著者

尾野 喜孝 岩元 久雄 高原 斉 岡本 正夫

出版者

九州大学

雑誌

九州大學農學部學藝雜誌 (ISSN:03686264)

巻号頁・発行日

vol.34, no.1, pp.39-46, 1979-12

被引用文献数

1

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Effect of castration on the live weight and the growth rates of skeletal muscle, abdominal fat, intermuscular fat, skin, bone and viscera were investigated in this study. Capons and cocks of New Hampshire (NH), Barred Plymouth Rock (BPR) and capons of BPR treated with testosterone propionate (TP) from 26 to 31 weeks of age were used. Live weights and the various weights of each organ and tissue were compared between the experimental groups at 20, 30 and 31 weeks of age. The results obtained were as follows: 1) Live weights of capons were the same as those of cocks in NH and BPR breeds during experimental periods. The weights of TP treated capons were increased gradually after the administration of TP and became 250 g heavier than those of BPR cocks and the capons at 31 weeks of age. 2) Castration had no effects on the growth of skeletal muscle until 20 weeks of age, but showed a marked effect on it after 20 weeks of age. Skeletal muscle weights of capons were apparently smaller than those of cocks at 30-31 weeks of age in NH and BPR breeds. TP administration recovered completely the decrease of these weights after castration, and became equal to those of cocks at 31 weeks of age. 3) Castration had also a marked effect on the growth of abdominal and intermuscular fat after 20 weeks of age in NH and BPR breeds. TP administration decreased the weights of abdominal and intermuscular fat in BPR capons, but these weights were heavier than those of the cocks at 31 weeks of age. 4) Castration exerted some effects on the growth of skin. These weights were increased following the castration in NH and BPR breeds, and became obviously to be heavier than those of cocks at 30-31 weeks of age (21-22 weeks after castration). 5) No effects were found on the growth rates of viscera and bone following the castration and the TP treatment. In conclusion, castration has a remarkable effect on the muscle production and the fat deposition. It decreases the skeletal muscle weight and increases the fat deposition. It is supposed that TP administration on the capon stimulates the growth of skeletal muscle.本実験では去勢が生体重,骨格筋,腹脂肪,筋間脂肪,皮膚,骨および内臓の成長に及ぼす効果について研究した.供試鶏としてはNew Hampshire(NH)種とBarred Plymouth Rock(BPR)種の去勢鶏と雄鶏,それにBPRの去勢鶏にtestosterone propionate(TP)を26~31週齢時まで投与したTP処理鶏を用いた.それぞれ計量した生体重,器官および組織について,去勢鶏と雄鶏間では20,30,31週齢時に,去勢鶏とTP処理鶏間では31週齢時に比較検討を行つた。その大要は次のとおりであつた.1.去勢鶏の生体重の成長は両品種とも雄罵と同じであつた.BPRのTP処理鶏のTP処理後の生体重の成長速度は次第に大きくなり,31週齢時におけるその生体重は,去勢鶏および雄鶏よりも250g重くなつた.2.去勢は20週齢時までは骨格筋の成長に何ら影響を及ぼさなかつたがそれ以後は著しい影響を及ぼし始め,30~31週齢時になると,去勢鶏の骨格筋重量は両品種とも雄鶏のそれに対し劣つていた.BPRのTP処理鶏の骨格筋重量は,TP投与により去勢のために劣つていた分を完全に回復し,31週齢時になると雄鶏のそれと等しくなつた.3.去勢はまた20週齢以後両品種の腹脂肪,筋間脂肪の成長にも著しい影響を及ぼし,去勢鶏の腹脂肪,筋間脂肪重量の増大をもたらした.そしてBPR去勢鶏へのTPの投与は腹脂肪,筋間脂肪重量のかなりの減少を引き起こした.しかし,31週齢時における雄鶏のそれらと等しくさせるにはいたらなかつた.4.去勢は両品種の皮膚の成長にも影響を及ぼし,去勢鶏の皮膚重量は30~31週齢時には雄鶏のそれよりも大きくなつた.5.内臓と骨の成長には,去勢の影響は見られなかつた.以上のことから,雄鶏の去勢は著しい産肉量の減少と脂肪量の増大という2つの効果をもたらした.そして,去勢鶏へのTPの投与は骨格筋の成長を刺激するものである.