| Two experiments were conducted to investigate performance , effects on microelements and bioavailabilities of Cu or Zn in one-day broilers.In exp. 1, 10 treatments included a basal corn-soybean meat diet or the basal diet supplemented with 40, 80 or 120 mg/kg Zn from sulfate, acetate and yeast were used for 3w. In exp.2, 200 one-day broilers were alloted randomly to 10 treatments that included a basal corn soybean meal diet or basal diet supplemented with 10, 50 or 100mg/kg Cu as sulfate, acetate or yeast for 21 day.the results are as follows:In exp.1, daily gains in chicks fed basal diet supplementde with yeast Zn were higher differently than those of acetate Zn (p<0.05), than sulfate Zn ( p<0.01), than basal diet(p<0.01). A linear increase in daily gain (p<0.05) was observed among chicks receiving increasing Zn concentrations.When zinc added to 120mg/kg, chicks had the highest daily gain(p<0.01). No differences(p>0.05) were noted in feed/meat in chicks supplemented with Zn, but significantly higher than those fed basal diet (p<0.05) . No differences(p>0.05 ) were observed in feed intake among treatments.Increasing added zinc concentration from 80 to 120mg/kg greatly influenced (p<0.05) concents of serum zinc, barsuF weight, thymus and spleen weight. No difference were noted in concent of serum zinc , barsuF weight, thymus weight, spleen weight in chicks by zinc source.Chicks fed yeast zinc or acetate zinc had greater concentrations of Zn in liver than those fed sulfate zinc or basal diet (p<0.05) .Zinc source have not effect on zinc concentrations in bone and Zn-Cu SOD activity in liver. With serum Zn, AKP activity,liver SOD activity, liver Zn and bone Zn as indicators, using multiple regression slope ratios with Zn sulfate set at 100%, bioavailability estimate were 88.24% and 100.00%, 109.04% and 121.64%, 128. 36% and 152. 19%, 78. 57% and 150. 00%, 86. 06% and 113. 99% for acetate Zn and yeast Zn, respectively.The results suggested that yeast Zn have higher bioavailability than Zn sulfate, but acetate Zn have similar bioavailability to Zn sulfate.In exp.2, Weight gain and feed intake in chicks were not affected by treatment, but feed/meat was increased(p<0.05)in chicks fed basal diets supplemented with 100mg/kg Cu.Spleen and Thymus was not influenced with copper source and copper level.Broilers fed diets with Yeast Cu have higher(p<0.05)Pancrea and liver Cu-ZnSOD activity than the other treatments. Cu-ZnSOD activity, pancrea weight, concertration of Cu in liver and bone, were increasingly higher with copper level(p<0.05).Concentration of zinc and iron in liver of chick fed diets added Cu from 50-100mg/kg as Yeast Cu, were signigicently higher than those of chick fed basal diets. The chicks fed the diets with supplemented100mg/kg copper,had the highest concentration of copper in liver and bone (p<0.05).Bone Cu or Liver Cu was used to sensitive indicators, multiple linear regression slope ratios gave relative estimates(relative to the standard. CuSO4, set as 100%) of 129.30% and 179.91%, 101.36% and 123.21% for acetate Cu and yeast Cu, respectively.The result indicated that bioavailabiiity in yeast Cu have higher values than CUSO4, but CuSO4 and acetate Cu have similar bioavailabiiity. |
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