90 



U. S. BUREAU OF FISHERIES 



These studies have indicated that effective cooking can be accom- 

 plished without detriment to vitamins in the oil, have established 

 the feasibility of screening and mechanically separating salmon press 

 liquors, and have demonstrated means of improving both oil recovery 

 and the vitamin potency of the oil. 



At the present time, attention is being given to a study of the 

 retention of vitamins A and D in the oil in salmon meal. If methods 

 can be developed whereby the fat in the meal can be prevented from 

 becoming rancid, and vitamin A and D values retained during storage, 

 it would be entirely possible to produce salmon meals which would 

 carry sufficient vitamin A and D unitage to preclude the necessity 

 of addmg any further supplement of these vitamins to the diet. 

 Meals of this type would be expected to carry a higher vitamin G 

 value also and would thus be of unusual value in poultry feeding. 

 All such work on fish meal also is valuable in rendering this product 

 more suitable for feeding fish reared in hatcheries. 



MANUFACTURE AND NUTRITIVE VALUE OF NONOILY FISH MEALS 



Previous issues of this publication have carried progress reports of 

 an extended investigation dealing with the manufacture of fish meal 

 from nonoily fish waste and the effect of manufacture on the com- 

 position and nutritive properties of these meals. During the past 

 year the assembled data were incorporated in report form and pub- 

 lished in the Investigational Report series of the Bureau. Since these 

 papers are now available to the public, interested persons are referred 

 to the following publications obtainable from the Government Print- 

 ing Office: Fisheries' Investigational Report No. 30, entitled "Effect 

 of Manufacture on the Quality of Nonoily Fish Meals"; Fisheries' 

 Investigational Report No. 31, entitled "Effect of Method of Man- 

 ufacture on the Composition of Haddock Fish-Meal Proteins"; and 

 Fisheries' Investigational Report No. 32, entitled "Studies on Drying 

 Cod and Haddock Waste." 



PREPARATION OF AUTHENTIC HALIBUT-LIVER OIL SAMPLES 



During the year, the Bureau was asked by the Food and Drug 

 Administration and the Bureau of Chemistry and Soils to prepare a 

 number of authentic hahbut-liver oil samples extracted from livers 

 of halibut taken in different localities at intervals throughout the 

 fishing season. The work was arranged and carried out through our 

 Seattle technological laboratory 



Eight liver samples were taken from an area bounded on the south 

 by Cape Shoalwater, on Willapa Harbor, and on the north by Cape 

 Spencer, in Southeastern Alaska, designated as area 2 by the Inter- 

 national Fisheries Commission. Ten samples were taken from area 

 3, the area between Cape Spencer and Cape Sagak in the Aleutian 

 Islands and two samples from the small area south of area 2. 



The livers from area 2 varied in fat content, as indicated by ether 

 extraction of samples of liver which had been desiccated under 

 reduced pressure, from 22 to 42 percent, the majority being around 

 30 percent. Samples were taken at intervals between July and 

 November, inclusive. The livers from area 3 varied in fat content 

 as determined above between 13 and 31 percent. Sampling extended 



