Kannan G, Heath J L, Wabeck C J, Souza M C, Howe J C, Mench J A
Department of Poultry Science, University of Maryland, College Park 20742, USA.
Poult Sci. 1997 Mar;76(3):523-9. doi: 10.1093/ps/76.3.523.
Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P < 0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P < 0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P < 0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P < 0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P < 0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.
1）不同的装笼持续时间是否会影响肉鸡的应激反应和肉质；2）运输后将装笼肉鸡留置是否会影响皮质酮（CORT）水平和肉质。在一项初步实验中，雄性肉鸡（n = 50）在宰杀前分别在笼中（每笼10只鸡）饲养0、1、2、3或4小时。装笼持续时间不影响血浆CORT水平、蒸煮损失、胸肌或大腿肌肉的剪切值，也不影响胴体皮肤变色情况。装笼持续时间也不影响胸肉的颜色（L*、a*、b*、色度和色相角），但确实改变了大腿肉的颜色，3小时装笼组的样品色相值最高（P < 0.01）。大腿样品的皮质酮浓度和色相值呈正相关（P < 0.05，r = 0.244）。在实验1中，肉鸡（n = 36）装笼1或3小时，每笼9只鸡。装笼时间不影响血浆CORT、肾上腺素或去甲肾上腺素浓度，也不影响胸肉和大腿肉样品的初始pH值、颜色或质地。在实验2中，肉鸡于清晨装笼（每笼9只鸡），并通过卡车运输3小时至加工设施。9笼鸡在宰杀前在黑暗安静的地方留置4小时（H组），其余9笼立即宰杀（NH组）。H组的皮质酮水平显著低于NH组（P < 0.01）。H组大腿肉的初始pH值也显著更低（P < 0.01），尽管胸肉pH值不受处理影响。留置对剪切值、颜色（胸肉和大腿肉）或总血红素浓度（大腿肉）没有影响。大腿肉的CORT水平和色相值之间存在显著相关性（P < 0.01，r = 0.302）。这些结果表明，尽管在本研究条件下总体肉质未受影响，但肉鸡宰前较高的应激水平可能会影响大腿肉的颜色。
