Table 3.
Vaccination of broiler chickens with Dps to prevent cecal colonization by C. jejuni NCTC11168a
| Vaccine | Log of geometric mean no. of CFU | % colonized (no. colonized/total no.) |
|---|---|---|
| Subcutaneous vaccination | ||
| Dps + Freund's adjuvant | 8.12 | 100 (13/13) |
| Freund's adjuvant only | 7.96 | 100 (12/12) |
| Oral Salmonella vaccination | ||
| Positive control | 6.64 | 100 (14/14) |
| χ9088(pYA3493) | 6.20 | 100 (10/10) |
| χ9088(pYA4495) | 3.72 | 100 (14/14) |
Chicks were challenged with 1 × 105 CFU of C. jejuni strain NCTC11168 10 days after vaccination. Ceca were harvested at 10 days postchallenge, and C. jejuni enumeration was performed by serial dilution and plating of cecal contents on selective medium. χ9088(pYA3493) was the empty vector; χ9088(pYA4495) was the vector encoding Dps. Negative-control groups (not shown) were negative for C. jejuni for both studies. An independent two-sample t test was used with OpenEpi statistical software (version 2.3.1). There was no significant difference between subcutaneous vaccination with Dps and Freund's adjuvant only (P = 0.469). There was no significant difference in the log number of CFU of C. jejuni recovered between the positive-control and empty-vector vaccinates (pYA3493) (P = 0.317). A marginally significant differencewas seen between vaccination with the empty vector (pYA3493) and the vector expressing Dps (pYA4495) (P = 0.04).