Abstract
Simple Summaryβ-adrenergic agonists have been widely used to improve meat production efficiency and can be a valuable tool for increasing world meat supply. They act as nutrient repartitioning agents, increasing lean tissue deposition but negatively affecting meat quality, notably reducing palatability. While this metabolic modifier improves the growth performance of Zebu breeds, they can impair even more meat quality in feedlot-finished cattle. This study was developed to evaluate the impact of zilpaterol hydrochloride (ZH) feeding duration and time on feed (90 or 117 days), on meat quality, and on composition properties of meat from young Zebu bulls. Supplementing ZH resulted in a leaner and less tender and juicy meat compared to non-supplemented animals, with few differences in fatty acid composition. Feeding animals for 90 or 117 days had a small impact on meat quality attributes. Feeding ZH to Zebu bulls would require additional tenderization practices to reduce the negative effects of ZH on meat quality.Ninety-six Nellore young bulls were fed (90 or 117 day) diets containing ZH (8.33 mg/kg) for 0, 20, 30, or 40 days to evaluate the effects of days on feed (DOF) and length of zilpaterol hydrochloride (ZH) supplementation on meat quality. At the end of feeding period, animals were slaughtered, and samples of the Longissimus muscle were collected to evaluate the chemical composition, fatty acid profile, color stability, shear force, and sensory profile. DOF did not affect chemical composition, shear force, sensory tenderness, and most of fatty acids; however, animals fed for 90 d had lower redness (p < 0.01), sustained juiciness (p < 0.01), and more flavor (p = 0.03) than those fed for 117 d. The ZH supplementation decreased lipid content and redness (p < 0.01), initial and sustained tenderness (p < 0.01), initial and sustained juiciness (p < 0.01), but increased protein (p < 0.01) and shear force (p < 0.01) as compared to non-supplemented animals. The ZH supplementation increased total PUFA, c9,c12-18:2, and 20:4-n6, and decreased c9-20:1 (p < 0.05). Feeding ZH impairs meat quality attributes of Nellore young bulls, regardless of duration of supplementation, while DOF has a small effect on meat quality properties.
Highlights
The Brazilian beef cattle production system is mainly based on Zebu breeds raised and finished under grazing conditions [1]
Ninety-six young Nellore bulls (377 ± 25 kg initial body weight (BW) and 24 months old) were used in a randomized complete block design with a 4 × 2 factorial arrangement to evaluate the effects of duration of zilpaterol hydrochloride (ZH) supplementation (0, 20, 30, or 40 days; 8.33 mg/kg; Zilmax®, MSD Animal Health, São Paulo, SP, Brazil) and days on feed (DOF) before slaughter (90 and 117 days)
The meat of young bulls fed for 117 days was redder (a*; p < 0.01) and had lower hue values (p < 0.01) than those fed for 90 days, while L*, b*, and Chroma were not affected by the DOF
Summary
The Brazilian beef cattle production system is mainly based on Zebu breeds raised and finished under grazing conditions [1]. The increasing market demands for higher meat quantity and quality have progressively increased feedlot finishing practices [2], especially using young bulls, because they grow faster than steers, utilize feed more efficiently, and have higher carcass dressing percentage and leaner meat despite poorer meat quality [3,4]. Growth promoters such as β-adrenergic agonists have been used to improve animal performance, feed efficiency, and lean meat yield. The magnitude of enhancement, the efficiency of gain, and the modification of carcass characteristics and meat quality are influenced by the duration of treatment with βAA [7]
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