Importance of spontaneous micronucleated erythrocytes in bottlenose dolphin (Tursiops truncatus) to marine toxicology studies.

The objective of the work was to characterize the presence of spontaneous micronucleated erythrocytes (MNES) from peripheral blood of bottlenose dolphins (Tursiops truncatus) to evaluate the possibility to use this species as potential bioindicator of genotoxic compounds. Forty-eight blood samples from 12 bottlenose dolphins were obtain from three Mexican dolphinariums, and from 10 dolphins was possible to obtain more than one sample at different sampling times. Smears were processed and observed with an epifluorescence microscope. The average of MNES and polychromatic erythrocytes (PCE) from the 48 samples was 24.3 +/- 6.1 MNES/10,000 total erythrocytes (TE), and 9.1 +/- 5.5 PCE/1,000 TE. MNES and PCE number did not show differences between gender and age. No variations in the MNES values of the bottlenose dolphins that were sampled more than one occasion were found. Comparisons among dolphinariums revealed differences in MNES frequency, with the highest significant frequency observed in dolphins from dolphinarium "A" (26.0 +/- 5.9 MNES/10,000 TE) than dolphinarium "B" (19.5 +/- 3.1 MNES/10,000 TE) (p < 0.05) and dolphinarium "C" (18.6 +/- 3.5 MNES/10,000 TE) (p < 0.007). The presence of MNES and PCE in the bottlenose dolphin may provide a useful marine mammal model to detect DNA damage by means of micronuclei test in peripheral blood erythrocytes to evaluate genotoxicity and cytotoxicity expositions.