Female greenback flounder Rhombosolea tapirina were treated with either des Gly10 [D-Ala6] LHRH ethylamide (LHRH-a) at 50 or 100 μg/kg intraperitoneal injection (ipi), LHRH-a cholesterol pellet (LHRH-a pellet) 100 μg/kg implanted intraperitoneally, or human chorionic gonadotropin (hCG) 1,000 IU/kg ipi. Treatment with hCG, LHRH-a (50 μg/kg) ipi and LHRH-a pellet increased the total number of ovulations above control levels. LHRH-a (100 μg/kg) ipi was not consistently more effective than the control and both LHRH-a (50 μg/kg) ipi and LHRH-a pellet induced more ovulations than LHRH-a (100 μg/kg) ipi. Of those fish that ovulated, most ovulated more than twice, and most ovulations occurred at daily intervals. Oocyte diameters increased and oocyte stage advanced significantly in response to all exogenous hormone treatments. This was accompanied by increases in plasma and ovarian levels of 17β-estradiol (E2), and in most cases, plasma and ovarian levels of testosterone (T). Plasma and ovarian levels of 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were not consistently elevated in association with reproductive events.

Item Type:	Refereed Article
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Fisheries Sciences
Research Field:	Aquaculture
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Fisheries - Aquaculture
Objective Field:	Fisheries - Aquaculture not elsewhere classified
Author:	Poortenaar, CW (Dr Carolyn Wendy Poortenaar)
Author:	Pankhurst, NW (Professor Ned Pankhurst)
ID Code:	18411
Year Published:	2000
Web of Science® Times Cited:	16
Deposited By:	TAFI - Aquaculture
Deposited On:	2000-08-01
Last Modified:	2001-03-20
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