Studies on the suitability of commercial dry diets for rearing of larval

The suitability of two commercial dry diets for rearing Coregonus lavaretus larvae was tested in a 58-day experiment. A diet of live zooplankton was used for comparison. The trials were conducted at water temperature of 12 °C in 800 l tanks, with a stocking density of 10 000-25 000 larvae per tank. Diets were evaluated by means of growth and liver histological analysis. Best growth was obtained with zooplankton, but one of the two dry diets (TetraWerke Az 20) also resulted in satisfactory gowth. Examination of liver structure using light and electron microscopy revealed no nutritional pathology for larvae fed with dry diet Az 20. Histological diagnosis presented evidence for a close association between hepatic protein synthesis and larval growth. From the data of the present study it can be concluded that a large-scale rearing of larvae of Coregonus lavaretus exclusively on dry food, is feasible.