Effects of the photoperiods on the testis activity of the male Pekin duck

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概要

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• This studiy was completed on December 18, starting on July 19, 1943. Besides the natural daylength of light the experimental light conditi ons were regulated by using two 60watt incandescent bulbs placed one meter above the center of the floor and in dark rooms. For the group I, the daily lengtn of exposure to light was increased suddenly up to 15 hours until the termination of this precocious experiment on August 31. Thereafter the night lighting was reduced by approximately 10 minutes a day every three days until the animals were given daily 9 hours of lighting. For the group II, the experiment was made in a completely opposite direction. In the last group, the ducks, not artificialy stimulated, derved as control.1. From the above mentioned observations it is clearly confirmed that spermatogenetic activity in the duck is controlled by light periods and the minimum photoperiod of a day necessary for the induction of the, male sexual maturity is from 12 hours to 13hours.2. Decreased illumination was not always effective in suppressing gonadal growth. In spite of the sudden or gradual reduction in the total light ration down to 9 hours daily, the testicular activation in the majority was so pronounced that there were observed few spermatozoa in the seminiferous tubules.3. The moulting was caused most strikingly by a sudden reduction of the long daily photoperiod, despite the fact that some of the testis were yet in full sexual activity.4. The body weight was greatest when the daily period of exposure to light was shorter than that which induced the maximum development of spermatogenesis.

• 公益社団法人 日本畜産学会の論文

公益社団法人 日本畜産学会 | 論文

• 低P飼料給与がめん羊の唾液流量,第1胃水分バランスおよび血液成分に及ぼす影響〔英文〕
• 親子鑑別における血液型の有効性 (豚の血液型に関する研究-5,6-)
• 着色羊毛の成因に関する研究-1-
• 子めん羊の皮膚温度の変化
• 羊の皮膚表面における蒸泄量について

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