ESTIMATED DAILY METHIONINE + CYSTINE REQUIREMENTS OF BROILER CHICKEN

Abstract

THE daily mthionine + cystine (MC) requirement of cobb-broiler chicken was estimated in three con­secutive experiments. In experiment 1, three groups of 30 day-old birds were fed one of eight diets. The diets contained bet­ween 0.52% and 1.08% MC in 0.08% stepwise in­crements. Liveweight gain peaked at 0.84% and 0.76% MC levels during 1-21 days (period 1) and 21-42 days (period 2) growth phases, respectively. MC intake/bird/d at these 0.84% and 0.76% MC levels was 0.21g and 0.42g respectively. Efficiency of feed utilisation was maximized at 0.76% MC level during each of the growth phases. In experiments 2, three groups (25/group) of 42-day old birds were fed one of eight diets. The diets contained between 0.48% and 1.04% MC in 0.08% stepwise increments. Liveweight gain and feed utilisation efficiency were maximized at 0.64% MC level during each of 42-63 days (period 3) and 63-84 days (period 4) growth phases. However, MC intake/bird/d was 0.58g during period 3 and 0.82g during period 4. Experiment 3 involved 9 diets ar­ranged in a 3 x 3 factorial design (Three energy levels: 2,800, 3,200 and 3,600 Kcal ME/kg diet; and three MC levels: 0.68%, 0.76% and 0.84). Each diet was fed to triplicate group of 30 day-old birds. The daily MC intake requirement of 1-28 day-old birds was 0.37g at 2,800 KcalME/kg diet; while that of 28-56 days old birds was 0.83 at 3,600 KcalME/kg diet.