Gonadal Oocyte Development in LHRHa Hormone Treated European Sea Bass (Dicentrarchus labrax L., 1758) Broodstock

Stages of oocyte maturation in sea bass (Dicentrarchus labrax) gonads after LHRHa hormonal treatment were investigated. LHRHa was injected into sea bass broodstock with an oocyte diameter of 527-580 µm. A second injection was given 12 h after the first injection. For each injection a dose of 10 µg/kg was used. At 24 h, oil globules in oocytes were randomly distributed. These oil globules started to fuse and change to a spherical shape from an ellipsoidal shape at 36 and 42 h. Ovulation was observed between 45 and 54 h after the first intramuscular injection. After 54 h from the first injection, oocytes became overripe due to no spawning occurring on time. The overripe rate in gonads was 90% at 60 h.

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