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Effects of cimaterol (CL 263,780) on growth performance and carcass quality of broilers fed on different levels of dietary protein and energy |
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Y. Y. Kim, I. K. Han, J. K. Ha, Y. J. Choi, M. Lee |
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| Abstract |
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The present study was carried out to investigate the effect of cimaterol on growth performance, carcass quality and cellular functional activity of broilers as affected by the various protein and energy levels. In starter period (0-21 days) all chicks were fed the basal diet which contained approximately 23 % crude protein and 3200 kcal of metabolizable energy per kg of diet. The cimaterol was added during 22-49 days and during the period of 8th week the cimaterol was withdrawn. In finisher period (22-49 days), a 2 횞 2 횞 3 factorial arrangement consisting of 2 levels of cimaterol (0 mg/kg, 0.25 mg/kg), 2 levels of protein (19%, 17%) and 3 levels of energy (3200, 2900, 2600 kcal/kg) was used. In the finisher period, the body weight gain and feed efficiency was improved by the supplementation of cimaterol. The high protein and high energy level with supplementation of cimaterol had showed the highest body weight gain and feed efficiency, without significant difference. The administration of cimaterol had no effects on percentage of abdominal fat content, giblet and neck. Eventhough the difference was not significant (p>0.05), carcass yield was improved slightly by the administration of cimaterol. The effect of cimaterol on carcass composition was clearly demonstrated that protein content of broilers was not increased (p>0.05) but fat content decreased significantly (p<0.05). The ultilization of nutrients in experimental diets was not significantly affected by feeding cimaterol compared to control group. The results of in vitro studies with liver and adipose tissue showed that cimaterol increased the lipolytic activities at 19% protein level whereas at 17% protein level this effect was variable. Lipogenic activities in liver and adipose tissue were not affected with the administration of cimaterol but the activities increased as energy decreased, particularly in liver tissue. In cell studies with acinar culture of liver tissues, cimaterol had no effect on protein synthetic activity but the parameter was increased at higher level of dietary protein and energy. Protein secretion in liver was increased by the supplementation of cimaterol. In addition, at high protein level the protein secretion was increased and has shown the highest values at medium energy level. |
| Keywords:
Cimaterol; Growth Performance; Carcass Quality; Protein and Energy Levels; Lipolytic and Lipogenic Activity; Protein Synthesis and Secretion |
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