UC Riverside

A primary mechanism reef predators use to cope with dietary toxins is through detoxification. Detoxification enzyme cytochrome P450 (CYP) (specifically CYP3 and CYP2) was found in higher concentration in butterflyfish that preferentially feed on allelochemically rich corals. Butterflyfish (Chaetodon sp.) have unique feeding strategies with some species being generalist feeders and others feeding on several species of chemically-defended coral. This research elucidates the coevolutionary relationship between butterflyfish and corals by understanding the role detoxification enzymes play in allowing butterflyfish of differing feeding strategies to consume toxic allelochemicals produced by corals. To examine this issue detoxification enzymes CYP1, 2, 3, epoxide hydrolase, glutathione S-transferase (GST) and UDP-glucuronosyltransferase (UGT) were analyzed in butterflyfish of species C. kleinii, C. lunulatus C. auriga and C. unimaculatus from Hawaii and Australia. These results have indicated that species consuming soft coral in have significantly increased CYP2 and 3A expression and catalytic activity, and GST activity. Also hard coral feeding preference on Poritis spp. over Acorapora spp. had significant CYP2 and 3A expression and catalytic activity, and GST activity. Further investigation into hard coral Porites lobata and the feeding deterrent compound homarine (found in the coral extract), it was found that oral exposure to P. lobata homogenate significantly induced content and catalytic activity of CYP2 and CYP3A, by 2-3 fold and by 3-9 fold, respectively, in preferred specialist C. multicinctus, but not in C. auriga or C. kleinii. Homarine caused a significant decrease of CYP3A and CYP2 at the high dose in C. kleinii and 60-80% mortality in that species. Soft coral Sinularia maxima and isolated compound 5-Episinuleptolide (5ESL) were deterrent to butterflyfish generalist feeders, but not specialists. Oral exposure to 5-ESL caused 100% mortality on the hard coral specialist C. multicinctus and the least toxicity on soft coral specialist C. unimaculatus, correlated with the incredible induction of CYP3A catalytic activities and concentrations, NADPH dependent metabolism, and CYP3A identified metabolite. My results indicate that dietary exposure to coral homogenates and the feeding deterrent constituent within these homogenates caused species-specific modulation of detoxification enzymes consistent with the prey selection strategies of generalist and specialist butterflyfishes