effect of betaine on performance and on carcass characteristics of broiler chicks in response to water salinity stress

the effect of saline water and dietary betaine on growth performance of 576 male broiler chicks from 11 to 42 days of age, and on carcass composition (percentages of carcass, sartorial, breast, liver, abdominal fat and heart) of a sub sample of 96 birds was studied in a crd experiment. three dose levels of sodium chloride (0, 1000 and 2000 mg/l) and 4 levels of betaine (0.000, 0.075, 0.150 and 0.225 percent) were added to drinking water and basal diet, respectively. feed was provided ad libitum and water in free access. data showed that betaine supplementation and added nacl in water increased and improved body weight and fcr, respectively (p< 0.05). feed intake increased through a consumption of high levels of added nacl, at the 11 to 21 and 29 to 42-d age periods(p< 0.01). chicks which consumed higher levels of nacl in water showed higher percentages of breast (p< 0.01). interaction between betaine and water salinity was significant on body weight and fcr at 21-d age experimental period(p< 0.05). the data imply that betaine supplementation may have been involved in protection of intestinal epithelium against osmotic disturbance (saline water), improved digestion and absorption conditions of the gastrointestinal tract and amended the usage of nutrients.