The tetrotoxin or TTX can paralyze and kill dozens of predators, and adults are afraid to eat pufferfish meat. But new research has found that the toxin also acts as another role: to relieve stress. Instead of making its own toxins, the Japanese tiger pufferfish accumulates toxins in organs and skin by producing TTX bacteria through the diet.
The captive tiger pufferfish have different diets and therefore lose their toxicity. To illustrate how TTX affects developing tiger pufferfish, the researchers added a month’s pure TTX dose to the young porpoise in captivity. The toxin-supplemented pufferfish are on average 6% longer and 24% heavier than those who eat non-toxic foods. At the same time, they are not as aggressive.
Growth rate and aggression are affected by stress, so the researchers looked at levels of two stress-related hormones: cortisol in the blood and corticosteroid-releasing hormones in the brain.
The researchers report in Toxin that the non-toxic pufferfish have higher cortisol levels than the toxic pufferfish, with a median level of four times that of the other.