ESTIMATED DAILY METHIONINE + CYSTINE REQUIREMENTS OF BROILER CHICKEN

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