Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon S7N 5A8, Canada.
Department of Mechanical Engineering, University of Saskatchewan, Saskatoon 57N 5A9, Canada.
Poult Sci. 2019 Jun 1;98(6):2448-2458. doi: 10.3382/ps/pez018.
Ross 308 broilers were observed at 2 ages to quantify how duration of darkness affects behavior and alters the gastrointestinal tract (GIT, segment and content weights) over 24 h. Four treatments provided 1 (1D), 4 (4D), 7 (7D), or 10 (10D) h of darkness. Birds (n = 4000) were housed in 8 rooms with 8 pens per room (2 replications per treatment and 4 replications per gender per room). The GIT data were collected on day 27 to 28 (6 males per treatment, euthanized at 2 h intervals for 24 h) and expressed as a percentage of body weight. Data were analyzed as a completely randomized design, with treatment nested within room. Production data were analyzed as a 4 (dark) x 2 (gender) factorial arrangement and GIT data as a 4 (dark) x 12 (time) factorial arrangement. Regression analyses established relationships between darkness and dependent variables. At 31 d, regression analyses showed no effect on body weight. The highest feed consumption was observed under 4D. Mortality was lowest under 10D. Birds on 10D were the most feed efficient and had the heaviest crops. Crop content interacted with time of day, with peaks prior to dark under 4D, 7D, and 10D. Empty gizzard weight increased linearly as dark increased (P < .01). Behavior was examined as a 4 (dark) x 2 (age) x 2 (gender) factorial arrangement of treatments. Five birds per gender per room were focally observed for 24 h. Dark data were examined using regression analyses and an analysis of variance assessed age and gender data. As dark increased, feeding bout frequency increased and total time spent at the feeder decreased linearly (P = 0.01 and P < .01, respectively). As birds aged, feeding frequency decreased and feed bout length increased. Males visited the feeder more frequently. Birds anticipated dark periods >4 h and increased feeding activity prior to dark. Broilers adapt their feeding behavior in response to dark exposure, which alters GIT segment and content weight and likely feed passage rate.
在两个年龄段观察 Ross 308 肉鸡，以量化黑暗持续时间如何影响行为，并在 24 小时内改变胃肠道（GIT，段和内容重量）。四种处理方式提供 1（1D）、4（4D）、7（7D）或 10（10D）小时的黑暗。将鸡（n=4000）饲养在 8 个房间中，每个房间有 8 个笼子（每个处理 2 个重复，每个房间每个性别 4 个重复）。在第 27 至 28 天收集 GIT 数据（每个处理 6 只雄性，每隔 2 小时处死一次，持续 24 小时），并表示为体重的百分比。数据以完全随机设计进行分析，处理嵌套在房间内。生产数据作为 4（黑暗）x2（性别）因子安排进行分析，GIT 数据作为 4（黑暗）x12（时间）因子安排进行分析。回归分析确定了黑暗与因变量之间的关系。在 31 天时，回归分析对体重没有影响。在 4D 下观察到最高的饲料消耗。10D 下死亡率最低。10D 下的鸡最具饲料效率，且嗉囊最重。嗉囊内容物与一天中的时间相互作用，在 4D、7D 和 10D 下，黑暗前出现峰值。随着黑暗的增加，空砂囊重量呈线性增加（P<.01）。行为作为 4（黑暗）x2（年龄）x2（性别）处理的因子安排进行检查。每个房间的每只鸡观察 24 小时。使用回归分析检查黑暗数据，并使用方差分析评估年龄和性别数据。随着黑暗的增加，采食次数的频率线性增加，而在饲料器上的总时间线性减少（P=0.01 和 P<.01）。随着鸡龄的增长，采食频率降低，采食时间延长。雄性更频繁地访问饲料器。鸡提前预测黑暗期>4 小时，并在黑暗前增加采食活动。肉鸡通过适应黑暗暴露来调整其采食行为，从而改变 GIT 段和内容重量，可能改变饲料通过速度。
