Growth performance and physiological changes of holding juvenile Siberian sturgeon at different sizes in rearing units

Abstract

An investigation was accomplished to find the effects of different sizes as a social stress on physiological responses and growth performance of Siberian sturgeon.Juvenile Siberian sturgeon were separated into two sizes (860.88 ± 22.32 g as larger fish and 427.28 ± 2.97 g as smaller fish). Three treatments including large size (L), small size (S), and mixed size (M) were considered. There were equal numbers of large and small fish in the M treatment. Sampling was carried out at 1st week (as a short-term sampling) and 8th week (as a long-term sampling) of the experiment. At the end of each sampling, haematocrit, glucose, cholesterol, triglyceride, total protein, lactate, and cortisol were measured. All growth parameters and feed utilization in large fish were not affected in the M treatment compared with the L treatment and also small fish in the M treatment compared with the S treatment. The final biomass in the S treatment was significantly higher than those in the L and M treatments. Haematocrit, glucose, cholesterol, triglyceride, total protein, lactate, and cortisol in the 1st week showed no significant difference with different sizes. However, in the 8th week, only haematocrit increased (by time not size) in the S treatment. Fish in the M treatment in both sizes did not experience the stress condition.Larger and smaller sizes had a positive social interaction; therefore, different sizes of Siberian sturgeon can maintain together without decreasing growth rate and also adverse physiological responses. K E Y W O R D Scortisol, Siberian sturgeon, size, social interaction, stress response

Physiological responses to air exposure stress in Siberian sturgeon ( Acipenser baerii Brandt 1869) injected with dexamethasone

“…Hypoxia and exercise stressors can trigger the fish to increase lactate as a result of the anaerobic metabolism (Rodnick & Planas, 2016; Sheng et al, 2019). Lactate levels show different values in fish species after the stress (Brown & Kieffer, 2019; Eslamloo & Falahatkar, 2014; Jafari & Falahatkar, 2019; Kieffer et al, 2001) which is reflected in species‐specific pattern and different methods for measurement (Fanouraki et al, 2011; Kieffer et al, 2001). The results revealed an increase in lactate levels up to 1 h that reflected increase of anaerobic activity of white muscle and metabolic rate through the periods of severe exercise (Pankhurst & Dedualj, 1994).…”

“…Before injection and any handling, a group of fish was sampled and considered as zero control ( n = 6 per treatment at each time point). Also, before each sampling, clove powder extract (400 mg L −1 ) was used to anesthetize fish (Jafari & Falahatkar, 2019) immediately after capturing. Anesthetization and blood sampling was performed in less than 2 and 1 min, respectively.…”

“…The coefficient of variations of the assay for cortisol including intra-assay and inter-assay were 6.6% and 7.8%, respectively. Moreover, the validity of AccuBind ELISA Microwells, Monobind kit for sturgeon species were reported by Jafari and Falahatkar (2019). To assess the parallelism between hormone standards and endogenous hormone in plasma, a sample containing a high concentration of cortisol was serially diluted with assay buffer.…”