Air-Ljft Dried Mackerel Offal Meal 



The test of air-lift dried mackerel offal meal was made to evaluate 

 this comparatively nevr product as a possible high-protein supplement during 

 warm- water periods. The raw material used in the manufacture of this meal was 

 the offal of the Pacific mackerel ( Pneumatophorus diego ) . The meal from this 

 offal was prepared by the usual wet-reduction method except that the wet press- 

 cake was dried by an air-lift process instead of by the more commonly used driers. 



The control diet was Diet i|6 with 20 percent each of beef liver, hog 

 liver, and hog spleen, 30 percent salmon viscera, and 10 percent of vacuum- 

 dried salmon ^n.scera meal. The diet testing the mackerel meal was Diet hS 

 with the same meat-viscera base as Diet U6 but with 10 percent of air-lift 

 mackerel offal meal instead of vacuuiji-dried salmon viscera meal. 



The final mean weights showed that the air-lift dried mackerel offal 

 meal contributed significantly less growth than did the vacuum-dried salmon 

 viscera meal (Table 2, Diets h5 and Ii6) . 



This difference does not necessarily mean that air-lift dried 

 mackerel offal meal was an inferior meal to other commercially available meals. 

 It should be mentioned that vacuum-dried salmon viscera meal, although producing 

 far more grovrbh than the other meals tested, is not commercially available as 

 yet, and on the basis of the 19^9 feeding trials in which vacuum-dried salmon 

 viscera meal was tested against the commercially available flame-dried salmon 

 offal meal, it may be inferred that the performance of air-lift mackerel offal 

 meal would be similar to that of flame-dried salmon offal meal. 



Preserved Salmon Eggs 



This series of experiments with preserved- frozen salmon ;ggs was a 

 continuation of previous research designed to exploit the supply of salmon 

 eggs now going to waste in Alaskao The use of preserved-frozen eggs rather 

 than fresh-frozen eggs was necessary since only limited freezing facilities were 

 abailable at Alaskan canneries. The four preservatives at the concentrations 

 tested in this experiment were sufficient to keeo the eggs for three or four 

 months or until the eggs could be shipped to the United Statf^s and further pre- 

 served by freezing. 



The pink salmon eggs selected for the test were held for 9 months in 

 cold storage, thawed, preserved by simply sprinkling the chemicals over each 

 layer of eggs, and then frozen again after several days. Because the preserved 

 eggs were not allowed to incubate for three or four months without refrigeration, 

 this evaluation is, necessarily, only a test of eggs to which oreservabives 

 have been added and not a test of the effect of incubation on the nutritive 

 value of the preserved eggs. 



Each type of preserved eggs was evaluated in tvo ;jays. First, they 

 were tested in a combination of 90 percent preserved eggs and 10 percent of 

 vacuum-dried salmon viscera meal. This trial constituted a rather severe test 

 and should have revealed any toxic effects which the preservatives may have had. 



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