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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