초록
Two experiments were conducted to determine the ileal digestibility of the amino acids contained in cottonseed meal using the regression technique and then applying the values obtained, in a growth trial, using growing-finishing pigs. For the digestibility trial, four 20 kg crossbred ($Yorkshire{\times}Landrace{\times}Beijing$ Black) barrows were fitted with simple T-cannula in the terminal ileum. After recovery, the barrows were fed one of four experimental diets according to a $4{\times}4$ Latin Square design. The pigs were fed com-soybean meal based diets supplemented with 0, 25, 50 or 75% cottonseed meal. For the growth trial, 128 crossbred ($Yorkshire{\times}Landrace{\times}Beijing$ Black) growing pigs (21 kg) were fed com-soybean meal diets supplemented with 0, 4, 8 or 12% cottonseed meal. Four pens (4 gilts and 4 castrates) were assigned to each treatment. The digestibility coefficients for the indispensible amino acids declined as the level of cottonseed meal in the diet increased. There was good agreement between the amino acid digestibilities for methionine, threonine and tryptophan determined using the regression technique and amino acid digestibilities previously published for cottonseed meal. However, for lysine, the value of 67% ileal digestibility obtained in the present experiment was higher than most previously published estimates which ranged from 42 to 73%. During both the growing (21-43 kg) and finishing (43-84 kg) periods, the addition of cottonseed meal decreased average daily gain and feed conversion in a linear manner (p<0.05). Feed intake was not significantly different between treatments. The overall results suggest that cottonseed meal can be used at levels of up to 8% in diets fed to growing-finishing pigs provided that the diet. has been balanced for digestible amino acids.