Studies on toxification of puffer fish.

作为河豚鱼受精机理研究的一部分，本研究采用人工受精的方法，在充气式水族箱中进行了以下试验：在室内用轮虫和桡足类饲养20天左右，然后转移到室外混凝土池中，用商品鳗鱼饲料饲养几年，一直提供实验鱼。在此期间，每隔两个月检查一次毒性。在各种条件下，我们检查了腹腔内或皮下注射毒素的蓄积情况。在注射方法方面未检测到蓄积差异。蓄积量与给药量成正比，在kusafugu和torafugu中回收的毒素分别为50%和30%，主要存在于kusafugu的肝脏和torafugu的皮肤中。将其中两种衍生物注射到养殖鱼中，并测定了其残留量和在鱼中的分布。本研究以无毒的河豚鱼为研究对象，探讨了河豚鱼是否会因TTX产生菌的作用而产生毒性。30只kusafugu和10只torafugu被喂食含有细菌的饮食30天。仅有的一种torafugu具有弱毒性，在肝脏和皮肤中的毒性分别为0.2和1.5 MU/g。

As a part of the research on the mechanism of toxification in puffer fish, following experiments were conducted.Eggs were obtained from the mature kusafugu and torafugu and fertilized artificially and hatched in aerated aquariums. The larvae were reared with rotifers and copepods for about 20 days in indoor aquariums and then transferred to out door concrete tank and reared with a commercial eel diet for a few years to provide the experimental fish all the time. During this periods, the toxicity was checked at the interval of two month.In various conditions, we examined the accumulation of toxin administered intraperitoneally or subcutaneously. No difference in accumulation was detected in regard to injection methods. The amount of accumulation was directly proportional to the amount of administration and the toxins recovered were 50 and 30 % in kusafugu and torafugu, respectively and were found mainly in the liver of kusafugu and skin of torafugu.The occurrences of TTX derivatives such as anhydTTX, 6-epiTTX, 4-epiTTXt and 11-deoxyTTX were reported. Two of these derivatives were injected into cultured fish and the amount of derivatives remained and the distribution in the fish. Their behavior were almost similar to that of TTX.We examined whether non-toxic puffer fish become toxic by administration of TTX producing bacteria or not. Thirty kusafugu and ten torafugu were fed the diet contained the bacteria for 30 days. The only one torafugu became weakly toxic with toxicities of 0.2 and 1.5 MU/g in the liver and skin, respectively.