problem were the leaching of dietary components from the artificial diet when 

 it became water soaked, or perhaps an inadequate lipid composition (soybean 

 oil). In reference to the latter point, the fatty acid composition of the artificial 

 diet is shown in Table 1 5-7 along with the spectrum for soybean oil and that of 

 silversides cultured on the salmon type diet. The soybean oil diet and the oil 

 resemble each other to some degree, since 16:0, 18:1cj9, and 18:2co6are the 

 major fatty acids of both analyses. Likewise, silversides fed this artificial diet 

 closely resemble the lipid make-up of the diet they were fed. However, it is 

 evident that fish fed the artificial diet were not similar in fatty acid 

 composition to the wild fish, and thus this diet had not accomplished the 

 major goal of providing a laboratory cultured fish of similar biochemical 

 composition to the wild fish (Table 1 5-5). 



Based on the biochemical analyses of the diets and cultured fish, and the 

 results of poor growth and survival, the salmon diet was modified by the 

 addition of a marine oil (cod liver oil). The soybean oil based diet was again fed 

 to verify past results. In addition to these two diets, the live brine shrimp diet 

 was used along with: a freeze-dried form of brine shrimp, a wild plankton diet, 

 Tetra Marin— a commercial aquarium food, and two semi-purified diets with 

 various amino acid compositions (Table 1 5-3). The cultured fish were again 

 analyzed for protein and lipid composition. 



The growth and survival results of fish fed these experimental diets are 

 presented in Table 1 5-8. The live brine shrimp diet gave the best survival (97 



Table 15-7. The Major Fatty Acids of Soybean Oil, 



an Artificial Diet (#7) with a Soybean Oil Base, 



and Silversides Cultured on the Diet 



224 



