as a source of fish food for salmon and trout. The experimental work was 

 limited in scope because of a lack of material available for test during the 

 first season's operations. For this reason the work was confined to the test- 

 ting of three meals prepared from salmon products and two types of frozen 

 waste plus the necessary controls. 



Selection of Products for Evaluation 



The cost of transportation is a major item in the economical utili- 

 zation of Alaskan cannery waste products. Since no artificial propaga- 

 tion of either salmon or trout is practiced on a large scale in the 

 Territory at the present time these products must be processed in some 

 manner to prevent spoilage during shipment if they are to be available for 

 use where needed. Meals, which reduce the weight by about 80 percent 

 and require no refrigeration, offer a practical answer to the problem of 

 the cost of transportation. However, previous experimentation has proved 

 that fish meals dried at the high temperatures encountered in the usual 

 commercial fish meal plants are not a complete ration for the feeding of 

 salmon or trout. 



To further explore the possibilities of salmon meals and to determine 

 if an alteration in the technique of preparation might preserve the anti- 

 anemia factors, two meals were prepared in the Seattle Laboratory of the 

 Division of Commercial Fisheries. Both meals were derived from salmon viscera 

 secured from the Columbia River canneries. Salmon viscera, including 

 the eggs and testes of the fish, was selected because previous work had 

 indicated that this product in the raw fresh, or frozen form was nutrition- 

 ally adequate for salmon fingerling when fed for an 18~week period. There- 

 fore it obviously contained the anti-anemia factors in the raw state. If 

 the meals prepared from this material would not support salmon fingerling 

 when fed as the single diet component, the loss of these factors could be 

 attributed to the methods of preparation. 



The first meal, wi-j.ch has been designated as low-temperatu re-dried 

 salmon viscera meal, was prepared by the tunnel drying process in which 

 warm air, at a temperature of from H0° to 150o F., was circulated over 

 thin layers of ground, pre-cooked viscera. This is a standard proced\ire^ 

 and meals prepared in this manner are known to be deficient in anti-anemia 

 factors. This meal would serve as a control in survival tests. 



The second meal, designated as acetone- extracted salmon viscera meal, 

 was prepared by the use of acetone to extract the oil and water from the 

 viscera. The anti-anemia factors have been denonstrated to be heat labile 

 and, as the acetone extraction was made at room temperature, it was possible 

 that tnese factors might be retained if they were not contained in the water 

 soluble or oil fractions of the salmon viscera. 



These two meals plus a beef liver control formed the first phase of 

 the experimental program. The purpose of this phase was merely to measure 

 the presence of these factors as indicated by the survival of the stock 

 with an absence of anemia. 



Th 

 the raws 



e growth potential of cannery waste products, either processed or in 

 's tate, presented another problem for evaluation. Rations whicn 



51 



