Comparison of the influence of dietary fibre sources with different proportions of soluble and insoluble fibre on Ca, Mg, Fe, Zn, Mn and Cu apparent absorption in rats

The 6 week experiment was performed on growing Wistar male rats. In the third and the sixth weeks digestibility trials were performed. The following high fibre preparations were supplemented to the control diet (C): high methoxylated citrus pectin (Cr), apple pomace (A), potato fiber ''Povex'' (P) and sugar beet pulp (B). Fibre supplementation, except Cr, significantly increased Ca, Mg, Fe, Mn Zn, Cu excretion in faeces and decreased their apparent absorption in both trials. Significant correlations (P less than or equal to 0.001) were found between crude, insoluble and total fibre intake and mineral excretion and apparent absorption. Apparent absorption of minerals increased from the third to the sixth week in group C and in group Cr, except Fe, while it decreased in groups P and B or showed tendency to decrease. In the sixth week the following differences (P less than or equal to 0.05) in apparent absorption were observed between diets, in descending order: Ca-C greater than or equal to Cr greater than or equal to A>P,B; Mn-C>Cr>B,P,A; Mg-C>A,Cr greater than or equal to P greater than or equal to B; Zn-Cr,C>A>B>P; Fe-C,A>Cr>P>B; Cu-C>Cr>P,B,A.