Zilpaterol [KLH]

Forty Dorper x Pelibuey male lambs were used to obtain the Longissimus dorsi muscle to evaluate the effect of zilpaterol hydrochloride (ZH) and soybean oil (SO) on chemical (moisture and intramuscular fat), physicochemical quality (pH, water holding capacity [WHC], Warner Bratzler shear force [WBSF], color) and sensory attributes of meat. Lambs were individually housed in pens and assigned randomly to 1 of 4 treatments (n = 10): (1) control (no ZH or SO); (2) supplemented with ZH (10 mg/animal daily); (3) addition of 6% SO, and (4) supplemented with ZH (10 mg/animal daily) + addition of 6% SO. Feeding ZH decreased color parameters and intramuscular fat (P<0.05), and increased pH and WBSF. Panelists observed a decreased in overall color, harder meat and higher content of connective tissue (P<0.05) by ZH supplementation. Feeding SO increased (P<0.05) a* value and WHC, without modifying the sensory characteristics. (C) 2013 Elsevier B.V. All rights reserved.

Bonsmara type steers were used to determine the effect of dietary zilpaterol hydrochloride (ZH) in combination with different dietary crude protein (CP) levels (100, 120 and 140 g CP/kg) on growth performance and meat quality. Treatment groups (T) consisted of 12 steers each. T1 - 100 g CP/kg + 0.15 mg ZH/kg live weight (LW); T2 - 120 g CP/kg + 0.15 mg ZH/kg LW; T3 - 140 g CP/kg + 0.15 mg ZH/kg LW and T4 - 120 g CP/kg + 0 mg/kg LW. Steers received the diets from an initial LW of 278 kg and fed to a target mass of 390 kg. After a seven day ZH withdrawal period the steers were slaughtered and carcasses electrically stimulated. Samples from m. longissimus thoracis, m. semitendinosus and in. triceps brachii were kept in airtight polyethylene bags and matured for ten days at 4 degrees C. Zilpaterol treatment increased the average daily gain (ADG) non-significantly (NS) by 9.6%. Zilpaterol treatment improved feed conversion ratio (FCR) by 20% (NS). 12 showed a significant 39.4% improvement in FCR in comparison with T4. Warner-Bratzler shear force (WBSF) of m. semitendinosus and in. biceps brachii samples differed between ZH treated groups. Cooking loss (CL) for m. longissimus thoracis was lower for T2 in comparison with T1, T3 and T4. ZH treatment for 35 days, electrical stimulation and a maturation period of 10 days generally left the WBSF and CL unaffected while the FCR in combination with 120 g CP/kg improved significantly.