Study on determination of reproductive potential in Iranian sturgeon broodstocks [Acipenser persicus borodin, 1897]

ABSTRACT

Reproductive potential had studied by determining of oocytes germinal vesicle [G.V] position amongst number of Iranian sturgeon spawners. To determine G.V. position the oocyte was bisected and examined under a dissecting microscope. The procedure made with a surgical scalpel or a single edge razor blade and making a cut along the animal vegetal axis. The different position of the G.V were observed and evaluated by classification index as following a] Spawners that were good candidates to spown by hormonotherapy in the regular spawing season were in stage IV and their classification index were less than 0.07 or 1/14/[p<0.07]. the results that were indicated with the eggs fertilization rate [%] were 90% 85% and 83% respectively. b] Spawners with classification index more than 0.07 were underdeveloped and didn't respond adequately to spawning induction a few of these spawners elected for further ripening but its fertilization rate were low as 70%- 76% respectively. Also the results of this study showed when the G.V. has migrated to the end of animal pole and is positioned in the cortical ooplasm with a dark spot area the, oocytes are considered capable of responding to the hormonal stimuli necessary for ovulation and best fertilization