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Effect of dietary Zn on high Cu intake in sheep

Journal Article · · J. Anim. Sci.; (United States)
OSTI ID:5017043
The objective was to determine whether high dietary levels of Zn will ameliorate or prevent chronic Cu toxicity in lambs fed a high Cu containing finishing diet. Four-month-old crossbred lambs were individually fed a pelleted diet of 35% cottonseed hulls, 5% alfalfa, 1.6% urea, 57.4% corn meal, vitamins A and D and minerals. The ration supplements and number of head per treatment were: group 1, none (4); group 2, 45 ppm Cu (5);group 3, 45 ppm Cu plus 250 ppm Zn (5), group 4, 45 ppm Cu plus 500 ppm Zn. The Cu and Zn supplements were CuSO/sub 4/ and ZnO. Plasma aspartate transaminase (AspT) activity, measured biweekly, was first elevated after 41 days feeding. Thereafter, in group 2, one lamb died and the AspT levels of the others gradually increased to a point where death from chronic Cu toxicity seemed imminent; the lambs in all groups were then slaughtered after 91 days feeding. Mean plasma AspT (SF units/ml) and liver Cu and Zn (..mu..g/g DM) at slaughter were, respectively: group 1, 65, 232 and 118; group 2, 308, 1074 and 135; group 3, 130, 705 and 139; group 4, 194, 1145 and 179. Neither Zn level reduced (P > .05) liver Cu; both reduced (P < .05) AspT activity late in the study, but not to control levels (P < .05). Thus, chronic Cu toxicity may be delayed, but not prevented, by high Zn levels.
Research Organization:
Dept. of Agriculture, Beltsville, MD
OSTI ID:
5017043
Journal Information:
J. Anim. Sci.; (United States), Journal Name: J. Anim. Sci.; (United States) Vol. 43:1; ISSN JANSA
Country of Publication:
United States
Language:
English