饲料蛋白质体外消化率及其影响因素的研究

STUDY ON THE RELATIONSHIP BETWEEN THE DIGESTIBILITY OF FEED PROTEINS AND PROTEIN QUALITY IN VITRO

采用胃蛋白酶－胰酶两步体外消化法测定了棉籽粕、酵母、玉米蛋白粉、肉粉、蚕蛹、酪蛋白、２种菜籽饼（粕）、３种鱼粉和６种豆饼（粕）等１７种蛋白质饲料的蛋白质体外消化率，并研究了它们与蛋白质质量的关系。体外消化测得酪蛋白的消化率最高，为９６．９％±０．１％，其次为棉籽粕和蚕蛹，其消化率分别为：９０．２％±０．４％和８９．８％±０．３％；鱼粉（９４）、肉粉、ＳＢＭ（开封）、ＳＢＭ（９１）、ＳＢＭ（东北）的消化率在９０％－８５％之间；ＲＳＭ（机）、酵母、鱼干、鱼粉（９３）、ＲＳＭ（浸）、ＳＢＭ（８８）、ＳＢＭ（９２）、ＳＢＭ（９０）的蛋白质消化率低于８５％．加工的方法和贮存的时间长短影响蛋白质的消化率，用染料结合法（考马斯亮蓝Ｇ２５０）测得饲料的真蛋白（ＣＢＢＧ）与蛋白含量（ＴＰ）的比值，与蛋白质体外消化率极显著的（Ｐ＜０．０１）相关关系。ＣＢＢＧ／ＴＰ值可作为监测蛋白质质量的一个指标。

A two-step in vitro digestion technique by using pepsin and pancreatin was taken to determine the digestibility of proteins feed proteins of cotton meal, yeast, corn gluten meal, meat meal, silkworm chrysalis, casein, two kinds of rapeseed meals, three kinds of fish meals and six kinds of soybean meals, and meanwhile the relationslip between protein digestibility in vitro and protein quality was invegasted. The value of CBBG/TP is a ratio of the true protein content determined with dye binding method(Comassie Blue G 250) to the true protein content determined by Kjeldahl method after a feed sample is treated witl 10% trichloroacetic acid. A significant relationshiP exists between CBBG/TP and protein digestibility(P<0. 01). The results indicate the value of CBBG/TP can be used as a parameter to indicate the protein quality.