Eitan Y, Soller M
Department of Genetics, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Israel.
Poult Sci. 1994 Jun;73(6):769-80. doi: 10.3382/ps.0730769.
A two-way selection program, carried out for high and low threshold BW at onset of lay (ThrWtLay), decreased photoperiodic drive of the high line (HL) relative to the low line (LL). Photoperiodic drive in modern broiler breeder females was compared to layer females in experiments using the HL and LL lines, a commercial layer cross (LX), and a commercial broiler breeder female line cross (BX). Treatment groups were: NS, natural decreasing light to 20 wk, followed by natural light supplemented to 16 h daily with artificial light; NN, natural decreasing light to end of experiment; DD, dark room from hatch to end of experiment; ND, natural decreasing light to 20 wk, dark room thereafter. Under NS, mean age and BW at first egg was greater for the HL line than for the LL line. The difference increased by a further 8.9 d and 217.5 g under NN. Similarly, under NS, mean age and BW at first egg was greater for BX than for LX, and the difference increased by a further 22.6 d and 256.1 g under NN. These interactions indicate greater photoperiodic drive of LX and LL stocks relative to the HL and BX stocks. Prepeak and peak egg production (EP) was greatest for the LX, lower for the LL, and lower yet for HL and BX. Photoperiodic drive may be of major importance in determining prepeak and peak EP. Except for the DD treatment, age and BW of the LX cross at first egg were virtually identical across treatments, those of the LL line were similar, whereas those of the HL and BX stocks showed differences. Similarly, EP curves of the LX cross were virtually identical across treatments, those of the LL line were relatively uniform, but those of the HL and BX stocks again showed great differences. Standard deviation and coefficient of variation of peak EP were very low for the LX cross, still low, but significantly greater for the LL line, and significantly greater yet again for both HL and BX stocks. Thus, increased photoperiodic drive may also be associated with greater stability of reproductive performance. Selection for early onset of lay on release from feed restriction may provide a means of increasing photoperiodic drive and consequent reproductive performance of broiler breeders.
一项针对产蛋初期高、低阈值体重（ThrWtLay）开展的双向选择计划，相对于低选系（LL），降低了高选系（HL）的光周期驱动。在使用HL系和LL系、一个商品蛋鸡杂交系（LX）以及一个商品肉种鸡母系杂交系（BX）的实验中，对现代肉种鸡母系的光周期驱动与蛋鸡母系进行了比较。处理组包括：NS，自然光照递减至20周龄，随后补充自然光至每天16小时；NN，自然光照递减至实验结束；DD，从出雏至实验结束置于暗室；ND，自然光照递减至20周龄，此后置于暗室。在NS条件下，HL系首次产蛋的平均年龄和体重高于LL系。在NN条件下，差异进一步增加了8.9天和217.5克。同样，在NS条件下，BX系首次产蛋的平均年龄和体重高于LX系，在NN条件下，差异进一步增加了22.6天和256.1克。这些相互作用表明，相对于HL系和BX系，LX系和LL系的光周期驱动更强。产蛋前期和产蛋高峰期的产蛋量（EP），LX系最高，LL系较低，HL系和BX系更低。光周期驱动可能在决定产蛋前期和产蛋高峰期的EP方面起主要作用。除了DD处理组外，LX杂交系首次产蛋时的年龄和体重在各处理组中几乎相同，LL系相似，而HL系和BX系则表现出差异。同样，LX杂交系的EP曲线在各处理组中几乎相同，LL系相对一致，但HL系和BX系再次表现出很大差异。LX杂交系产蛋高峰期的标准差和变异系数非常低，LL系仍然较低，但显著更高，HL系和BX系则更高。因此，增加光周期驱动也可能与繁殖性能的更高稳定性相关。选择在解除限饲后较早开始产蛋，可能提供一种增加肉种鸡光周期驱动及随之而来的繁殖性能的方法。
