Renema R A, Robinson F E, Zuidhof M J
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada, T6G TP5.
Poult Sci. 2007 Oct;86(10):2267-77. doi: 10.1093/ps/86.10.2267.
A 3 x 4 x 2 factorial design trial was conducted to determine the effect of 3 broiler breeder strains, 4 target BW profiles, and 2 photostimulation ages on sexual maturation traits. A total of 560 pullets from each strain (Hubbard Hi-Y, Ross 508, and Ross 708) were housed in 24 pens. The BW profiles diverged at 4 wk and subsequently converged at 32 wk of age as follows: standard (approximate mean target BW profile of the 3 strains), low (12-wk BW target = 25% lower than standard followed by rapid gain to 32 wk), moderate (12-wk BW target = 150% of standard followed by lower rate of gain to 32 wk), and high (12-wk BW target = 200% of standard followed by minimal growth to 32 wk). Birds were photostimulated at 18 (18WK) or 22 (22WK) wk. Eight birds per interaction (n = 192) were killed and dissected at sexual maturity (first oviposition). Body weight profile affected timing of sexual maturity with the 18WK but not the 22WK treatment. There was no effect of BW profile on initial egg weight. Mean BW at sexual maturity was 3.40, 3.21, 3.01, and 2.84 kg for high, moderate, standard, and low birds, respectively. This affected shank and keel length, indicating differences in frame size. Ovary weight at sexual maturity was 6 g heavier in the low treatment (55 g) compared with other BW profiles. This was related to recent feeding level, which was highest at sexual maturity in the low treatment. Arrangement of ovarian large yellow follicles (LYF) changed with photostimulation age. Birds that were photostimulated at 18WK had 1.33 LYF hierarchies, compared with 1.22 in 22WK birds. The 18WK-high birds had increased excess LYF production (55% paired) compared with other BW profiles, whereas both small yellow follicle number and atresia were increased. Feeding profiles affected growth and conformational traits, with little effect on reproductive morphology at sexual maturity.
进行了一项3×4×2析因设计试验，以确定3种肉种鸡品系、4种目标体重模式和2个光刺激年龄对性成熟性状的影响。每个品系（哈伯德Hi-Y、罗斯508和罗斯708）的560只小母鸡被饲养在24个鸡舍中。体重模式在4周龄时出现差异，随后在32周龄时趋同，如下所示：标准（3个品系的近似平均目标体重模式）、低（12周龄体重目标比标准低25%，随后快速增重至32周龄）、中（12周龄体重目标为标准的150%，随后增重速度较低至32周龄）和高（12周龄体重目标为标准的200%，随后至32周龄生长极少）。鸡在18周龄（18WK）或22周龄（22WK）时进行光刺激。在性成熟（首次产卵）时，每组相互作用处死并解剖8只鸡（n = 192）。体重模式影响18WK处理组性成熟的时间，但不影响22WK处理组。体重模式对初产蛋重没有影响。高、中、标准和低体重鸡在性成熟时的平均体重分别为3.40、3.21、3.01和2.84千克。这影响了胫长和龙骨长，表明体型存在差异。低体重处理组性成熟时的卵巢重量比其他体重模式重6克（55克）。这与近期的饲养水平有关，低体重处理组在性成熟时饲养水平最高。卵巢大黄卵泡（LYF）的排列随光刺激年龄而变化。18WK进行光刺激的鸡有1.33个LYF等级，而22WK进行光刺激的鸡有1.22个。与其他体重模式相比，18WK-高体重鸡多余LYF的产生增加（配对增加55%），而小黄卵泡数量和闭锁均增加。饲养模式影响生长和体型性状，对性成熟时的生殖形态影响较小。
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