TABLE 3.
Immunization of chickens with RASV strains and E. acervulina oocyst challenge
| Group | Primary immunizationa | Secondary immunization | Oocyst challengeb | Weight gain (g) (mean ± SEM)c | Feed conversion ratioc |
|---|---|---|---|---|---|
| G1 | BSG | BSG | No | 141 ± 7 Ad | 2.93 A |
| G2 | χ8879(pYA3870) (T3SS-vector control) | χ9242(pYA3493) (T2SS-vector control) | Yes | 127 ± 2 B | 2.94 A |
| G3 | χ8879(pYA3658) (T3SS-EAMZ250) | χ8879(pYA4157) (T3SS-SO7) | Yes | 140 ± 3 A | 2.75 A |
| G4 | χ8879(pYA3658) (T3SS-EAMZ250) | χ9242(pYA4184) (T2SS-SO7) | Yes | 136 ± 5 AB | 2.76 A |
| G5 | χ8879(pYA4157) (T3SS-SO7) | χ9242(pYA4184) (T2SS-SO7) | Yes | 132 ± 1 AB | 2.71 A |
| G6 | χ9242(pYA4184) (T2SS-SO7) | χ9242(pYA4184) (T2SS-SO7) | Yes | 135 ± 1 AB | 2.85 A |
a
Chickens received a primary immunization when they were 1 week old and a secondary immunization 1 week later. Strains χ8879 (ΔsptP1033::xylE ΔasdA16 ΔphoP233) and χ9242 (ΔphoP233 ΔasdA16 ΔaraBAD23 ΔrelA198::araC PBAD lacI TT) were used for immunization.
b
Three weeks after the secondary immunization, chickens in groups G2 to G6 were inoculated with 105 E. acervulina oocysts.
c
Right before the oocyst challenge and on day 6 postchallenge, the body weights were recorded, and the weight gain and feed conversion ratio (grams of feed consumed per gram of body weight gained) were calculated.
d
Means that are not followed by the same letter are significantly different (P < 0.05).