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Conflicting demands on detoxification pathways influence how common brushtail possums choose their diets


Marsh, KJ and Wallis, IR and McLean, SR and Sorensen, J and Foley, WJ, Conflicting demands on detoxification pathways influence how common brushtail possums choose their diets, Ecology, 87, (8) pp. 2103-2112. ISSN 0012-9658 (2006) [Refereed Article]

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Copyright 2006 Ecological Society of America

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DOI: doi:10.1890/0012-9658(2006)87[2103:CDODPI]2.0.CO;2


Most herbivores eat more and survive better when they have access to a variety of foods. One explanation involves the detoxification of plant secondary metabolites (PSMs). By feeding from a variety of plants that contain different classes of PSMs, animals can use multiple detoxification pathways and presumably consume more food. Although popular, this theory is difficult to test because it requires knowledge of the detoxification pathways of each PSM in the diet. We established that common brushtail possums (Trichosurus vulpecula) use various combinations of oxidation, hydrolysis, and conjugation with glucuronic acid (GA) or glycine to detoxify six PSMs. Compared to their ingestion of a single PSM, possums ate more when offered a choice between two diets containing PSMs that require apparently independent detoxification pathways (benzoate and 1,8-cineole, benzoate and p-cymene, benzoate and orcinol, benzoate and salicin, or orcinol and 1,8-cineole). However, possums still did not eat as much of these diets as they did of a basal diet free of PSMs. This suggests that detoxification pathways are never independent, but are separated instead by degrees. In contrast, possums offered a choice of two PSMs that require competing detoxification pathways (1,8-cineole and p-cymene, 1,8-cineole and salicin, or orcinol and salicin) ate no more than when offered diets containing one of the compounds. There was an exception: even though both rutin and orcinol are detoxified via conjugation with GA, the feeding behavior of possums did not suggest competition for detoxification pathways. This implies that the supply of GA is not limiting. This study provides the first convincing evidence that herbivorous mammals can eat more by selecting mixed diets with a diversity of PSMs that make full use of their detoxification potential. It also emphasizes that other behavioral and physiological factors, such as transient

Item Details

Item Type:Refereed Article
Keywords:Australia, common brushtail possum, detoxification limitation hypothesis, diet choice, diet mixing, generalist herbivore, glucuronic acid (GA), glycine, plant secondary metabolites, Trichosurus vulpecula
Research Division:Biomedical and Clinical Sciences
Research Group:Pharmacology and pharmaceutical sciences
Research Field:Clinical pharmacology and therapeutics
Objective Division:Health
Objective Group:Other health
Objective Field:Other health not elsewhere classified
UTAS Author:McLean, SR (Professor Stuart McLean)
ID Code:40203
Year Published:2006
Web of Science® Times Cited:76
Deposited By:Pharmacy
Deposited On:2006-08-01
Last Modified:2011-05-10
Downloads:2 View Download Statistics

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