Center for Meat Safety and Quality, Colorado State University, Fort Collins 80523-1171.
J Anim Sci. 2013 Dec;91(12):5989-97. doi: 10.2527/jas.2013-7042. Epub 2013 Oct 28.
Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on LM shear force and sensory attributes was determined using pens (n = 40) British × Continental crossbred steers randomly allocated to one of the following treatments: control; RH fed at 200 (RH 200) or 300 mg • steer(-1) • d(-1) (RH 300), or 400 mg • steer(-1) • d(-1) (RH 400) top-dressed for the final 30 d of feeding; or ZH fed at 7.5 mg/kg, beginning 23 d before slaughter with a 3-d withdrawal. Two replicates (pens) per treatment were represented in four blocks. Eighteen carcasses per pen were randomly selected and one 5-cm LM sample was removed from both carcass sides to be used for shear force and sensory evaluation. Samples were aged for 14 d, frozen at -28.8 °C, and cut into 2.5-cm steaks. All steaks were cooked to an internal temperature of 71.1 °C before being evaluated for Warner-Bratzler shear force (WBSF), slice shear force (SSF), or being fed to trained sensory panelists. Increasing dose and potency of β-agonist increased WBSF by 4 to 17% and SSF by 5 to 24% (P < 0.05). Steaks from steers fed ZH had higher WBSF and SSF values compared with all other treatments (P < 0.05), whereas steaks from controls and steers fed RH 200 were not different (P > 0.05). Probability of steaks failing to meet shear force standards to be certified tender (WBSF <4.4 kg, SSF < 20 kg) was increased from an initial probability of <0.06 in steaks from steers in the control treatment to 0.10 to 0.20 in steers fed RH 400 or ZH (P < 0.05). No difference was detected in panel ratings for overall tenderness of steaks from steers fed RH 200 compared with controls (P > 0.05). Steaks from steers fed RH 300 and RH 400 were comparable for all sensory attributes; however, both RH 300 and RH 400 were rated lower for overall tenderness than controls (P < 0.05). Panelists failed to detect differences in overall tenderness of steaks from steers fed RH 400 and ZH (P < 0.05). Panelists detected no difference in flavor profile or juiciness among treatments (P > 0.05). Results from this study indicated β-agonists negatively affected beef tenderness and these effects may be more noticeable in steers supplemented with ZH and higher doses of RH.
盐酸莱克多巴胺（RH）和盐酸齐帕特罗（ZH）对 LM 剪切力和感官特性的影响使用笔（n = 40）进行了测定，英国 × 大陆杂交公牛随机分配到以下处理之一：对照组；RH 以 200（RH 200）或 300mg • 牛（-1）• d（-1）（RH 300）或 400mg • 牛（-1）• d（-1）（RH 400）的形式在最后 30 天的饲养中进行顶部涂抹；或 ZH 以 7.5mg/kg 的剂量开始，在屠宰前 23 天开始，停药 3 天。每个处理的两个重复（笔）在四个块中表示。每支笔随机选择 18 头牛胴体，从胴体两侧取出 5cm LM 样本，用于剪切力和感官评价。样本在 14 天内老化，在-28.8°C 下冷冻，然后切成 2.5cm 的牛排。所有牛排在内部温度达到 71.1°C 之前进行烹饪，然后进行 Warner-Bratzler 剪切力（WBSF）、切片剪切力（SSF）或喂给经过训练的感官小组。β-激动剂剂量和效力的增加使 WBSF 增加了 4%至 17%，SSF 增加了 5%至 24%（P<0.05）。与所有其他处理相比，ZH 处理的牛的牛排 WBSF 和 SSF 值更高（P<0.05），而对照组和 RH 200 处理的牛的牛排则没有差异（P>0.05）。初始概率<0.06的控制处理牛的牛排达到剪切力标准的可能性增加到<0.06，达到 0.10 到 0.20在 RH 400 或 ZH 处理的牛的牛排中（P<0.05）。与对照组相比，RH 200 处理的牛的牛排总体嫩度的小组评分没有差异（P>0.05）。RH 300 和 RH 400 处理的牛的牛排在所有感官属性方面均具有可比性；然而，与对照组相比，RH 300 和 RH 400 处理的牛的牛排的总体嫩度均较低（P<0.05）。小组成员未能检测到 RH 400 和 ZH 处理的牛的牛排总体嫩度的差异（P<0.05）。小组成员未发现处理之间的风味特征或多汁性存在差异（P>0.05）。本研究结果表明，β-激动剂对牛肉嫩度有负面影响，这些影响在补充 ZH 和 RH 更高剂量的牛中可能更为明显。
