著者

岡 正雄 白旗 総一郎

出版者

長崎大学水産学部

雑誌

長崎大学水産学部研究報告 (ISSN:05471427)

巻号頁・発行日

no.18, pp.30-40, 1965-02

被引用文献数

1

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"Koraiebi" Penaeus orientalis KISHINOUYE, from the Yellow Sea was studied especially on the manifestation of maturity of its ovary by the examination of the preparing sections of the ovary. For this purpose, the ovarian eggs were first classified as follows from their morphological characteristics according to the degree in advancement toward ripeness: 1. Early nucleolus stage: The small nucleoli (plasmosomes) lie scattered in the nucleus. 2. Later nucleolus stage: The nucleoli are gathered into one or two bodies of a conspicuously large size. 3. Pre-yolk stage: The nucleoli grow long on the periphery of the nucleus. The ovarian egg is covered with a follicle layer. 4. Primary yolk globule stage: The redivided small nucleoli arrange themselves on the periphery of the nucleus. The cytoplasm is full of yolk globules. 5. Secondary yolk globule stage: The nucleoli are linked in a ring, which then reduces to a sphere. Neutral fat is found in the cytoplasm. 6. Tertiary yolk globule stage: No nucleolus can be found in the nucleus. The nucleus is reduced by the oppression of the yolk globules. 7. Pre-maturation stage: The nucleus disappears, while a water-soluble jelly-like substance appears on the circumference of the cytoplasm. 8. Maturation stage: No sample could be obtained, so the examination is left to a future study. The preparing sections were made of the anterior dorsal part of the ovary -where ovarian eggs developed most rapidly in the whole ovary- which was the part representative of the maturity of the whole ovary. Utilizing those sections, we obtained the average containing ratio of the ovarian eggs at every stage in one oviferous pouch of the ovary. Next, the maturing stages of the ovarian eggs were weighted 1, 2, 3, ……7, respectively and were expressed quantitatively. The weighted average, obtained from the calculation by multiplying these weights by the containing ratios of the respective stages, was represented as the maturity of the ovary. From this expression, the degrees of maturity of the ovary were obtained in order of dates of collection, and the tendency formed by them was extrapolated. The estimated date that the ovary attained to the ripe phase corresponded to the reported actual date of ripeness.1964年,黄海において漁獲されたコウライエビの卵巣切片の標本から卵巣熟度を表現することを試みた. 先づ卵巣卵をその特徴的形態からつぎのように分類した. (1)仁前期:卵径0.1-0.2mm,核内には小仁が散在する. (2)仁後期:卵径0.2-0.3mm,核内には大型仁がみられる. (3)前卵黄期:卵径0.3-0.5mm,仁は核壁にそって伸びる,部厚い卵上覆がみられる. (4)第1次卵黄球期:卵径1.8-2.5mm,小仁が核壁に並び,卵黄小球が細胞質内に充満する. (5)第2次卵黄球期:卵径の変化認められず,仁は環状につながり次第に縮少して球形となる.細胞質内には中性脂肪があらわれる. (6)3次卵黄球期:卵径はかわらない.仁はみられなくなる.核は圧縮され,中性脂肪は細胞質周辺にあつまって塊状となる. (7)前成熟期:卵径の変化は認められない.核は極端に縮少,あるいは消失,細胞質周辺にはゼリー状物質が充塡されている空胞がみられる. 成熟期卵(8)については標本の入手が出来なかった. 卵巣の各部分における成熟の違いをしらべたところ頭胸部に近い背部が一番速く成熟してゆくことがわかった.しかし,他との違いは卵巣卵で一階級程度の違いしかなく,他の部分はほとんど均一であるので平均的にみるといづれの場所を卵巣熟度として代表してもさしつかえないので背部の前の位置を代表的切片製作位置として定めた. 切片の熟度に関しては卵巣卵を分類順に1,2,………7,8,と重みをつけ切片標本内における卵巣内卵嚢あたりの階級別卵巣卵の含有率に対してそれぞれを加重しこれらの総平均を求めて総括的に表わした. この表現法を用いて経時的に卵巣成熟過程を追跡しそれを外挿すると排卵は5月上旬から中旬におこることが推定されたが実際の報告と一致したのでこの表現法は適切であったといえる.