The influence of “Hayward” kiwi fruit (Actinidia deliciosa) from organic and conventional cultivations on the content of some trace elements in the rat kidneys and assessment of copper, manganese and zinc bioavailability / Wpływ owoców kiwi “Hayward” (Actinidia deliciosa) z upraw ekologicznej i konwencjonalnej na zawartość niektórych mikroelementów w nerkach szczura i ocena biodostępności manganu, miedzi i cynku

The conditions of fruit cultivation may affect their content of some mineral elements. The study aims at determining the content of some microelements (Cu, Zn and Mn) in diets with “Hayward” kiwifruits from the organic (ecological) (OHC) and conventional (CHC) cultivation and also determining their effect on the mineral profile of the kidneys of rats loaded for 28 days with a diet containing 1% of cholesterol (C) and the assessment of bioavailability of these elements in rats. The mineral composition of the diets and kidneys was examined using a flame atomic absorption spectrophotometer (Perkin-Elemer 1100B). The bioavailability of Cu, Zn and Mn was calculated using the “three-point assay” [Littell et al. 1995]. In the atherogenic diets containing 5% of “Hayward” kiwifruit, the content of the investigated elements was higher than in the control diet and the highest content was noted in the diet with kiwifruit from the ecological cultivation. The content of Mn, Cu and Zn in rat kidneys was 1.1–1.4, 8.2–8.4 and 36.8–42.4 mg/kg, respectively. The bioavailability of Cu determined in respect to the C group was significantly lower in both CHC and OHC groups, whereas Mn was lower only in the OHC group. There were no significant differences in Zn bioavailability. The obtained results of the bioavailability of selected trace elements, determined on the basis of their concentration in the rat kidneys, did not show a clear evidence of the advantages of organically cultivated “Hayward” kiwifruit over conventional cultivation, in spite of their different contents in the examined fruits.