The acute phase response in the Sudan plated lizard, Gerrhosaurus major

The Sudan plated lizard (Gerrhosaurus major), previously reported to be an afebrile species, was utilized in a series of experiments to test for various aspects of the acute phase response. Treatment of individuals with the antibiotic Baytril resulted in a slight (0.5 degree C) but significant reduction in mean selected body temperature (MSBT), while treatment with saline did not lower MSBT. Nonantibiotic treatment individuals had depressed plasma iron levels (86.6 +/- 22.4 micrograms Fe 100 ml-1 plasma) and treatment with Baytril produced a significant increase in plasma iron concentration (186.8 +/- 19.5 micrograms Fe 100 ml-1 plasma). Necropsy of randomly selected individuals indicated that animals obtained from the commercial supplier had Aeromonas, Arthrobacter, Pseudomonas and Salmonella infections and antibiotic treatment eliminated these infections. The growth rate of Aeromonas sobria is reduced when the bacteria are grown at 32 degrees C and reduced iron concentration compared to 34.5 degrees C and low iron concentration, which suggests that a fever response may not be beneficial in reducing bacterial growth. Saline injected, bacteria injected and antibiotic injected Gerrhosaurus major have high plasma zinc concentrations compared to the previously studied febrile species, Dipsosaurus dorsalis. This difference suggests that zinc concentrations in afebrile species deserve further study.