Changes in chemical composition and caloric content of developing eggs of the Shrimpcrangon crangon

Abstract

1. Changes in chemical composition and caloric content as well as the cumulative efficiencies of yolk utilization have been studied in the developing eggs and freshly hatched protozoea of the shrimpCrangon crangon L. 2. Per unit dry weight of the fresh egg the following relative increases were observed during the development: 16.8% water, 5.9% ash, 10.6% protein, and 0.5% non-protein nitrogen. During the same period (fresh egg to freshly hatched protozoea) fat content decreased from 32.6% to 15.6% and energy content from 6443 to 5287 cal/g dry organic substance. 3. The cumulative efficiencies of yolk utilization for the different constituents varied; they were 70.3% for dry weight, 54.0% for total energy, 83.0% for protein, and 33.6% for fat. 4. Of the 0.0453 cal expended on the metabolic processes of the embryo, only 20.8% was drawn from the oxidation of protein, while fat oxidation contributed as much as 75.0%. 5. Considerable quantities of inorganic salts (0.29µg/egg) were absorbed from the surrounding sea-water by the egg during its development.