levels of meats appeared to be a practical ap- 

 proach in the development of an adequate, eco- 

 nomical diet for salmon fingerlings . 



The 1961 trials demonstrated the practic- 

 ability of the meal combination, the effect of two 

 protein levels on growth, the effect of energy 

 calorie supplementation on protein utilization, 

 and the fact that vitamin supplementation was 

 unnecessary under the conditions of the experi- 

 ment. 



PRELIMINARY INVESTIGATIONS 



Feeding trials were conducted at the 

 Entiat station during 1959 and 1960 (unpublishecO 

 in an attempt to develop partially reconstituted 

 dry meal diets that would be nutritionally ade- 

 quate for Chinook salmon . Several composite 

 meal formulations were fed at protein levels 

 varying from 15 to 27 percent of the wet weight. 

 The protein levels were controlled by the use of 

 water as a dilutent in the bound diets . 



In these experiments the diets were forti- 

 fied with vitamins either by including relatively 

 high levels of dried brewer's yeast or by feeding 

 a vitamin supplement. In one experiment the 

 vitamin supplement was fed at levels equal to, 

 double, and triple the level required for maximum 

 storage in trout as determined by Phillips (1946) 

 and McLaren etal. (1947). Neither brewer's 

 yeast nor the vitamin supplement proved capable 

 of preventing anemia in the meal combinations 

 fed. 



Although no satisfactory diet was developed 

 from these trials, the results indicated that pro- 

 tein levels below 20 percent in the meal combina- 

 tions fed were inadequate for Chinook salmon and 

 that the methods of vitamin fortification employed 

 were insufficient. Based on the results of these 

 experiments, the 1961 feeding trials were form- 

 ulated to include meat fortification to a meal 

 mixture in an attempt to obtain the normal growth 

 rates and conditions necessary to adequately 

 assess alterations in diet composition. 



METHODS AND TECHNIQUES 



The techniques, methods, and equipment 

 used in the 1961 experiments were identical to 



those described by Burrows et^ajL (1951; 1952) 

 with the following exceptions: 



1 . Fall Chinook fingerlings were utilized 

 as test animals instead of the summer race of 

 Chinook which had been used previously in feed- 

 ing trials conducted at Entiat. The fall chinook 

 adapted to changes in environment and diet more 

 readily than did the summer chinook and proved 

 to be a much more satisfactory test animal. 



2 . EXie to construction of additional facil- 

 ities during the experimental period the six-foot 

 circular rearing tanks were set up outside and 

 were supplied with Abernathy Creek water for 

 the first nine weeks of the experiment. An un- 

 determined amount of natural food both water- 

 borne and terrestrial was, therefore, available 

 to the fish . These conditions are in contrast 

 with those at Entiat where the tanks were inside 

 and supplied with spring water which was prac- 

 tically devoid of natural food. 



3 . The chemical composition of feeds was 

 used as the basis for diet formulation. Proxi- 

 mate chemical analyses of feeds and of fish were 

 conducted using official AOAC methods for deter- 

 mining moisture, protein, and ash. Fat was 

 analyzed by a modification of the chloroform - 

 methanol method as described by Folch et al. 

 (1951). Caloric levels were calculated on the 

 basis of available calories as developed by 

 Phillips and Br ockway (1959). 



4. Protein levels were controlled by the 

 addition of water to provide bulk in the diets. 

 This method of controlling protein intake, de- 

 veloped by Phillips and Brockway (1959), is 

 versatile in that the caloric level may be in- 

 creased by substituting fat or carbohydrate for 

 a portion of the water while still retaining the 

 desired protein level. The addition of water 

 allows preparation of mush -type diets which, 

 when adequately bound and ricer fed, are read- 

 ily consumed by chinook salmon. 



5. The experimental diets fed in the 1961 

 trials differed radically from those used in pre- 

 viously reported experiments in that they were 

 composed principally of dry meals supplemented 

 with meats. Meat supplementation varied from 

 10 percent to 50 percent of the meat -meal 



