supported as much growth as hog spleen and significantly more growth than 

 either whole cod or hakej (Table 2, ^iets Uii> li3, Ii2j and 35) « 



Based on the results of this experiment, halibut sawdust may be 

 recommended as one of the best inexpensive substitutes for hog spleen in t he 

 meat-vise era-meal combination when used during the warm-water period. The use 

 of halibut sawdust during a cold-water period should be deferred until such 

 evaluations have been madeo 



Tuna Liver as a Substitute for Beef i>iver 



Tuna liver was previously tested as a single component diet in the 

 I9U9 trials = The growth produced by tuna liver was very slight, yet, through- 

 out the experimental period^ the gills retained a healthy, dark red color. 

 Since tuna liver displayed anti-anemic properties, it was tested in the present 

 experiment as a substitute for beef liver in the meat-viscera-meal combination. 



The components of the tuna liver variant. Diet UO, were 20 percent 

 each of tuna liver, hog liver, and hog spleen, 30 percent of salmon viscera, 

 and 10 percent of vacuum- dried salmon viscera meal« The tuna liver was obtained 

 from the yellowfin tuna ( Neothunnus macropterus ) . 



A comparison of the tuna liver variant and the beef liver variant 

 disclosed no significant difference in mean lot weights (Table 2, ^iets UO and 

 U6) , Also it can be seen that the blood count and hemoglobin level of the tuna 

 liver variant were satisfactoryo 



Tuna liver in this particular combination had a satisfactory growth 

 potential quite different from its growth potential as a single component diet. 

 Tuna liver, moreover, had enough anti-anemic properties to be a meal combination. 

 Since tuna liver is in abundant supply at a cost lower than beef liver, the 

 possibilities of its use in salmon culture, during the warm-water period, should 

 not be overlooked. 



Animal Protein Factor (APF ) 



Because of the popularity and interest in the animal protein factor 

 (APF), this laboratory tested the effect of certain APF concentrates on anemia 

 and growth. 



Two different APF concentrates were selected for test. The first 

 was a Merck product containing 12.5 tnilligrams of vitamin Bn2 per pound. 

 This concentrate was added at the rate of .73 grams per 100 grams of ration 

 to Diet 31 which contained 50 percent salmon viscera, iiQ percent hake, and 

 10 percent vacuum-dried salmon viscera meal. Diet 30, identical to Diet 31 

 except for the deletion of the APF supplement, served as the control. The 

 second APF concentrate was largely a protein substrate used by Lederle for 

 the production of aureomycin and contained unknown amounts of vitamin B-^p 

 and aureomycin. This second concentrate was added at the rate of .73 grams 

 per 100 grams of ration to Diet 33 which contained 25 percent beef liver, 25 

 percent hog liver, 1^5 percent canned salmon, and 5 percent vacuum-dried salmon 



18 



