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溫度對黑鯛性轉變之影響

  • 出版日期:107-06-30
  • 標題title(英):
    The Effect of Temperature on Sex Change in Protandrous Black Porgy (Acanthopagrus shlegceli)
  • 作者:李彥宏‧陳紫媖
  • 作者auther(英):Yan-Horn Lee and Tzyy-Ing Chen
  • 卷別:26
  • 期別:1
  • 頁碼:63-72

本研究探討溫度變化對黑鯛性轉變過程之生殖腺發育、性轉變比例及血清黃體促素 (LH) 濃度之影響。首先在繁殖季節前 (9月),將2–3年齡黑鯛蓄養在33 °C,在進入繁殖季時 (12月),再分養至18 °C、23 °C、28 °C及33 °C水溫環境,至隔年繁殖季節末 (2月) 採樣。結果顯示,黑鯛在自然環境下,性轉變為雌性比例60% (水溫23 °C);長期處於高溫環境 (33 °C),黑鯛性轉變為雌性比例為0%;18 °C組為5.55% (1/18);23 °C組為5.26% (1/19);28 °C組為25% (4/16)。其中各組雄魚之平均產精量,除了28、33 °C組未採集到精液,對照組、18 °C及23 °C組之黑鯛均有產精現象。從生殖腺組織切片觀察,高溫33 °C飼養下的黑鯛,雖然到了進入性轉變的繁殖季節,但是生殖腺發育卻受到抑制,僅有1尾黑鯛表現為雄性功能 (雄性比例1/8)。另外於繁殖季初期 (12月18日),分別移入18、23和28 °C環境下,經過45天後 (2月1日),生殖腺已發育為成熟的精、卵巢,但性轉變為雌魚的比例,仍明顯低於對照組 (60%)。黑鯛LH濃度,在繁殖季前 (10、11月) 及繁殖季 (1月) 均有高值,而在高溫環境下,初期血清LH明顯受到抑制,但於12月達到高值,且回復蓄養到23及28 °C下,血清LH濃度有明顯增加。本研究確認溫度環境因子會影響雌雄同體魚黑鯛之性轉變機制,高溫抑制黑鯛生殖腺發育及成熟,且明顯抑制黑鯛性轉變為雌性,並影響血清LH濃度。

摘要abstract(英)


This study aimed to determine the effects of temperature on gonadal development, sex change ratio and serum luteinizing hormone (LH) concentration in hermaphrodite protandrous black porgy, Acanthopagrus schlegeli. Before the breeding season (September), 2- to 3-year-old black porgy were first reared at 33 °C, then these fish were divided into four groups that were further reared at 18 °C, 23 °C, 28 °C and 33 °C at the beginning of the spawning season (December). The fish were then sacrificed at the end of the breeding season in the next year (February). The results indicated that 60% of black porgy had a sex-change to female in the control group (23 °C). In the high-temperature group (33 °C), no black porgy changed sex, while the female proportions of the other groups were 5.55% (18 °C), 5.26% (23 °C), and 25% (28 °C) after 45 days. Spermination was observed in the 18 °C, 23 °C, and control groups. In terms of histology, the gonadal development of the 33 °C -reared fish was suppressed, and only one of the fish had male function (that is, spermids were observed) during spawning season. In the other groups, the gonads of the fish had already developed into ripe ovaries or testes after 45 days of rearing, but the female ratios in these groups were obviously lower than that in the control group (60%). The serum LH concentration of the control fish surged during the prespawning (Oct. and Nov.) and spawning seasons (Feb.), but the LH surge was observed only in one fish from the 33 °C -reared group. In the 23 °C - and 28 °C -reared groups, the serum LH levels increased after 45 days of rearing. This research confirmed that high water temperature influences sex change mechanism in hermaphroditic black porgy through the inhibition of gonadal development and gonadal maturation, as well as its effects on sex change in black porgy and serum LH concentration.