Abstract：
Genetic selection for breast yields and fewer days to market has inadvertent effects on broiler meat quality. Woody breast (WB) and white striping (WS) are pectoralis major myopathies prevalent in commercial broilers. Effects of voluntary exercise on these disorders, specifically, are unknown. A second-generation laser enrichment device shown to induce activity in Ross 308 and 708 birds was implemented using 1,360 Ross 708 broilers randomly assigned to laser enrichment or control for 49 d. Laser-enriched birds were exposed to 6-min laser periods 4 times daily. Seventy focal birds were gait and contact dermatitis scored weekly. Blood was collected wk 5 to 7 from 56 broilers for serum corticosterone, myoglobin, and troponin. Seventy broilers were sampled for breast muscle width, fillet dimensions, and WB and WS at wk 6 and 7. One and 2-day postmortem, fillet compression force and water-holding capacity were measured. Serum corticosterone was reduced by up to 21% in laser-enriched birds wk 5 to 7 (P < 0.01). Serum myoglobin was increased in laser-enriched broilers by 5% on wk 5 (P < 0.01) but increased in control birds wk 6 to 7 by up to 13% (P < 0.01). Serum troponin was reduced in laser-enriched broilers by 9% at wk 5 (P < 0.01). Laser exposure increased breast width and fillet weight at d 42 by 1.08 cm (P < 0.05) and 30 g (P < 0.05). At d 49, fillet height was increased 0.42 cm in laser-enriched birds (P < 0.05). Laser enrichment reduced severe WS incidence at d 42 by 24% (P < 0.05) and on d 49 by 15% (P < 0.10). Severe WB score was numerically reduced by 11% in laser enrichment on d 42 and 18% on d 49 (P > 0.05). Water-holding capacity was improved in laser-enriched breasts (P < 0.01) and expression of myostatin and insulin-like growth factor 2 were increased on d 49 (P ≤ 0.01. Laser enrichment reduced markers of stress and muscle damage while improving breast muscle quality and is therefore a potential effective enrichment for commercial broilers.
摘要：
乳房产量的遗传选择和上市天数的减少对肉鸡的肉品质有无意的影响。木质乳房（WB）和白色条纹（WS）是商品肉鸡中普遍存在的胸肌主要肌病。自愿锻炼对这些疾病的影响，具体来说,是未知的。使用随机分配给激光富集或对照49d的1,360只Ross708肉鸡实施了第二代激光富集装置，该装置可在Ross308和708鸟类中诱导活动。将富含激光的鸟类每天4次暴露于6分钟的激光周期中。每周对70只局灶性禽鸟进行步态和接触性皮炎评分。从56只肉鸡5至7周收集血液用于血清皮质酮，肌红蛋白,和肌钙蛋白.对70只肉鸡进行了胸肌宽度采样，圆角尺寸,世界银行和WS在第6周和第7周。死后一天和两天，测量圆角压缩力和保水性。富含激光的鸟类wk5至7的血清皮质酮降低了21％（P<0.01）。富含激光的肉鸡的血清肌红蛋白在第5周增加了5％（P<0.01），而在第6至7周的对照鸟类中增加了13％（P<0.01）。在第5周，激光富集肉鸡的血清肌钙蛋白降低了9％（P<0.01）。激光照射使第42天的乳房宽度和圆角重量分别增加1.08cm(P<0.05)和30g(P<0.05)。在第49天，富含激光的鸟类的鱼片高度增加了0.42cm（P<0.05）。激光富集使第42天的严重WS发生率降低了24％（P<0.05），第49天的严重WS发生率降低了15％（P<0.10）。在第42天激光富集中，重度WB评分在数值上降低了11％，在第49天降低了18％（P>0.05）。在第49天，激光富集乳房的保水性提高（P<0.01），肌肉生长抑制素和胰岛素样生长因子2的表达增加（P≤0.01。激光富集减少了压力和肌肉损伤的标记，同时提高了乳房肌肉的质量，因此是商业肉鸡的潜在有效富集。
