ABSORPTION COEFFICIENTS ASSESSMENT OF CU AND ZN ORGANIC TRACE ELEMENTS AND THEIR DEPOSITION IN EGG YOLK
Gabriela Maria Cornescu, H. Grosu, Arabela Elena Untea, Tatiana Dumitra Panaite, Anca Bercaru
The aim of this study was to evaluate the influence of Cu and Zn supplements (organic sources) added to laying hens diets on absorption coefficients and egg yolk concentration. The experiment was conducted for 6 weeks on 192 laying hens, housed in cages (2 birds/cage), divided into 3 groups (C, E1, E2). All batches received a similar basal diet (17.96% CP and 2724,31 kcal/kg ME). Diet E1 used the same level of Cu and Zn as diet C, but in chelated form (6 mg Cu/kg and 60 mg Zn/kg). Compared to C, diet E2 had the same level of Cu (inorganic source) but the Zn concentration was 160 mg /kg from organic source. Every two weeks, egg samples were collected randomly (18 eggs/batch). During the balance weeks, all droppings were daily collected in order to form average weekly samples/cage, from which Cu, Zn was determined by FAAS. The apparent absorption coefficients of Cu did not differ significant, but it was noticed a slight increasing of Cu coefficient for the group which received organic Cu: 20.89% (E1), 18.83% (E2) vs 17.45% (C). Organic source of Zn lead to a better absorption, significant uninsured, for E1 (12.70%) and E2 (15.60%) compared to C (9.07%). Alternatively, the analytical results showed a significant (P=0.05) improvement of Zn concentration in egg yolk for E2 (75.86±1.51 mg/kg) compare to C (71.19±2.23 mg/kg) and E1 (73.24±2.24 mg/kg). The chelate source of trace minerals can be a way of obtaining Zn enrichment eggs but only using amounts of Zn above conventional rate.
Key words: hens, Zn, Cu, organic minerals, egg yolk