Bester, a hybrid sturgeon (Huso huso L. females ´ Acipenser ruthenus L. males), neither spermiate nor ovulate in the captivity. Thirteen-year-old adult male and female bester were injected with LH-RHa (0.1-0.3 mg/kg B.W.) intramuscularly and spawning status of the treated fish was checked 24-48 hours later. Additionally, changes in serum levels of DHP in both the responded and the non-responded individuals were monitored 0, 1, 3, 6, 9, 12, 24, 48 and 72 hours after treatment.
Between 70-100 percent of the LR-RHa injected males individuals, and 11-40 percent of the females spawned 24-48 hours after the treatment; the rest did not respond to the injection. In the responded males, 3-9 hours after the treatment, serum levels of DHP increased; while in the females it occurred first after 12-24 hours. In contrast, during the same period, serum levels of DHP remained low in all non-responded individuals. The present study indicated that using 0.1-1.3 mg/kg B. W. of LH-RHa can induce oocyte maturation and ovulation in the females and spermiation in the males cultured bester. The results suggested additionally DHP as an appropriated steroid that could be used in the final maturation stage of the gonads.