postruminal infusions of a mixture of crystalline l-amino acids ( simulating the nonsulfur-containing essential amino acid pattern of casein ; sim ) at levels of 100 , 200 and 300 g/d also led to linear increases ( p less than .01 ) in n retention with steers retaining 30.9 , 38.9 and 50.5 g n/d ( averaged across methionine supplementation ) , respectively .
C0002525
essential amino acid
C0025646
methionine