Journal of Chemical Ecology, Vol.
Plenum Publishing Corporation
ROLE OF TOXINS IN INTAKE OF VARIED DIETS
E. A. BURRITT* and F. D. PROVENZA
Department of Rangeland Resources
Utah State University
; accepted April
Abstract—Herbivores foraging on toxic plants may consume a variety of
foods that contain different toxins to increase food intake and to avoid
toxicosis. We studied whether lambs offered two foods, each containing a
different toxin, could ingest more food than lambs offered one food with a
single toxin. Thirty-two lambs were allotted to four groups that received: (
a ration with toxin A, (
) a ration with toxin B, (
) two rations, one with toxin
A and the other with toxin B, and (
) a ration with no toxins. Toxin pairs used
in the study were (
) amygdalin and lithium chloride (LiCl), (
) LiCl and LiCl,
) sparteine and saponin, (
) oxalate and nitrate, and (
) tannin and saponin.
For an hour each morning, lambs were offered their ration(s) and intakes
were measured. Lambs were maintained on an alfalfa pellet or grass hay diet.
Each trial lasted either ﬁve or six days. Whether or not lambs ate more when
offered foods with different toxins depended on the kind and amount of toxin
in the food. Lambs offered rations with amygdalin and LiCl or oxalate and
nitrate consumed more food than lambs offered a ration with only one of
these toxins. Lambs offered rations with sparteine and saponin or tannin and
saponin did not eat more food than lambs offered a ration with either saponin
or sparteine or tannin alone. Nor did lambs eat more when offered two rations
both containing LiCl. In all trials, lambs offered toxins showed no signs of
toxicosis, and they ate less food than lambs offered rations without toxins. Our
results indicate that in some cases ruminants can increase intake of toxic foods
by consuming foods containing different toxins. However, currently the only
way to determine how speciﬁc toxins may interact in the body to inﬂuence
intake would be to conduct feeding trials using plants or ground diets that
Key Words—Toxins, secondary compounds, intake, sheep, lithium chloride,
amygdalin, saponin, sparteine, oxalate, nitrate tannin, toxins.
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