| Developing efficient, ecological, environmental animal husbandry, promoting ecological breeding mode and reducing the trace element pollution to the environment is the focus of the current research of animal nutrition.This study aimed to research the ideal balance profile of Cu, Fe, Zn and Mn for boilers via uniform design method.In experiment 1, One-day aged male broilers(n=900) were allotted to 15 groups with 6 replicates of 10 birds for 1~21 d. A corn-soybean meal diet with Cu, Fe, Zn and Mn at respective 8, 123, 40 and 60 mg/kg was used as a basal diet. Fourteen experimental diets were formulated by adding Cu, Fe, Zn and Mn at respective 2~8, 10~37, 10~40 and 15~60 mg/kg in the basal diet according to Uniform design method. The growth performance during the experiment period was measured and the excretion samples were collected at 17~20 d for the determination of Cu, Fe, Zn and Mn content. The growth performance and excretion of Cu, Fe, Zn, Mn in the manure of broilers was determined to build the ideal balance profile of these elements.(Result)The results in experiment 1 showed that when the levels of Cu, Fe, Zn and Mn were 16.96, 166.66, 46.01 and 60.26 mg/kg respectively, ADG got the optimum value. when the Cu excretion got the minimum value, the optimum dietary contents of Cu, Fe, Zn and Mn were 8.30、126.93、90.90、58.13 mg/kg; when the Fe excretion got the minimum value, the optimum dietary contents of Cu, Fe, Zn and Mn were 18.14、121.81、55.61、58.86 mg/kg; when the Zn excretion got the minimum value, the dietary contents of trace elements were Cu 12.68, Fe 122.15, Zn 41.42, Mn 62.23 mg/kg; For minimal Mn excretion, the content of Cu, Fe, Zn and Mn were 8.05、140.68、65.51、60.70 mg/kg respectively. When dietary level of Cu, Fe, Zn and Mn was 8.54, 130.66, 38.19, 64.07 mg/kg respectively, the total excretion of Cu, Fe, Zn and Mn got the minimum value.In experiment 2, Experiment was based on the ideal balance profile built in exp.1 to testify its practicability using 720 broilers using two treatments with 4 replicates of 90 birds. A basal diet was feed to the control diet with Cu, Fe, Zn and Mn at respectively 15.19、203.08、76.78、86.13 mg/kg. A corn-soybean meal diet with Cu, Fe, Zn and Mn at respectively 16.96, 166.66, 46.01, 60.26 mg/kg was used as an experimental diet. The growth performance during the experiment period was measured and the excretion samples were collected at 17~20 d for the determination of Cu, Fe, Zn and Mn content. The growth performance and excretion of Cu, Fe, Zn, Mn in the manure of broilers was determined to testify the practicability the ideal balance profile of these elements.(Result) The levels of Cu, Fe, Zn and Mn has no significant effect on live performance for 1~21 d broiler(P>0.05). The excretion of Cu and Mn was markedly decreased(P<0.05), while Fe excretion, Zn excretion and total excretion has no significant effect(P<0.05).(conclusion) 1) The recommandation of trace elements for 1~21 d broiler were respectively Cu 16.96 mg/kg, Fe 166.66 mg/kg, Zn 46.01 mg/kg, Mn 60.26 mg/kg. 2) There is a dilemma between growth performance and mineral excretion for 1~21 d broiler, however, too high level of trace elements is unnecessary although the level supporting optimal growth is higher than that minimizing mineral excretion.In experiment 3, a total 940 one-day-old male Arbor Acre broilers were fed a corn-soybean meal diet with Cu 16.96 mg/kg, Fe 166.66 mg/kg, Zn 46.01 mg/kg, Mn 60.26 mg/kg from 1 to 21 day. Nine hundred broilers were selected from the flock according their body weight at 21 day. Birds were divided into 15 group randomly, with 6 repeats of 10 birds. A basal diet and 14 experimental diets were feed respectively. The contents of Cu, Fe, Zn and Mn in the basal diet were 8, 125, 40 and 60 mg/kg, respectively. Fourteen experimental diets were formulated by adding 2~8 mg/kg Cu, 10~35 mg/kg Fe, 10~40 mg/kg Zn, 15~60 mg/kg Mn based on the basal diet according to Uniform design method. The growth performance during the experiment period was measured and the excretion samples were collected at 38~42 d for the determination of Cu, Fe, Zn and Mn content.(Result) The result showed that Cu, Fe, Zn and Mn content between NRC recommendation and double the recommendation had no significant effect(P>0.05) on ADG(average daily gain) and F/G(feed/gain) for 22~42 d broiler. The contents of Cu, Fe, Zn and Mn in the diet has a significant effect on the trace element excretion(P<0.01). According to the analysis of optimal solution, when the Cu excretion got the minimum value(23.11 mg/kg), the optimum dietary contents of Cu, Fe, Zn and Mn were 7.15, 116.28, 82.82 and 60.95 mg/kg; when the Fe excretion got the minimum value(438.34 mg/kg), the optimum dietary contents of Cu, Fe, Zn and Mn were 14.78, 116.81, 38.15 and 63.72 mg/kg; when the Zn excretion got the minimum value(102.60 mg/kg), the dietary contents of trace elements were Cu 7.69, Fe 127.40, Zn 40.70, Mn 133.26 mg/kg; For minimal Mn excretion(159.37 mg/kg), the content of Cu, Fe, Zn and Mn were 11.07, 136.97, 46.13 and 59.05 mg/kg respectively; when the total mineral excretion got the minimum value 218.94 mg/kg, the optimum combination of Cu, Fe, Zn and Mn were 7.36, 125.74, 38.23 and 62.76 mg/kg, respectively.In experiment 4, One-day aged male broilers(n=720) were allotted to 2 groups with 4 replicates of 90 birds for 1~21 d. A corn-soybean meal diet with Cu, Fe, Zn and Mn at respective 15.19、203.08、76.78、86.13 mg/kg during 1~21 d and 15.24、202.32、77.48、87.06 mg/kg during 22~42 d was used as a basal diet. A corn-soybean meal diet with Cu 16.96 mg/kg, Fe 166.66 mg/kg, Zn 46.01 mg/kg, Mn 60.26 mg/kg was feed from 1 to 21 day, from 22~42 d, Cu, Fe, Zn and Mn content in the diet respectively were 7.36、125.74、38.23、62.76 mg/kg. The growth performance during the experiment period was measured and the excretion samples were collected at 38~42 d for the determination of Cu, Fe, Zn and Mn content.(Result) the result indicated that: the contents of Cu, Fe, Zn and Mn in the diet has no significant effect on ADG、ADFI and F/G(P>0.05). 2) Cu and Fe excretion has no significant change(P>0.05), while Zn excretion, Mn excretion and total excretion were significantly decreased(P<0.05).It concluded that Cu, Fe, Zn and Mn contents between NRC recommendation and double the recommendation has no significant effect(P>0.05) on ADG and F/G for 22~42 d broiler. Excretion of copper, iron, zinc or manganese was affected by the add level of other elements, and there is an optimum integration of trace elements for the lowest excretion of any trace element. When dietary level of Cu, Fe, Zn and Mn was 7.36, 125.74, 38.23, 62.76 mg/kg respectively, the requirement of broilers for trace elements could be satisfied, at the same time, the minimum value of total excretion for Cu, Fe, Zn and Mn could be got. |
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