Applegate T J, Bacon W L, Lilburn M S
Ohio State University, Ohio Agricultural Research and Development Center, Department of Animal Sciences, Wooster 44691-4096, USA.
Domest Anim Endocrinol. 1997 Nov;14(6):391-8. doi: 10.1016/s0739-7240(97)00044-1.
The independent effects of age and body weight (BW) on photostimulatory response in turkey breeder hens were studied by measuring changes in plasma luteinizing hormone (LH; ng/mL) before and 3 d after photostimulation. The study was conducted with hens from two BW groups at 24-25, 27-28, and 31-32 wk of age. There was approximately a 1-kg difference in BW between groups within an age. Six hens per BW and age group were cannulated (jugular vein) and serially sampled during each of two 6-hr periods. Samples were collected at 10-min intervals. The two sampling periods were the last 6 hr of the short-day photoperiod (SD) and the same period during the third long day after photostimulation (LD). The photostimulatory response (PR) or difference between the SD and LD baseline LH concentrations was greatest in the 24-25-wk-old hens. The PR was unaffected by hen BW at any age. The baseline LH concentration during the SD photoperiod declined as hens aged. After photostimulation, baseline LH and LH peak amplitude concentrations were higher in 24-25-wk-old hens compared with the older ages. The number of LH peaks increased after photostimulation, but there were no significant effects attributable to age or BW within an age. In conclusion, the PR was affected by hen age but not hen BW or BW within a particular age.
通过测量光照刺激前和光照刺激后3天血浆促黄体生成素（LH；ng/mL）的变化，研究了年龄和体重（BW）对火鸡种母鸡光刺激反应的独立影响。该研究使用了来自两个体重组、年龄分别为24 - 25周、27 - 28周和31 - 32周的母鸡。在每个年龄组内，两组母鸡的体重相差约1千克。每个体重和年龄组有6只母鸡进行插管（颈静脉），并在两个6小时时间段内进行连续采样。每隔10分钟采集一次样本。两个采样时间段分别是短日照光周期（SD）的最后6小时和光照刺激后第三个长日照期间的相同时间段（LD）。光刺激反应（PR），即SD和LD基线LH浓度之间的差异，在24 - 25周龄的母鸡中最大。在任何年龄，PR均不受母鸡体重的影响。随着母鸡年龄的增长，SD光周期期间的基线LH浓度下降。光照刺激后，24 - 25周龄母鸡的基线LH和LH峰值浓度高于年龄较大的母鸡。光照刺激后LH峰值数量增加，但在同一年龄组内，年龄或体重没有显著影响。总之，PR受母鸡年龄影响，但不受母鸡体重或特定年龄内的体重影响。
