Occurrence of Thiaminase in Some Common Aquatic Animals 

 of the United States and Canada 



By 



R. A. GREIG 



National Marine Fisheries Service 

 Technological Laboratory, Ann Arbor, Michigan 48107 



and 



R. H. GNAEDINGER 



Pet Food Nutritional Research, Ralston-Purina Company, 

 Checkerboard Square, St. Louis, Missouri 63199 



ABSTRACT 



Two tables are presented that survey the presence or absence of thiaminase in 

 freshwater and marine fish and shellfish. 



INTRODUCTION 



The presence of thiaminase in fish that are 

 routinely used raw in rations for animals can 

 cause a dietary deficiency. The disease in mink 

 is commonly called Chastek paralysis (Green, 

 Evans, and Carlson, 1937). Knowledge about 

 the presence or absence of thiaminase in aquatic 

 animals is therefore important to mink ranch- 

 ers and other animal feeders, scientific re- 

 searchers, commercial fish vendors, and others. 



Thiaminase is an enzyme that destroys 

 thiamine (vitamin Bi) and, like many enzymes, 

 its activity is greatly reduced or destroyed up- 

 on heating to moderate temperatures (50°- 

 100° C). Thus, mink ranchers, for example, 

 can cook the fish before feeding it to the animals 

 to avoid a Chastek paralysis problem (Lee, 

 1948; Gnaedinger and Krzeczkowski, 1966). 

 However, mink ranchers generally prefer to 

 avoid cooking the fish because mink show a 

 preference for raw fish and cooking adds to 

 the operational costs. Knowledge whether fish 

 do or do not contain thiaminase is therefore 



vitally important to animal feeders, particu- 

 larly mink ranchers, for safety and economic 

 reasons. 



Also, scientific researchers at times need to 

 consider whether or not an aquatic animal 

 involved in their research contains thiaminase. 

 For example, in biological research where 

 fishes are held in aquaria for feeding studies 

 or other research, the presence of thiaminase 

 in the animals being fed to the fish could pos- 

 sibly cause a vitamin deficiency or other prob- 

 lems that could impede the research (Wolf, 

 1942). 



Many species of aquatic organisms have been 

 assayed for thiaminase activity in various lab- 

 oratories throughout the world. Most of these 

 assays, however, were made in conjunction 

 with specific research programs that were de- 

 signed to study a particular species native to 

 the area of the research laboratory. As a re- 

 sult, the data on the occurrence of thiaminase 

 in aquatic specimens is scattered throughout 

 various research papers published over the 

 years. 



