Diets 15 and l6 in Table 2 demonstrate that 12.5 per cent of beef liver 

 is not adequate for the prevention of anemia during a lk-week period 

 when fed in conjunction with a comparable amount of hog spleen and a 

 high level of canned salmon. An increase of the beef liver content 

 of the diet to 25 per cent provides adequate fortification. The in- 

 clusion of 15 per cent beef liver in the Cortland diet resulted in a 

 significant reduction in mortality at water temperatures below 50 degrees 

 F. when compared with the 50 per cent spleen combination (Table 5, 

 Diets h and 5). Such an effect is not apparent at temperatures above 

 50 degrees (Table h, Diets 2 and 3)» 



Canned Beef Liver 



Beef liver, preground and canned under 2$ pounds of vacuum, was 

 fed at the 100 per cent level in 19hh (Table 2, Diet lli) „ Contrary 

 to expectations these fish did not develop an anemia during the course 

 of the experiment. After 6 weeks of feeding, however, the fish showed 

 indications of an acute avitaminosis, orobably a thiamin dificiency 

 and the experiment was abandoned at the end of a 52-day period. 

 Whether beef liver, preserved in this manner, retains the anti-anemic 

 factor in sufficient quantity to support blueback salmon is proble- 

 matical, but in view of the indicated reduction in vitamin content, 

 it is deemed unlikely. 



Flukey Hog Liver 



Flukey hog liver, when fed as the sole diet component for a lU 

 week period, will maintain blueback salmon without anemia and with a 

 comparable growth rate to that of fish fed beef liver. Erythrocyte 

 counts taken of fish fed exclusively on either beef or hog liver 

 (Table 2, Diets 1 and 5) indicate no difference in red blood cell con- 

 tent between the two groups. Sample counts of four fish fed beef 

 liver gave an average count of 1, Vlb, 000 red cells per cubic mil- 

 liliter of blood while those fed hog liver averaged 1, lhO,000. In 

 view of the variation that exists between fish within a lot, these 

 cannot be considered significant differences. 



It is indicated, however, that hog liver apparently does not 

 contain as great an amount of the anti-anemic factor as does beef 

 liver. The results of feeding trials with diets in which 50 per 

 cent hog spleen was combined with either beef liver or hog liver 

 at the 50 per cent level (Table2, Diets 2 and h) form the basis for 

 this statement. At the end of Ik weeks, the hog liver-hog spleen fed 

 fish showed positive evidence of an acute anemia while the beef liver- 

 hog spleen fish had no such symptoms. 



12 



