赤点石斑鱼Epinephelus akaara(Temminck et Schlegel)是我国名贵海产经济鱼类。近几年来,因盲目钩捕,在东南沿海资源日益减少。因此,国内外一些学者对赤点石斑鱼性腺发育进行周年研究,并开展了人工繁殖和育苗试验。然而,由于此鱼雌雄同...赤点石斑鱼Epinephelus akaara(Temminck et Schlegel)是我国名贵海产经济鱼类。近几年来,因盲目钩捕,在东南沿海资源日益减少。因此,国内外一些学者对赤点石斑鱼性腺发育进行周年研究,并开展了人工繁殖和育苗试验。然而,由于此鱼雌雄同体,雌性先熟,在六龄鱼才转变为雄鱼。由此常见因缺少雄鱼无法开展人工繁殖。所以,作者在非繁殖季节,试图用外源性雄激素拌入饵料中,喂低龄和高龄赤点石斑鱼,目的在于诱发其性逆转,现已取得显著的效果,这对于解决雄鱼困难,提供科学依据。展开更多
性类固醇激素与生物生殖、配子排放以及性腺发育密切相关,Srd5a1基因在性类固醇激素合成过程中扮演重要角色。为了探究性类固醇激素合成相关酶基因Srd5a1对雌性三角帆蚌卵巢发育的影响,应用RACE克隆得到了该基因全长cDNA序列,通过实时...性类固醇激素与生物生殖、配子排放以及性腺发育密切相关,Srd5a1基因在性类固醇激素合成过程中扮演重要角色。为了探究性类固醇激素合成相关酶基因Srd5a1对雌性三角帆蚌卵巢发育的影响,应用RACE克隆得到了该基因全长cDNA序列,通过实时荧光定量(qRT-PCR)、原位杂交技术以及不同浓度17β-雌二醇(E2)和17α-甲基睾酮(MT)激素处理来探究基因的表达特性。结果显示,Srd5a1 cDNA全长2224 bp,包括446 bp 5′-UTR、953 bp 3′-UTR和825 bp ORF,编码274个氨基酸。Srd5a1基因在性腺中的表达呈二态性,在卵巢中表达量更高;且在卵巢排放期的表达量最高,极显著高于其他各时期。原位杂交结果显示,Srd5a1基因在卵巢卵母细胞、卵泡以及精巢精母细胞中有表达。不同浓度E2和MT处理24 d后,Srd5a1基因的表达发生了变化。综上,Srd5a1基因可能在雌性三角帆蚌卵巢卵母细胞发育成熟和配子排放中发挥一定作用,对探索三角帆蚌性腺生长发育具有重要意义,同时为实现三角帆蚌单性化养殖提供理论参考价值。展开更多
17α-methyltestosterone is used to induce the sex reversal of Tilapia sp. to obtain cultures mono-sex to an economically viable. This practice may lead to environmental contamination and problems in human health. Ther...17α-methyltestosterone is used to induce the sex reversal of Tilapia sp. to obtain cultures mono-sex to an economically viable. This practice may lead to environmental contamination and problems in human health. Therefore methods need to be developed to detect residues of 17α-methyltestosterone in aqueous matrices. A simple high-performance liquid chromatographic method using ultraviolet detection (245 nm) and testosterone as internal standard has been developed for the monitoring 17α-methyltestosterone in freshwater samples of tilapia aquaculture. The method described involves limited sample preparation as it includes a filtration followed by a single solid-phase extraction step using C18 cartridge. Validation data indicated that the HPLC-UV method for 17α-methyltestosterone determination in the concentration range of 50 - 2000 μg/L provided good linearity, sensitivity, accuracy and precision. Method performance was efficiently applied to monitoring the freshwater samples of fish ponds and the surrounding aquatic channels.展开更多
This study was carried out to examine the effect of combining factors for immersion technique on masculinization of red tilapia(Oreochromis spp.).Three selected doses(1000,1,500,and 2000μg/L)of 17α-methyltestosteron...This study was carried out to examine the effect of combining factors for immersion technique on masculinization of red tilapia(Oreochromis spp.).Three selected doses(1000,1,500,and 2000μg/L)of 17α-methyltestosterone(17 MT)immersion,2 exposure times(3 and 6 h)once or twice a week,and interaction of these factors were tested.A total of 12 treatment combinations under 3×2×2 factorial experiments in randomized complete block design were conducted to compare with the negative control group(no 17 MT-treated)and positive control group(17 MT-treated feed administration).One hundred red tilapia larvae(14 days post-hatch)were randomly allocated in each treatment and were operated in a 10-L glass jar for 21 days.At the end of the treatment regime,the survival rate was determined.Then,fish were raised in a 150-L glass tank using normal commercial feed for 2 months and sex ratios were determined via the gonad squash technique.None of the immersion treatments tested resulted in a statistically significant(p>0.05)decrease in survival rate.All 17 MT-treated groups produced progenies with a significantly higher(p<0.001)proportion of males than the predicted 1:1 sex ratio.Influences of some factor combinations in the masculinization of red tilapia were observed.The male ratio was significantly affected by the dose-period and dose-frequency treatments(p<0.05).The highest male proportion(95.33%±0.58%)was recorded at 1000μg/L of 17 MT for 6 h once a week which was significantly higher(p<0.05)than other groups.The production cost of the best group was the cheapest(THB0.0066/fish)and decreased from the traditional procedure by about 10.81%.Therefore,this technique could be implemented for decreasing cost and operating process in commercial tilapia farms.展开更多
文摘赤点石斑鱼Epinephelus akaara(Temminck et Schlegel)是我国名贵海产经济鱼类。近几年来,因盲目钩捕,在东南沿海资源日益减少。因此,国内外一些学者对赤点石斑鱼性腺发育进行周年研究,并开展了人工繁殖和育苗试验。然而,由于此鱼雌雄同体,雌性先熟,在六龄鱼才转变为雄鱼。由此常见因缺少雄鱼无法开展人工繁殖。所以,作者在非繁殖季节,试图用外源性雄激素拌入饵料中,喂低龄和高龄赤点石斑鱼,目的在于诱发其性逆转,现已取得显著的效果,这对于解决雄鱼困难,提供科学依据。
文摘性类固醇激素与生物生殖、配子排放以及性腺发育密切相关,Srd5a1基因在性类固醇激素合成过程中扮演重要角色。为了探究性类固醇激素合成相关酶基因Srd5a1对雌性三角帆蚌卵巢发育的影响,应用RACE克隆得到了该基因全长cDNA序列,通过实时荧光定量(qRT-PCR)、原位杂交技术以及不同浓度17β-雌二醇(E2)和17α-甲基睾酮(MT)激素处理来探究基因的表达特性。结果显示,Srd5a1 cDNA全长2224 bp,包括446 bp 5′-UTR、953 bp 3′-UTR和825 bp ORF,编码274个氨基酸。Srd5a1基因在性腺中的表达呈二态性,在卵巢中表达量更高;且在卵巢排放期的表达量最高,极显著高于其他各时期。原位杂交结果显示,Srd5a1基因在卵巢卵母细胞、卵泡以及精巢精母细胞中有表达。不同浓度E2和MT处理24 d后,Srd5a1基因的表达发生了变化。综上,Srd5a1基因可能在雌性三角帆蚌卵巢卵母细胞发育成熟和配子排放中发挥一定作用,对探索三角帆蚌性腺生长发育具有重要意义,同时为实现三角帆蚌单性化养殖提供理论参考价值。
文摘17α-methyltestosterone is used to induce the sex reversal of Tilapia sp. to obtain cultures mono-sex to an economically viable. This practice may lead to environmental contamination and problems in human health. Therefore methods need to be developed to detect residues of 17α-methyltestosterone in aqueous matrices. A simple high-performance liquid chromatographic method using ultraviolet detection (245 nm) and testosterone as internal standard has been developed for the monitoring 17α-methyltestosterone in freshwater samples of tilapia aquaculture. The method described involves limited sample preparation as it includes a filtration followed by a single solid-phase extraction step using C18 cartridge. Validation data indicated that the HPLC-UV method for 17α-methyltestosterone determination in the concentration range of 50 - 2000 μg/L provided good linearity, sensitivity, accuracy and precision. Method performance was efficiently applied to monitoring the freshwater samples of fish ponds and the surrounding aquatic channels.
文摘This study was carried out to examine the effect of combining factors for immersion technique on masculinization of red tilapia(Oreochromis spp.).Three selected doses(1000,1,500,and 2000μg/L)of 17α-methyltestosterone(17 MT)immersion,2 exposure times(3 and 6 h)once or twice a week,and interaction of these factors were tested.A total of 12 treatment combinations under 3×2×2 factorial experiments in randomized complete block design were conducted to compare with the negative control group(no 17 MT-treated)and positive control group(17 MT-treated feed administration).One hundred red tilapia larvae(14 days post-hatch)were randomly allocated in each treatment and were operated in a 10-L glass jar for 21 days.At the end of the treatment regime,the survival rate was determined.Then,fish were raised in a 150-L glass tank using normal commercial feed for 2 months and sex ratios were determined via the gonad squash technique.None of the immersion treatments tested resulted in a statistically significant(p>0.05)decrease in survival rate.All 17 MT-treated groups produced progenies with a significantly higher(p<0.001)proportion of males than the predicted 1:1 sex ratio.Influences of some factor combinations in the masculinization of red tilapia were observed.The male ratio was significantly affected by the dose-period and dose-frequency treatments(p<0.05).The highest male proportion(95.33%±0.58%)was recorded at 1000μg/L of 17 MT for 6 h once a week which was significantly higher(p<0.05)than other groups.The production cost of the best group was the cheapest(THB0.0066/fish)and decreased from the traditional procedure by about 10.81%.Therefore,this technique could be implemented for decreasing cost and operating process in commercial tilapia farms.
