The Effect of Dietary Inorganic and Organic Trace Mineral Supplementation on Growth Performance, Fecal Mineral Excretion and Apparent Digestibility of Growing Male Pigs in the Tropics

Sixty (60) growing male Yorkshire pigs with average weights ranging from 80-82kg were assigned to five dietary treatments to investigate the effect of dietary inorganic and organic trace mineral supplementation on growth performance; fecal mineral excretion and apparent digestibility. Trace minerals considered were copper, iron and zinc. The diets were composed as follows. Control diet (TRT1) was supplemented with commercially recommended levels of copper as CuSO4, iron as FeSO4, and zinc as ZnSO4, at concentrations of 90, 174 and 168 mg/kg respectively. These concentrations of Cu, Fe and Zn were 13.9, 1.79 and 1.80 times the NRC recommendations respectively. Diet 2 (TRT2) contained commercially recommended levels of Cu, Fe and Zn, from organic sources at concentrations of 24, 135 and 96 mg/kg respectively. These concentrations of Cu, Fe and Zn were 3.5, 1.41 and 1.02 times the NRC recommendations respectively. Organic sources of Cu, Fe and Zn concentrations from TRT2 were reduced by 25 and 50% respectively for diets 3 and 4(TRT3 and TRT4). There was no significant difference (P>0.05) in average daily weight gain. However average daily feed intake of pigs on TRT1 was significantly (P<0.05) less than pigs fed the diets containing the organic forms of the trace minerals (TRT2 – TRT4). Carcass composition was not significantly (P<0.05) affected by the different diets. Pigs fed TRT1 excreted significantly (P>0.05) higher concentrations of fecal trace minerals than pigs fed the other diets (TRT2 –TRT4). TRT4 containing 50% reduced trace minerals from TRT2 appeared to be the most beneficial in reducing fecal mineral excretion. Apparent digestibility of Cu was significantly (P<0.05) higher for pigs fed the diets containing organic trace minerals (TRT2-TRT4). Negative apparent digestibility values for Cu were recorded for pigs fed TRT1