Rikhardsson G, Johnson K A, Johnson D E
Dept. of Anim. Sci., Colorado State University, Fort Collins 80523.
J Anim Sci. 1991 Jan;69(1):396-404. doi: 10.2527/1991.691396x.
The effects of cimaterol, a beta agonist, on basal metabolic rate, heat increment, maintenance requirements and carcass characteristics were determined using six treated and six control Suffolk ewe lambs. The lambs were fed a pelleted diet (18.7% CP, 2.64 Mcal ME/kg) with or without .5 mg cimaterol/kg BW.75 daily for 70 d. Heat production was monitored for 2 d on each animal at three levels of intake by respiration calorimetry. A 7-d total collection digestion trial was conducted on each animal at both high and low levels of intake. Cimaterol-fed lambs gained more (P less than .05) weight (174 vs 107 g/d) and had a higher (P less than .01) gain/feed ratio (151 vs 90 g/kg) than controls. Cimaterol did not affect diet digestibility or methane production. It reduced (P less than .01) urinary N excretion by 12% and improved (P less than .001) N retention by 18%. Cimaterol also increased carcass weight (26.9 vs 22.1 kg), dressing percentage (57.2 vs 53.9), longissimus muscle area (22.5 vs 15.0 cm2) and leg score (14.3 vs 12.2). Heat production was, on the average, elevated 7 to 10% on d 1 to 4 of cimaterol feeding but reverted to control levels by d 10. Cimaterol did not have any long-term thermogenic effects, either expressed as partial efficiency of ME use for growth (.48 vs .49), as maintenance ME requirements (76 vs 75 kcal/kg BW.75) or as fasting heat production (84 vs 80 kcal/kg BW.75) for treated vs control lambs, respectively. Results indicate little long-term thermogenic effect of cimaterol, even though growth rate and protein deposition were increased.
使用6只经处理的和6只对照萨福克母羊羔，测定了β-激动剂西马特罗对基础代谢率、热增量、维持需要量和胴体特性的影响。这些羔羊每日饲喂一种颗粒饲料（18.7%粗蛋白，2.64兆卡代谢能/千克），饲料中添加或不添加0.5毫克西马特罗/千克体重的0.75次方，持续70天。通过呼吸测热法在三种采食量水平下对每只动物监测2天的产热情况。在高采食量和低采食量水平下对每只动物进行为期7天的全收粪消化试验。饲喂西马特罗的羔羊体重增加更多（P<0.05）（174克/天对107克/天），且增重/采食量比更高（P<0.01）（151克/千克对90克/千克），高于对照组。西马特罗不影响日粮消化率或甲烷产生量。它使尿氮排泄量降低（P<0.01）12%，并使氮保留率提高（P<0.001）18%。西马特罗还增加了胴体重（26.9千克对22.1千克）、屠宰率（57.2%对53.9%）、背最长肌面积（22.5平方厘米对15.0平方厘米）和腿部评分（14.3对12.2）。在饲喂西马特罗的第1至4天，平均产热升高7%至10%，但到第10天恢复到对照水平。西马特罗对生长的代谢能利用部分效率（0.48对0.49）、维持代谢能需要量（76千卡/千克体重的0.75次方对75千卡/千克体重的0.75次方）或禁食产热（84千卡/千克体重的0.75次方对80千卡/千克体重的0.75次方），分别对处理组和对照组羔羊均没有任何长期的产热效应。结果表明，即使生长速度和蛋白质沉积增加，西马特罗的长期产热效应也很小。
