The effect of feeding frequency and salinity on blood factors, immunity and stress indicators of stellate sturgeon (Acipenser stellatus) juveniles

The aim of this study was to evaluate the effect of feeding frequency and salinity on blood factors, immunity and stress indices of farmed stellate sturgeon (Acipenser stellatus) in 1399. For this purpose, 810 juvenile stellate sturgeon (average weight 12.24 g) in 9 treatments and each with three replications with three salinity levels and three feeding frequency levels were considered. Treatments included: Treatment 1: Twice daily feeding and zero salinity, Treatment 2: Four times daily feeding and zero salinity, Treatment 3: 6 times daily feeding and zero salinity, Treatment 4: Twice daily feeding and 6 g salinity Per thousand, treatment 5: four times a day feeding and salinity 6 grams per thousand, treatment 6: six times a day feeding and salinity 6 grams per thousand, treatment 7: twice daily feeding and salinity 12 grams per thousand, treatment 8: Four times feeding load 12 grams per day and salinity per thousand and treatment 9: 6 times per day and salinity 12 grams per thousand. The fish were reared for eight weeks. Blood samples were then taken from the fish. The results showed that in most cases, the number of white blood cells, red blood cells, blood indices in treatments 4 and 6 were higher than other treatments (P<0.05). Also, the amount of IgM, lysozyme and total immunoglobulin in treatments 3 and 4 were higher than other treatments (P<0.05). The results of stress indicators showed that the serum glucose and cortisol levels of fish had a statistically significant difference (P<0.05). According to the results, it can be said that it is possible to breed stellate sturgeon in different salinities and increasing the number of feedings helps this fish to withstand different environmental conditions. However, due to economic issues and labor costs, it is recommended to feed the fish 4 times a day.