氨基酸和蛋白质对牛瘤胃细菌生长的影响

Effect of Amino acids and Protein on Rumen Microbial Growth

用经洗涤的瘤胃细菌稀释液在体外作培养，确定不同的氨基酸刺激瘤胃细菌生长的效果。添加或不添加酪蛋白，由各种氨基酸组成的混合氨基酸对细菌的生长具有刺激作用。不管是否添加酪蛋白或水解酪蛋白，不同组合的氨基酸均不能刺激细菌的生长。当氨作为唯一的氨源时，它对细菌的生长无刺激性。瘤胃细菌的生长与培养基内的碳水化合物含量存在线性函数关系。结果显示，氨基酸和蛋白质对瘤胃细菌的刺激作用，决定于所提供的氨基酸和蛋白质种类的多少，而不是取决于某些特殊的限制性氨基酸。

Effect of amino acid on rumen microbial growth was determined with washed cell suspensions in vitro. Rumen microbial growth was stimulated by complete amino acid mixtures with or without casein, but could not be stimulated by subgroups of amino acids with or without casein or casein hydrolysates. There was little growth apparent when ammonia as a sole nitrogen source. Rumen microbial growth was a linear funtion of amount of carbohydrate. Experiments demonstrated that the rumen microbial growth stimulation from both amino acids and proteins was subjected to the number of amino acids in a given mixture rather than the specific growth-limiting amino acids.