Department of Animal Science
Date of this Version
1992
Abstract
The response time to cimaterol (CIM), a P-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were conducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet containing 1 ppm of CIM. Trial 1 consisted of 55, 31-d-old broiler chickens individually fed for up to 48 h. At 0, 6, 12, 18, 24, and 48 h, five CON and five CIM-fed chickens were killed. Trial 2 consisted of 160, 33-d-old broiler chickens group-fed for up to 14 d. At 2,4,6, 8, 10, 12, and 14 d, 10 CON and 10 CIM-fed chickens were killed. The breast muscle (BM) and leg muscle (LM) weight, cathepsin B and L activities, DNA, RNA, and protein concentration, and BM shear force value (SFV) were measured in both trials. Thigh muscle (TM) SFV were measured in Trial 2 only. Fiber size of BM was measured (five birds per treatment) at d 2, 6, 10, and 14. In Trial 1, BM weight and SFV were lower in CIM-fed birds at 6 h (P < ,051. In Trial 2 BM SFV were higher at d 8 (P = ,061 and d 10 (P c .05) in CIM-fed chickens. The SFV of CIM-fed chickens were higher at d 4, 8, lo, 12, and 14 (P < .051. The BM of CIM-fed chickens had a higher protein:DNA ratio (P < .05) at d 6 through 14, whereas LM of CIM-fed chickens had a higher protein:DNA ratio at d 8, 10, and 14. Fiber size of the BM in CIM-fed chickens tended to be larger at d 10 (P = .13) and at d 14 (P = ,17). Total BM weight and BM as a percentage of final body weight (FBW) was higher at d 10 and 14 (P < .01) in CIM-fed chickens. Total LM weight and LM as a percentage of FBW was higher at d 14 (P < .01) in CIM-fed chickens. In the BM of CIM-fed chickens, protein:DNA ratio increased by d 6, SFV by d 8, muscle fiber size by d 10, and BM weight and BM as a percentage of FBW by d 10. The TM or LM of CIM-fed chickens showed increases in SFV by d 4, protein:DNA ratio by d 8, and LM weight and LM as a percentage of FBW by d 14. Response times to treatment with CIM differed for the various traits measured (i.e., meat tenderness, muscle composition, fiber size, or carcass characteristics).
Comments
Published in Journal of Animal Science 1992. 70:2144-2150. Copyright © 1992 American Society of Animal Science. Used by permission.