mohammad ali yazdani sadati

Induction of gynogenesis requires the spermatozoa with degraded DNA with high motility, simultaneously. In this study, to obtain this capability in Siberian sturgeon spermatozoa, UV radiation with a dose of 4257 j/m2 was applied. First, the seminal fluid was separated from the spermatozoa using a centrifuge, and then 10% of the sperm was prepared and irradiated with UV radiation for 30, 60, 90, 120, and 150 seconds to obtain the best motility and percentage of DNA damage using the comet assay method in comparison with the control. Simultaneously, the fertilization ability of these sperms was tested in sterlet sturgeon eggs and the rate of hatched larvae. Based on the results, the best duration of irradiation of spermatozoa was determined to as 90 seconds. The DNA degradation rate was 32.27±1.96 percent, the motility rate was 50% with forwarding movement, the fertilization rate was 52.1±0.52 percent, and the egg hatching rate was 1.1±0.11 percent. Therefore, genetically inactivated Siberian sturgeon sperm could be used in interspecific gynogenesis studies in sturgeon. Either to producing offspring of all females or to protect their extinction.

The use of selected bacteria to improve growth parameters and the microbial population in the host is one of the new ideas carried out for manipulating the bacterial population in aquatic organisms. These bacteria also consumed in the diets of farmed fish to optimize the balance of the microbial population of the gastrointestinal tract and they have a great effect on the growth and survival provides them. This study aimed to investigate the effect of commercial aquaculture probiotic (CA probiotic, Superzist, Zistyar Varna, Iran) on the growth performance and survival of juvenile of Siberian sturgeon. A number of 120 of Acipenser baerii with average of weight (109.3±3.7 g) were randomly distributed to 12 fiberglass tank containing 350-liter fresh water and 10 fish per tank. Fish were fed 2-3% body weight three times daily for 63 days. The CA probiotic comprising Bacillus subtilis, Lactobacillus acidophilus, L. delbrueckii, L. rhamnosus, L. plantarum in amount of 100, 200 and 300 mg/kg were added to basal diet (4mm pellets, Skretting, Italy). At the end of experiment, the survival rate of fish in the treatments were 100% and there were no significant difference in the treatments (P>0.05). There were no change in SGR in the treatments. Biomass increase, WG and BWI were increased and FCR and PER were decreased by increasing the amount of CA probiotic in the diet but there were no significant (P>0.05).

The purpose of the present study was to investigate the effect of nonylphenol as a monomer of a pollutant on Persian sturgeon (Acipenser persicus) hematological parameters changes. Injections of different treatments of 1.10 and 100 mg/kg body weight of fish nonylphenol were carried out in sample fish with a mean weight of 250 grams and injections repeated three times in three consecutive weeks. After 72 hours of the last injection, taking blood samples, some hematological indices including white and red blood cells, differential white blood cell count, and secondary hematologic factors were analyzed. After counting, the low levels of hemoglobin, hematocrit and red blood cells in the treated group compared to the control group were considered the reason for exposing the animal to the stress, because diminished hemoglobin protein, red blood cell count and hematocrit indicate the condition of anemia under conditions of exposure to the contaminating substance. The total number of white blood cells in the treatments increased compared with the control. The differential count of eosinophil white blood cells in the treatments of 10 and 100 mg nonylphenol per kg body weight of fish showed a significant increase and also neutrophil significantly increased in all treatments. Lymphocyte significantly increased in treatments of 10 and 100 mg nonylphenol per kg body weight of fish, but there was no significant change in monocyte count compared to the control group. Secondary hematologic indices (MEH, MEV and MEHC) have significant changes in direction were observed, consistent with an increase in white blood cells numbers.