摘要
利用养殖草鱼雌性个体所表现出的生长优势,探讨通过性逆转培育全雌草鱼品种的方法,具有较好的应用前景。实验采用拌料投喂诱导方式,在饲料中设置0、50、100和200 mg/kg 4个浓度梯度的17α-甲基睾酮(MT),连续投喂150 d,观测不同处理水平草鱼性腺结构和血液中类固醇激素雌二醇(E2)、睾酮(T)和11-酮基睾酮(11-KT)含量的变化规律,探讨草鱼性逆转过程中的特征变化。性腺的组织切片结果显示,从投喂30 d开始,各处理组卵巢中开始出现精原细胞。30~150 d,50 mg/kg MT处理组草鱼卵母细胞的生成及成熟受到抑制,发育迟缓;100 mg/kg MT处理组的生殖细胞受抑制程度要高于50 mg/kg MT处理组,实验结束时性腺已被大量精原细胞占据,有向精巢发育的趋势;200 mg/kg MT处理组精卵兼性状态较50 mg/kg MT处理组明显,但精原细胞的数量少于100 mg/kg MT处理组,对照组卵巢未出现精原细胞。血清类固醇激素测定结果显示,投喂不同剂量的MT,E_2浓度均显著升高,于45 d时达到最高值,之后趋于平稳下降,但仍显著高于对照组,未经处理的雄性草鱼,随着早期精巢的发育,其E_2水平也逐渐升高。随着MT投喂时间的延长,各处理组T浓度分别有不同程度的降低,45 d时各处理组降幅最大,且与MT浓度呈正相关,11-KT则有不同程度升高。研究表明,100 mg/kg MT为其性逆转较适宜的浓度,MT可使早期雌性草鱼血清E_2升高,发挥雄激素效应,从而促进卵巢卵细胞退化,精原细胞增殖。
By using the growth superiority demonstrated by the female individuals of the cultured grass carp,the method of breeding the whole female grass carp species by sex reversal is discussed,which has a good application prospect.The 17α-methyltestosterone(17α-MT)was selected to induce female-to-male as the male hormone,and set 4 concentration gradients evenly mixed with feed,i.e.0 mg/kg,50 mg/kg,100 mg/kg,200 mg/kg,which were respectively fed for 150 days.The objective of this study was to investigate the effects of different MT-treated diet on gonadal development and the changes of estradiol-17β(E2),testosterone(T)and 11-ketotestosterone(11-KT),and further the characteristics in the process of grass carp sex reversal.The morphological changes of grass carp were investigated by observing the changes of gonadal structure and serum steroid hormone content at different treatment levels to explore the sex reversal.Histological sections of gonads results showed that spermatogonia began to appear in the ovaries of all treatment groups from the 30 th day after feeding.With the prolongation of feeding time,50 mg/kg MT treatment group can inhibit the formation and maturation of oocytes,resulting in developmental delay;The inhibition of germ cells in 100 mg/kg MT treatment group was higher than that in 50 mg/kg MT treatment group,the gonads had been occupied by a large number of spermatogonia,and there was a tendency of developing testis at 210 d.The ovaries-testes state of 200 mg/kg MT treatment group at 210 d was more obvious than 50 mg/kg MT treatment group,but the number of spermatogonia was less than 100 mg/kg MT treatment group,while the control group ovary did not exhibit spermatogonia.The results of serum steroid hormone revealed that E2 increased significantly which to some extent depended on the MT dosages,reached the highest value at 45 days and then decreased steadily,but was still significantly higher than that of the control group,however.With the development of early stage testis,E2 level of control male also gradually increased.With the prolongation of MT feeding time,the concentrations of T in each treatment group decreased to different extents,and the biggest drop occurred in all treatment groups at 45 days,which was positively correlated with the MT concentration.The 11-KT increased to varying degrees.The results show that:100 mg/kg was more suitable concentration to bring about sex reversal,MT can cause the early female fish serum E2 to increase,and exert the effect of androgen,thereby promoting ovarian egg cell degradation,and spermatogonia proliferation.
作者
姚汶励
姜鹏
白俊杰
YAO Wenli;JIANG Peng;BAI Junjie(Key Laboratory of Tropical &Subtropical Fishery Resource Application &Cultivation,Ministry of Agriculture and Rural Affairs,Pearl River Fisheries Research Institute,Chinese Academy of Fishery Sciences,Guangzhou 510380,China;National Demonstration Center for Experimental Fisheries Science Education,Shanghai Ocean University,Shanghai 201306,China)
出处
《水产学报》
CAS
CSCD
北大核心
2019年第4期801-809,共9页
Journal of Fisheries of China
基金
现代农业产业技术体系建设专项(CARS-45-04
CARS-46-03)
广东省自然科学基金(2015A030313702)~~
关键词
草鱼
17α-甲基睾酮
性腺发育
性类固醇激素
Ctenopharyngodon idella
17α-methyltestosterone
gonadal development
sex steroid hormone