Assessment of nutritional influences on coregonid (Coregonus lavaretus) larvae using growth, survival, and histological diagnosis (Abstract)
Segner, H.; Rösch, R.; Schmidt, H.; von Poeppinghausen, K. (1989). Assessment of nutritional influences on coregonid (Coregonus lavaretus) larvae using growth, survival, and histological diagnosis (Abstract), in: De Pauw, N. et al. (Ed.) Aquaculture: a biotechnology in progress: volume 1. pp. 699
In: De Pauw, N. et al. (1989). Aquaculture: a biotechnology in progress: volume 1. European Aquaculture Society: Bredene. ISBN 90-71625-03-6. 1-592 pp., meer
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Documenttype: Congresbijdrage
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| Auteurs | | Top |
- Segner, H.
- Rösch, R.
- Schmidt, H.
- von Poeppinghausen, K.
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| Abstract |
The impact of a diet on fish larvae is realized on different levels of organization. The evaluation of nutritional influences at the organismic level by means of the morphometric-statistic approach is most widely used. In this study, nutritional effects are also analyzed at the organ and cellular level using histological diagnosis. Newly-hatched larvae of Coregonus lavaretus from Lake Constance were reared over 58 days on two different artificial diets. Control fish were fed on live zooplankton. During the first 21 days of the experiment, the mean weight gain was similar in all three treatments. Final dry weight was highest in fish fed zooplankton (24.2mg, specific growth rate: 8.2 %.d-1, though also one of the dry diets gave very satisfactory growth (final dry weight: 16.2mg, specific growth rate: 6.7 %.d:-1). Clear influences of diet on survival rates were not found. A food-specific liver structure could be observed earlier than the corresponding food-specific differences in growth. In the intestinal tract, histochemically detectable brush-border enzyme activities were found to be more dependent on ontogenetic than on nutritional influences. Distinct differences between dry and live feeds existed in respect to the consistence of food items in the gut of the larvae. The histological findings suggest that differences in gut's resorptive and digestive processes have an impact on the different growth results obtained with dry diets compared to live food. Therefore, further research should be carried out to improve some aspects of food performance in the larval alimentary tract. |
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