AQUATIC PHYSIOLOGY AND BIOTECHNOLOGY
Year:2019 | Volume:7 | Issue:2|Papers Count:8

In this study, the effect of sublethal doses of endosulfan poison (16, 32 and 64μ g/L) was investigated on the expression of antioxidant enzyme genes (catalase and superoxide dismutase) in zebrafish (Danio rerio) during 14 days. For this purpose, sampling was done from each treatment on days 1, 2, 7 and 14 after exposure. RNA was extracted from liver, cDNA was synthesized and antioxidant enzyme gene expression was evaluated using Real-time PCR. The results of different time intervals showed an increase in the relative expression of studied genes in the endosulfan treated samples compared to the control group (P<0. 05). The expression of both genes had the highest relative increase in the first 24 hours compared to other times and this trend was observed in all three doses of the study. Similarly, the relative expression of the studied genes showed a dose-dependent trend in all days of exposure. The results of this study indicated that changes in the gene expression of SOD and Cat enzymes can be considered as an effective indicator in ecotoxicology studies.

Silaffin is one of the proteins found abundantly in microalga Chaetoceros. It is used in the cosmetics, health and nutrition industries. In this study, extracted silaffin from two microalgae Chaetoceros muelleri and Chaetoceros calcitrans have been compared. For the experiment, the silica wall of the samples prepared from Bandar Abbas was extracted by using EDTA and SDS and their protein concentration was measured by Bradford method. Then, molecular weight was estimated by SDS-PAGE electrophoresis to identify the available amino acids. Amino acids were analyzed by HPLC. Results showed a significant difference in the amount of silaffin extracted from C. muelleri compared to C. calcitrans (P<0. 05). Also, there was no significant difference between two microalgae in the amount of aspartic acid, asparagine, glycine, valine and tyrosine + alanine (P>0. 05). However, the amount of glutamic acid, serine, phenylalanine, isoleucine, leucine, methionine, tryptophan, arginine, threonine, and glutamine + histidine was significantly different (P<0. 05). C. muelleri in terms of the protein content of silaffin can be a better option for use in different industries with a biotechnological approach in food and pharmaceutical industries.

The aim of this study was to determine the early sex of 21 pieces of 18-month-old farmed fish using ultrasonography as a new method of sex determination and small surgery. For this purpose, a linear array transducer ultrasonography with the frequency of 9-13 MHz was used. The overall accuracy of sex determination using ultrasonography (7 males, 10 females and 4 not correct determined) and small surgery (9 males and 12 females) were 80. 95% and 100%, respectively. There was no correlated to morphometric parameters including TL, SL, W and CF in 18 months beluga sturgeon with sex (P>0. 05). Although a small surgical procedure is an invasive procedure, it is the safest method and no casualties have been reported. Fish morphometric parameters including TL, SL, W and CF related to sex determination by both methods using logistic regression test showed no significant relationship with fish sex (P<0. 05), then cannot be used as an indicator of sex determination at this age.

Nowadays, the aquaculture industry is challenged with dietary mycotoxin contamination and their undesirable effects on fish. It is believed that feed containing antioxidants might be useful to modulate or even eradicate such problems. This study was to investigate the protective role of thyme and rosemary powder in the diet to reduce the toxic effects of dietary aflatoxin B1 and zearalenone contamination on some immune indices of rainbow trout fingerlings. Total number of 180 fish (3± 0. 2g) were allotted into three treatments including treatment one as control group (without toxin), treatment two received feed containing 50µ g/kg aflatoxin B1 + 400µ g/kg zearalenone and treatment three fed diet contaminated with 50µ g/kg aflatoxin B1 + 400µ g/kg zearalenone and contained 2% rosemary and 2% thyme powder (triplicate) for 4 weeks. The results showed that lysozyme and complement activity, serum total antibody content along with red and white blood cell counts were not affected by experimental diets (P>0. 05). While lymphocyte proliferation and neutrophils phagocytosis indices and lymphocyte to neutrophil ratio were affected by treatments (P<0. 05), as the lowest and the highest level of these indices, belonged to treatments two and three, respectively (P<0. 05). The results showed that adding rosemary and thyme powder to mycotoxin contaminated diet could improve immune parameters of rainbow trout especially lymphocyte proliferation and lymphocyte to neutrophil ratio.

Biological and natural products have been considered as the most important source of medicines from ancient times. The aim of this study was to evaluate the antioxidant, antibacterial and cytotoxicity properties of brittle star Ophiocoma erinaceus. Extracts of brittle star central disk and arms were separated by using three solvent types, n-hexane, ethyl acetate, and methanol. The antioxidant activity of each of the extracts was assessed via measuring of reducing power and total antioxidant capacity. Total phenolic and flavonoid contents were also measured spectrophotometrically. The antibacterial effect against three strains of Grampositive and one Gram-negative bacteria were also investigated. Cytotoxicity test was carried out using the Artemia larvae. Methanolic extracts were found to have the highest antioxidant activity via both methods, and ethyl acetate extract of arms and methanolic extract of the central disk showed the highest antibacterial activity on Pseudomonas aeruginosa and Serratia marcescens, respectively (P<0. 05). The highest toxicity level was also observed for extracts of 500 and 1000 μ g/mL concentration respectively. The findings suggest that this species has antioxidant, antibacterial and toxicity properties. Therefore purification and identification of these effective compounds are proposed.

Caviar of beluga (Huso huso) and Persian sturgeon (Acipenser persicus) are the most expensive in the worldwide market. Because of that, all female production is very important in these species. In this research, the effects of dietary 17-β estradiol on growth performance and sex reversal of beluga and Persian sturgeon were investigated. Initial mean weights of beluga and Persian sturgeon were 172 and 47g, respectively and stocking densities were 25 individuals per 1000-liter tank and 14 individuals per 200-liter tank, respectively. In both species, fish were fed 0 (control) and 30 mg estradiol/kg with two replicates for beluga and three replicates for Persian sturgeon. Results showed that the growth performance of both species was significantly affected by dietary estradiol 40 and 100 days after the beginning of the experiment, respectively. Histological assessment of gonad tissue indicated that females were predominant in both species comparing with the control group. Sex composition was 72. 5% female, 17. 5% male, and 10% undetectable in the hormonal treatment of beluga and 85% female, 10% male and 5% undetectable in the hormonal treatment of Persian sturgeon, but females were lower than 60% in the control group of both species. In conclusion, the dietary administration of estradiol was relatively successful in sex reversal of both sturgeon species. However, determination of the optimum level of estradiol requires more studies because of its negative effects on growth performance and fish health.

The present study purposed to determine the dose-and time-dependent changes in digestive enzyme activity (lipase, amylase and protease) and intestine histopathological alterations in Persian sturgeon, Acipenser persicus after exposure to sublethal concentrations (0, 0. 05, 0. 1 and 0. 2 LC50) of malathion for 7 days. Based on the results, the activity of lipase, amylase and protease levels substantially decreased in the fish exposed to malathion (P<0. 05). These activities were significantly dose-and time-dependent (P<0. 05) and the lowest was in 0. 2mgL-1 at the end of the experiment. Histological studies of the processed tissues showed marked histological alterations than the control group. The pathologic lesions of the intestine included blood congestion, loss of epithelial cells, fusion of microvilli, loss of microvilli, sloughing of epithelial cells, flattening of intestinal microvilli, vacuolization of cell cytoplasm, hypertrophy of epithelial cells, shrinkage of microvilli and also cell necrosis in muscularis were observed exposure to sublethal concentrations of malathion. In most cases, the severity of changes follows a dose-and time-dependent manner. Results showed that low concentration of malathion (0. 05 LC50) can pose undesirable alternation in Persian sturgeon fingerling, an economic species of the Caspian Sea.

In this study, the effect of ethanolic extract of dill plant on growth, body composition and antioxidant activity in rainbow trout with an average weight of 12± 0. 32g was investigated. The fish were fed in 500, 1000, 1500 and 3000 mg/kg feeds for 56 days. The results indicated that the growth factors had the highest body weight gain, specific growth rate and best FCR in 1000 and 1500 mg/kg treatments (P<0. 05). On the other hand, the highest and lowest amount of carcass protein was in treatments of 3000 and 1500 mg/kg, respectively. Also, the highest and lowest levels of fat were observed in treatments of 1500 and 3000 mg/kg of the ethanolic extract, respectively (P<0. 05). In addition, the highest levels of superoxide dismutase and catalase enzyme activity were observed at levels of 1500 and 1000 mg/kg, respectively and the lowest levels for both enzymes were in 3000 mg/kg treatment. Based on the results of the present study, the concentrations of 1000 and 1500 mg/kg extract increased the weight and activity of the superoxide dismutase and catalase enzymes in this fish.