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Tetsuro?Shiraishi Kohei?Ohta Akihiko?Yamaguchi Mari?Yoda Hisashi?Chuda Michiya?MatsuyamaEmail author 《Fisheries Science》2005,71(3):531-542
ABSTRACT: Final oocyte maturation and ovulation of captive chub mackerel Scomber japonicus with fully yolk-accumulated oocytes were induced by a single injection of human chorionic gonadotropin. Reproductive parameters, including spawning frequency and batch fecundity, which are required to estimate spawning biomass in pelagic fish by the daily egg production method, were analyzed. Germinal vesicle migration (GVM) occurred at 18–24 h post-injection, and the hydration and ovulation of oocytes were completed at 30 and 36 h post-injection, respectively. The results of the maturation process suggest that fish with GVM-stage ovaries captured in the daytime from the field are capable of spawning on the night following their capture. The oocytes used in the oocyte size-frequency distribution method for batch fecundity estimates should be at late GVM and more advanced stages. The results of sequential artificial insemination showed that the quality of ovulated eggs held in the ovarian lumen rapidly deteriorated as time progressed after ovulation. This indicates that the fertilization window for the ovulated eggs of chub mackerel lasts only a few hours, and spawning behavior should be performed within a few hours after ovulation in the wild population. 相似文献
3.
Nagai Hiroshi Shibahara Shuya Matsushima Ryoji Uchida Hajime Kanamori Makoto Nogata Yasuyuki Kamio Michiya 《Fisheries Science》2021,87(1):145-150
Fisheries Science - The solitary European sea squirt Ascidiella aspersa was introduced to northern Japan, causing dense coverage of the aquacultured Japanese scallop Mizuhopecten yessoensis. There... 相似文献
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Tetsuro Shiraishi Kumiko Okamoto Michio Yoneda Takeshi Sakai Seiji Ohshimo Shizumasa Onoe Akihiko Yamaguchi Michiya Matsuyama 《Fisheries Science》2008,74(5):947-954
The age and growth of chub mackerel Scomber japonicus collected from the East China Sea and the northern waters off Kyushu between June 2000 and June 2001 were determined by observing
the otolith surface after dipping it in xylene. The translucent and opaque zones on the otolith surface were identified, and
the number of translucent zones was counted. Monthly changes in the frequency of fish with translucent zones on the otolith
margin, and in the marginal increments, indicated that the translucent zones were formed between April and June. The seasonal
pattern of annulus formation on the otolith became clear by observing the otoliths of fish with known ages, and the otolith
formation in wild fish was consistent with that of fish with known ages. The mean gonadosomatic index of male and female fish
was high from March to May, and spawning females were observed from mid-March to mid-May. The estimated ages were 1–5 years
for males and 1–6 years for females. The von Bertalanffy growth parameters did not significantly differ between male and female.
The model was obtained as FL
t=406×{1−exp[−0.372×(t+1.68)] 相似文献
5.
Michiya Matsuyama Shinji Adachi Yoshitaka Nagahama Katsuhiko Maruyama Shuhei Matsura 《Fish physiology and biochemistry》1990,8(4):329-338
Ovarian developmental stages and serum steroid hormone levels were examined at six different times of day (0100, 0600, 1000,
1300, 1600, 2000 h) in a marine teleost, the Japanese whiting Sillago japonica, which has an asynchronous-type ovary containing oocytes at various stages of development and spawns every day during a period
ranging up to three months. The largest oocytes in the ovaries at the active vitellogenic or post-vitellogenic stages were
found between 0100 and 1300 h. Oocyte maturation indicated by germinal vesicle breakdown (GVBD) occurred at 1600 h, and ovulated
oocytes were observed in the ovaries collected at 2000 h. These processes were accompanied by a significant daily change in
serum steroid hormone levels. The serum level of estradiol-17β showed a peak in fish with mature oocytes sampled at 1600 h.
In these fish, the second-largest oocytes in the ovaries were at the initial stage of vigorous vitellogenesis, the secondary
yolk stage. Therefore the highest level of serum estradiol-17β was considered to be due to the second-largest oocytes. Testosterone
levels remained low and constant throughout the experimental period. The serum levels of 17α,20β-dihydroxy-4-pregnen-3-one
(17α,20β-diOHprog) peaked at 1600 h at which time all fish had mature oocytes. These results indicate that the Japanese whiting
possesses a diurnal rhythm of oocyte development including vitellogenesis, oocyte maturation and ovulation, and further suggest
that daily cycles in oocyte growth and maturation which simultaneously take place in an ovary are regulated by diurnal secretions
of estradiol-17β and the maturation-inducing steroid, 17α,20β-diOHprog. 相似文献
6.
Sonoko Yamaguchi Koichiro Gen Koichi Okuzawa Michiya Matsuyama Hirohiko Kagawa 《Fisheries Science》2006,72(4):835-845
ABSTRACT: In order to investigate the influence of estrogen and androgen on reproductive activities of male teleosts, male red sea bream were implanted with silicone capsules containing estradiol-17β (E2), testosterone (T) or 11-ketotestosterone (11-KT) in immature and early spermatogenic stages. One month after implantation of either E2 or T, the gonadosomatic index decreased in accordance with testicular regression in both stages. Implantation of E2 decreased circulating 11-KT levels but did not affect gonadotropin (GTH) subunits, follicle stimulating hormone-β (FSHβ), luteinizing hormone-β (LHβ), α glycoprotein subunit (αGSU) gene expression, and serum LH levels in both stages. Alternatively, T decreased serum 11-KT and LH levels, and FSHβ and LHβ mRNA levels in the early spermatogenic stage but not in the immature stage. These results suggest E2 may directly inhibit testicular development through the suppression of 11-KT production. Meanwhile, T may decrease serum 11-KT levels through the suppression of FSH and LH secretion, resulting to inhibition of testicular development in the early spermatogenic stage. Treatment with 11-KT did not affect the testis in either stage, whereas 11-KT increased LHβ and αGSU mRNA levels in immature, and decreased FSHβ mRNA levels in the early spermatogenic stage. These results suggest that 11-KT may have different effects on GTH subunit gene expression in each reproductive stage. 相似文献
7.
Mitsuo Nyuji Tetsuro Shiraishi Sethu Selvaraj Vu Van In Hajime Kitano Akihiko Yamaguchi Kumiko Okamoto Shizumasa Onoue Akio Shimizu Michiya Matsuyama 《Fisheries Science》2011,77(5):731-739
The physiological functions of pituitary gonadotropins (GtHs) are well established in higher vertebrates, whereas those in
teleosts are still poorly understood. To describe the role of GtHs during gonadal development of female chub mackerel Scomber japonicus, changes in follicle-stimulating hormone (FSH) and luteinizing hormone (LH) cells were investigated immunohistochemically
during the seasonal reproductive and spawning cycles. FSH and LH cells were identified in the different cell types of the
proximal pars distalis (PPD); FSH cells were located in the central PPD, whereas LH cells were localized along the border
of the pars intermedia. To examine changes in FSH and LH cells, the percentage of FSH or LH cell-occupying area in the PPD
was evaluated and represented as FSHβ-immunoreactive (ir) or LHβ-ir levels, respectively. FSHβ-ir levels increased significantly
from immature to the completion of vitellogenesis, whereas LHβ-ir levels were maintained at high levels from early vitellogenesis
to post-spawning. During the spawning cycle, which consisted of four stages from just after spawning to the next oocyte maturation,
both FSHβ-ir and LHβ-ir levels showed no significant changes among different stages; however, LHβ-ir levels remained relatively
high, and FSHβ-ir levels were constantly low. These results suggest that both FSH and LH may be involved in vitellogenesis
and LH may act at final oocyte maturation in female chub mackerel, although the role of FSH during the spawning cycle is still
unclear. 相似文献
8.
Kohei OHTA Sonoko YAMAGUCHI Akihiko YAMAGUCHI Koichi OKUZAWA Koichiro GEN Hirohiko KAGAWA Michiya MATSUYAMA 《Fisheries Science》2002,68(3):680-687
ABSTRACT: The red seabream Pagrus major is a useful experimental fish for studying the endocrine control of oogenesis in teleosts. This study investigated the steroidogenic pathway for estradiol-17β (E2) biosynthesis in the ovarian follicles of red seabream. Intact follicles were isolated during vitellogenesis and incubated in vitro with different radiolabeled steroid precursors. When 17-hydroxyprogesterone (17-P), dehydroepiandrosterone (DHEA), or androstenedione (AD) were used as precursors, both testosterone (T) and estrone (E1) were synthesized by follicles, leading to estradiol-17β (E2) production. Serum steroid levels measured by enzyme-linked immunosorbent assay showed that T, E1, and E2 were present in the circulation at levels ranging from 1 ng/mL to 2 ng/mL throughout the day during the spawning season. In vitro conversion of E1 into E2, however, was 15.8-fold greater than T conversion into E2, suggesting that E2 is synthesized mainly via E1 rather than T. The results showed that E2 was synthesized from pregnenolone via 17-hydroxypregnenolone, DHEA, AD, and E1. Thus, the study demonstrated the complete steroidogenic E2 synthesis pathway in the ovarian follicles of red seabream, and revealed that E1 is the major precursor of E2. 相似文献
9.
Effects of synthetic kisspeptin peptides and GnRH analogue on oocyte growth and circulating sex steroids in prepubertal female chub mackerel (Scomber japonicus)
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Sethu Selvaraj Hirofumi Ohga Mitsuo Nyuji Hajime Kitano Naoki Nagano Akihiko Yamaguchi Michiya Matsuyama 《Aquaculture Research》2015,46(8):1866-1877
In recent years, kisspeptin peptides, encoded by kiss genes have been used to manipulate reproductive processes in farmed animals, including fish. Our previous studies demonstrated that the chub mackerel brain expresses kiss1 and kiss2 and intramuscular injection of synthetic Kiss1 pentadecapeptide (Kiss1‐15) but not Kiss2 dodecapeptide (Kiss2‐12) accelerates spermatogenesis in prepubertal male chub mackerel (Scomber japonicus). In the present study, we evaluated their effects in prepubertal female chub mackerel. The gonadosomatic index (GSI) values of experimental fish did not show any significant changes. Condition factor (CF) values increased significantly in Kiss1‐15 treated fish, in comparison with control and GnRH analogue (GnRHa) injected fish. Histologically, only perinucleolar oocytes were found in all experimental fish. However, Kiss and GnRHa treated fish showed a significant increase in the perinucleolar oocyte diameter, in comparison with the control fish. Gene expression analyses revealed decreased expression of gnrh1 in the telencephalon‐preoptic region of the brain of Kiss2‐12 and GnRHa injected fish, in comparison with control fish. In contrast, GnRHa injected fish exhibited higher levels of fshβ in the pituitary, with no changes in the levels of lhβ among different treatments. Levels of circulating sex steroids, testosterone, and estradiol‐17β were significantly higher in Kiss1‐15 injected fish, in comparison with control fish. These results indicate that synthetic kisspeptin peptides and GnRHa can induce oocyte growth in prepubertal female chub mackerel. 相似文献
10.
Weina Jiang Satoshi Tan Yusuke Hanaki Kazuhiro Irie Hajime Uchida Ryuichi Watanabe Toshiyuki Suzuki Bryan Sakamoto Michiya Kamio Hiroshi Nagai 《Marine drugs》2014,12(12):5788-5800
The toxin-producing cyanobacterium, Moorea producens, is a known causative organism of food poisoning and seaweed dermatitis (also known as “swimmer’s itch”). Two new toxic compounds were isolated and structurally elucidated from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies, as well as optical rotations and CD spectra indicated two new lyngbyatoxin derivatives, 2-oxo-3(R)-hydroxy-lyngbyatoxin A (1) and 2-oxo-3(R)-hydroxy-13-N-desmethyl-lyngbyatoxin A (2). The cytotoxicity and lethal activities of 1 and 2 were approximately 10- to 150-times less potent than lyngbyatoxin A. Additionally, the binding activities of 1 and 2 possessed 10,000-times lower affinity for the protein kinase Cδ (PKCδ)-C1B peptide when compared to lyngbyatoxin A. These findings suggest that these new lyngbyatoxin derivatives may mediate their acute toxicities through a non-PKC activation pathway. 相似文献