Effects of high dose of vitamin A on reproduction and egg quality of Japanese flounder Paralichthys olivaceus   总被引：2，自引：0，他引：2  

Hirofumi Furuita  Hideki Tanaka  Takeshi Yamamoto  Manabu Shiraishi  Toshio Takeuchi 《Fisheries Science》2001,67(4):606-613

ABSTRACT: The present study was conducted to investigate the effects of dietary vitamin A on reproduction and egg quality in Japanese flounder Paralichthys olivaceus . Broodstock were fed experimental pellets containing two levels of vitamin A [11 × 10³ IU/100 g (control diet; CD), 337 × 10³ IU/100 g (experimental diet; ED)] for approximately 2 months before spawning and during the spawning period. Two groups of five females (average weight 1.4 kg) and 10 males (average weight 0.7 kg) were randomly allocated to two 30 m³ indoor tanks. Total egg production of the CD group was slightly higher than the ED group. Percentage of buoyant eggs and hatching rate of the ED group were significantly higher than the CD. In other egg quality parameters, such as percentage abnormal larvae and starvation tolerance of larvae, no notable difference was found between these two groups. At the end of the experiment, the skin color of broodstock in the ED group was darker than that of the CD group. Vitamin A content in eggs of the ED group was significantly higher than that of the CD group. However, the difference in vitamin A content in eggs between the ED and CD groups was much smaller than that in the liver of the females between the two groups. These results indicate that feeding broodstock a higher level of vitamin A increases the vitamin A content in eggs but does not affect egg quality in Japanese flounder because excess dietary vitamin A was stored mainly in the broodstocks' liver.  相似文献   

Growth changes in bighand thornyhead <Emphasis Type="Italic">Sebastolobus macrochir</Emphasis> off the Pacific coast of northern Honshu,Japan     

Tsutomu Hattori  Yoji Narimatsu  Masaki Ito  Yuji Ueda  Kunihiro Fujiwara  Daiji Kitagawa 《Fisheries Science》2007,73(2):341-347

ABSTRACT:     The biomass of bighand thornyhead Sebastolobus macrochir was increased by the high recruitment success of the 1999–2002 year classes off the Pacific coast of northern Honshu, Japan. In this study, the growth of bighand thornyhead was examined over a 9-year period from 1996 to 2004 in this area. The growth of the 1999 year class and the 2000–2002 year classes was reduced at 3 and 2 years old, respectively, while the 1999–2002 year classes were smaller than the 1993–1998 year classes. In 2-, 3- and 4-year-old fish, the relationship between abundance and mean standard length was expressed by negative linear regressions, while fish became smaller when abundance of the year class was larger. Mean bottom temperatures were stable at depths of 350–900 m; variations in water temperature were small in the main distribution area of bighand thornyhead. We discuss the factors affecting the growth of bighand thornyhead via changes in the demersal fish community and feeding habits.  相似文献   

Nutrient requirement for zoospore formation in two alariaceous plants Undaria pinnatifida (Harvey) Suringar and Alaria crassifolia Kjellman (Phaeophyceae: Laminariales)   总被引：2，自引：0，他引：2  

Takeshi Kumura  Hajime Yasui  Hiroyuki Mizuta 《Fisheries Science》2006,72(4):860-869

ABSTRACT:   Sporophyll formation in two alariaceous plants, Undaria pinnatifida and Alaria crassifolia , was studied in relation to the nutrient requirements. The sporophylls of U. pinnatifida formed zoosporangia when they had N and P contents greater than 1.4 kgN/m³ and 0.74 kgP/m³. This indicates that these values are the critical nutrient levels for zoospore formation in U. pinnatifida . In the sporophytes of A. crassifolia , many sporophylls with zoosporangia showed nutrient contents higher than 6.25 kgN/m³ and 1.70 kgP/m³. These results suggest that the U. pinnatifida can form zoospores at lower levels of N and P contents than A. crassifolia . Both species often formed zoosporangial sori on the blades in the late period of each reproductive season. The fertile parts of the blade showed N and P contents higher than the critical levels. This phenomenon indicates that the blades have the capability to form zoosporangial sori if there is a sufficient accumulation of nutrients for zoospore formation. The zoospore formation on the blade seems to be accomplished by an overflow of excess nutrients from sporophylls into the blade, or by accumulating sufficient nutrients to form sori even if the sporophylls are not formed.  相似文献   

Anti-oxidant activity of methanol extracts from Indonesian seaweeds in an oil emulsion model   总被引：2，自引：0，他引：2  

Joko  SANTOSO  Yumiko  YOSHIE-STARK  Takeshi  SUZUKI 《Fisheries Science》2004,70(1):183-188

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Localization of Eimeripain,an Eimeria tenella Cathepsin B-Like Cysteine Protease,during Asexual and Sexual Intracellular Development in Chicken Ceca     

Makoto MATSUBAYASHI  Takeshi HATTA  Takeharu MIYOSHI  ANISUZZAMAN  Kazumi SASAI  Kayoko YAMAJI  Kameo SHIMURA  Takashi ISOBE  Kiyoshi KITA  Naotoshi TSUJI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(4):531-537

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Effect of Postbreeding Intramuscular Administration of Deslorelin Acetate on Plasma LH and Progesterone Concentrations and Conception Rate in Mares     

Satoshi KINO  Takeshi OSAWA  Shuji MIZUNO  Gen WATANABE  Kazuyoshi TAYA  Yoshiaki IZAIKE 《Journal of Equine Science》2014,25(1):23-27

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Bovine papillomavirus type 10 with a deletion associated with a lingual papilloma in a cow     

Wei Zhu  Jianbao Dong  Kazuyuki Uchida  Ken-ichi Watanabe  Hiroyuki Nakayama  Yoshitaka Goto  Takeshi Haga 《Veterinary journal (London, England : 1997)》2014,199(2):303-305

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Spermatogenesis and its endocrine regulation   总被引：2，自引：2，他引：2  

Rüdiger W. Schulz  Takeshi Miura 《Fish physiology and biochemistry》2002,26(1):43-56

Three major phases compose spermatogenesis: mitotic proliferation of spermatogonia, meiosis of spermatocytes, and spermiogenesis, the restructuring of spermatids into flagellated spermatozoa. The process is fuelled by stem cells that, when dividing, either self-renew or produce spermatogonia that are committed to proliferation, meiosis, and spermiogenesis. During all phases, germ cells are in close contact with and require the structural and functional support of Sertoli cells. In contrast to germ cells, these somatic cells express receptors for sex steroids and follicle-stimulating hormone (FSH), the most important hormones that regulate spermatogenesis. A typical Sertoli cell response to an endocrine stimulus would be to change the release of a growth factor that would then mediate the hormone's effect to the germ cells. Recent studies in the Japanese eel have shown, for example, that in the absence of gonadotropin Sertoli cells produce a growth factor (an orthologue of anti-Müllerian hormone) that restricts stem cell divisions to the self-renewal pathway; also estrogens stimulate stem cell renewal divisions but not spermatogonial proliferation. Gonadotropin or 11-ketotestosterone (11-KT) stimulation, however, induces spermatogonial proliferation, which is in part mimicked by another Sertoli cell-derived growth factor (activin B). Since FSH (besides luteinizing hormone, LH) stimulates steroidogenesis in fish, and since FSH is the only gonadotropin detected in the plasma of sexually immature salmonids, increased FSH signalling may be sufficient to initiate spermatogenesis by activating both Sertoli cell functions and 11-KT production. Another important androgen is testosterone (T), which seems to act via feedback mechanisms that can compromise FSH-dependent signalling or steroidogenesis. The testicular production of T and 11-KT therefore needs to be balanced adequately. Further research is required to elucidate in what way(s) 11-KT stimulates later stages of development, such as entry into meiosis and spermiogenesis. At this period, LH becomes increasingly important for the regulation of androgen production. Results from mammalian models suggest that during the later phases, the control of germ cell apoptosis via Sertoli cell factors is an important regulatory mechanism. In many species, sperm cells cannot fertilize eggs until having passed a maturation process known as capacitation, which includes the acquisition of motility. Progestins that are produced under the influence of LH appear to play an important role in this context, which involves the control of the composition of the seminal plasma (e.g., pH values). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Annual dynamics of marine birnavirus (MABV) in cultured Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> and sea water     

Manami Inaba  Takeshi Kimura  Rika Kikukawa  Mitsuko Iwasaki  Masato Nose  Satoru Suzuki 《Fisheries Science》2007,73(3):615-622

ABSTRACT:   Seasonal changes in the infection state of marine birnavirus (MABV) in Japanese flounder Paralichthys olivaceus and in rearing sea water are described. Sea water and 10–11 healthy fish were sampled monthly from April 2002 to February 2003. The MABV genome was detected throughout the year in > 80% of the fish examined at each sampling. The virus was isolated from the liver, kidney, and spleen, but not from the brain. The detection rate in each organ increased from April to October, and then decreased. Detection of virus antigen by the indirect fluorescent antibody technique also showed that the virus was present from spring to autumn (June–September) in the liver, kidney, and spleen, but not the brain. Sequence analysis of the MABV genome at the VP2–NS region revealed two specific mutations compared to the standard yellowtail strain (Y-6). It is suggested that the infection state of MABV in Japanese flounder changes to a latent or persistent infection after autumn. MABV was detected in sea water between September and February, suggesting that virus particles in the environment are relatively higher during cool seasons.  相似文献   

Changes in the retinal cone density distribution and the retinal resolution during growth of juvenile Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>     

Shinsuke Torisawa  Tsutomu Takagi  Yasunori Ishibashi  Yoshifumi Sawada  Takeshi Yamane 《Fisheries Science》2007,73(5):1202-1204

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