亲吻素-1基因对雄性哺乳动物生殖调控的研究进展简     

荀文娟  周汉林  侯冠彧  曹婷  施力光 《中国畜牧兽医》2014,41(1):171-174

亲吻素-1（Kiss-1）基因参与哺乳动物性腺轴的调节,同时也参与其他生殖功能的调控,作者综述了Kiss-1基因在雄性哺乳动物生殖系统的研究进展,并对该领域今后的研究方向进行了分析。  相似文献   

Evidence of sex reversal towards both directions in reared red spotted grouper Epinephelus akaara   总被引：1，自引：0，他引：1  

Shigenobu Okumura 《Fisheries Science》2001,67(3):535-537

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Genetic covariation in production traits of sub-adult black bream Acanthopagrus butcheri after grow-out     

Robert G Doupé  & Alan J Lymbery 《Aquaculture Research》2005,36(11):1128-1132

Predicting the suitability and reliability of traits associated with juvenile growth as indirect selection criteria for choosing future broodstock requires accurate and repeatable estimates of genetic (co)variation for growth traits at different ages. We compared juvenile wet weight of black bream Acanthopagrus butcheri (Munro) at 6 months of age with wet weight, dressed weight, fillet yield and gonad weight in tagged individuals at 18 months of age, following 12 months of farm grow‐out. Fish survival and tag retention was high, and there was significant among‐family variation for all traits. The phenotypic correlations among wet weight, dressed weight and fillet yield at 18 months of age were very high (0.93–0.97) and similar to their genetic correlations (0.96). Importantly, the phenotypic correlations between wet weight at 6 months and wet weight, dressed weight and fillet yield at 18 months were high (0.63–0.65), and so too were their genetic correlations (0.66–0.73), indicating the potential for using wet weight in the hatchery as a selection criterion for improved weight and meat yield of fish at harvest. Gonad weight shared little or no phenotypic or genetic correlation with these other traits, suggesting that selection for faster growing fish will not affect fecundity or sexual maturation rate. It appears, however, that cultured black bream do become sexually mature more rapidly than wild fish, as 78% of all fish harvested in this study had developing or mature gonads, whereas less than 50% of fish in wild populations are reproductively mature by the same age. Precocious sexual development may lead to uncontrolled spawning in grow‐out ponds and a potential loss of selection gains.  相似文献   

Characterization of molecular variants of GnRH, induction of spermiation and sex reversal using salmon GnRH-A and domperidone in the protogynous diandric fish, Synbranchus marmoratus Bloch, (Teleostei, Synbranchidae)     

M.A. Ravaglia  F.L. Lo Nostro  M.C. Maggese  G.A. Guerrero  G.M. Somoza 《Fish physiology and biochemistry》1997,16(5):425-436

This paper studies the molecular variants of gonadotropin-releasing hormone (GnRH) present in the brain of the protogynous swamp eel, Synbranchus marmoratus, and the effects of the administration of salmon GnRH analogue (sGnRH-A) and the dopamine receptor antagonist, domperidone (DOM) on final maturation and gamete release in this species. Evidence for the presence of two GnRH variants, sGnRH and cIIGnRH were obtained by reverse phase high-pressure liquid chromatography (RP-HPLC) and radioimmunoassay with different antisera. The effects of treatment with sGnRH-A+DOM were checked by three ways: oocyte and milt release by stripping, histological analysis of the gonadal tissue, and androgen serum levels at different times throughout the experiment. In males, spermiation was induced after three weeks of treatment. In the female group, sGnRH-A+DOM did not induce ovulation at the end of the experiment. Histological analysis of the gonads from the female group showed evidence of sex reversal. All the treated fish had elevated androgen serum levels from the third week, with respect to control fish. In all cases, serum estradiol levels were undetectable. These results suggest that treatment with sGnRH analog and DOM induce sex reversal in female and spermiation in males. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Effect of water temperature and growth variation on the sex ratio of experimentally reared eels     

K. Holmgren 《Ecology of Freshwater Fish》1996,5(4):203-212

In a controlled experiment, elvers (Anguilla anguilla L.) were reared for 137 weeks at 17, 20 and 26°C. Most eels with macroscopically sexable gonads were males. The proportions of females were 14% of sexable individuals at 26°C and 7–8% at 17 and 20°C. During the first 15 weeks, 20–50% of initial numbers were lost, but this early mortality was not significantly size selective. In spite of a long term experiment, a significant number of the survivors never attained a sexable size. Nongrowers (7–9 cm) were still alive nearly three years after being caught as glass eels. Among the earliest fast growers, 5% females, or less, were found. The proportion of females increased in later grading groups, but the pattern of increase did not indicate that males and females have separated mean ranks in a fixed growth hierarchy. Water temperature influenced observed sex ratios, but probably not through direct influence on the sex differentiation. Some alternative hypotheses, dealing with population density and individual growth status, are discussed.  相似文献   

The cytochrome P450 system of Atlantic salmon (Salmo salar): II. Variations in hepatic catalytic activities and isozyme patterns during an annual reproductive cycle     

Håvard E. Larsen  Malin Celander  Anders Goksøyr 《Fish physiology and biochemistry》1992,10(4):291-301

A group of Atlantic salmon (Salmo salar) was followed through their first year of maturation and spawning. At monthly intervals, starting with juvenile fish in December, 5–7 fish of each sex were killed, and liver and plasma were sampled. The last sampling point was of spawning fish in November a year later. Variables in the cytochrome P450 (P450) system were studied in hepatic microsomes, and estradiol 17 was measured in the plasma of females to assess the maturational status. The P450 1A1-mediated 7-ethoxyresorufin O-deethylase (EROD) started at high levels in winter, but decreased to non-detectable activities in pre-spawning females. Decreases, but not to the same extent, were also observed during this period in total cytochrome P450, cytochrome b₅, NADPH-cytochrome P450 reductase, and in the content of two immunochemically determined P450 isozymes. At the same time, LSI levels increased in maturing females (starting in July), and GSI levels increased in both sexes (starting in May). Sex specific differences were observed in pre-spawning fish in September and October, with levels of total P450, b₅, NADPH-cytochrome P450 reductase, EROD and P450 isozymes significantly lower in females. At the same time, plasma estradiol-17 levels reached peak values in females. The results point to the important role of sex steroids such as estradiol-17 as major factors in the regulation of final sexual maturation. However, this study also indicates that there may be estradiol-17 independent events of equal importance in the early stages of gonadal maturation that may involve the P450 system. The changes observed in the P450 system (as a major drug and steroid metabolizing system) of Atlantic salmon during sexual maturation may be of importance both in the endogenous transduction of hormonal signals, and as a pharmacological basis for designing therapeutic treatment of diseases in the aquaculture industry.Parts of this work were presented at the 5th International Symposium on Responses of Marine Organisms to Pollutants, April 1989 in Plymouth, United Kingdom (Larsen and Goks\/oyr 1989).  相似文献   

中华绒螯蟹副性征的研究     

张渡娥 《淡水渔业》1992,(5)

在解剖、测量性成熟和未成熟中华绒螯蟹外部形态和性腺之基础上,试用“双百分率法”和“差异显著性检测法”对中华绒螯蟹的副性征进行了研究。结果表明,性成熟后的雌、雄中华绒螯蟹均具有较明显的副性征。  相似文献   

Environmental sex determination, external sex differentiation and structure of the androgenic gland in the Pacific white shrimp Litopenaeus vannamei (Boone)     

Rafael Campos-Ramos  Rodolfo Garza-Torres  Danitzia A Guerrero-Tortolero  Alejandro M Maeda-Martínez  & Hortencia Obregón-Barboza 《Aquaculture Research》2006,37(15):1583-1593

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Effects of (D-Ala6, Pro9N ethylamide) — LHRH on plasma levels of gonadotropin, 17α,20β-dihydroxy-4-pregnen-3-one and testosterone in male goldeye (hiodon alosoides Rafineque)     

N. W. Pankhurst  G. van der Kraak  R. E. Peter  B. Breton 《Fish physiology and biochemistry》1986,1(3):163-170

Male goldeye were treated with (D-Ala⁶, Pro⁹-N ethylamide) — LHRH (LHRH-A) in saline or a silastic pellet (100 µg.kg^–1 body weight) and changes in plasma gonadotropin (GtH), 17,20-dihydroxy-4-pregnen-3-one (17,20P) and testosterone (T) levels were determined by radioimmunoassay. LHRH-A increased plasma GtH levels, with the response to LHRH-A in saline being of much greater magnitude and duration than the response to silastic pellet implants. Seasonal differences were found in the response to LHRH-A. Spermiated fish were the most responsive, recrudescing fish the least, and regressed fish displayed an intermediate response. Plasma 17,20P levels were elevated in response to LHRHA in fish of all sexual stages although the magnitude of the increase was not related to the magnitude of the increase in GtH levels. Treatment with LHRH-A also resulted in a transitory increase in plasma T levels. The endocrine control of GtH and steroid secretion in goldeye is discussed in relation to studies in cyprinids and salmonids. Address for reprint requests: Department of Zoology, University of Alberta, Edmonton, Alberta T6G 2E9 Canada.  相似文献   

不同氮肥施用比例对辽北地区精确定量栽培水稻生长的影响     

李非 《中国稻米》2014,20(5):65-67

以常规施肥方式为对照,通过对比3种氮肥施用比例应用效果,探索了适合辽北地区水稻精确定量栽培的施肥模式。结果表明,氮肥中基蘖肥和穗粒肥比例以6∶4较为合理,结合晒田能够有效控制水稻无效分蘖,提高穗粒数、结实率及千粒重,进而增加产量,与常规施肥方式相比产量增加18.6%。  相似文献