Comparison of reproductive development in triploid and diploid female rainbow trout Oncorhynchus mykiss.
نویسندگان
چکیده
The diploid rainbow trout Oncorhynchus mykiss reached sexual maturity 3 years after hatching and its oogenesis underwent four stages, which were oogonia, primary oocyte, secondary oocyte and egg. Reproductive development and hormone changes of 4 to 35 month-old female O. mykiss were investigated using histological and radioimmunoassay methods in order to provide a theoretical and practical basis for the use of triploid female O. mykiss. The oogonium of the triploid female could develop into the oocytes of the prophase with abortion occurring later; the oogonium was surrounded by stroma cells to form the oogonium cluster and the gonads showed a virilescent tendency when the oogonium clusters were gradually replaced by spermatogenic-like cytocysts. After 13 months, amounts of gonadotropic hormone (GtH-I, GtH-II) and oestradiol (17beta-E(2)) in triploid females were lower than in diploid fish at corresponding time periods, but the amounts of testosterone (T) increased consistently after 21 months and were more than in diploid fish in the corresponding time periods (P > 0.05). The infertility of triploid females resulted from meiosis failure, which caused developmental abortion of oocytes and oogonium formed cytocysts before the prophase oocytes. The cytocyst formation was due to the lack of the normal interaction of ovum and follicular cells, the development of follicular cells producing steroids were inhibited, the arylate path from T to 17beta-E(2) was interrupted, concentration of 17beta-E(2) decreased and concentration of T increased in the blood, the content of vitellogenin (Vg) decreased in the liver with a low 17beta-E(2) and high T caused to ovaries to show a tendency to be virilescent.
منابع مشابه
Effect of thermal stress on some hematological parameters of diploid and triploid Rainbow trout (Oncorhynchus mykiss)
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متن کاملبررسی امکان تولید جمعیت تمام ماده تریپلوئید قزل‌آلای رنگین‌کمان (Oncorhynchus mykiss)
In order to reduce the adverse effects of sexual maturation on growth and survival of rainbow trout, production possibility of all-female triploid was investigated by means of early heat shock on eggs fertilized by masculinized male’s sperm. Fish ploidy level was determined by erythrocyte size measurement and confirmed by gill nucleolus (NORs) counting as well as chromosome number. Sexual ratio...
متن کاملFlesh characteristics of pan-size triploid and diploid rainbow trout (Oncorhynchus mykiss) reared in a commercial fish farm
Sexual maturation of rainbow trout during production has a negative effect on the slaughter yields and flesh quality. Induction of triploidy is a method to prevent the development of fertile trout. In many investigations sexually mature triploid and diploid rainbow trout had been compared. In the present study the slaughter characteristics and flesh quality of female immature diploid and triplo...
متن کاملبررسی امکان تولید جمعیت تمام ماده تریپلوئید قزل‌آلای رنگین‌کمان (Oncorhynchus mykiss)
In order to reduce the adverse effects of sexual maturation on growth and survival of rainbow trout, production possibility of all-female triploid was investigated by means of early heat shock on eggs fertilized by masculinized male’s sperm. Fish ploidy level was determined by erythrocyte size measurement and confirmed by gill nucleolus (NORs) counting as well as chromosome number. Sexual ratio...
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ورودعنوان ژورنال:
- Journal of fish biology
دوره 76 7 شماره
صفحات -
تاریخ انتشار 2010