determined gravimetrically. The lipid material was saponified with 10 ml 0.5 N 
potassium hydroxide-methanol. 
Fatty acids were methylated with 14 percent boron trifluoride-methanol 
(28). Fatty acid methyl esters (FAME) were injected into a single column 
Varian Aerograph 1200 gas-liquid chromatography unit operated isothermally 
at 180°C and equipped with a flame ionization detector. FAME were separated 
on a 15 percent diethylene glycol succinate (DEGS) column, on 100-120 mesh 
Chromosorb W-HP, 2.1 m long x 3.2 mm O.D., supplied with 75 ml/min flow 
of nitrogen as the carrier gas and a three percent ethylene glycol succinate 
polyester-Z (EGSP-Z) column (same dimensions as DEGS) on 100-120 mesh 
Gas Chromosorb Q support with 40 ml/min nitrogen. Indentification and 
quantification of the FAME were made with an electronic integrator (Hewlett 
Packard 3380A) supplied with the relative retention times of authentic 
standards and literature values for published oils (2). Cod liver oil was used as a 
secondary standard (3) and heptadecanoic acid (17:0) was used as an internal 
standard (16). Unresolved chromatogram peaks were detected by comparing 
the profiles of the two individual column separations. 
RESULTS AND DISCUSSION 
Artemia Diet—Batch Culture 
The total protein levels and amino acid profiles are given in Table 15-4 for 
the wild silversides, their eggs, and laboratory cultured fish of various ages. The 
cultured fish had been fed the live 3-day-old brine shrimp diet. The amino acid 
spectrum of the silversides was very similar to the spectrum of migrating 
Atlantic salmon (23). 
The brine shrimp analysis was similar to the results of Gallagher and Brown 
(18) who also analyzed San Francisco Bay brine shrimp. These authors stated 
that methionine in the brine shrimp may be limiting compared to standard egg 
albumin levels. However, our results showed that the methionine levels in brine 
shrimp were very similar to the level found in the silverside eggs. The major 
differences between the 3-day-old brine shrimp and the silverside eggs were the 
lower levels of threonine, serine, proline, valine, and leucine, and the higher 
levels of arginine in the brine shrimp. 
The silverside eggs contained higher levels of threonine, serine, proline, 
alanine, leucine, and tyrosine, and lower levels of glycine and methionine than 
were found in the wild fish. The amino acid profile of the 5-day-old silversides 
changed substantially from the profile of the eggs. Most of the changes resulted 
in a general decrease in amino acids from the egg to the larval stage. 
220 
