Effects of salt bath on growth parameters and the adhesion of bacteria to juvenile stellate sturgeon (Acipenser stellatus, Pallas, 1771) gill and skin

The long nose sturgeon (Acipenser stellatus, Pallas, 1771) is an anadromous sturgeon species, yet little is known with regard to salt bath effect on bacterial adhesion on superficial organs of this species and its growth. This study was conducted to determine the optimal salt bath concentration on growth parameters and total bacteria count on juvenile stellate sturgeon gill and skin. A total of 200 fishes with mean initial weight 494.5 ± 2.17 g and length 62.63 ± 0.18 cm (mean ± SD) were randomly distributed into 12 concrete pools in groups of 25. Fishes exposed to acute salinity of 0, 5, 10, and 15ppt for 30 minutes. Salt bath is used 5 times for 60 days (1, 15, 30, 45 and 60). At the end of 60th day, growth indices including body weight, SGR, BWI, ADG, PER and FE revealed a significant increase at 5ppt salinity (P< 0.05) and fishes exposed to 15ppt exhibited the poorest growth. No statistical significant difference was observed between control and other treatments in total protein and albumin, also in total bacteria count in gill and skin of fishes (P>0.05) but higher levels of total protein and albumin and lower level of total bacteria observed in 5ppt treatment. The results of this study indicate that high acute salinity may compromise the growth of juvenile long nose sturgeon and suggest that, in commercial operations, salinity should be 5ppt.