INTRODUCTION 



The 195o feeding trials with blueback salmon (Oncorhynchus nerka) were 

 conducted at the Leavenworth Laboratory to develop adequate diets for the 

 artificial propagation of salmon. In these experiments various combinations 

 of previously tested products and several untried foods were evaluated on the 

 basis of growth, survival, and the presence or absence of recognizable deficiency 

 symptoms . 



The 1950 trials consisted of two experiments: The first was largely an 

 evaluation of previously tested foods in production diets and was conducted 

 for a 2U-week period which was divided into 12 weeks when the water was 

 relatively cold (ii5*) followed by 12 weeks when much warmer (5U°). '^he sec- 

 ond, being more ejiploratory in nature, evaluated less thoroughly the foods 

 and diet combinations tested and was conducted for 12 weeks during a warm- 

 water period. 



The first experiment was designed to make the following appradsals: 



(1) a comparison of the growth and mortality resulting from the experimental 

 diets with the standard beef liver control; (2) an evaluation of the effect 

 of the deletion of spleen from the meat-viscera combination; (3) a comparison 

 of salmon eggs and salmon viscera in spveral combination diets ; (ii) a test 



of salmon milt and its effect on mortality and growth when used in combination 

 diets; and (5) a determination of the contribution of a salmonwaste meal and 

 crab meal to some of the foregoing diets. Trials were conducted also with 

 high-level salmon viscera diets to evaluate yeast and liver supplements as 

 well as diets with decreasing levels of salmon viscera and increasing levels 

 of beef liver and hog liver. 



■'■he following comparisons were made in the second experiment: (1) beef 

 liver and the meat-viscera-meal control diets with the experimental diets; 



(2) mackerel offal meal with salmon viscera meal; (3)four differently pre- 

 served lots of salmon eggs with fresh-frozen salmon eggs; (k) hake, whole 

 cod, and halibut sawdust with hog spleen in the meat-viscera-meal control; 

 (5) halibut sawdust with whole cod in single component studies; (6) comb- 

 ination diets utilizing salmon milt, salmon eggs, and salmon viscera meal 

 with comparable diets in the first experiment; (7) tuna liver with beef liver 

 in the meat-viscera-meal control; and (8) diets with and without APF (Animal 

 Protein Factor) concentrates. 



The conditions of experiment for the first and second groups of feeding 

 trials are comparable and sure presented as one section, but the results and 

 recommendations are developed separately because two distinct sets of trials 

 are invdlved. 



