Environmental Regulation and Influence of the Eyes and Pineal Gland on the Gonadal Cycle and Spawning in Channel Catfish (ictalurus punctatus)
Environmental Regulation and Influence of the Eyes and Pineal Gland on the Gonadal Cycle and Spawning in Channel Catfish (ictalurus punctatus)
复制标题
眼睛和松果体的环境调节以及对斑点叉尾鮰性腺周期和产卵的影响
DOI：
10.1086/physzool.59.6.30158617
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
N. C. Parker
中科院分区：
文献类型：
--
作者：
K. Davis;C. Goudie;B. A. Simco;R. M. Gregor;N. C. Parker
2月或8月，当它们21或27个月大时，将失明、松果体切除或失明和松果体切除的雌性斑点叉尾鮰（Ictalurus punctatus）与正常（未手术）对照鱼一起放置在恒温（21±2℃）的室外水箱或土池（环境条件）中。在接下来的繁殖季节对鱼进行取样。 3岁鱼的性腺体指数（GSI）和血浆雌激素浓度发生季节性变化，但2岁鱼的变化不太明显或缺乏。性成熟（≥3岁）鱼的GSI水平在水箱中比在池塘中提前约一个月达到峰值；水族箱中鱼的雌激素峰值低于池塘鱼的雌激素峰值。与正常对照鱼相比，池塘中的所有实验鱼（两个年龄）的卵巢吸收延迟了约 1 个月。暴露于恒定的 21 C 水中可以使性腺提前复发。所有在八月份进行手术改变的性成熟鱼群都会在第二年春天产卵。有眼睛的鱼比没有眼睛的鱼（失明的50%，失明和松果体切除的56%）更早产卵，产卵率更高（对照68%，松果体切除75%）。眼睛和松果体对于春季性腺成熟或斑点叉尾鮰产卵都不是必需的，但其中之一或两者可能在这些事件的计时中发挥作用。建议将可能受环境温度影响的年度内部振荡器作为物种生殖周期的主要控制。通过松果体、眼睛或两者获得的光信息似乎会影响性腺吸收的时间。
Blinded, pinealectomized, or blinded and pinealectomized female channel catfish (Ictalurus punctatus) were placed with normal (unoperated on) control fish in outdoor tanks at constant temperature (21 ± 2 C) or earthen ponds (ambient conditions) in February or August, when they were 21 or 27 mo old. Fish were sampled through the following reproductive season. The gonadosomatic index (GSI) and plasma estrogen concentration changed seasonally in 3-yr-old fish, but the changes were less marked or lacking in 2-yr-olds. The GSI levels of sexually mature (≥3 years old) fish peaked about a month earlier in the tanks than in the ponds; the estrogen peak for fish in the tanks was lower than that for pond fish. All experimental fish (both ages) in ponds delayed ovarian resorption for about 1 mo, compared with normal control fish. Exposure to constant 21 C water allowed earlier gonadal recrudescence. All groups of sexually mature fish that were surgically altered in August spawned during the following spring. Fish with eyes spawned earlier and had higher spawning percentages (control 68%, pinealectomized 75%) than did fish without eyes (blinded 50%, blinded and pinealectomized 56%). Neither the eyes nor the pineal is essential for spring gonadal maturation or for spawning in channel catfish, but one or both may have a role in timing these events. An annual internal oscillator that may be modified by environmental temperature is suggested as the primary control of reproductive cycling in the species. Light information obtained through the pineal, eyes, or both appears to affect the time of gonadal resorption.