YOLK RESORPTION IN FASTED OR FED BROWN TROUT (SALMO-TRUTTA L) ALEVINS

Evolution of body and yolk weights of brown trout (Salmo trutta L.) alevins was studied during 91 days following fertilization. The alevins were reared under a mean temperature of 8,8-degrees-C (range: 3,8-degrees-C-12,3-degrees-C). They were either fed from the opening of the oesophagus or fasted. This study shows that yolk resorption can be described, from fertilization, by means of a theoretical model, which takes into account body weight of fasted alevins. No difference in yolk resorption between fasted and fed alevins was detected. Before the complete yolk resorption, body weight of fed alevins was significantly higher than that of fasted alevins. Consequently, early feeding should be recommended to reduce the period of alevin stage.