Responses of beluga (Huso huso) to salinity exposure: a laboratory evaluation of the effect of field-based salinity levels on osmoregulatory characteristics and growth performance

There is a need for a better understanding of how sturgeon, especially hatchery reared juveniles, respond to salinity challenges. Therefore, here we examined the effects of different field-based salinities (Freshwater [FW] (0.5), 3, 6, 9 and 12 ppt) on osmoregulatory characteristics and growth performance of juvenile beluga sturgeon, Huso huso, (22.1±1.1 g body weight) over a 60-day period. Survival rate was relatively high in all treatments although there was a sign of adverse effects of salinity on the survival as fish at 12 ppt salinity. Growth performance was better in fish reared at 3 ppt, followed by 6, 9 and 12 ppt. Overall, an increase in plasma sodium, potassium, calcium, magnesium and glucose levels was found in association with the increase of salinity, while the FW control group maintained basal levels. Haematocrit levels were also affected by the salinity and the observed levels in FW, 3 and 6 ppt salinities were lower than other salinity concentrations. The results indicated that the beluga sturgeon juveniles are able to survive and acclimate to moderate salinities. Here, we also discussed the importance of evaluating and comparing specific mechanisms of acclimation in populations across brackish waters of the southern Caspian Sea as such investigations may aid and improve aquaculture strategies

The effect of different levels of Celmanax dietary supplement on growth, nutrition and biochemical indices of blood plasma in beluga (Huso huso Linnaeus, 1758) cultured in brakish water and pen culture

The aim of this study was to investigate the effects of different levels of Celmanax commercial prebiotic on growth performance, nutritional efficiency, blood and plasma biochemical indices in beluga, Huso huso (Linnaeus, 1758) in a 120-day feeding period. So that, 120 individuals of beluga with the average weight of 4.66 ± 0.26 kg were transferred to 12 holding cage nets, 1.20 × 1 × 2 m in size at a depth of 1.5 m with a completely randomized design as four treatments with three replications including control (without prebiotic) and three experimental treatments fed by diets containing 0.5, 1, 1.5 g/kg prebiotic. The results exhibited that adding Celmanax to the diet, especially 0.5 g/kg, significantly enhanced relative weight, daily growth rate, specific growth rate, feed conversion ratio and relative eating (p0.05). There were also no significant differences between the treatments fed by prebiotic compared to control with respect to hemoglobin, mean corposcular volume and mean corpuscular hemoglobin (p>0.05). Analyses on biochemical indices indicated that there were significant differences in total protein, glucose and triglyceride in blood plasma levels. Totally, according to the results, 0.5 g/kg Celmanax in diet can effectively enhance growth performance, nutritional efficiency and blood indices in cultured beluga