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Fig. 3. The amount of L-tryptophan (TRP) in the telencephalon (A), hypothalamus
(B), optic tectum (C) and brain stem (D) of isolated juvenile rainbow trout
fed feeds supplemented with L-tryptophan to a level corresponding to two (2X),
four (4X) and eight (8X) times the L-tryptophan content of the
non-supplemented control feed (1X). Stressed fish (filled square) were exposed
to a standardised stressor (lowering the water level); non-stressed fish were
undisturbed fish kept isolated (open triangle). Different letters indicate a
significant difference at the P<0.05 level (LSD post-hoc
test). Values are means ± S.E.M. from 5-7 individuals.