Methods for determining manganese bioavailability in organic foods

Abstract

The aim of this work was to determine the best method for estimation of the bioavailability of manganese (Mn), using two animal tissues (tíbia and kidney) and two ways of expressing feed Mn and tissue Mn (concentration or total mass). Rice bran (RB) was used as the organic source of Mn, and Mn sulphate was used as the standard source of the mineral Mn. A total of 700 chicks were assigned randomly to boxes of 25 chicks (2 boxes/(sex × treatment)). There were 7 treatments, one of them without added Mn and the others with three levels of added MN (30, 60, and 90 ppm) from each of the Mn sources (RB or Mn sulphate). The methods were compared by the coefficient of determination (R²), the F-test and the coefficient of variation of the multiple regression models. The best way to estimate the availability of Mn was using tibia Mn concentration as response and diet Mn concentration as regressors.