Heavy metal concentration in some commercial poultry feeds available in Abuja, Nigeria

The concentrations of heavy metals in some commercial poultry feeds available in Abuja, Nigeria was investigated. Poultry feed rations (starter, grower, finisher and layer) of seven different feed brands available in Abuja were purchased from their various distribution outlets. The nitric acid digestion method followed by Flame Atomic Absorption Spectrophotometry technique were used for metal content quantification. Analytical method validation was performed using IAEA-V-8 Rye flour certified reference material and good recoveries were obtained in all the metals indicating the accuracy of the applied analytical procedure. The mean of heavy metal concentrations (μg/g dry weight) in the poultry feeds were 2.31 ± 1.23, 0.43 ± 0.20, 1.66 ± 0.82, 23.35 ± 5.26, 238.09 ± 45.80, 0.61 ± 0.26, 99.57 ± 15.63 and 68.21 ± 11.92 for Pb, Cd, Ni, Cu, Fe, Co, Mn and Zn respectively. Generally, the levels of iron, manganese, zinc and copper in the poultry feeds were higher than FAO/WHO, National Research Council (NRC) and Standard Organisation of Nigeria (SON) maximum recommended limits in feeds. Pearson correlation analysis on the metals in poultry feeds showed a significant (p < 0.01) positive strong correlations between Co/Ni (0.658), Mn/Cu (r = 0.566), Zn/Cu (r = 0.683) and Zn/Mn (r = 0.758) suggesting that these metals could have had the same pathway into the feeds.