12 U.S. BUREAU OF FISHERIES 



IMPROVED METHODS FOR MANUFACTURING FISH MEAL FROM NONOILY 

 FISH WASTE 



Tlie experimental work on improved methods for the manufacture 

 of fish meal from nonoily fish waste as outlined in the 1932 report was 

 completed during 1933. A comprehensive report of the investigation 

 is now in the process of preparation. Data obtained during the course 

 of the investigation indicate the following: 



1. The digestibility, vitamin value and general nutritive value of 

 the meal is affected by drying time, temperature of drying and method 

 of applying heat, while the essential amino acid, Cystine, is affected 

 more by temperature. 



2. Of the various factors affecting the general nutritive value of 

 fish meals which were investigated ; namely, digestibility of the protein, 

 biological value of the protein, essential amino acids and vitamin 

 potency, vitamin G appeared to have greatest influence on the feeding 

 results obtained with the fish meal. 



3. Vitamin G is found largely in the head portion of cod and had- 

 dock fillet waste. - 



4. Vitamin G is found in the water soluble proteins and is therefore 

 partially removed by wet processes for nonoily fish reduction generally 

 used. 



5. By satisfactory control of the temperature within a dryer, by 

 regulation of steam pressure and vacuum, the glue problem encount- 

 ered in the dry reduction of this type of material can be overcome. 



6. Operation made possible by the conditions of (5) above, permit 

 the preparation of a fish meal of greater general nutritive value with 

 greater final yield of finished product. 



DEVELOPMENT OF FISH FLOUR 



Owing to the fact that quite satisfactory use is now being made of 

 nonoily fish waste in the preparation of fish meal and the necessity to 

 curtail work on account of reduced appropriations, the fish flour 

 work was temporarily discontinued, for the purpose of undertaking 

 an investigation needing more immediate attention. 



HADDOCK-LIVER OIL 



The investigation concerning the physical, chemical, and biological 

 properties of haddock-liver oil which was discussed in the 1932 report, 

 was completed during the past year and a report of the results obtained 

 is being prepared for publication. As stated in the last report, con- 

 cern had been expressed as to the possibility of the properties of 

 haddock-liver oil dift'ering sufficiently from cod-liver oil to make an 

 oil prepared largely from haddock livers incapable of meeting the 

 existing United States Pharmacopoeia requirements for cod-liver oil, 

 with resjject to chemical and physical properties of the oil sprcified 

 by the United States Pharmacopoeia. 



The data obtained indicate that there is little likelihood of this 

 occurring in the case of crude oils, but if the United States Pharma- 

 copoeia requirements are held for winterized or cold-pressed oils, it is 

 entirely possible that an oil of this nature will exceed the up])er limit 

 for iodine number. This is especially true in the oils from livers of 

 haddocjc taken during the summer months and on Georges Bank. 



