An experiment was conducted: 1) to compare the response of broiler chicks fed diets supplemented with betaine or choline on an equi-molar basis and 2) to examine the effect of using higher levels of supplemental betaine on broiler chicks performance. A total number of 240 unsexed day-old HUBBARD broiler chicks were distributed into 6 treatments of 40 chicks each in four replicates (10 chicks per replicate). The diets were formulated to contain about 21.6% and 17.7% CP and about 2971 and 3057 Kcal ME/Kg feed at starter and finisher period, respectively. The control (T1) diets were supplemented with 690 ppm choline chloride (50%) to supply 300 ppm choline (according to Egyptian recommendations). The chicks of treatment 2 (T2) were fed diets supplemented with 175 ppm of commercial betaine (91%) to supply an equivalent amount of molecules that choline furnished in control diets. The birds of treatment 3 (T3) and 4 (T4) were fed diets supplemented with choline chloride (50%) or betaine (91%) at levels of 1650 or 420 ppm, respectively to supply the recommended level of choline (715 ppm) to "HABBARD" broilers . However, treatments 5 (T5) and 6 (T6) were fed diets containing higher levels of betaine (665 ppm for T5 and 910 ppm for T6).
The results of entire experimental period revealed that the values obtained with respect to the performance of chicks and carcass characteristics were nearly similar.
Under the conditions of this experiment, it could be concluded that:
1- Betaine can effectively replace choline in broiler feed whilst maintaining performance.
2- On an equi-molar basis, 1 kg betaine (91%) can replace about 4 kg choline chloride (50%).
3- Using betaine (91%) up to 910 ppm in broiler diets gave no extra benefit, as long as these diets were formulated to contain enough essential amino acids and birds reared under no stress conditions.