Eitan Y, Soller M
Department of Genetics, The Hebrew University of Jerusalem, Israel.
Poult Sci. 2000 Sep;79(9):1227-32. doi: 10.1093/ps/79.9.1227.
Previous studies indicate that responsiveness to photoperiod (PR) has deteriorated in White Rock heavy breed females and males, and that selection for increased PR in females has a positive effect on egg production. In order to determine whether PR can be affected by selection in males, a two-way selection experiment for high and low PR, as expressed through early and late onset of mature semen production under suboptimal photoperiod, was implemented in White Rock heavy breed males. In each selection line, the selected males in each generation were mated to unselected females of the same line. After four generations of selection, males and females of the two selection lines did not differ significantly in 6-wk body weight. Males of the high-PR line, however, achieved mature semen production 18.9 d earlier (P < 0.01) and at a body weight 587 g lighter (P < 0.01) than the males of the low-PR line. Females of the high-PR line came into lay 25.9 d earlier (P < 0.01) and at a body weight 375 g lighter (P < 0.01) than females of the low-PR line; they also produced 13.9 more eggs over a 14-wk test period (P < 0.01). These results show that it is possible to affect PR by selection in males, with parallel effects on female PR and reproductive performance. This result carries the potential of improving reproductive performance of male and female broiler chickens through mass selection for early sexual maturity among males.
以往的研究表明，白洛克重型品系的雌性和雄性对光周期的反应性（PR）已经下降，并且对雌性增加PR的选择对产蛋量有积极影响。为了确定PR是否会受到雄性选择的影响，对白洛克重型品系雄性进行了一项双向选择实验，通过在次优光周期下成熟精液产生的早晚来表示高PR和低PR。在每个选择系中，每一代选择的雄性与同一系未选择的雌性交配。经过四代选择后，两个选择系的雄性和雌性在6周龄体重上没有显著差异。然而，高PR系的雄性比低PR系的雄性提前18.9天达到成熟精液产生（P<0.01），体重轻587克（P<0.01）。高PR系的雌性比低PR系的雌性提前25.9天产蛋（P<0.01），体重轻375克（P<0.01）；在14周的测试期内，它们还多产13.9枚蛋（P<0.01）。这些结果表明，通过雄性选择有可能影响PR，并对雌性PR和繁殖性能产生平行影响。这一结果具有通过对雄性进行早期性成熟的群体选择来提高雄性和雌性肉鸡繁殖性能的潜力。
