Blood and ceca samples were then placed on ice before microbiological analysis.
For the second blood collection technique, the broilers were administered 20 mg of ketamine HCL into their breast muscle. The broilers were placed back into transport coops for approximately 10 minutes, until drug effect was noted, as indicated by the broiler’s inability to maintain an upright posture. The aforementioned skin preparation procedures were used but, in addition, the skin was aseptically reflected to expose the brachial vein of each broiler. Betadine was applied to the outer area of the exposed brachial vein and allowed to sit for one minute. The sterile needle was inserted directly into the exposed blood vessel. A total of 125 broilers were sampled with the first blood collection technique and 123 broilers with the second technique.
From the individual blood samples, a 0.1 mL aliquot was directly streaked onto Campy-cefex agar plates, which were incubated at a temperature of 42 C for 48 hours in a microaerobic environment containing 5 percent O2, 10 percent CO2 and 85 percent N2. With the first blood collection technique (Table 1), Campylobacter were recovered from 12 percent of the blood samples and 42.4 percent of the ceca samples. With the second technique (Table 2), the results were very similar with 11.4 percent of the blood and 50.4 percent of the ceca samples being positive. There was no significant difference between the two blood collection techniques for aseptic blood sampling. All of the isolates were found to be C. jejuni and the C. jejuni present in each positive sample was probably low in number because none were isolated by direct plating, which has a minimal detection level of approximately 100 colony-forming-units per mL of blood. They were only detected following an enrichment step.
In conclusion, findings from this study confirm that C. jejuni can be naturally recovered from the circulating blood of commercial broilers. Market-age broilers were tested and further studies are needed to determine whether Campylobacter presence in the blood of broilers can be found throughout the production cycle. Avian blood characteristically differs from mammalian blood in that the blood glucose level in avian blood is approximately double that found in mammals and plasma protein content is substantially lower. The interaction of Campylobacter spp. with the components within avian blood needs to be further elucidated. The immunologic response of chickens to Campylobacter presence within the blood, plus Campylobacter survivability mechanisms in chicken blood and transient time in blood all need to be further understood. Additional studies on Campylobacter ecology within birds may provide valuable insight into the significance of this organism in the blood.