【摘要】 本研究在体外条件下对肉仔鸡消化道内pH环境以及蛋白质水解酶对黑曲霉植酸酶活性的影响进行了研究。结果表明,该植酸酶为酸性植酸酶,最适pH为5.5。该植酸酶对pH环境和蛋白质水解酶较为敏感。当环境pH远离其最适pH时其活性迅速下降,且大部分酶活损失发生在30 min内,然后趋于稳定。在pH3.0和pH6.0条件下,加入胃蛋白酶和胰酶后,植酸酶活性亦进一步迅速降低,然后趋于稳定,但与胃蛋白酶相比,胰酶对植酸酶活性的影响更大。从植酸酶在14、28和42日龄肉仔鸡胃和小肠稳定性的研究可以看出,植酸酶在胃存留率分别为42%、40%和49%,在小肠内的存留率仅19%。植酸酶在胃内的稳定性好于小肠,小肠内环境不利于植酸酶存活。植酸酶活性受肉仔鸡消化道pH和蛋白酶的影响较大,这可能是影响植酸酶作用效果的主要因素之一。更多还原

【Abstract】 The effects of pH value and protease in broiler gastro-intestine on Aspergillus niger phytase activity and the ability of phytase to survive in broiler proventriculus,gizzard and small intestine were studied in vitro.The results show that the phytase optimum pH value is 5.5 and is susceptible to broiler gastrointestinal pH and protease.When the phytase incubation at the pH which is higher or lower than its optimum pH5.5,the phytase activities decreased rapidly and most of phytase activity disappeared during 30 min.Following incubation at pH3.0 and pH6.0 in the presence of pepsin and pancreatin respectively,more phytase activity disappeared.Phytase is more susceptible to pancreatin than that to pepsin.42%,40% and 49% of phytase were survived on 14,28 and 42 days broiler proventriculus and gizzard respectively and about 19%of phytase survived in small intestine of broiler in different ages in vitro.The phytase is more stable in proventriculus and gizzard than that in small intestine,where pH and pancreatin is not favor to phytase.The results suggest that phytase is susceptible to pH and protease in broiler gastrointestinal tract,which may be the main reason why only a small part of inorganic P could be replaced by phytase in broiler diet.更多还原