Thiamine-modifying properties of fish and meat products.

The presence of antithiamine factors in fish has been known since the early 1940's when it was noted that foxes fed raw carp developed polyneuritic symptoms or Chastek paralysis which was characteristic of thiamine deficiency (1). This condition could be pre vented by heating the fish or including ad ditional thiamine in the diet and was later shown to be caused by the presence of an enzyme "thiaminase" in the raw fish. Fish, both fresh water and salt water, have been assayed for this enzyme in many parts of the world and, in general, thiaminase appears to be more prevalent in fresh water than in salt water fish (2). This review concerns work in our laboratory on antithiamine and thiamine modifying factors in fish and meat products and also investigations on a reaction of hemin with thiamine. Our initial work on antithiamine factors involved two species of fish which are common ly eaten raw in Hawaii, the Skipjack and Yellowfin tuna. Since thiamine-destroying activity was found in both species, we analyzed approximately 30 additional species of fish found in Hawaiian waters (3). In this study we used the p-aminoacetophenone method for the analysis of thiamine. We found that a number of fish had antithiamine activity that was not destroyed by boiling the homogenate in addition to thermolabile (enzyme) activity. The highest enzymatic activity was in the Skip jack tuna liver. Goatfish had high thermo stable activity, while surgeonfish and marlin had little or no activity. Our interest has centered on the thermo stable activity. In another series of experi ments, we studied the effects of incubation temperature and pre-boiling of the Skipjack