Effects of Different Zn Additive Dosage on Growth Performance and Zn Content in Tibia of Gushi Chicken
CAO Gong-ming et al(Northwest University for Nationalities,Lanzhou,Gansu 730030)
[Objective] The aim was to provide the scientific basis for making chicken feed formula.[Method] With Gushi chicken as the tested animals,the effects of different supplemental Zn additive dosage(0,30,60,90,120 mg/kg) on their growth performance,leg abnormality rate and Zn deposition amount in their tibia were studied on the basis of 35.3 mg/kg Zn in the basal diet.[Result] Supplemental Zn with different additive dosage all had significant or very significant effects on growth performance and leg abnormality rate of Gushi chicken.The daily feed intakes of chicken in tested groups with 60,120 mg/kg supplemental Zn addition were the highest with the lowest feed efficiency.When additive dosage of supplemental Zn was 60 mg/kg,the growth performance of the chicken was the best,and the deposition amount of Zn in tibia of chicken basically reached the highest level.When additive dosage of supplemental Zn was 90 mg/kg,the deposition amount of Zn in tibia of the chicken reached the balance with the lowest leg abnormality rate.[Conclusion] It was proper when additive dosage of supplemental Zn was 60-90 mg/kg in this test,that was the requirement of Gushi chicken on Zn was 96.3-125.3 mg/kg.