Induced Ovulation, Spawning, Egg Incubation, and Hatching of the Cyprinid Fish Labeo victorianus in Captivity

Abstract

Two spawning inducing agents—Aquaspawn (a rapidly metabolized synthetic decapeptide gonadotropin‐releasing hormone [GnRH]) and Dagin ([D‐Arg6, Pro9‐NEt]‐sGnRH) combined with 20 mg/kg of the water‐soluble dopamine receptor antagonist metoclopramide (GnRH + MET)—were tested for their efficacy in stimulating ovulation in Labeo victorianus held in its natural environment and under captive conditions. Successful ovulation, when migratory vesicle oocytes became completely transparent, was obtained with GnRH + MET, while GnRH only caused oocyte clearance up to the highly translucent phase. L. victorianus eggs were non‐adhesive, semi‐buoyant, and transparent at ovulation. First hatching occurred after 26 h and lasted for 8 h at 24 C. Water temperature was shown to significantly affect spawning latency and incubation time. Thus, L. victorianus could be successfully induced to spawn using a synthetic gonadotropin‐releasing hormone coupled with a dopamine antagonist followed by natural fertilization in floating net cages at temperatures between 24 and 27 C.

Efecto de la temperatura y salinidad del agua en la incubación de huevos de botete diana Sphoeroides annulatus

“…1d). Se ha reportado para muchas especies de peces que al incrementar la temperatura de incubación más allá del rango óptimo de cada especie, se acelera el desarrollo embrionario y se acorta el tiempo de eclosión; sin embargo, puede provocar anormalidades en las larvas eclosionadas e incrementar la mortalidad (Hansel & Falk-Petersen 2001, Rutaisire & Booth 2004, Cingi et al 2010, Shi et al 2010. En este estudio, aunque no fue calculado, se observó que el aglomerado de los glóbulos de aceite del vitelo era más pequeño en los huevos incubados a 31ºC.…”

Application of synthetic hormone LHRH-A2 on the artificial propagation of Persian sturgeon Acipenser persicus

“…Thus, induction of broods can be replaced by using LHRH-A2 in the dose of 3.5, 7, 8 lg kg -1 as well as pituitary gland hormone. The range of effective doses of GnRHa varies from 5 to 100 lg kg -1 in different species (Glasser et al 2004;Rutaisire and Booth 2004;Kucharczyk et al 2005;Heyrati et al 2007). The rate of 100% spermation was exhibited by all male breeders.…”

Induction of final oocyte maturation in Cyprinidae fish by hypothalamic factors: a review

“…The unsatisfactory potency of natural GnRH peptides was improved by synthesising a superactive GnRHa, which is able to induce a significant increase in LH levels even at centuple smaller doses than with the use of natural GnRH forms (Table 1), (Kouril et al, 1986(Kouril et al, , 2007. The range of effective doses of GnRHa varies from 5-100 μg/kg and in the case of DI from 5-20 mg/kg of effective matter (Kouril et al, 1986;Drori et al, 1994;Brzuska, 1999;Szabo et al, 2002;Glasser et al, 2004;Mikolajczyk et al, 2004;Rutaisire and Booth, 2004;Kucharcyzk et al, 2005;Heyrati et al, 2007 Due to the strong dopaminergic inhibition of LH secretion, typical for the family Cyprinidae, a majority of trials with ovulation induction using only GnRHa failed (Weil et al, 1980;Sokolowska et al, 1984). According to the results of other authors Yaron, 1995;Heyrati et al, 2007) and our own, the only exceptions to the strong dopaminergic activity in Cyprinidae we know are tench (Tinca tinca), (Kouril et al, 1986) and rudd (Scardinius erythrophthalmus), (Hamackova et al, 2001) in which even a dose of 1 μg/kg mGnRHa was able to stimulate ovulation in a small number of females.…”