Determination of the best time to transfer Beluga (Huso huso) juveniles from natural to commercial diets

To adapt juveniles of Beluga (Huso huso) to commercially prepared diets and to determine the best time for the transition from natural to prepared diets, an experiment was conducted over a period of 40 days. Six different diets were formulated with 2 levels of protein (50, 53%) and 3 levels of oil, including fish oil and sunflower oil (10, 14, 18%), each with three replicates for feeding larvae of beluga (initial body weight 0.06 g). The results showed that Beluga larvae, in contrast to larvae of other fish species, cannot feed on commercial diets immediately after absorption of the yolk sac under the given experimental conditions. Based on these results, the earliest time for transferring Beluga to feed on commercial diets is 3 to 4 days after absorbing the yolk sac, but the minimum time for development of their digestive system to enable them to feed on commercial foods is 30 days at an average weight of 2 grams.