Animal and Poultry Science, University of KwaZulu-Natal, Scottsville 3209, South Africa.
Poult Sci. 2010 Jan;89(1):108-14. doi: 10.3382/ps.2009-00312.
Ross 308 broiler breeder females, maintained in litter-floor pens, were reared from 2 d of age on 8-h photoperiods and transferred abruptly to an 11-, 12-, 13-, or 14-h photoperiod at 20 wk of age and at a mean BW of 2.09 kg. Four qualitative dietary treatments were superimposed upon each photoperiodic treatment, but, in the absence of any significant interactions of photoperiod with diet, only photoperiodic means are reported. Age at 50% egg production (ASM) was progressively advanced as photoperiod increased from 11 to 13 h but was similar for 13-h and 14-h birds. Egg production was significantly related to ASM, with peak egg numbers being stimulated by a transfer to 13-h photoperiods. Rate of lay after 48 wk of age declined more rapidly in the 14-h birds than in any of the other groups, suggestive of an earlier onset of adult photorefractoriness. More eggs were laid outside the nest box and more cracked and dirty eggs were produced by birds on 11- and 12-h photoperiods than on 13- or 14-h photoperiods. Mean egg weight was positively correlated with ASM but negatively related to photoperiod; the number of eggs thought to be double-yolked was not significantly affected by photoperiod. Total egg mass output was not significantly affected by photoperiod. Birds exposed to 11-h and 12-h photoperiods were heavier at 60 wk than birds transferred to 13- or 14-h photoperiods. These findings show that a transfer from 8 to 13 h at 20 wk optimizes egg-laying performance in broiler breeder females, especially when they are kept beyond 60 wk of age.
罗斯 308 肉鸡种母鸡，饲养在垫料地板笼中，从 2 日龄开始每天接受 8 小时光照，20 周龄时体重达到 2.09 千克时，突然将光照时间延长至 11、12、13 或 14 小时。每个光照周期都叠加了 4 种定性饮食处理，但由于光照周期与饮食之间没有任何显著的相互作用，因此只报告了光照周期的平均值。随着光照时间从 11 小时增加到 13 小时，产蛋率达到 50%的年龄（ASM）逐渐提前，但 13 小时和 14 小时的鸡龄相似。产蛋率与 ASM 显著相关，转至 13 小时光照周期可刺激产蛋高峰期。48 周龄后，14 小时组的产蛋率下降速度明显快于其他组，提示成年鸡的光感受性障碍更早出现。11 小时和 12 小时光照周期下的鸡，在巢箱外产蛋的比例以及破蛋和脏蛋的比例都高于 13 小时或 14 小时光照周期下的鸡。平均蛋重与 ASM 呈正相关，与光照时间呈负相关；被认为是双黄蛋的数量并没有受到光照时间的显著影响。总蛋重输出不受光照时间的显著影响。60 周龄时，暴露在 11 小时和 12 小时光照周期下的鸡比转至 13 小时或 14 小时光照周期下的鸡更重。这些发现表明，在 20 周龄时，从 8 小时延长到 13 小时可优化肉鸡种母鸡的产蛋性能，特别是当它们的饲养时间超过 60 周龄时。
