Community Research and Development Information Service - CORDIS

Nutritional status of fish larvae

Various indicators of nutritional status have been compared in feeding and starving turbot larvae reared in large outdoor tanks and in laboratory systems. The study included whole larvae parameters such as length, dry weight and relative condition. Organ related parameters included otolith diameter and intestinal histology and biochemical parameters involved measurement of fatty acids, ascorbic acid, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), total protein and free amino acids.

The biochemical composition of the larvae at hatching seemed to be dependent on maternal nutrition. During yolk sac absorption the larvae showed a decrease in the lipids content and an increase in the protein content. After day 8 the influence of food became visible.

Comparisons of feeding and starving larvae from the same readings showed that most of the investigated parameters were affected by starvation, but generally the natural variations between readings were higher than the effects of starvation. Only the parameters lipid droplets in intestinal cells, relative condition and relative otolith diameter seemed to be associated with starvation in fish larvae.

After onset of starvation, lipid droplets disappeared within 24 h, relative condition decreased by approximately 5% per day and relative otolith diameter increased by about 5% per day. The slowest growing among feeding larvae showed no reduction in relative condition, but an increased relative otolith diameter.

Reported by

Danish Institute for Fisheries Research
PO Box 101
9850 Hirtshals
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