Se'-ond, they were tested as a substitute for salmon viscera in the meat-viscera- 

 meal combination. For examplej Jicts 20 through 2ii contained 10 percent of 

 vacuum-dried salrrxsn viscera meal ap :.n absorbing agent and 90 percent of the 

 various kinds of salmon eggs, and Diets 2$ through 29 contained, in addition 

 to 30 percent of preserved e^gs and 10 percent salmon meal, 20 percent each 

 of beef liver, hog liver, and hog spleen. The type of eggc in each diet was 

 as follows; fresh-frozen eg^s in Diets 19 and 25, eggs preserved with 2.0 per- 

 cent sodium benzoate and 2.0 percent salt in Diets 21 and 26, eggs preserved 

 with 1.0 percent sodium benzoate, 0,1 percent sodum bisulphite, and 2.0 per- 

 cent salt in Diets 22 and 27, eggs preserved with 0.5 percent sodium bisulphite 

 in Diets 23 and 28., and finally, eggs preserved '.vdth 0.2 percent sodium 

 bisulphite and 2.0 percent salt in Diets 2\x and 29. 



It should be mentioned that of the preserved egsS tested, those con- 

 taining Oo5 percent sodiam bisulphite were the least apt to leach when fed, 

 and approached the fresh-frozen eggs in feeding consistency. Excessive leach- 

 ing of essential nutrients may have been an important factor affecting the 

 high-level evaluations. 



The final mean weights of the high-lffvel tests of salmon egj-^s showed 

 that fresh-frozen salmon eggs. Diet 20, produced significantly greater mean 

 lot weights than the preserved eggs (Table 2, ^iets 20, 21, 22, 23, -nd 2li). 

 Of the preserved eggs, those preserved with 0.5 percent of sodium bisulphite 

 made significantly greater gains in weight than the other diets (Table 2, Diets 

 21, 22, 23, and 2U) o The final mean weights of the low-level tests or those 

 in which salmon eggs were substituted for sal ran viscera in the meat-viscera- 

 meal combination showed that there were no differences between the v^eights 

 produced by the control or the preserved eggs except those preserved xd.th 2.0 

 percent sodium benzoate and 2 percent salt. Diet 26 (Table 2, Diets 25, 26, 

 27, 28, and 29). Oiet 26 produced gains that were inferior to the others at 

 the five percent confidence level. It should be mentioned also that a few 

 fish in each of the lots being fed preserved eggs at the 90 percent level 

 demonstrated the nervousness, loss of equilibrium and the retracted head which 

 are associated with a thiamin deficiency, ^^o such sjTnptoms were observed 

 when eggs were fed at the 30 percent level. 



It was evident from these differences that in the r,ieat-egg-meal comb- 

 ination preserved eggs and fresh-frozen eggs made comparable gains in most in- 

 stances. From these differences, moreover, it may be concluded that 0.5 per- 

 cent sodium bisulphite was one of the most satisfactory preservatives in the 

 loW"level egg test and the most satisfactory in the high-level test, with 

 this in mind and also the fact that the eg^s preserved vdth 0.5 percent sodium 

 bisulphite were the least apt to leach, sodium bisulphite appeared to be the 

 best preservative of the group. Further tests on the effect of incubation 

 before freezing are necessary, however, before practical use may be made of 

 this information. 



Hake 



Hake (Merluccuis productus) is an abundant and inexpensive source of 



15 



