| In this experiment,1-day-old Arbor Acres broilers as the test animal and used corn-soybean meal diet as the basal diet. Then adding different organic and inorganic zinc sources, constitute five kinds of experimental diets The experiment was designed to compare the effects of five kinds of zinc source on broiler chickens, to provide a scientific basis for the selection and application of broiler zinc additives. AA broilers was taken as the test animal and used single-factor experimental design in the study, a total of4801-day-old male broiler chicks were assigned randomly into five dietary treatments for three weeks. Dietary treatments included a basal corn-soybean meal diet supplemented with the ZnO, ZnSO4, Lys-Zn, Met-Zn and Gly-Zn to ensure the zinc levels of the meal diet to90mg Zn/kg. According to the indicators, Experiment is divided into two phases, the first phase of the feeding experiments, from1-21days, After3weeks, parts of broiler chicks were selected and slaughtered randomly to get tissue samples for measuring of performance, immuno-potency, tissue zinc concentration intestinal structure, Tissue metallothionein(MT) concentration and intestine MT mRNA Level. Then, the texting of Zinc apparent metabolic rate was conducted from the first22days to the first25days. The results showed as follow:1.Supplementation with Zinc-amino acid chelate had the tendence to improve the growth performance compared with inorganic Zinc, but there were no significant difference among five different-source zinc(P>0.05).2.There were significant effect on zinc concentration in Pancreas and Tibia. Compared with inorganic zinc, groups treated with Zinc-amino acid chelate had significantly higher zinc concentration in Pancreas and Tibia(P<0.05), and groups treated with Met-Zn and Gly-Zn were better than other Zinc sources; In the three amino acid chelated zinc, Lys-Zn treated groups had significantly lower zinc concentration in Pancreas and Tibia(P<0.05); In the two inorganic zinc, ZnSO4treated groups had significantly higher zinc concentration in Pancreas and Tibia than ZnO group(P<0.05); there were no significant effect on zinc concentration in serum and liver among five different-source zinc(P>0.05).3.There were significant effect on Zinc apparent metabolic rate. The order followed by Gly-Zn>Met-Zn>Lys-Zn>ZnSO4>ZnO(P<0.05).4. Met-Zn and Gly-Zn treated groups had significantly higher MT concentration in pancreas than inorganic groups(P<0.05), compared with group with ZnO, Met-Zn and Gly-Zn treated groups increased31.05%(P<0.05) and27.96%(P<0.05), and added the MT concentration in pancreas by24.36%(P<0.05) and20.97%(P<0.05) than that of group with ZnSO4. Groups treated with Met-Zn and Gly-Zn had higher MT mRNA level in the intestine, than other Zinc sources; In the three amino acid chelated zinc, Lys-Zn treated group had significantly lower MT Zn(P<0.05), and there were no significant effect on MT concentration in liver, MT mRNA levels in ileum and jejunum(P>0.05). In the two inorganic zinc, there were no significant effect on MT concentration in liver and pancreas, MT mRNA level in the intestine(P>0.05).5. Groups treated with Met-Zn and Gly-Zn had higher blood copper-zinc superoxide dismutase activity than groups with ZnSO4and ZnO(P<0.05). Compared with ZnSO4and ZnO, group treated with Lys-Zn increased the blood copper-zinc superoxide dismutase activity by1.32%(P>0.05) and2.74%(P>0.05). In the liver, groups treated with Met-Zn and Gly-Zn had higher blood copper-zinc superoxide dismutase activity than groups with inorganic zinc. There were no significant effect on copper-zinc superoxide dismutase activity in blood and liver than groups with Zinc-amino acid chelate(P>0.05). There were no significant effect on the activity of Alkaline phosphatase, malondialdehyde, lactate dehydrogenase, glutathione peroxidase(P>0.05).6. There were no significant effect on immune organ index, immune globulin and intestinal structure among five different-source zinc(P>0.05).In summary, under the same condition of zinc levels, Groups treated with Met-Zn and Gly-Zn zinc had higher concentration in Pancreas and Tibia, MT concentration and MT mRNA levels, copper-zinc superoxide dismutase activity in blood and liver, and had higher Zinc apparent metabolic rate than other groups. So, groups with Met-Zn and Gly-Zn were better than others, and group with ZnO was relatively poor. |
