YOUNG, K.A.; SKOPEC, M.M.; DEARING, M.D.; University of Utah; University of Utah; University of Utah: The efficacy of an in vivo assay to determine the differences in detoxification pathways in species of Neotoma.

Diet selection in herbivores may depend on the ability to detoxify plant secondary compounds (PSC). However, the way in which wild herbivores detoxify PSC is largely unknown. We evaluated an in vivo, non lethal assay (sleep time under anesthesia) as a means to determine detoxification rates in four species of woodrats (Neotoma lepida, N. fuscipes, N. floridana, N. cinerea). The four species included exhibit different dietary intake levels of PSC. Neotoma floridana, N. lepida, N. cinerea are generalist herbivores, whereas N. fuscipes is an oak specialist. Given the variety in exposure to dietary toxins, we hypothesized that there would be a species difference in induced sleep times. Specifically, we hypothesized that the specialist should have the shortest sleep time. We injected individuals from each species with hexabarbital (dose 100mg/kg) or tribromoethanol (dose 50 mg/kg) and monitored their sleep time. Tribromoethanol and hexabarbital are eliminated through different detoxification pathways. Only the N. floridana injected with hexabarbital showed a significant increase in sleep time as compared to the other species. There were no significant differences between the species in the tribromoethanol induced sleep times. The results indicate that the in vivo assay is not ideal to study the differences in constitutive detoxification pathways among woodrat species. The assay may not be sensitive enough to detect the constitutive detoxification differences among species, or the detoxification pathways for PSC are different than the pathways for tribromoethanol and hexabarbital. However, it is possible that differences in sleep times may be detected in woodrats induced through dietary exposure to PSC.