salmon viscera meal was found to be superior. Differences in the 

 degree of maturity of the fish from the two sources may have altered 

 the percentage composition of the visceral portions and invalidated 

 the conclusion drawn from this experiment due to the introduction 

 of an additional variable. 



ill. In the tunnel process of dehydration, 100-degree drying tem- 

 peratures produced a salmon viscera meal superior to one dried at 

 lh5 degrees. 



l5o Salmon viscera meal, dehydrated by an acetone-extraction pro- 

 cess at room temperatures produced a growth response comparable to 

 that of tunnel drying at lUS degrees. Acetone extraction reduced the 

 vitamin content of the meal particularly in certain vitamins of the 

 B-complex. Because of the vitamin reduction, this process is con- 

 sidered infeiior to tunnel drying. 



16 9 Salmon waste meals made no measurable contribution to the 

 growth and caused an increase in mortality when fed at the 10 per 

 cent level in the diet at water temperatures approximating US degrees. 

 At temperatures of 5>0 degrees or above the deleterious effects noted 

 at colder temperatures were absent and a si. d. 'leant growth response 

 was noted 



Potential Production Diets 



170 Three diets, tested and found applicable to the production hatchery 

 have been developed from these feeding trials. A starting diet, con- 

 sisting of 50 per cent, each of beef liver and hog liver proved su- 

 perior to any all-meal diet tested. It was particularly adapted to 



a starting diet because of the variations in consistency which could 

 be attained. A cold water diet, fed at water temperatures approximating 

 li5 degrees and consisting of 22.2 per cent, each, of beef liver, hog 

 liver, and hog spleen and 33.il per cent of salmon viscera, was superior 

 to any other diet at these water temperatures when both growth and 

 survival were considered. The addition of salmon waste meals, at the 

 10 per cent level, to the meal and viscera mixture resulted in a sig- 

 nificant contribution to the growth of the fish without an increase 

 in mortality when fed at water temperatures above $0 degrees. At 

 warm water temperatures this diet equaled or excelled any other diet 

 tested as a ration for blueback salmon. 



18. A hog liver-salmon viscera combination may serve as a substitute 

 for beef liver during periods of high food intake. 



19. The Cortland No. 6 meal mixture, fed at the 50 per cent level in 

 combination with either 50 per cent hog spleen or 15 per cent beef 

 liver and 35 per cent hog spleen, was found to produce gains comparable 

 to the meat-viscera-meal combination when fed at water temperatures 



36 



