The low vitamin content of the acetone extracted meals is du« 

 to the ronoval of the water soluble vitamins during the treatment 

 with acetone. Since the acetone extraction process is expensive, the 

 meal would have to tie better than the meals prepared by other methods 

 for the process to be ccnmercially feasible. However, when the meals 

 were compared, both in vitamin content and as to ccnponent of thS 

 hatchery diets, the acetone-extracted meals were of poorer quality^ 



The moisture determinations show that the air-dried meals, with 

 one exception, had a lower moistiore ccantent then the meals extracted 

 with acetone at room temperature. This is important fixam the stand- 

 point of preservation, since the amoiint of moisture is an importaait 

 factor in determining vrtietber or not mold growth will occur during the 

 storage of the meal. 



It has been reccenmended that a diet fed to hatchery fish have a 

 low fat content. The percentage of oil in the raw offal was 8.09 per- 

 cent as compared with U.5^ percent in the raw viscera samples. As a 

 result, the meals mside from the total offal contained more oil than the 

 meals made frcmi the viscera. 



A high protein content is said to be desirable in hatdiery diets. 

 The raw viscera samples have 20,0 and 18.05 percent protein as compar- 

 ed to 15.25 percent in the raw total offal. This differentiation 

 again appears in the meals where there is an average of 15 percent more 

 in the air-dried meals prepared from viscera than there is in those pre- 

 pared from the total offatl. 



There has been much controversy as to whether hog liver is as ef- 

 fective in a fish hatchery diet as beef liver. Both the proximate and 

 vitamin analyses of the hog liver and beef liver are similar. Beef liver 

 has been considered a better material to feed the fish. From the analy- 

 ses, it is indicated that, as some hatchery workers have suggested, this 

 nay be due to a difference in texture rather than to a superiority in 

 the constituents of the beef liver over the hog liver. Hog spleen, vdiich 

 is said to be of poor quality for the fish diets, had a lower vitamin 

 and protein content than beef and hog liver. 



Since beef liver is considered the standard for fish hatchery diets, 

 it is interesting to note the comparison of the analyses of the beef 

 liver and the salmon viscera. The proximate analyses of the two mater- 

 ials are all within the same range, although the water content of the 

 visce.'a is sli^tly hi^er and the protein content slightly lower than 

 that of the beef liver. However, there is not enou^ difference to feel 

 positive that the relationship would not change in different samples of 

 the two materials. The vitamin oontent of the beef liver is signifi- 

 cantly hi^er than that of the salmon viscera. Since the daily vitamin 

 requirement for salmon is not known, possibly the vitamin content of the 

 salmon viscera may still be hi^ enough to furnish sufficient thiamine, 

 riboflavin, and niacin for the salmon. The results of the feeding tests 

 will give an indication of the answer to this question. 



86 



