Culture of atlantic silversides fed on artificial diets and brine shrimp nauplii.

Abstract

In a joint study, live, unfed 3-day-old brine shrimp, Artemia salina, and artficial, flake diets were fed to Atlantic silversides, Menidia menidia, either separately or in various combination. The combination diets also varied in proportion of live to artifical components. After each experiment was terminated, growth and survival of the silversides were determined and analyses were made for amino acid and fatty acid compostion. Overall grwoth and survial data showed that unstreessed fish and could be cultured on a combination of artificial + brine shrimp diet in as little as a 7:1 day (artificial: brine shrimp) feeding ratio. Biochemical data were compared to reported requirement levels for essential amino acids and essential fatty acids in marine fish, and it was concluded that all diets seemed adequate in these two components. These data also indicated that fish accepted both artificial and live diets equally. Results further showed that dietary amino acids were generally not stored by silversides beyond levels required for tissue formation, whereas dietary fatty acids were accumulated to a much greater degree. Altantic silversides cultured on an artificial diet alone, exhibited poorer growth and survival than fish cultured exclusively on a live brine shrimp diet. Although the reason for the live diet's nutritive superiority remains a question, our results seem to eliminate an amino acid, fatty acid or diegestive enzyme as the key to promoting good grwoth.