Effects of controlled
delivery and acute injections of LHRHa on bullseye puffer fish (Sphoeroides
annulatus) spawning
N.J. Duncan, G.A. Rodriguez M. de O, D. Alok, Y.
Zohar-2003
Aquaculture, 218(1-4): 625-635
Abstract:
Mature bullseye puffer (Sphoeroides annulatus)
fish were caught and taken into captivity. Fish with a mean oocyte diameter
greater than 0.45 mm were divided equally into three experimental groups (n=11)
that were treated with a saline injection (control), multiple injections of
luteinizing hormone-releasing hormone analogue (LHRHa) (day 0––20 µg kg-1,
day 2––40 µg kg-1, day 4––80 µg kg-1, day
6––160 µg kg-1) and a single administration of slow-release
ethylene vinyl acetate (EVAc) co-polymer implants containing the identical
LHRHa (day 0––75 µg per fish <800 g or 150 µg per fish >800 g).
A total of 82% of the fish spawned in each of the two LHRHa groups
(injection and implant) compared to just 18% in the control group. The
majority of the fish treated with LHRHa, eight in the injection group and
nine in the implant group, spawned during the first week after
administration. There were no significant differences in mean egg size
(group means 0.64–0.71 mm) and percentage fertilization (group means
90.2–97.3%) among the LHRHa-treated groups and when compared with the
control fish that received saline injection and fish that ovulated naturally
without any treatment. The successful spawning using LHRHa-based spawning
protocols is an important step in the development of the culture of the
bullseye puffer.
(CIAD
Unidad Mazatlan, AP 711, Mazatlán CP 82000, Sinaloa, Mexico, e-mail:
nduncan@victoria.ciad.mx)