FISHERY INDUSTRIES OF THE UNITED STATES, 1935 93 



staff. These research associates are: George E. Tarrant, chemist, 

 and Harokl E. Crowther, Joseph F. Puncochar, bacteriologists. 

 Chemical data are being obtained to determine the effectiveness of 

 the chemicals being studied and their chemical reactions on the pro- 

 tein and other ingredients of the fish waste and bacteriological studies 

 are being undertaken to determine the effectiveness of these chemicals 

 and in preventing or retarding bacterial spoilage. 



Among the chemicals which have been studied thus far are formal- 

 dehyde and acetaldehyde. This work has not progressed to a point 

 yet where any definite results can be reported. The effect of chemical 

 preservation on the feeding value of fishery byproducts is being tested 

 with farm animals at the Virginia State Agricultural Experiment 

 Station, Blacksburg, Va., and with experimental animals in our 

 nutrition laboratory at College Park, Md. 



NUTRITIVE VALUE OF AQUATIC PRODUCTS 



Since a large part of our technological investigations is devoted to 

 food research, studies of the various nutrition or food factors in aqua- 

 tic products are an essential and important part of our investigative 

 program. In fact this phase of our program must be closely coordin- 

 ated with other technological investigations as the relative nutritive 

 value of experimentally prepared and preserved fishery products is the 

 only true yardstick or standard of measurement for evaluating im- 

 provements in methods of manufacture, preservation, handling, and 

 storage of such products. 



During 1935 our nutrition investigations were carried on in our 

 College Park laboratory, in the laboratories of the State Medical 

 College, Charleston, S. C, and in the laboratories of the Massachu- 

 setts State College, by Charles F. Lee, E. J. Coulson, and Dr. Francis 

 P. Griffiths, of the technological staff, and by student assistants. 



FISH-LIVER OILS 



Most of the work in our nutrition laboratory at College Park, Md., 

 consisted of studies of the content of vitamins A and D in experi- 

 mentally prepared fish-liver oils forwarded from other technological 

 laboratories of the Bureau. These liver oils consisted of halibut, 

 swordfish, haddock, and salmon. Several series of samples of oils 

 from cooked and uncooked swordfish livers were examined to deter- 

 mine the effect of dift'erent solvents, used in extracting the oils from 

 the livers, on the vitamin potency of the extracted oils. It was found 

 that such solvents as petroleum ether, ethyl ether, and ethylene 

 dichloride, produced the best oils. 



The tests cf the effect of these solvents on the vitamin potency of 

 extracted oil proved to be very accurate because in three cases where 

 livers were extracted several times with the same solvent, the oils 

 derived from each fraction were identical in vitamin content. 



Twenty-three samples of salmon oils prepared by our temporar}^ 

 technological laboratory in Alaska during the summer of 1934 were 

 studied for their content of vitamins A and D. Tests also were made 

 on 13 salmon oils, being used at the same time in poultry feeding 

 tests in Washington State College in a cooperative project with this 

 Bureau. These salmon oils varied over a wide range in vitamin 

 potency from 120 to about 900 international vitamin A units per 



