spleen was replaced by beef lung to produce a diet with a similar bind. In 

 previous tests (Burrows et al. 1952), this substitution gave equally as good 

 growth as the standard dietj in the 1952 trials the substitution was a good 

 diet but did not compare as favorably with the spleen diet as previously. 

 The spleen used in 1952 was untrimmed, and its higher fat content may have 

 made a greater contribution to the weight gains of the fish than was made by 

 an identical diet in 195l in which the fat content of the spleen was less. 



Beef liver has been one of the more expensive meats in the past but its 

 use has been found necessary in most diets to prevent anemia. In these trials 

 certain combinations of meat and fish products were tested in an effort to 

 eliminate beef liver f rom t he diet. The beef liver, hog liver, beef lung, 

 and viscera combination (Diet 10) was used as the control. Herring (Clupea 

 pallasi) and arrow-toothed halibut ( Atheresthes stomias) were substituted for 

 beef liver in separate combinations (Diets 11 and 12) . These two fish pro- 

 ducts were tested previously (Burrows et al. 1952) in exploratory trials in 

 which these products were substituted for spleen in the standard meat-vis- 

 cera mixture and were found to produce good growth. At the end of 13 weeks 

 the herring diet (Diet 11) was discontinued because of heavy mortality caused 

 by a thiamine deficiency. The fish fed arrow-toothed halibut (Diet 12) made 

 gains comparable to those of fish fed a similar diet containing beef liver 

 (Diet 10), but were inferior to fish fed the standard ration (Diet 2) in 

 growth produced. 



Both arrow-toothed halibut and herring w ere tested as replacements in 

 another combination. Previous trials had indicated that a combination of 

 hog liver 25 percent, beef lung 25 percent, and salmon viscera 50 percent 

 (Diet 13) was comparable to the standard meat-viscera combination in growth 

 potential and nutritional adequacy. In the present tests the hog liver was 

 deleted and herring substituted in Diet Ik and arrow-toothed halibut substi- 

 tuted in a similar combination in Diet 15. In these trials the hog liver, 

 beef lung, viscera combination, again, was not comparable, in weight gains 

 of the fish, to standard meat-viscera mixture containing the hog spleen. 

 The herring combination (Diet lh) was discontinued at the end of 12 weeks 

 because of a high mortality attributed to a thiamine deficiency in the fish. 

 Diet 15 containing arrow-toothed halibut produced gains comparable to those 

 of hog liver combination (Diet 13) with no symptoms of a nutritional 

 deficiency. 



In the diets using herring and arrow-toothed halibut, it was not the 

 intent to use these products to supply the antianemic qualities and vitamin 

 content of the beef or hog liver deleted from these combinations s but rather 

 to determine whether compatible combinations could be found in which other 

 meat and viscera mixtures would supply the vitamin deficiencies which might 

 occur because of the inclusion of the fish products. The occurrence of a 

 thiamine deficiency in both the combinations in which herring was included 

 indicated that hog liver and beef lung or beef lung alone in combination with 

 salmon viscera supplied inadequate amounts of thiamine to overcome the thia- 

 minase reaction of the herring. The presence of thiaminase was indicated by 



