INTRODUCTION 



The 1951 feeding trials at the Entiat Salmon-Cultural Laboratory- 

 were a continuation of the feeding experiments reported by Burrovfs 

 et al. (1951), Robinson et al. (195la) and Robinson _et al, (195lb). In 

 the present evaluations both blueback salmon ( Oncorhynchus nerka) and 

 Chinook salmon (0= tshavjytscha ) were used as the test animals. The 

 primary purpose of these and the previous trials was the development of 

 adequate diets for the artificial propagation of salmon from food pro- 

 ducts either unfit or undesirable for human comsumptiono All products 

 tested were commercially available or could be made available in suffi- 

 cient quantity to provide an adequate source of fish food. 



Three separate but related experiments were conducted. The first 

 consisted of a 12-week cold-water phase and a 12-vfeek warm-water phase. 

 In the latter only a portion of the diets fed in the first phase were 

 carried through for the 2l4-week period. The second experiment was 

 composed of diets fed for a 12-week warm-water period and was more 

 exploratory in nature. In both the first and second experiments blue- 

 back salmon were the test animals. The third experiment was of 2U weeks' 

 duration during both the cold- and warm-water periods. For the first 

 time in these diet studies chinook salmon were used as the test animals. 



Results of the 19^1 trials provided evaluations of beef lung, whale 

 liver, arrow -toothed halibut flesh, and herring flesh, both as single 

 rations and in combination with other products, as diet components for 

 salmon. Additional information was secured on the value of preserved 

 salmon eggs and tuna liver in composite diets. Toxicities probably due 

 to hypervitaminosis A developed in certain diets, and the symptoms were 

 noted. It was demonstrated that the mortalities which occur from feed- 

 ing meals at cold water temperatures were probably not due to the 

 unavailability of the protein or certain amino acids, but possibly to a 

 vitamin deficiency. No differences could be demonstrated between the 

 nutritional requirements of chinook and blueback. Three potential 

 production diets were developed. These diets contained no beef liver 

 yet produced growth rates equal to or better than the standard control 

 diet containing beef liver, with no evidence of nutritional inadequacy. 



To evaluate results, control diets were established in each experi- 

 ment. Within groups of each experiment, changes in the diets were made 

 either by substitution or by supplementation. In the first procedure, 

 a single product was withdrawn in part or in its entirety and another 

 product was substituted. In the second, a combination of products was 

 supplemented by the addition of another material and the entire previous 

 combination reduced a proportionate amount. In the presentation, com- 

 parisons were made only between diets within an experiment. Each 

 experiment has been presented separately and comparisons made between 

 experiments by deduction based on the relative standings of comparable 

 diets with reference to their individual controls. 



