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YASUNORI KOYA KIYOSHI SOYANO KAZUHISA YAMAMOTO HIROYUKI OBANA TAKAHIRO MATSUBARA 《Fisheries Science》2003,69(1):137-145
ABSTRACT: The present study investigates the relationship between oocyte development and serum steroid hormone levels in captive Pacific herring, Clupea pallasii , during the first reproductive cycle. The process of oocyte development in Pacific herring belongs to the group-synchronous type. Maturity of the ovary was divided into six periods based on histological observation (i.e. immature (April to September), onset of vitellogenesis (August to October), progress of vitellogenesis (October to December), completion of vitellogenesis (December to March), maturation and spawning (March to April) and spent (late April)). The pattern of seasonal change in the gonadosomatic index (GSI) well reflected the ovarian maturity. Serum vitellogenin levels showed good correlation with change in GSI, which increased from September to a peak (4.2 ± 0.3 mg/mL) in March. Serum estradiol-17β (E2) levels elevated from September and reached a peak (15.8 ± 4.2 ng/mL) in December, and remained comparatively high until March, suggesting that the active vitellogenin synthesis during vitellogenesis is controlled by the high E2 level. 17,20β-Dihydroxy-4-pregnen-3-one showed a single sharp peak (2.4 ± 0.28 ng/mL) in early April of the second year, suggesting it was a maturation-inducing steroid in this species. 相似文献
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MICHIO AOYAMA HIROHITO GOTO HITOMI KAMIYA IKUO KANEKO SATOSHI KAWAE HIROKI KODAMA YASUSHI KONISHI KENN-ICHI KUSUMOTO HISATO MIURA EIICHI MORIYAMA KIYOSHI MURAKAMI TOSHIYA NAKANO FUTOSHI NOZAKI DAISUKE SASANO TAKAO SHIMIZU HIROKI SUZUKI YASUSHI TAKATSUKI AKITO TORIYAMA 《Fisheries Oceanography》2008,17(3):206-218
Impact of climate change on marine biogeochemical parameters and ecosystem is one of the important issues of our environment. Direct evidence of marine pelagic ecosystem changes is found with warming of sea water and sea‐level rise in the main stream of the Kuroshio in the East China Sea and the western North Pacific during these three decades based on the analysis of long‐term comprehensive hydrographic observations. In terms of annual mean, the warming rate of surface air temperature and sea surface temperature ranged from 0.15 to 0.21°C per decade in and around the main stream of the Kuroshio in the East China Sea, which exceed the global mean warming rate of 0.128 ± 0.026°C per decade during the period from 1956 to 2005 reported in IPCC 2007. One of the features in this rapid warming region is an increase of number of Pterosagitta draco, a cosmopolitan warm‐water zooplankton. Biogeochemical parameters, such as wet weight of zooplankton, plant pigment and nutrients concentration in the upper 200 m have been decreasing while dissolved oxygen content and seawater temperature have been increasing in the upper 200 m in the main stream of the Kuroshio in the East China Sea. These observed linear trends of the biogeochemical parameters would be foresights for temperate oceans in the future. 相似文献
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HCG与LHRHa对雌性蜂巢石斑鱼产卵期间生理变化的影响及比较 总被引：1，自引：1，他引：0
选取日本冲绳地区雌性蜂巢石斑鱼为对象,描述与分析了HCG与LHRHa对该鱼催产效果的差异及注射后所引起的性腺发育变化和排卵相关的性类固醇变化,希望能为蜂巢石斑鱼的人工繁殖提供可靠的理论基础,以及在实践生产中的重要参考。结果表明,HCG与LHRHa均显著促进了决定排卵的性成熟诱导物质MIS的释放以及鱼的产卵; 产卵后的蜂巢石斑鱼雌二酮E2的水平显著下降,验证了蜂巢石斑鱼卵巢发育及产卵随月亮周期变化的周期性; 在渔业生产中注射催产药物前,确定对象鱼卵泡发育阶段对于提高催产成功率十分重要。在LHRHa注射组,完成卵黄化的蜂巢石斑鱼催产效果最佳,卵黄化早期的鱼不产卵; HCG对卵泡发育初期的蜂巢石斑鱼的催产效果优于LHRHa,但催产效果仍不理想,而对于完成了卵黄化鱼的催产效果不如LHRHa。结合LHRHa的其他优势,本研究认为在具备检验鱼体卵巢发育阶段实验技术的条件下,更加推荐LHRHa作为雌性蜂巢石斑鱼的催产药物。 相似文献
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KIYOSHI TANAKA TERUHISA KOMATSU YUTAKA MICHIDA SEI‐ICHI SAITOH 《Fisheries Oceanography》2011,20(3):206-218
Numerical experiments were performed to investigate the transport processes of eggs and larvae of Sergia lucens in Suruga Bay, Japan, focusing on the physical effects of the river water spreading. In the experiments, labeled particles, which were regarded as the eggs or early larvae of S. lucens with no (or weak) swimming ability, were passively transported in flow fields that were calculated by an ocean general circulation model. In the innermost region of the bay (off the Fuji River mouth) where there is no continental shelf, a retention area where the eggs and larvae could stay in a nutrient‐rich environment for a long time was formed, especially in the upper part of their habitation layers, by the large bulge with anticyclonic (clockwise) circulation. No retention area was formed in the western region of the bay (off the Oi and Abe River mouths) or in an additional experiment in which a continental shelf was artificially created in the innermost region. It was estimated that in the retention area, the residence time of the eggs and early larvae is prolonged by about a month. The formation of the retention area is controlled by the dynamics of the river water spreading, affected by the bottom topography and the Earth’s rotation. Moreover, the reason why S. lucens are only caught in abundance in Suruga Bay was discussed. 相似文献
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小南瓜是北方半干旱区增加经济产值的适生作物之一。该试验以日本"赤甘栗"小南瓜品种为试材,在3种密度(1 666、2 500、5 000株·hm~(-2))、2个灌溉量(3~4、6~8mm·d~(-1))和4个牛粪氮添加水平(N 25、50、75、100kg·hm~(-2))处理下进行大田试验,研究不同水、氮供应及种植密度对小南瓜产量的影响。结果表明:在中密度和高密度栽培下,小南瓜产量会随着氮添加量的增加而增加,但未受灌溉量的影响,但水分生产率会随着灌溉量增加而降低;在低密度栽培下灌溉量和氮添加量的增加都会导致小南瓜产量的增加,且水分生产率随着氮的提高会相应提高但未受灌溉量的影响;内蒙古半干旱地区春末夏季气候有利于小南瓜的种植,在定植密度为1 667株·hm~(-2)时,随氮肥的提高小南瓜产量及水分生产率均可增加,在3~4、6~8mm·d~(-1)灌溉水平下小南瓜产量分别为6.99、15.34t·hm~(-2)。 相似文献
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YASUNORI KOYA KIYOSHI SOYANO KAZUHISA YAMAMOTO HIROYUKI OBANA TAKAHIRO MATSUBARA 《Fisheries Science》2002,68(5):1099-1105
The present study investigates the relationship between testicular development and serum steroid hormone levels in captive Pacific herring Clupea pallasii during the first reproductive cycle. The maturity of the testis was divided into five periods based on histological observation. These are early spermatogenic stage (April to July), mid-spermatogenic stage (August to November), late spermatogenic stage (December to March), functional maturation stage (early April) and spent stage (late April). The pattern of seasonal change in gonadosomatic index (GSI) clearly reflected testicular maturity. 11-Ketotestosterone (11-KT) levels increased from October to a peak level (6.58 ± 1.87 ng/mL) in January, and were maintained at this level until March. In contrast, testosterone levels were consistently low, less than 1 ng/mL, at all times. These results suggest that 11-KT is the predominant androgen that controls spermatogenesis in this species. 17,20β-Dihydroxy-4-pregnen-3-one (DHP) showed a single sharp peak (3.38 ± 0.35 ng/mL) in early April of the second year, suggesting that milt production is induced by DHP as in some other teleost species. 相似文献
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ABSTRACT: The annual reproductive cycle, including the first maturity of ovarian development and plasma levels of testosterone (T) and estradiol-17β (E2), was examined in female Japanese catfish Silurus asotus reared under natural conditions. In addition, the possible period that final oocyte maturation and ovulation can be induced by human chorionic gonadotropin (hCG) injection were investigated. Results showed that female Japanese catfish matured 1 year after hatching under reared conditions. The beginning of vitellogenesis was in March and ovarian development and plasma T and E2 levels peaked in June. Thereafter, the gonadosomatic index gradually decreased to October and regression of oocytes at the tertiary yolk globule stage was observed. Female Japanese catfish could be induced to final oocyte maturation and ovulation by hCG treatment during the period from June to September. In addition, the fertilization rates were relatively high and stable during this period. These results suggest that yearling female Japanese catfish can be used as brood stock for seed production. This is the first study to investigate the annual reproductive cycle in Japanese catfish. These data will provide useful information regarding brood stock management and seed production. 相似文献
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Evaluation of Low Level Laser Therapy on Primary Healing of Experimentally Induced Full Thickness Teat Wounds in Dairy Cattle 总被引：1，自引：0，他引：1
SEYED MEHDI GHAMSARI DVM DVSC KIYOSHI TAGUCHI DVM DVSC NORITSUGU ABE DVM MVSC JEZIE A. ACORDA DVM MAgr DVSC MOTOYOSHI SATO DVM DVSC HARUO YAMADA DVM DVSC 《Veterinary surgery : VS》1997,26(2):114-120
Objective —The purpose of this study was to evaluate the effect of low-level laser therapy (LLLT) on sutured wounds of the teat in dairy cattle.
Study Design —By using the Latin square design, the effect of LLLT was evaluated by radiography, measurement of microcirculation flow, histopathology, tensiometry, and hydroxyproline analysis.
Animals or Sample Population —Sixteen teats of four dairy cattle.
Methods —Full thickness wounds were made on the cranial surface of the teats. Teats were distributed into four groups; group A and B wounds were closed with a Gambee pattern, group C and D wounds were closed with three-layers of continuous suture pattern. Group B and D wounds were treated with 3.64 J/cm2 of LLLT using a helium-neon system continuous wave (632.8 nm) output of 8.5 mW.
Results —The teat wall in non-LLLT groups was significantly thicker than in LLLT groups on day 7, 14 and 21. The mean blood flow differences between control and sutured sites in LLLT groups were significantly lower than those in non-LLLT groups. The morphology of the epidermis in LLLT groups more closely resembled the normal epidermis than that of non-LLLT groups. Collagen fibers in LLLT groups were denser, thicker, better arranged and more continuous with existing collagen fibers than those in non-LLLT groups. The mean tensile strength was significantly greater in LLLT groups than in non-LLLT groups.
Conclusion —The LLLT affects various aspects of the healing process, including minimizing inflammation, formation of edema, improvement of skin regeneration and enhancement of collagen synthesis.
Clinical Relevance —The LLLT could accelerate healing of sutured wounds of the teat in dairy cattle. 相似文献
Study Design —By using the Latin square design, the effect of LLLT was evaluated by radiography, measurement of microcirculation flow, histopathology, tensiometry, and hydroxyproline analysis.
Animals or Sample Population —Sixteen teats of four dairy cattle.
Methods —Full thickness wounds were made on the cranial surface of the teats. Teats were distributed into four groups; group A and B wounds were closed with a Gambee pattern, group C and D wounds were closed with three-layers of continuous suture pattern. Group B and D wounds were treated with 3.64 J/cm
Results —The teat wall in non-LLLT groups was significantly thicker than in LLLT groups on day 7, 14 and 21. The mean blood flow differences between control and sutured sites in LLLT groups were significantly lower than those in non-LLLT groups. The morphology of the epidermis in LLLT groups more closely resembled the normal epidermis than that of non-LLLT groups. Collagen fibers in LLLT groups were denser, thicker, better arranged and more continuous with existing collagen fibers than those in non-LLLT groups. The mean tensile strength was significantly greater in LLLT groups than in non-LLLT groups.
Conclusion —The LLLT affects various aspects of the healing process, including minimizing inflammation, formation of edema, improvement of skin regeneration and enhancement of collagen synthesis.
Clinical Relevance —The LLLT could accelerate healing of sutured wounds of the teat in dairy cattle. 相似文献
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