| The purpose of this study was to evaluate the effect of adding phytase in diet to the optimum demand for zinc and manganese.This experiment is divided into in vitro test and animal vivo test.Broilers in vitro experiment is simulated to 21 age environment,stomach and small intestine in vitro digestion of two kinds of feed,respectively is corn-bean pulp feed I(set with phytase and without phytase group),zinc content is 40.71 mg/kg,corn-bean pulp feed II is the feed I add 0.1% on the basis of the trace element premix(set with phytase and without phytase group),zinc content is 100.53 mg/kg.The content of free zinc ions(uncomplexation)in digestive juice was measured by atomic absorption spectrometry,and the content of zinc was calculated.The animals were randomly divided into 6 groups of 696 14-day-old AA+ broilers,each with 12 repeats(caged),each with 9 to 10 chickens.The design was based on 2×3 factorial design,2 phytase levels(0 FTY /kg,2 000 FTY /kg)and 3 zinc and manganese combination(30 mg/kg,40 mg/kg;60 mg/kg,70 mg/kg;90 mg/kg and 100 mg/kg)mixture of 6 feed,respectively is low in zinc manganese without phytase manganese in zinc in groups,do not add phytase group and high zinc manganese without phytase group and low zinc manganese adding phytase group,zinc manganese and phytase in the group and high zinc manganese phytase group.The experiment was divided into two periods(14~27days)and after(28~42 days).Record the hollow body weight and excess material of the meat chicken at each stage,and calculate the growth performance.In the middle stage,the nutrient metabolic rate was calculated by using exogenous indicator method.At the end of the experiment,the seru m was prepared by fasting blood,and the activity of the enzyme in serum was determined.After blood collection,the right tibia of broilers was taken to determine the content of ash content in tibia and the deposition of zinc and manganese.The results show that:(1)In vitro digestion corn-bean pulp feed I determination without phytase and adding phytase free zinc content were 2.81 mg/kg and 4.78 mg/kg,corn-bean pulp feed II did not add phytase and add phytase free zinc content were 6.17 mg/kg and 7.38 mg/kg.(2)In the growth of the broilers.The average daily weight gain(P=0.001)of high zinc manganese and phytase group was the highest,the weight ratio of the broiler was lowest(P=0.022).During the fattening period of broilers,the average daily gain weight of high-zn high manganese and phytase group was the highest(P=0.038).(3)Adding phytase feed can significantly increase the activity of total superoxide dismutase(P=0.037),significantly improve manganese superoxide dismutase activity(P=0.007),the phytase and zinc manganese have limits on the total superoxide dismutase significant interaction(P=0.006).Phytase can significantly increase the content of serum glutamic pyruvic transaminase(P=0.007),significantly increased the activity of aspertate aminotransferase(P=0.038),significantly improve the activity of creatine phosphate kinase(P=0.001),phytase and zinc manganese of creatine phosphate kinase have significant interaction effect(P=0.01).Feed in the level of zinc and manganese can significantly reduce the chicken serum urea nitrogen content(P=0.041),but had no significant effect on serum alkaline phosphatase(P=0.694),the content of serum alkaline phosphatase with zinc,manganese level rises.(4)The phytase added significantly increased(P=0.047),serum zinc content of zinc manganese level has a significant influence on chicken serum zinc content(P=0.033),high zinc,manganese and adding phytase group,the highest content of chicken serum zinc.(5)There was no significant effect on the metabolic rate of organic dry matter,crude protein and energy(P>0.05)in the diet with phytase and zinc and manganese.However,the utilization rate of crude protein increased with the increase of Zn-Mn level.(6)The level of dietary zinc and manganese had significant effects on zinc and manganese content in feces and urine(P=0.000),low zinc and low manganese and the addition of phytase group,with the lowest levels of zinc and manganese in fecal urine.(7)The phytase can improve the tibia ash and zinc content,significantly increase the manganese concentration in tibia(P=0.019),dietary zinc and manganese levels had obviously effect on zinc and manganese concentration in broiler tibial(P=0.029 or P=0.006).High zinc-high manganese and phytase group,tibia ash,tibia zinc and manganese content were the highest.To sum up,the addition of zinc and manganese was 90 mg/kg,100 mg/kg and phytase group,and the growth performance of broilers was the best.Phytase can improve the activity of antioxidant enzymes in serum and affect the liver function of broilers.The addition of phytase promotes the utilization of protein,and the increase of zinc and manganese promotes the healthy growth of chicken bones.The addition of phytase can reduce the excretion of zinc and manganese,which is beneficial to environmental protection. |
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