nad xower amouiiLs ol vitamins and protein than did the steam vacuiim- 

 dried chinook salmon vascera meai. The blue crab meal nad a higher 

 vitamin content, more protein and xat, and less ash than the Dungeness 

 crao meai. This dilference in the proximate composition between tne 

 two types oi crab meal is accounted lor by the iact, tnao the meat is 

 removed irom ohe Dxingeness crab legs, out not irom uriose ol tne oiue 

 crab. 



None of the mixed diets had as high a vitamin content as the beef 

 liver. Despite this. Burrows (1947 and l95l), Robinson (l95l A and B), 

 and their co-workers iound that several of these mixed diets resulted 

 in better growth and lower mortality of hatchery fish than did lOO 

 percent beef liver. This suggests that uninvestigated factors were 

 sigmiicant. 



Salmon viscera meals added to a meat-salmon viscera diet resulted 

 in a higner percentage of protein. This higher protein content may nave 

 been a partial explanation of the addioional growth response of tne 

 natchery fisn when the meat-salmon-visc era -meal combination was fed. How- 

 ever, crab meal also showed evidence of containing a growth factor and 

 did not increase the protein content of the mixed diets. This also seemed 

 to indicate that factors other than those studied may be important in the 

 nutrition of hatchery fish. 



Summary 



1. Animal livers, fish viscera, and other raw materials used in 

 hatchery-fish diets snowed variation in composition among different lots 

 of the same item. 



2. The composition of hog liver and of beei liver was essentially 

 the same. 



3. Tne livers and the digestive tracts of salmon had higher vitamin 

 contents tnan did the eggs or whole viscera; however, the eggs had the 

 nignest protem content. 



4* Yellowfin tuna livers had about the same vitamin content as beef 

 liver. 



5. Acetone-extracted salmon viscera meals held a much lower vitamin 

 content than the viscei-a meals prepared by other methods. 



6. The salmon viscera meals contained more protein and less fat than 

 the salmon offal meals. 



7. Blue crab meal had more vitamin, protein, and fat, but less ash 

 than the Dungeness crab meal. 



8. Comparison of analytical data with results of feeding tests indi- 

 cated that certain diets possessed growth factors other than those con- 

 sidered in this investigation. 



20 



