Two nitrogen bala nce trials after partial deletion of die tary amino acids(AA) were conducted to i nvestigate the ideal balance patterns of dietary digestible lysine(Lys)，sulphur containing amino acid(SAA)，threonine(Thr)and tryptophan(trp)for the growing(35-6 0kg)and finishing (60-90kg) pigs．Eightee n Yorkshire × Landrace crossbred castrat es were employed for the trials．Six isoe nergetic diets based on corn，soybean mea l and corn gluten meal were prepared for each trial．They were basal diet(BD)with 16.1％ and 14.9％ crude protein(CP)for ea ch s tage，25％-low-CP diet(s) supplemented wit h all the four (positive control，PC)or w ith three of the four AAs to have an equ al digestible AA content，except the exam ined one which was 25％ lower than that i n BD．The result showed that the ideal am ino acid pattem expressed on digestible basis was Lys 100，SAA 49，Thr 72，Trp 19 f or growing stage and Lys 100，SAA 34，Thr 64，Trp 23 for finishing stage of pigs．
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