THE EFFECTS OF NATURAL ZEOLITE SUPPLEMENTATION TO DIET ON SERUM ELEMENT CONCENTRATIONS IN LAYING HENS

SUMMARY This experiment was conducted to determine the effects of a dietary natural zeolite (NZ) supplementation on some serum mineral (Ca, Cu, Mg, P, Al and Zn) concentrations in laying hens. For that, 96 White Lohman LSL laying hens aged of 70 weeks were randomly divided into 4 equal groups (n = 24) according to the zeolite content added to the standard diet regimen (2 650 kcal/kg ME and 16% crude protein) during 8 weeks: 0% in the group I (controls), 1% in the group II, 2% in the group III and 3% in the group IV. The Zn, Cu and Al concentrations were determined by flame atomic absorption spectrophotometry (AAS) and Mg, Ca and P concentrations were measured using a semi-automated Chemistry Analyzer. Whereas zeolite supplementation did not affect serum Ca concentration, Zn and Al concentrations were significantly increased and P, Mg and Cu concentrations significantly decreased in supplemented birds compared to controls. Moreover, a zeolite dose – effect relationship was evidenced, birds receiving the highest zeolite dose exhibiting the more marked alterations of serum element concentrations. Strong negative correlations between P and Al concentrations and between Zn and Cu or Mg concentrations were also observed in supplemented laying hens. Because of the roles of these minerals in the formation of eggshell, these results suggest that natural zeolite supplementation may be harmful in laying hens.