The Role of Diet in Modulating Gut Detoxification Mechanisms

Livestock ingest numerous potentially toxic compounds, including natural plant and fungal metabolites, insect chemical defenses, human-made environmental pollutants, and therapeutic drugs. In turn, animals evolved physiological mechanisms to protect themselves from these ingested toxins. Enzymes have been described that first activate toxins cytochrome P-450 and then conjugate the compounds (glutathione-S-transferase, GST) to detoxify, enhance elimination, or both. Two additional members of this defense have recently been described. P-glycoprotein (Pgp) and multidrug resistance associated protein (MRP) differ from the detoxifying enzymes in that they are membrane-bound efflux transport proteins that mediate a reduction in intracellular toxin accumulation. The relationship between phase I and II metabolism of dietary toxins and the efflux transport proteins has not been examined for any livestock species. In this report the role of dietary constituents in the regulation of detoxification pathways and the importance of this regulation to animal agriculture are discussed.