Study on Zn relative concentration and chemical state in broilers duodenum by micro-X-ray fluorescence and micro-X-ray absorption fine structure

Abstract

Micro-X-ray fluorescence (μ-XRF) and micro-X-ray absorption fine structure (μ-XAFS) are not widely used in animal science. The objective of this experiment was to employ μ-XRF and μ-XAFS technique to determine the change of Zn quantity, distribution and chemical state (Zn2+ chemical state, organic zinc chemical state) into intestinal wall using different zinc sources. 45 newly hatched healthy (1-d-old) commercial male broilers were used in this experiment. The chicks were fed a corn–soybean meal basal diet (90.50mg/kg) from day 1 to 21, but were fed a semipurified diet (12.51mg/kg) after day 21 to deplete the body Zn stores. At 28d of age, after an overnight fast, 45 birds were randomly allotted to 3 perfusion groups (ZnMet, ZnLys, ZnSO4) with 15 replicates/group for in situ ligated intestinal loops of broilers in experiment. Duodenum of each bird was used as 1 replication of intestinal segments. The solutions injected into the duodenal loops were buffered with 15.5mmol/L of morpholineoethanesulfonic acid. In the treatment groups of different Zn sources, 0.616mmol/L (40mg/L) was added to the media. The 3.5mL of Zn dose was injected and incubated 30min in the abdomen cavity. The μ-XRF and μ-XAFS were used to analyze the relative quantity, distribution and chemical state of Zn in the intestinal wall, and atomic absorption spectrometry (AAS) was used to verify Zn concentration in the whole intestinal sac. The results showed that ZnMet and ZnLys group samples have a greater amount of zinc in the intestinal wall specific region than ZnSO4 group. The Zn chemical state of organic Zn and ZnSO4 group were identical in intestinal wall specific region. In addition, the Zn concentration achieved using ZnMet was greater than that for ZnLys and ZnSO4 (P<0.05) as measured by AAS. As observed in this experiment, organic zinc was more easily absorbed than inorganic Zn.