نشریه علوم آبزی پروری ایران
سال ششم شماره 2 (پاییز 1397)

Many studies have shown that marine resources contain bioactive compounds that can be used as food preservatives in the food industry. Hence in our research, Methanolic extracts of marine cucumber Holothuria leucospilota were extracted and fillets fish stored in the refrigerator were treated with, in different concentrations (0.5, 1 and 2%), in order to evaluate the chemical quality of fillets. The fillets were kept in the refrigerator for 16 days and chemical tests including volatile bases nitrogen (TVB-N), thiobarbitoric acid (TBA) and pH test were done every 4 days. The results showed that the amount of volatile bases nitrogen (TVB-N) in treated samples with extract in 1 and 2% concentration did not exceed the acceptable level until the last day, while the amount of this index in the control samples until the 8th day and the treated samples with 0.5% concentration of the extract, was acceptable until the 12th day. Thiobarbitoric acid (TBA) was acceptable in all treatments, except in treatment with 2% concentration until 8th day, though the treated samples with an extract of 2% concentration in the last day of storage were more than expectation. The pH index was lower in the samples treated with sea cucumber extract throughout the storage period than the control samples. Based on the results obtained in this study, it can be concluded that cucumber extract can be used as a natural preservative for fish fillets during the short-term storage period in a refrigerator condition and up to 2% concentration is suggested for this procedure.

The present study investigates the effect of different levels of probiotic Lactobasillus casei on expression of vitellogenin (Vtg) gene in Zebrafish (Danio rerio). For this purpose, Zebrafish with average weight of 0.15±0.01 gr fed on diet supplemented with 0%, 105, 106 and 107CFU/gr of probiotic for 6 weeks. After this period and sex determination, females fed with probiotic for 1 month. At the end of feeding trial, RNA extracted from liver and brain, cDNA synthesized with Superscript RTase kit and PCR were done using Vtg primer and Beta-actin as housekeeping gene. Evaluation reproduction gene expression showed increase in fish fed probiotic compare to control. Vtg gene expression showed significant increases in fish fed 106 and 107CFU/gr of probiotic compared to 105. According to the results it seems that using probiotic could consider as a new strategy for improving reproductive performance.

The antioxidant extract of four seaweeds Sargassum angustifolium, Padina astraulis, Cystoseria merica, Colopomenia sinuosa was prepared by ultrasonic methods with three solvents (water, water/ethanol and ethanol) under 25 kHz, 400W conditions. In this study, aquatic extract of S. angustifolium had the highest phenolic content (P<0.05). The amount of phenolic compounds in water/ethanol extracts of S. angustifolium were significantly higher than other seaweed extracts. (P<0.05). The aqueous extract of C. merica had the highest amount of DPPH radical scavenging relative to the aqueous extracts of other seaweeds (P<0.05). The aqueous/ethanolic extracts of S. angustifolium had significantly higher radical scavenging than other algae/ethanol extracts (P<0.05). Also, the anti-radical properties of Ethanol extract of C. merica was higher than ethanloic extract of other algae (P<0.05). The water extracts in all species had more phenolic contents, but in DPPH test, water/ethanol extracts of S. angustifolium had highest radical scavenging activity. The result show that S. angustifolium and C. merica were suitable for antioxidants extraction.

One of the most important factors during transportation of fishes is stress reduction. The effects of Celmanax liquid yeast commercial perbiotic and commercial product Protexin Aquatech including a blend of five strains of probiotic bacilli (Bacillus licheniformis, B. subtilis, B. polymyxa, B. laterosporus and B. circulans) on the biochemical parameters and hematological factors of common Carp juveniles were investigated during 12 h transportation in plastic bags. During 90 days, 150 juveniles with average weight of 60.50±1.50 g were fed by diet supplemented with Celmanax perbiotic at the level of 1 ml per kg, and by diet supplemented with probiotic bacilli at concentrations of 1×106 CFU per 100 g food. Then the fish were introduced to 40 liter plastic bags in stocking density of 1 kg/m3. In this study, four treatments were performed and three replications for each treatment including control, 0. 5 g per liter salinity + Celmanax, 5 g per liter salinity + Celmanax and 0. 5 g per liter salinity + probiotic bacillitreatment. 10 fish were sampled from plastic bags and at the begining and end of experiment. There were no significant differences in values hematocrite and Hb Calcium and glucose levels in different treatments. (P>0.05). The control group had the highest levels of cortisol (P<0.05). The results showed that using Celmanax prebiotic and probiotic bacilli in long-time transportation of Common Carp (over than 12 hours), can reduce fish stress.

In order to investigate the effects of different levels of vitamin B1 to water, on Nile tilapia (Oreochromis niloticus) and Saffron plant (Crocus stativus), growth in an aquaponic system, 240 Nile tilapia fries and 120 corms of saffron were randomly introduced into 12 experimental groups and influenced by treatments of adding 0 (control), 5, 10 and 20 mg L-1 vitamin B1 to water, weekly, for a-60 day experimental period. At the end of the experiment, weight gain and other indices of fish growth performance did not show any significant differences (P≥0.05) among treatments, but some growth performance indices of saffron plants such as corm weight and root weight in treatment of 20 mg L-1 vitamin B1 were significantly higher(P≤0.05) than other treatments. Biochemical parameters in serum showed highest in treatment with 20 mg vitamins B1 per liter of water. The highest amount of glucose and the lowest amount of cortisol in blood serum of fish recorded in treatment of 20 mg L-1 vitamin B1 that they were 139.76±8.8 and 201.13±29.77, respectivly. It was indicated that, adding 5 to 10 mg L-1 of vitamin B1 to water, have a positive effects on the biological conditions of the plant and fish in an aquaponic culture of Nile tilapia and saffron plant system.

The present study was carried out to investigate the physicochemical changes of farm-raised Beluga minced meat during the storage period in the refrigerator under the influence of hydroalcoholic extract of Ulva intestinalis macroalgae as a natural preservative. The minced fish was prepared with concentrations of 0 (control), 12.5, 25 and 37.5 mg/kg of the macroalgae extract. A sample with synthetic antioxidant (BHT) was included. Physicochemical properties (peroxide, volatile nitrogen, free fatty acids, thiobarbituric acid and color) of the samples were measured on 0, 4, 8 and 12 days. On the fourth day of the storage, the lowest values of peroxide index (5.1 meq/kg oil), thiobarbituric acid (0.23 mg malondialdehyd/ kg of meat), volatile nitrogen (25.55 mg N/100 g) and free fatty acids (0.47% oleic acid) was measured in treated samples with 36.5 mg of macroalgae extract compared to control and BHT treatments (P<0.05). The results of color indicated that the red and yellow indexes were increased during the storage period, while the highest amount of them were observed in treated samples with the macroalgae extract compared to control and BHT samples. Therefore, this algal extract might be considered a natural preservative and the best antioxidant effects was obtained in 37.5 mg of the extract per kilogram of the minced meat, which can be prolonged Beluga minced meat up to 12 days.

Macrobenthic communities typically change in response to alternation of the abiotic conditions and human interferences. The aim of this research was to study the macrobenthic community structure dynamics and a biological evaluation of water quality in Sari-Su River. For this purpose, samples were collected seasonally from four stations (Fountains, Agriculture, Rural and Urban) from 2016 to 2017. Samples were collected using Sorber sampler. A total of 1061 species belonging to eight order and eighteen families, including Ephemeroptera (46%), Diptera (40%), Oligocheta (7%), Odonata (4%) and Trichoptera (3%) were identified. The abundance and diversity of macrobenthos showed a significant spatial and temporal differences. The stations 1 (42%) and 2 (36%) have the highest densities of macrobenthic, station 4 in urban area (6%) has less. Multi-dimensional Scaling (MDS) and clustering analysis showed that, due to the frequency of Ephemeroptera and Diptera orders at stations 2, 3 and 4 of all seasons, the groups are separated in 4 separate sections. Also, the results indicate that the highest Shannon-Weaver (1.66) and Margalof (1.64) were in stations 2 and 3 and in all seasons. One-way analysis of variance showed that water temperature, pH and ammonia were significant difference between seasons. The Hillsenhof index was found to be the highest and lowest in spring (6.75) in autumn (6.25), respectively. There was significant correlations between the different index of biological and some water parameters. Garbage evacuation, agricultural drainage, animal waste are the main causes of the water quality decrease in the studied stations. According to water quality indicators of Sari-Su River, the upstream area are without pollution (Oligosaprobic) and down land area has the highest pollution (Polysaprobic).

The present study investigates the effect of dietary administration of the hydroalcoholic extract of fennel (Foeniculum vulgare) on expression of genes related to reproduction (ER-a and Vtg) in female zebrafish (Danio rerio). For this purpose, zebrafish with average wight of 0.15±0.01 gr fed on diet supplemented with 0, 75, 100 and 150 mg/kg of diet for 6 weeks. After this period and sex determination, females fed with fennel for 1 month. At the end of feeding trial, RNA extracted from liver, cDNA syntesised with SuPrimeScript RTase kit and PCR were done using primers relate to Vtg, ER-a and Beta-actin as housekeeping genes. Evaluation of reproduction gene expression showed increase in fish fed fennel compare to control. Vtg and ER-a gene expression didn’t show significant differences in fish fed 75and 100 mg/kg (P>0.05). Diet supplemented with 150 mg/kg of fennel showed significant increases compared to two other fennel-fed groups. According to the results it seems that using fennel could considered as a new strategy for improving reproductive performance.

Fishes grow and survive in the habitats that have environmental essentials for living to fulfill their needs. The present study aimed to calculate habitat suitability index of Capoeta buhsei using the kernel smoothing in the Jajrood River. A method was provided to calculate the bandwidth needed for the kernel smoothing, i.e. 1000 band width (0-1000) were separately examined and the one with the lowest root mean square error was selected as the best. Nine environmental factors were measured: pH, temperature, EC, TDS, DO, depth, width of the river, water current velocity, and diameter of the substrate stones. The suitability curves were fitted. Four methods of calculating HSI were examined: arithmetic and geometric mean, maximum and minimum methods. This species preferred the habitats with fast water current, deep and wide areas of the river with low temperature having large stones. The first station (upstream) with a habitat suitability index of 0.796 was the most suitable living place for Capoeta buhsei in the Jajrood River.

The persent study was carried out to investigate the effect of different levels of dietary mistletoe (LM) on growth performance and hematological parameters of Siberian sturgeon (Acipenser baerii). Thirty six fish (mean initial weight 721.6±119.8 g) were fed 3 times a day with three different diets including 0, 50 and 500 mg/kg LM for 12 weeks. Biometry was done to calculate growth and nutritional indices every two weeks interval and six fish were randomly sampled at the end of experiment to measure hematological parameters. The obtained results showed that no significant difference in growth performance in comparison with the control group (P>0.05). However, the hematological parameters were not affected by LM hydroalcoholic extract (P>0.05). This study showed that using dietary LM did not have a significant effect on growth and hematological parameters of Siberian sturgeon.