WATER-SOLUBLE VITAMIN REQUIREMENTS 

 OF SILVER SALMON 



Good fish husbandry requires the use of 

 diets which provide the nutrients essential for 

 normal growth of the fish. A lot of "practical" 

 information has been accumulated by fish cultur- 

 ists on food for silver salmon (Oncorhynchus 

 kisutch ), but there is little published data on 

 specific nutritional requirements for this species. 

 Nutritional investigations with other fish, rain- 

 bow trout (Salmo gairdneri) , chinook salmon (O. 

 tshawytscha) and sunfishes ( Lepomis) , have 

 yielded more concrete data on qualitative and 

 quantitative needs for growth and metabolism . 

 Vitamin requirements (Phillips et al . 1945, 1947, 

 1949, 1950; McLaren etal . 1947; Wolf 1951; 

 Halver 1957a), general protein requirements 

 (Tunison et al . 1942, 1943; Gerking 1952; De 

 Long, Halver and Mertz 1957) and amino acid 

 requirements (Halver 1957b; Halver, DeLong 

 and Mertz 1957, 1958) have been described 

 which can serve as a basis for formulating test 

 diets and experimental rations for determining 

 the basic nutritional requirements of silver sal- 

 mon. If the general requirements for all 

 nutrients is in the same general range as that 

 found for trout and chinook salmon, and if the 

 same experimental techniques can be applied to 

 studies with silver salmon, then it should be 

 possible to use existing test diets to develop 

 specific nutritional deficiency syndromes in sil- 

 ver salmon and determine the spectrum of the 

 water-soluble vitamin requirements for this 

 species . 



As a preliminary logical step, silver 

 salmon were tested with the same vitamin -test 

 diet used for qualitative vitamin requirement 

 studies with chinook salmon (Halver 1957a) and 

 which also maintained rainbow trout for at least 

 one reproductive cycle (Halver and Coates 1957). 

 Since silver salmon fingerlings grew when fed 

 this diet as sole ration, it was then possible to 

 delete one vitamin at a time from the complete 

 vitamin mixture in the diet, to feed these specif- 

 ic water-soluble vitamin deficient diets to 

 various individual lots of fingerlings, to describe 

 the specific vitamin-deficiency syndromes as 

 they occurred in each respective lot of fish, and 

 to determine which water-soluble vitamins were 



required for growth and fresh water survival of 

 silver salmon. 



EXPERIMENTAL 



The complete vitamin-test diet was 

 formulated from the materials listed in table 1. 

 The procedure used was the same as that de- 

 scribed in detail for the preparation of diets 

 used previously to induce vitamin deficiency 

 syndromes in chinook salmon (Halver 1957a). 

 Prior to mixing the diet, the crystalline vitamin 

 supplement, the amino acid supplement and the 

 alpha -cellulose flour were mixed for two hours 

 in a ball mill and then stored at 5° to 10° C, 

 until used. To ensure more accurate and re- 

 producible weights, sufficient alpha -cellulose 

 flour, amino acids, and vitamins for at least 4 kg 

 of diet were mixed at one time. The mineral 

 mixture was also ground for two hours in a ball 

 mill and stored in the cold in a tight container 

 until needed. 



To prepare 400 gm of mixed diet contain- 

 ing 25 percent solids and 75 percent water, 15 gm 

 of purified gelatin were added to 300 ml of water 

 and heated on a hot plate until the temperature 

 rose to 60° to 70° G. After the gelatin had lique- 

 fied, the container was removed from the hot 

 plate, placed in a mechanical mixer and stirred 

 at medium speed with a dough hook until the tem- 

 perature dropped to 40° to 50° C. Then 54 gm 

 vitamin test casein, 7 gm purified corn oil, 8 gin 

 white dextrin and 4 gm mineral mixture were 

 added and thoroughly blended. Finally, the cod 

 liver oil and the alpha -cellulose flour containing 

 the vitamin mixture and the amino acid supplement 

 were added and stirred until a homogeneous mass 

 was obtained (30° to 35° C.). For convenience in 

 feeding, the mixture was poured into ice cube con- 

 tainers, hardened in a refrigerator at 10° C., and 

 stored in screw-top glass jars at 5° to 10° C. 

 until used. 



Approximately 7,000 silver salmon from 

 the 1956 brood were fed two weeks on a complete 

 vitamin test diet containing one-fourth the normal 

 amount of vitamin mix at the Washington State 



