in previous years. This discrepancy between years is probably explained 

 by a difference in the source of meals. 



The reason for the superior growth produced by the vacuum-dried 

 product probably was attributable to the method of preparation^ since 

 the tunnel-dried meal and the vacuum-dried meal were from the same 

 source and were dried at comparable temperatures as was mentioned in 

 the description of diet coitiponents. In view of the marked superiority 

 of this vacuumwdried meal, the commercial production of vacuum-dried 

 meals -would appear to be justified on the infest Coast. 



Comparison of Hake with Hog Spleen or Hog Liver 



Hake (Merluccius productus ), disintegrated whole and then frozen, 

 was tested as an inexpensive substitute for hog spleen in the stan- 

 dard meat-viscera mixture. In the two diets comprising the test^ the 

 variable was 20 per cent hog spleen in Diet 2 and 20 per cent hake in 

 Diet 3. The common base was 20 per cent beef liver, 20 per cent hog 

 liver^ 30 per cent salmon viscera, and 10 per cent 100° tunnel-dried 

 salmon viscera meal. 



The hake variant brought about significantly less mortality ana 

 a significantly greater mean lot weight during the first 12 weeks of 

 the experiment J but failed during the second 12 weeks of experiment 

 to maintain or increase this weight advantage significantly over the 

 hog spleen variant (Table 5). 



From this experiment it may be said that hake offers a fair sub- 

 stitute for hog spleen in the Leavenworth production diet. Care must 

 be used, however, in preparing and handling the diet, for hake does not 

 have the binding properties possessed by hog spleen. 



The other comparison, hake with hog liver, was made with Diet h 

 containing I4O per cent hake, liO per cent salmon viscera, and 20 per 

 cent crab meal and with Diet 5 containing 1^0 per cent hog liver, 1^0 

 per cent saLmon, and 20 per cent crab meal. Hake produced a sig- 

 nificantly smaller mean weight and a significantly greater mean mor- 

 tality (Table 1, Diets h and $)• 



Hog Liver-Salmon Viscera with Various Supplements 



During the 19hQ experiments a diet of hog liver UO per cent, salmon 

 viscera IiO per cent and salmon viscera meal 20 per cent, displayed a 

 very good growth ratej however, a serious anemia and resultant mortality 

 occurred. To combat this anemia, diets were compounded using the hog 

 liver-saLnon viscera base supplemented variously with crab meal, her- 

 ring stickwater, and beef liver (Table 1, Diets 5, 6, 7, 8, and 9) . 



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