Authors : D.J. Pasnik , J.J. Evans and P.H. Klesius
Abstract: Experiments were conducted to study the influence of tricaine Methanesulfonate (MS-222) on blood glucose levels and percent cumulative survival of Nile tilapia (Oreochromis niloticus) challenged with Streptococcus agalactiae 30 days post-vaccination with S. agalactiae vaccine or sham-vaccination with Tryptic Soy Broth (TSB). Anesthesia-treated fish were placed in an MS-222 (50 mg L 1) solution to achieve stage 3 of anesthesia, while control fish were placed in a sham anesthetic solution containing water but no MS-222 for an equal amount of time. All fish were then injected intraperitoneally with S. agalactiae vaccine or TSB and later injected intraperitoneally with 750 cfu S. agalactiae/fish. Blood glucose levels among the groups immediately after anesthesia (92.8�5.6 and 73.2�4.2 mg dL 1) or sham anesthesia (56.7�2.6 and 58.9�3.5 mg dL 1) were significantly higher in the MS-222-treated groups (p<0.0001). No other significant differences in blood glucose levels between treatment groups were observed at subsequent sampling points. Percent cumulative survival among challenged vaccinated fish was 50% when treated with MS-222 versus 100% when not treated with MS-222 (p<0.0001). However, percent cumulative survival among challenged non-vaccinated fish was 80% when treated with MS-222 versus 29% when not treated with MS-222 (p<0.0007). Increased blood glucose levels prior to vaccination were significantly correlated to decreased percent cumulative survival after challenge (r2 = 0.5364; p = 0.0022). Given increased blood glucose and decreased survival among MS-222-treated, vaccinated fish, consideration should be given when anesthetizing Nile tilapia with MS-222 prior to vaccination.
D.J. Pasnik , J.J. Evans and P.H. Klesius , 2008. Influence of Tricaine Methanesulfonate on Streptococcus agalactiae Vaccination of Nile tilapia (Oreochromis niloticus). Veterinary Research, 2: 28-33.