Influence of molybdenum and sulfate supplementation and withdrawal of diets containing high copper broiler litter on tissue copper levels in ewes.

Thirty-six mature, nongestating, crossbred ewes were allotted randomly to three diets for 140 d: basal (six ewes); 50% basal and 50% broiler litter, dry basis (24 ewes) and 50% basal and 50% deep stacked broiler litter with the addition of 25 ppm molybdenum (Mo) and 5 g sulfate (SO4)/kg feed (six ewes). The control diet and the broiler litter contained 8 and 257 ppm Cu, dry basis, respectively. Liver samples from six ewes in each group were obtained by biopsy initially and at 40, 80 and 120 d and at slaughter (140 d). The remaining 18 litter-fed ewes were fed the basal diet after 140 d and six were slaughtered after 30-, 60- and 120-d. Liver Cu content continually increased (P less than .01) by feeding broiler litter (404 vs 1,543 ppm, dry basis), and was decreased (962 ppm) by supplementing Mo and SO4. During the withdrawal period, liver and duodenum Cu levels were not reduced (P greater than .05). A linear increase (P less than .001) in serum glutamic oxalacetic transaminase (SGOT) was observed with time during the withdrawal period. Serum Cu decreased at 30-d withdrawal and increased thereafter (quadratic effect (P less than .05). Hepatic Cu-metallothionein levels increased 15-fold above control values in the litter-fed ewes (P less than .05).