Broiler breeders do not respond positively to photoperiodic increments given during the laying period
Broiler breeders do not respond positively to photoperiodic increments given during the laying period
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DOI：
10.1080/00071660701261336
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发表时间：
2007-06
影响因子：
2
通讯作者：
P. Lewis;R. Gous;W.K. Ghebremariam-;P. Sharp
中科院分区：
文献类型：
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作者：
P. Lewis;R. Gous;W.K. Ghebremariam-;P. Sharp
1. 肉种鸡在第 20 周时将光周期增加 3 小时，达到 11 小时，然后在初始增加后立即增加光周期，达到 16 或 17 小时，或者在产蛋率峰值后的不同日龄开始，以 30 分钟、1 或 2 小时的增量增加光周期。从 20 周开始，将对照维持 11 小时。在 20 周龄时转移到 11 或 16 小时并在 41 或 61 周龄时进一步增加光周期的鸡只测量血浆 LH 浓度（7 天后）的变化。 2. 转移至 16 或 17 小时光周期的鸡只，无论何时以及如何达到最大光周期，在 52 至 60 周龄之间的产蛋率低于 20 周龄至 11 小时的鸡只。然而，11 小时的鸡在地板上产下更多的蛋，并产生更多数量的破裂蛋和脏蛋，导致可下蛋的数量相似。 3.虽然在41周龄时将鸡从11小时光周期转移到16小时光周期显着增加了血浆LH浓度，但对随后12天的产蛋量没有影响。无论是在 41 周还是 61 周时，其他光周期增加均不会显着增加血浆 LH。 4. 在肉种鸡中得出的结论是，在产蛋期从 11 或 16 小时开始增加光周期，对 LH 分泌影响很小或没有影响，不能补偿与年龄相关的产蛋量下降，并对产蛋率产生不利影响。
1. Broiler breeders were given a 3-h increase in photoperiod to 11 h at 20 week and then a series of increases to reach 16 or 17 h either immediately after the initial increment or in 30-min, 1- or 2-h increments starting at various ages after peak rate of lay. Controls were maintained on 11 h from 20 weeks. Changes in plasma LH concentration (after 7 d) were measured in birds that had been transferred to 11 or 16 h at 20 weeks and given further increases in photoperiod at 41 or 61 weeks of age. 2. Birds that were transferred to 16- or 17-h photoperiods, irrespective of when and how the maximum photoperiod was reached, had inferior rates of lay between 52 and 60 weeks of age to birds maintained on 11 h from 20 weeks. However, the 11-h birds laid more eggs on the floor and produced a larger number of cracked and dirty eggs, resulting in similar numbers of settable eggs. 3. Although transferring birds from 11- to 16-h photoperiods at 41 weeks of age significantly increased plasma LH concentration, there was no effect on egg production during the ensuing 12 d. None of the other increases in photoperiod significantly increased plasma LH, whether given at 41 or 61 weeks. 4. It is concluded in broiler breeders, that increases in photoperiod applied during the laying period, from 11 or 16 h, have little or no effect on LH secretion, do not compensate for age-related declines in egg production, and adversely affect rate of lay.