Beluga sturgeon is a valuable fish in the world. But the species is presently critically endangered, which makes researching to improve its production critical toward sustainable fish production. Optimum dietary requirements for developing commercial diets to enhance beluga sturgeon metabolic capacities during culturing are unavailable. Presently, Beluga farmers either use commercially available diets intended for other fishes or use diets formulated based on the dietary requirements of other freshwater fishes. To surmount the challenge of Beluga taking 8 - 10 years to reach maturity, there is the need to develop diets that specifically meet the requirements of the fish at various stages of development. Hence, this study investigated nutrient utilization and gut health of beluga sturgeon.
T hree unknown Beluga sturgeon populations (2012, 2013, and 2018) maintained on identical diets and hatchery conditions but differed by age were evaluated . Samples of blood, tissues and gut samples were collected for proximate compositional analyses. Tissue and gut samples were used for histopathological and microbial analyses. The results show that weight (P=0.0000250), hepatosomatic index (P=0.000147), and Visceral somatic index (P=0.000927) were significantly different between the years. Fish from the 2018 population were different and had a higher weight than fish from 2012 (P=0.0012) and 2013 (P= 0.000019). Three histological sections of each fish evaluated for all microscopic pathology show mucosal goblet and epithelial cell hyperplasia, chronic, multifocal, minimal to moderate, with minimal to mild lymphocytic inflammation for all the fish from 2012, 2013, and 2018. Differences in the presence or absence of pancreatic tissue lymphoid follicles and coelomic adipose tissue were observed for all the fish. The observed pathological differences in the fish could be attributed to decreased nutrient absorption and utilization. Other analyses of the tissues and gut samples are ongoing and will be presented.