29 



THIAMINASE IN STARFISH 



The presence of thiaminase in starfish was first detected in the course of 

 a bio-assay intended to determine the thiamine content of raw starfish (Lee, 1948-B) . 

 Rats had been maintained on a thiamine test diet (U. S. Pharmacopoeia XI ) for 

 a depletion period of 28 days. After this period, rats were assigned to test 

 groups if their weight was less than 100 grams for females, 105 grams for males 

 even though they were still gaining in weight. This unorthodox procedure was 

 necessary in order to assemble a test group within a reasonable time, as the avail- 

 able strain of the rats were quite resistant to thiamine depletion. 



Groups of six rats were used on each test level, the animals being evenly 

 distributed as to sex, with no more than one rat from any litter in a group. Rats 

 were housed in individual cages in a room with temperature maintained at 80° ± 2° F. 

 The assay period was four weeks, with liveweight and food consumption records 

 taken weekly. 



The first series was composed of ten groups. All rats received the basal 

 thiamine test diet . Three groups received as supplement £ , 1 , and li grams of 

 raw starfish per day, 3 groups were given 20, 50, and 80 micrograms of thiamine 

 per 100 grams of diet, and 3 groups received \, 1, and l£ grams of raw oysters 

 as a supplement. 



The control rats all continued to gain weight during the test period, averag- 

 ing 8.1 grams per week. The groups receiving thiamine made much larger gains. 

 Groups receiving 20, 50, and 80 micrograms gained 14.1, 20.8, and 24.0 grams per 

 rat per week, respectively. All rats fed oysters also gained more than the con- 

 trols . 



The rats fed raw starfish, however, did very poorly. Of those receiving £ 

 gram per day, 1 rat gained in weight, 4 rats lost 8 to 27 grams from their start- 

 ing weight, although they lived for the 4-week period. One rat was killed on the 

 23rd day after a loss in weight of 27 grams. When one gram of starfish was fed 

 per day, one rat again gained weight, one lost 39 grams before death on the 20th 

 day of test, and 4 others lost 11 to 29 grams during the 4 weeks. One of these 

 latter rats developed severe polyneuritis, but the symptoms were alleviated and 

 there was a slow gain in weight for 2 weeks after it was given 10 micrograms of 

 thiamine in a single dose. When l£ grams of starfish was fed daily, the final 

 liveweights were 20 to 34 grams below the starting weights and 4 of the 6 rats 

 developed symptoms of acute polyneuritis. The growth curves for these groups 

 are shown in Figure 1. 



In view of the evidence that these rats were suffering from an acute thiamine 

 deficiency, 12 of the rats which had been losing weight were selected from the 

 groups fed starfish and were divided into 2 sub-groups. These were fed the basal 

 diet plus 150 micrograms of thiamine per 100 grams of diet with 1 group getting, 

 in addition, 1 gram per day of raw starfish. In 2 weeks, the former sub-group 

 made an average gain of 66.6 grams, while those getting both thiamine and star- 

 fish gained 58 grams. 



In the meantime, to determine the possible presence of directly toxic agents 

 in the starfish, 2 groups of 11 rats each were fed the regular stock diet, with 1 

 group getting a daily supplement of 1 gram of raw starfish per rat per day. Over 

 a 3-week period, the controls averaged 23.7 grams per week, and the starfish group, 

 22.4 grams per week, an insignificant difference. 



