Determination of the effective dose of the live Mycoplasma synoviae vaccine, vaxsafe MS (strain MS-H) by protection against experimental challenge

Abstract

The minimum effective dose of the Mycoplasma synoviae-H (MS-H) vaccine was determined through protection against experimental challenge. Chickens were vaccinated by eyedrop with the following doses of a vaccine: 1.2 × 10 5, 2.4 × 105, 4.8 × 105, 9.6 × 105, 1.92 × 106, and 3-84 × 10 6 color change units (CCU), then challenged 6 wk after vaccination. Rapid serum agglutination results indicated that 100% of birds receiving an MS-H dose of ≥4.8 × 105 CCU had antibodies to MS and enzyme-linked immunosorbent assay results showed that 60% of birds receiving a dose of 4.8 × 105 or 9.6 × 105 CCU and 100% of birds receiving a dose of 1.92 × 106 or 3.84 × 10 6 had antibodies to MS. At postmortem after ..