Practical and research recommendations for optimization of Beluga (Huso huso) larval rearing

Behavioral, skeletal, histological and enzymatic changes of beluga (Huso huso), withthe aim of optimizing the biotechnical rearing protocol and reducing mortality of thisspecies during larval rearing, were studied. Based on the results of these studies, thebest indicator for start feeding the beluga larvae is the end of benthic swimming andonset of schooling swimming, and use of other indicators such as melanin plugexpulsion or yolk sac exhaustion that have been used in several sturgeon species, arenot suitable for beluga. Also, in order to reduce mortality and expenses, with respectto development of all parts of digestive system as well as activity of all digestiveenzymes and also jaw teeth formation and calcium absorption prior to the start ofexogenous feeding, it is highly recommended that larvae do not require long-termuse of live food and weaning procedure should be start immediately after mixedfeeding period (12- 14 dph; 199.2- 253.5 ddph). Furthermore, to reduce the cost offood, according to high level of amylase activity from 28 dph (490 ddph) onwards,decrease of protein/carbohydrate ratio in the diet after this time is recommended.Also, regarding surveys of feeding apparatus skeletal system of beluga, with respectto IHY bone formation and dysfunction of jaw teeth as well as the emergence ofsuction ability in 28 dph (490 ddph), sinking food in addition to immersed food canalso be used from this day onwards. Furthermore, to reduce mortality andabnormality during endogenous feeding, the studies on optimizing the quality ofbrood stock diet and also physicochemical condition of water are recommended.

Keywords:

Beluga (Huso huso) , Larvae , Digestive system , Feeding apparatus