Department of Animal Science
Date of this Version
1989
Abstract
To investigate the impact of cimaterol (CIM) on muscle protein turnover, carcass and muscle composition, muscle cathepsin B+L activity and meat tenderness, 21-d-old broiler chickens (n = 88) were assigned to dietary treatments of either 0 or 1 ppm CIM. Fractional synthesis rates (FSR), fractional accretion rates (FAR), proximate composition and collagen content were determined in the breast muscle (BM; pectoralis major) and a group of leg muscles (LM; gastrocnemius and peroneous longus) from groups of six birds per treatment within each of two time periods (age = 38 or 56 d). Whole body composition,' serum hydroxyproline content and BM cathepsin B+L activity also were measured. Fractional degradation rates (FDR) were calculated as the difference between FSR and FAR. Feeding CIM increased (P < .01) whole body protein content. Weights of LM and percentage of body weight as BM and LM were increased (P < .05) when CIM was included in the diet. Although FSR was)lot significantly reduced by CIM feeding, it decreased (P < .05) with increasing age. Due to decreases in FAR, FDR thereby was reduced by CIM 31.5% and 11.9% in BM and 38.2% and 37.4% in LM at 38 d and 56 d of age, respectively. Cathepsin B+L activities also were reduced 33.6% (P < .01) and shear forces were increased by 41% (P c .05) by CIM feeding. For chickens fed CIM, the correlation between cathepsin B+L activity and shear force was -.63 (P < .01). Feeding CIM improved carcass leanness and muscling due to reductions in FDR and proteolytic enzyme activity. Feeding CIM also reduced meat tenderness
Comments
Published in Journal of Animal Science 1989. 67:2646-2654. Copyright © 1989 American Society of Animal Science. Used by permission.