The Effects Of Phytases From Different Microbials On The Degradation Kinetics Of Phytate In Commonly Used Feedstuffs

The study was conducted to investigate the effects of phytases from different microbials on degradation of phytate phosphorus and minerals of different feedstuffs by in vitro and in vivo experiment, respectively.In experiment 1, At 37℃pH5.50, The degradation kinetics of phytates from rice bran, soybean meal, rapeseed meal and Corn germ meal were evaluated at 0, 10, 20, 30, 40, 60, 120, 180, and 240 min using phytases derived from Aspergillus ficuum, Aspergillus niger, Pichia pastoris and Escherichia coli, respectively. The results indicated that both feedstuff and phytase×feedstuff affected the rate and extent of phytate phosphorus degradation significantly(P<0.01).In experiment 2, two feedstuffs, i.e., soybean meal and ricebran, and two phytase, i.e., derived from Aspergillus niger and Escherichia coli, were chose according to the results of above in vitro experiments. The availability of phytate phosphorus and minerals were evaluated using forty-eight adult cocks. There were 8 cocks in each feed and enzyme combination. Each cock was forced fed 75 g/d, the excretion was collected in the following 24h. Tthe experiment lasted 3 days. The result showed that:①Feedstuff affected the totle contents of mineral elements in excreta. With phytase derived from Escherichia coli, The contents of totle Ca, Cu, Mn in excreta the soybean meal diet significantly higher than that of the ricebran diet and the contents of totle Zn,Mg in excreta were significantly lower. Supplementation of phytase from Aspergillus niger, The contents of totle Ca in excreta the soybean meal diet significantly higher than that of the ricebran diet and the contents of Zn,Mg in excreta were lower.②Feedstuff and phytase affected the soluble contents of Ca, Cu, Zn, Mn in excreta. Supplementation of two phytase increased the extent of degradation of phytate phosphorus,contents of soluble Ca, Zn in soybean meal group and phytate phosphorus, solubleCa, Mn, Zn in ricebran meal group significantly. The contents of soluble Ca, Cu, Zn in excreta were higher in soybean meal diet than in ricebran diet.③Feedstuff affected the potential utilization of Cu, Zn, Mg in excreta. Phytase affected the potential utilization of Ca, Mn, Zn in excreta. Supplementation of two phytase increased the potential utilization of Mn, Zn in excreta in soybean meal and Ca, Mn, Zn in ricebran meal group. There were no difference between two phytase. With phytase derived from Escherichia coli, The potential utilization of soluble Mg, Zn in excreta were higher in soybean meal diet than in ricebran diet and the potential utilization of Ca in excreta were lower than in ricebran diet; With phytase derived from Aspergillus niger, The potential utilization of soluble Mg, Zn, Cu in excreta the soybean meal diet significantly higher than that of the ricebran diet and the potential utilization of Ca in excreta were lower.