Biology Reference
In-Depth Information
Figure 5.
Effects of T
4
or TU treatments in
S. lagocephalus
post-larvae maintained 37 days in
experimental aquariums as compared to controls on the the corner of mouth angle. T
4
or TU
treatments were given in the water for 10 days.
fi nally occurred a few days after the treatment ended allowed to assess that
the TU-treatment was reversible and non-toxic. A similar phenomenon was
observed for the standard length. In other species, T
4
treatment accelerated
quite immediately the metamorphosis stage, while TU treatment stopped
the evolution of metamorphosis (
Paralichtys
olivaceus
: Inui and Miwa,
1985; Miwa and Inui, 1987;
Paralichtys
dentatus
: Schreiber et Specker,
1998;
Plectropomus
leopardus
: Trijuno et al., 2002;
Hippoglossus hippoglossus
:
Solbakken et al., 1999;
Megalops
cyprinoides
: Shiao and Hwang, 2006).
Moreover, it has been shown in some species that administration of TU
stopped the metamorphic process and that THs were able to reverse
metamorphic stasis induced by TU treatment (
Paralichtys
olivaceus
: Miwa and
Inui, 1987;
Verasper variegatus
: Tagawa and Aritaki, 2005;
Solea senegalensis
Manchado et al., 2008;
Megalops
cyprinoides
: Shiao and Hwang, 2006). In
Paralichtys
olivaceus
, abnormal non-metamorphosing fi sh treated with T
4
undergo a delayed metamorphosis (Okada et al., 2005).
Taillebois et al. 2011 fi ndings are consistent with previous laboratory
experiments conducted in some teleosts, including Elopomorphs and
Pleuronectiforms, which have a true metamorphosis. They show, for the
fi rst time in a Gobioid fi sh, that thyroid status is involved in the control of
drastic morphological changes in larval stage, which come with a switch
in its habitat and feeding mode.
