Fig. 1. The number of aggressive acts performed during repeated 30 min resident/intruder tests by isolated juvenile rainbow trout before (day 0) and after 3 and 7 days of receiving an experimental wet feed supplemented with (A) 1.5 % (experiment 1) or (B) 0.15 % (experiment 2) L-tryptophan (TRP). In both experiments, the control fish were fed experimental wet feed without supplementary tryptophan. Values are means + S.E.M. (N=12 in all groups). *P<0.05 (repeated-measures MANOVA followed by contrast analysis, see text for further details).
