Effects Of Zinc Compound Amino Acids Chelate On Laying Production And Quality Of Eggs

This trial studied the influence of dietary different levels of zinc compound amino acids chelate (be called AA-Zn) on laying production, zinc content in eggs and serum biochemical parameters. Three hundred and fifteen commercial brown-eggshell Roman layers (egg production rate 80%) were selected and allotted randomly to seven equal treatments (Group A, B, C, D, E, F and G) in 60 weeks old. Each group (45 layers) set three equal repetitions; there were 15 layers in each repetition. The trial used one-way plan in the practical condition, the Group A (contrasted group) fed the basic diet containing ZnSO₄ 35ppm (NRC level), the experimental groups (B, C, D, E, F and G) fed the same diet containing different consistencies of AA-Zn, B: 17.5ppm, C: 35ppm, D: 70ppm, E: 140ppm, F: 350ppm, G: 700ppm. The trial continued for 60 days. The result show that (1)AA-Zn improved the laying performance , compared with the Group A(ZnSO₄) the egg production rates of the Group B, C, D, E, F and G increased 5. 91%, 6. 76%, 10. 42% (P<0. 05), 8. 39%, 5.00% and 5.05% respectively, the day-egg yields increased 5. 25%, 5. 33%, 10. 79% (P<0. 05), 7. 68%, 5. 17% and 5. 17% respectively , the feed efficiency increased 5. 02%, 5. 02%, 9. 62% (P<0. 05), 7. 11%, 6. 28% and 4. 18% respectively, the laying production of the Group D was best, with increasing dietary AA-Zn levels above 70ppm the laying production decreased, the laying productions of the Group B(AA-Zn: 17. 5ppm) and C(AA-Zn:35ppm) were better than the Group A(ZnSO₄:35ppm),AA-Zn economized the source of zinc.(2) AA-Zn improved the zinc content in eggs, the 70ppm, 140 ppm,700 ppmAA-Zn (the Group D, E and G) increased (P<0. 01) the zinc content in eggs more than the 35ppm ZnSO4 (the Group A), and the 140ppm AA-Zn (the Group E) increased (P<0. 05) it more than the 17. 5ppm AA-Zn (the Group B), with increasing dietary AA-Zn levels the zinc contents in eggs increased in a cubic curve manner (n=6, Rz=0.976, P<0. 01), 155. 25ppm AA-Zn increased increased the biggest zinc content; but the zinc content in eggs was limited, it did not increased doubly with increasing dietary AA-Zn levels. The 140ppm AA-Zn increased the egg-shape index(P<0.05), AA-Zn had no effect on eggshell thickness, eggshell weight, Haugh unit and the contents of Cu and Fe in eggs (p>0. 05), but compared with ZnS04 AA-Zn decreased the broken (soft) eggshell rats (p>0. 05), AA-Zn improved the quality of eggs.(3) AA-Zn increased the levels of the serum Zn and AKP, 70ppm and 700ppm AA^Zn increased the levels of the serum Zn more than the 35ppm ZnS04 andl7. 5ppmAA-Zn (P<0.01), the 70ppm AA-Zn increased the levels of the serum AKP more than the 35ppm ZnS04 (P<0. 05), 70ppm AA-Zn decreased the serum Ua less than the 35ppm ZnSd, (P<0. 05), the levels of the serum Cu, Fe, Ca, P, ALT and AST had no difference among the groups of the trial (p>0.05), and the contents of Zn, Fe and Cu in feathers had no difference (p>0.05). AA-Zn increased the absorbable and utilizable rate of zinc; AA-Zn had no effect on the absorbability and utilization of Cu, Fe, Ca and P, also on the animal normal metabolism.