Dietary tryptophan modulation and aggressive behavior in mice.
The effects of a tryptophan-free diet on isolation-induced fighting and predatory cricket killing in mice were examined. The results demonstrated that consumption of a tryptophan-free diet for 18-20 days decreased both the number of fighters and duration of isolation-induced fighting; increased the number of cricket-killing mice and decreased the latencies to attack and the latencies to kill crickets; reduced brain serotonin 27%; increased water intake 38%; and decreased body weight 27% without affecting food intake. To determine if these effects were due specifically to the lack of dietary tryptophan, other groups of mice were fed a 5% tryptophan load in the standard chow; a 0.15% tryptophan supplement in the tryptophan-free diet; or a 3 grams/day restricted chow diet. The lack of tryptophan in the diet produced the marked inhibition in isolation-induced fighting, the reduction in brain serotonin, and the large decrease in body weight. The other non-specific effects appeared to be related to general factors such as dietary need for the cricket killing or diet composition (other than the lack of tryptophan) for the water intake.
D000374:Aggression / Q000187:drug effects*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects; D004327:Drinking Behavior / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects; D005527:Food, Fortified; D006801:Humans; D008297:Male; D051379:Mice; D012701:Serotonin / Q000378:metabolism; D014364:Tryptophan / Q000494:pharmacology*
D012701:Serotonin; D014364:Tryptophan