31 



average loss being 6.7 grams per week. One rat died after 2 weeks on test while 



another developed polyneuritis in 



THIAMINE DEPLETION DIET: 

 A - NO SUPPLEMENT 

 8 • PLUS i OX RAW STARFISH 

 C - PLUS I OX COOKEO STARriSH 

 - PLUS STARFISH LIPOIDS 



FIGURE 2 - GROWTH CURVES FOR RATS RE- 

 CEIVING THIAMINE BASAL TEST DIET 

 ALONE AND ADMIXED WITH 10 PERCENT 

 STARFISH RAW AND AUTOCLAVED, ALSO 

 WITH LIPOIDS FROM STARFISH IN AMOUNT 

 EQUIVALENT TO 10 PERCENT OF STARFISH. 



3 weeks. The group fed the diet containing 

 cooked starfish had an average loss in weight 

 of 1.5 grams per week, two rats making small 

 gains while the other four lost from 3 to 19 

 grams. When fed the diet containing starfish 

 oil, 5 of 6 rat3 gained weight, averaging 7.1 

 grams per week. The growth curves for these 

 groups are shown in Figure 2. 



On the basis of this test, it was con- 

 cluded that starfish oil was in no part re- 

 sponsible for the poor growth which resulted 

 when raw starfish was fed. The destructive 

 principle was not as rapidly and completely 

 destroyed by autoclaving as had been expected, 

 on the basis of reports of heat lability of 

 thiaminase in other materials. This greater 

 heat stability was later confirmed when con- 

 siderable amounts of thiaminase were found in 

 ground dried starfish meal (Lee, 1948-B) . 



Relatively heat stable forms of thiaminase 

 have more recently been reported in Indian oil 

 seeds (Bhagvat and Devi, 1944) and in a fern, 

 Pteris aquilina (Weswig, et al, 1946). It 

 now seems probable that "thiaminase" is not a 

 single enzyme, but rather that there are a 

 number of thiamine-destructive principles dif- 

 fering in heat stability, properties on dialysis, 

 and presumably in chemical structure.. 



Another attempt at a quantitative determination of the thiaminase in starfish 

 was made with a fourth series of rats fed on the thiamine test diet plus 10 percent 

 ground raw starfish, and a group of thiamine supplements. From 10 to 100 micro- 

 grams of thiamine per 100 grams were fed in the diet containing starfish, with a 

 control group being fed the basal diet plus 25 micrograms of thiamine pe> 100 

 grams. A new lot of starfish had been obtained for this test to lessen the chance 

 of loss of thiaminase which may have occurred in handling or storage of the first 

 lot. The test indicated, however, that the new starfish sample contained less 

 thiaminase than the previous sample. The group fed the basal diet plus 10 percent 

 starfish of the fourth series showed a loss of weight of 2.4 grams per rat per 

 week, only 36 percent of the weight loss of the group in the preceding series 

 fed an identical diet exoept for the lot of starfish. 



The growth curves of this test series are shown in Figure 3. About the best 

 estimate of the amount of thiamine destroyed is 4 micrograms per gram of starfish. 

 The fact that the thiaminase content was lower than was expected led to a selection 

 of supplement levels with too great a spread for accurate evaluation in this low 

 range. The test was not repeated, however, as the procedure was not satisfactory 

 when raw starfish was fed, and results did not Justify use of further time and 

 additional rats for this purpose. 



