Abstract: An in vivo experiment was conducted to determine the effect of dietaq betaine supplementation (Betafine) as a replacement for choline on broiler performance and carcass characteristics. The dets containing four betaine levels at 0,33,66 and 100% in replacement for choline and tow basal diets (containing of 2.5% oil and lack~ngo f oil) were used in a Completely Randomized Design (CRD) with a 2x4 factorial arrangement and four replicates of 10 birdslreplicate Three hundred twenty-day-old Ross broiler chicks were randomly distributed in cages and fed the experimental diets from 0-49 days of age. Feed and water were provided ad-libiturn. Feed intake, body weight gain and feed conversion ratio were recorded weekly. At 49 days of age, one bird from each replicate was selected for blood sample collection and comparison of carcass characteristics. Betaine replacement for choline had no effect on feed intake, weight gain and feed conversion ratio but, a significant different (p<0.05) in body weight gain (at 0-3 and 3-6 weeks of age) and feed conversion ratio (at 0-3 weeks of age) was obsenred among different treatments. Betaine as a replacement for choline increased the breast weight andreducedthe abdominal fat (p<0.05), but had no significant effect on thigh, liver, fat of liver percentages and blood parameters. The present findings indicated that although replacement of betaine imtead of choline in diets of broiler ddn\\\\\\\\\\\\\\\'t improved significantly feed intake, weight gain, feed conversion ratio, percentage of carcass characteristics and blood parameters, but resulted in significant reduction of abdominal fat and significant increase of breast meat.

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