Signal grass (Brachiaria decumbens) is widely grown on livestock farms in
many countries including Malaysia due to its high productivity and nutritive value.
Unfortunately, it is toxic to sheep and goats causing a severe hepatic and renal
damage, and death. Two experiments were conducted to determine the effect of the
toxicity of signal grass (B. decumbens) on the activity of drug-metabolizing enzymes
(DME) in sheep and cattle. It was hypothesized that the activities of selected
enzymes would be affected during intoxication and that differences in the activity
level of the enzymes in the two species might explain why cattle were safe from the
toxic effect of the grass. Twenty-three healthy Wiltshire-Malin crossed rams, aged 1 4-
1 6 months were used, fifteen for the first experiment and eight for the later. In the
first experiment, aniline 4-hydroxylase (A4H), aminopyrine N-demethylase (AND),
UDP-glucuronyl transferase (UDPGT), glutathione S-transferase (GST) and
cytochrome P450 of the liver and kidney of the control and intoxicated sheep wer
