This study aimed to evaluate the effects of molybdenum (Mo) and organic and inorganic sources of copper (Cu) and sulfur (S) on the performance, carcass traits, and blood concentration of these minerals in lambs. Forty male non-castrated crossbred Dorper x Santa Inês lambs (20 ± 1.2 kg of body weight and 90 ± 2 d of age) were randomly allocated into one of the ten following treatments: (T0) control, basal diet; (T1) Mo; (T2) inorganic Cu and inorganic S; (T3) inorganic Cu and organic S; (T4) organic Cu and inorganic S; (T5) organic Cu and organic S; (T6) Mo plus inorganic Cu and inorganic S; (T7) Mo plus inorganic Cu and organic S; (T8) Mo plus organic Cu and inorganic S; and (T9) Mo plus organic Cu and organic S. Regardless of the source, Mo, Cu, and S were added at levels of 10 mg, 10 mg, and 2000mg/kg DM, respectively. The mineral supplements (Mo, Cu, and S) were added into the total mixed ration (TMR) by mixing them apart with the mineral and vitamin premix and then put into the TMR. The animals were kept in individual pens and received a total mixed ration for 84 days. Body weight and blood sampling was performed every 28 days. All animals were slaughtered after 84 days, and carcass traits were evaluated. Although organic sources of Cu and S added to Mo supplementation had increased the ADG throughout the study, this effect did not reflect in the heavier final BW outcomes for this treatment. In addition, no effect of these treatments was observed on the carcass traits. The serum Cu concentration was higher for the T0 group compared to the other groups; otherwise, Mo reduced the serum Cu concentration compared to the other groups. Considering the interaction among the minerals and their sources at 84 d of study, organic sources of Cu and S treatment and Mo associated with inorganic sources of Cu plus organic S treatment had an increased serum Cu concentration compared to other groups. Regardless of time, organic sources of Cu and S increased serum S concentration. At 84 days after enrollment, serum Mo concentration was lower for the control group compared to the other groups. Further, Mo supplementation increased its blood concentration compared to the control group throughout the study. The control group had the highest ceruloplasmin activity compared to the other groups; otherwise, at 84 d of the study, either Mo or inorganic S supplementation reduced ceruloplasmin activity. Serum ceruloplasmin activity was higher when Cu supplementation, regardless of source, was associated with organic S. However, at d 84 of the study, inorganic Cu associated to organic S supplements increased serum ceruloplasmin activity. In this current study, it was not possible to identify a pattern in the variables studied, however, further studies are needed to confirm that organic sources of Cu and S interacted alone without a defined pattern.
Keywords: ceruloplasmin activity; mineral antagonism; mineral supplementation; ruminants.