Biology Reference
In-Depth Information
30.2
Methods
In the first experiment, gilthead sea bream larvae were reared according to stan-
dard procedures (Moretti et al.
1999
) and fed control or taurine-enriched live prey
(1.5% of live prey dry weight). Growth and survival were monitored along the
experimental period (until 31 days after hatching). In the second experiment,
Senegalese sole larvae were also reared according to standard procedures (Dinis
et al.
1999
), being co-fed with live prey and control or taurine-supplemented (3%
of total composition) microdiets during the pelagic phase (25 days after hatching).
After settlement, larvae from both treatments were only fed live prey according to
standard procedures (until 32 days after hatching). A metabolism trial was con-
ducted in parallel with this experiment, where larvae from the control and taurine
treatments were fed live prey enriched with a radiolabelled amino acid mixture
[further details can be found in Pinto et al. (
2010
)]. The metabolic fate of radiola-
belled amino acids was quantified on sole retained, catabolised and evacuated
fractions, as described in Conceição et al. (
2007
). On the third experiment,
Senegalese sole larvae were reared following standard procedures (Dinis et al.
1999
) and sampled from first feeding until post-metamorphosis. Additionally,
sole juveniles were also sampled and several tissues were collected, mainly focus-
ing on organs of the digestive tract. The expression profile of TauT was subse-
quently analysed through qPCR on larval and juvenile tissues [for further details
see Pinto et al. (
2012
)]. Statistical analysis was performed on data from all experi-
ments to detect group mean differences, following procedures by Zar (
1999
) .
30.3
Results
Results from the first experiment showed that dietary taurine supplementation did
not significantly affect growth and survival of gilthead sea bream larvae.
In the second experiment, dietary taurine supplementation did not significantly
affect growth, survival and metamorphosis pattern of Senegalese sole at the end of the
pelagic phase (25 days after hatching). However, by the end of the trial (32 days after
hatching), newly settled Senegalese sole larvae from the taurine treatment showed a
significantly higher growth than larvae from the control treatment. In addition, about
20% of the larvae from the taurine treatment had completed metamorphosis, whereas
none of the larvae from the control treatment had finished this process. Results from
the metabolism trial showed that dietary taurine supplementation significantly
increased the amino acid retention in Senegalese sole, but only when higher taurine
levels were found in larvae from the Taurine treatment (9 days after hatching).
Results from the third experiment showed that the expression of TauT increased
during Senegalese sole larval development, significantly increasing at the onset of
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