RUFFED GROUSE TOLERANCE AND BIOTRANSFORMATION OF THE PLANT SECONDARY METABOLITE CONIFERYL BENZOATE

Ruffed Grouse (Bonasa umbellus) consumption of quaking aspen (Populus tremuloides) flower buds is determined, in part, by the concentration of coniferyl benzoate (CB) in the bud. Understanding the physiological effects of this compound may clarify whether the association between annual fluctuations in CB and Ruffed Grouse population levels has a ca use/effect relationship. We determined the maximum level of dietary CB that Ruffed Grouse can tolerate by feeding captive grouse a formulate d diet treated with eight concentrations of CB. Loss of body mass was used to indicate toxicity. Biotransformation products from CB were ide ntified in order to determine the detoxication mechanisms employed and the presence of potentially toxic CB metabolites. Ruffed Grouse will consume up to 2 g kg-1 day-1 of CB before rapid mass loss ensues. High dietary levels of CB were associated with decreased food intake and i ncreased water excretion. Serum uric acid, aspartate aminotransferase, and alanine aminotransferase levels did not change significantly with increased levels of dietary CB. Mass loss that was associated with a CB intake of 2.3 g kg-1 day-1 could be explained by decreased food int ake but could not be attributed to any specific toxic effect. It is un certain whether the decreased food consumption that occurred at high C B intake levels was prompted by toxicity avoidance or decreased food p alatability. Ruffed Grouse appear to use glucuronic acid, sulfate, and ornithine conjugation, along with hydrolysis, reduction, and oxygenat ion reactions, when detoxifying CB. Nine biotransformation products we re identified, including ferulic acid and 4-vinylguaiacol. The latter compounds are known to interfere with reproduction in other animals.