排序方式： 共有10条查询结果，搜索用时 31 毫秒
1
1.
Efficacy of 17 α‐methyl testosterone and letrozole on sex reversal of protogynous grouper,Epinephelus tauvina (Forskal, 1775) and spawning performance of sex‐reversed males 
下载免费PDF全文
下载免费PDF全文 Ritesh Ranjan Biji Xavier Biswajit Dash Loveson L Edward Relangi D Suresh Pilli Suresh Kumar 《Aquaculture Research》2015,46(9):2065-2072
This study aimed to test the efficacy of 17 α‐methyl testosterone (17 α‐MT) alone and in combination with letrozole, an aromatase inhibitor, for the induction of sex reversal in protogynous greasy grouper, Epinephelus tauvina. Further, the long‐lasting effects of these treatments and spawning performance of sex‐reversed males were also investigated. Greasy grouper with oocytes in the perinucleolus stage were implanted with 5 mg 17 α‐MT kg?1 body weight (T1), 5 mg 17 α‐MT and 0.2 mg letrozole kg?1 body weight (T2) and 5 mg 17 α‐MT with 0.4 mg letrozole kg?1 body weight (T3) and no androgens/enzyme inhibitor implanted (C). The 17 α‐MT alone and in combination of letrozole‐induced sex reversal in greasy grouper, whereas untreated control fish (C) showed normal ovarian development. However, T2 and T3 group showed 100% sex reversal and completion of spermatogenesis up to functional male phase in 2 and 3 months, respectively, whereas T1 group resulted in only 66.67% functional male with motile spermatozoa after 4 months. Sex‐reversed males successfully fertilized the eggs during induced spawning. There were significant differences on fertilization and hatching rates between T2 group (79.00 ± 4.36%; 77.67 ± 2.87%, respectively) and T1 group (57.67 ± 3.17%; 63.87 ± 2.91%, respectively). The result suggested that 17 α‐MT (5.0 mg kg?1 BW) in combination with letrozole (0.2 mg kg?1 BW) has the potential to produce 100% sex‐reversed male in short period in greasy grouper, which might greatly help in seed production of greasy grouper. 相似文献
2.
Zeqian Qin Fang Yang Lu Tian Ruiyi Chen Dongdong Xu Yutaka Takeuchi 《Aquaculture Research》2020,51(3):882-889
The objective of this study was to test the efficiency of an aromatase inhibitor, letrozole (LZ), to induce masculinization in blue drum (Nibea mitsukurii) and gynogenetic yellow drum (N. albiflora). Two experiments (Exp‐1 and Exp‐2) were performed to investigate the effect of LZ on the growth, sex ratio and gonad development in these two fishes. In Exp‐1, blue drum were treated with oral administration of letrozole at different doses (0, 1, 10, 100 mg/kg). In Exp‐2, gynogenetic yellow drum were orally administered different doses of LZ (0, 10, 100 mg/kg) and a dose of 10 mg/kg 17α‐methyltestosterone (MT). The treatments in both experiments were performed from 25 to 85 days post hatch (dph). As a result, all the LZ‐treated fish were phenotypic males despite of slower growth than the control during the treatment period. Free spermatozoa were observed from 150 dph onwards and the gonadosomatic index of the LZ‐treated fish did not differ significantly from that in the control at maturity. However, the sex‐reversed fish induced by MT exhibited a high proportion (33.4%) of testicular abnormalities. Our results showed that oral administration of LZ was efficient in inducing sex reversal in drums, and thereby facilitated their mono‐sex culture. 相似文献
3.
试验旨在研究反季节给繁殖母羊补喂褪黑素（melatonin,MLT）及在MLT基础上补喂来曲唑（letrozole,LE）和N-甲基-D-天冬氨酸（N-methyl-D-aspartate,NMDA）对母羊血浆繁殖相关激素水平的影响,为调控母羊发情药物的开发及应用提供新思路。试验选取40只（3.0±0.5）岁经产萨福克母羊（平均体重为76.23 kg±12.25 kg）随机分为4组,每组10只,分别为对照组和试验Ⅰ、Ⅱ、Ⅲ组,分别饲喂基础日粮、基础日粮+MLT 10 mg/（只·d）、基础日粮+MLT 10 mg/（只·d）+LE 7 mg/（只·d）、基础日粮+MLT 10 mg/（只·d）+LE 7 mg/（只·d）+NMDA 300 mg/（只·d）。结果显示,与对照组相比,试验Ⅰ组母羊血浆中促卵泡素（FSH）、雌二醇（E2）、雌三醇（E3）及双氢睾酮（DHT）水平均极显著升高（P<0.01）,睾酮（T）水平显著降低（P<0.05）;试验Ⅱ组,母羊血浆MLT和LH水平均极显著升高（P<0.01）,FSH水平显著升高（P<0.05）;试验Ⅲ组,母羊血浆中MLT和促性腺激素释放激素（GnRH）水平均显著升高（P<0.05）。与试验Ⅰ组相比,试验Ⅱ组母羊血浆中MLT显著升高（P<0.05）,LH和T水平均极显著升高（P<0.01）。试验Ⅲ组与试验Ⅰ、Ⅱ组相比,FSH水平极显著降低（P<0.01）。综上所述,MLT和LE对母羊繁殖相关激素的释放有促进作用,且两者结合使用可达到调控母羊繁殖相关激素水平的效果;MLT、LE和NMDA组合应用对母羊繁殖激素调控效果不佳。 相似文献
4.
Ze‐Xia Gao Han‐Ping Wang Geoff Wallat Hong Yao Dean Rapp Paul O'Bryant Russ MacDonald Wei‐Min Wang 《Aquaculture Research》2010,41(9):1282-1289
In the present study, the efficacy of Letrozole, a potent nonsteroidal aromatase inhibitor (AI), on gonadal sex differentiation and sex reversal was examined in bluegill sunfish (Lepomis macrochirus). In Experiment 1, using AI diet treatments (50, 150, 250 and 500 mg kg−1) from 30 to 90 days posthatch (dph), AI interrupted ovarian cavity formation at a dose of 500 mg kg1 diet and one intersex fish was identified in this group. The proportions of males in all the treated groups were significantly higher than those in the control group. In Experiment 2, using AI immersion treatments (250, 500 and 1000 μg L−1) during 30–50 dph, the treated groups of 500 and 1000 μg L−1 produced significantly more males than the control and 250 μg L−1 groups. Histological examination revealed no differences in ovary or testis tissue between control and AI‐treated fish. There were no significant differences detected in body weight and length among the AI treated and control groups (P>0.05) for both experiments. The results from these two experiments suggest that inhibition of aromatase activity by AI could influence sex differentiation in bluegill sunfish. 相似文献
5.
来曲唑促排卵研究进展 总被引：2，自引：0，他引：2
来曲唑在治疗不孕症的临床应用具有较大潜力，有高效选择性抑制芳香化酶的活性、显著降低雌激素水平、不与雌激素受体结合、半衰期短的优越性。使用来曲唑有促排卵作用，能避免过度刺激卵巢，保证排卵功能健全，而且通常是单一排卵，对子宫内膜容受性影响小，提高妊娠率；若联合用药，可大大减少外源性促性腺激素的剂量；其促排卵副作用小，安全性好，胎儿致畸率很小。来曲唑可能成为新一代促排卵药物。 相似文献
6.
目的观察延长来曲唑的用药时间对多囊卵巢综合征（PCO S）模型大鼠血清性激素水平和卵巢形态的影响。方法 60只雌性SD大鼠随机等分为3组,21天组和30天组分别给予来曲唑连续灌服21、30 d,对照组不作任何处理。HE染色观察卵巢组织学变化,放免法测定大鼠血清性激素水平。结果对照组卵巢可见多个黄体及不同发育阶段的卵泡;来曲唑组有较多囊状扩张卵泡,尤以30天组更明显,但黄体数量明显减少。与对照组比较,来曲唑组的T水平升高（P〈0.01）,E2、P水平降低（P〈0.01）,且21天组的FSH、LH水平升高（P〈0.05或0.01）。30天组的FSH、T水平明显低于与21天组（P〈0.05或0.01）。结论适当延长来曲唑的使用时间可使FSH水平降低、LH水平增加,卵巢多囊变更为典型。 相似文献
7.
试验旨在研究醋酸甲羟孕酮（medroxyprogesterone acetate,MPA）与前列腺素（prostaglandin,PG）、N-甲基-D-天冬氨酸（N-methyl-D-aspartate,NMDA）和来曲唑（letrozole,LE）的不同配伍对母羊血浆繁殖相关激素水平的影响。选取3岁经产萨福克母羊39只,平均体重（75.51±11.55） kg,随机均分为3组,试验Ⅰ组饲喂基础日粮+34 mg/（d·只） MPA+1 mL/只PG,试验Ⅱ组饲喂基础日粮+34 mg/（d·只） MPA+600 mg/（d·只） NMDA,试验Ⅲ组饲喂基础日粮+34 mg/（d·只） MPA+14 mg/（d·只） LE,试验期18 d。结果发现,补饲MPA基础上进行PG处理,母羊血浆中FSH水平呈极显著升高（P<0.01）;补饲MPA基础上进行NMDA处理,母羊血浆中E2、MLT、FSH和LH水平均呈极显著升高（P<0.01）;补饲MPA基础上进行LE处理,母羊血浆中MLT、LH和T水平均呈极显著升高（P<0.01）。综合比较各生殖激素之间的关系及变化规律,在本试验条件下,建议MPA与NMDA和LE分别结合使用,可作为调控母羊繁殖性能的药品;且通过比较激素水平得出,MPA与NMDA组合效果最佳。 相似文献
8.
ZHAO Guo-dong WANG Gen XIE Jing-long YANG Jian-tao TANG Xue-mei ZHANG Juan-li YANG Kai-lun 《中国畜牧兽医》2017,44(11):3229-3235
This study was aimed to investigate the effects of the different compatibility of medroxyprogesterone acetate (MPA) with prostaglandin(PG), N-methyl-D-aspartate (NMDA) and letrozole (LE) on plasma related hormones levels of reproductive ewes. Thirty-nine and 3-year-old multiparity Suffolk ewes with average weight (75.51+11.55)kg were selected,and assigned into 3 groups,test group Ⅰ:Basis diet+34 mg/d MPA+1 mL/ewe PG, test group Ⅱ:Basis diet+34 mg/d MPA+600 mg/d NMDA, test group Ⅲ:Basis diet+34 mg/d MPA+ 14 mg/d LE, respectively, the trial period lasted for 18 days. The results showed as follows:On the basis of supplemental feeding MPA with PG treated,the levels of FSH in plasma of ewes were extremely significantly increased (P<0.01); Treated with NMDA, the levels of E2, MLT,FSH and LH in plasma of ewes were extremely significantly increased (P<0.01), respectively;Treated with LE, the levels of MLT,LH and T in plasma of ewes were extremely significantly increased (P<0.01), respectively. This study suggested that MPA+NMDA and MPA+LE could be used as medicines for regulate and control oestrus of ewes, and the effect of MPA+NMDA was the best. 相似文献
9.
本试验旨在探究补喂来曲唑对速步马运动性能、血浆抗氧化指标与激素水及体重的影响。选取平均年龄为2.5岁、平均体重为(398.16±25.34)kg的经过良好速步训练的伊犁马公马10匹,随机分为2组,分别为对照组和试验组,每组5匹。所有马匹每天每匹饲喂混合牧草10 kg、颗粒精料3 kg,在此基础上试验组马匹每天每匹补喂5 mg来曲唑,进行30 d的饲喂试验和训练试验。分别在试验第0天、第10天、第20天、第30天清晨空腹颈静脉采血,测定血浆中激素指标;在试验第0天和第30天早晨空腹称重,并进行1 000 m速步赛,分别在赛前1 h、赛后即刻、赛后20 min、赛后2 h颈部静脉采集血液,测定血液酸碱度相关指标和血浆抗氧化指标。结果显示:补喂来曲唑能够提高试验马匹1 000 m速步赛成绩;赛后2 h时,试验组马匹血浆中过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活力,总抗氧化能力(T-AOC)及尿酸(UA)含量均高于对照组,其中GSH-Px活力、T-AOC分别达到极显著(P0.01)和显著水平(P0.05),而血浆中丙二醛(M DA)含量则显著低于对照组(P0.05)。就血液酸碱度相关指标而言,在赛后即刻、赛后20 min、赛后2 h试验组血液中碳酸盐(HCO-3)含量低于对照组(P0.05),而碱剩余(BEecf)、p H则高于对照组(P0.05)。试验第10天、第20天、第30天时试验组马匹血浆中睾酮(T)、雄烯二醇(AD)水平均高于对照组(P0.05)。此外,补喂来曲唑还可提高速步马体重。因此,给速步马补喂5 mg/(匹·d)来曲唑可缩短1000 m速步赛比赛用时,提高机体的抗氧化能力和酸碱缓冲能力,并使血浆中T和AD水平上升,同时增加速步马的体重。 相似文献
10.
1