Iranian Scientific Fisheries Journal
Year:2015 | Volume:24 | Issue:2|Papers Count:15

The present study conducted to investigate the effect of cortisol injection on growth indices, food intake and plasma cortisol in juvenile common carp (Cyprinus carpio). After 2 weeks adaptation, 240 fish with 19.5±0.2 g average weight were randomly distributed in to 12 fiberglass tanks with four treatments and three replicates (20 fish per tank). Based on body weight, cortisol (mixed with oil) was injected to treatments with different dosages at 0 (C0), 1 (C1) and 10 (C10) mg/g. At the end of 21 days, fish were weighed and growth parameters showed significant reduction in C10. No significant change was observed in hepatosomatic index among different treatments. Food intake were recorded daily during the experiment and showed significant reduction in days 1 to 8, 16 and 19 in C10 compared to control group. Blood was taken to determine plasma cortisol at the start, day 3, day 7 and day 21 of the experiment. Cortisol concentrations showed significant reduction in C10 compared to C0 group three days after the initiation of the experiment. The results showed that increasing of cortisol in a short time after injection, affected by changes of blood plasma cortisol and reduction of food intake could negatively have an effect on growth.

In this study, effect of different feeding levels on water quality, growth performance and survival of western white shrimp Litopenaeus vannamei post larvae were studied in biofloc rearing system. Shrimp postlarvae of PL10 with mean weight of 3±0.7 mg and mean length of 4.4±0.93 mm were fed for three weeks in fiberglass containers with 200 liters volume of water and density of 10 post larvae per liter in four tretments including one control with water exchange and three biofloc treatments at different feeding levels of 25, 20 and 15% of body weight. According to the results, in the values of water quality parameters including salinity, dissolved oxygen, pH, nitrite and nitrate, no significant differences were observed among the groups (p>0.05). The highest increase in body weight (58.42 mg), growth rate (2.78 mg per day), specific growth rate (15.09 %/day), biomass (84020 mg) and survival rate (71.9%) were obtained in biofloc treatment at 25% feeding level .The highest feed conversion ratio (2.05) and the lowest feed efficiency (48.62%) were obtained in water exchange treatment without floc, showing significant difference compared to the other treatments (P<0.05). The results from this study reveals that by using biofloc rearing technology can decrease the amount of water exchange and feed utilization compared to body weight in culture of western white shrimp post larvae. Moreover, the presence of biofloc improves growth performance and production of L. vannamei post larvae in biofloc rearing system.

Anzali wetland is one of the most important places for migratory fishes. Zooplankton organisms are the first consumers in the ecosystem. They are perfect food for the larvae of fishes. Six stations from different areas of wetland were examined for the study of zooplankton population during March 2011 to April 2012. Sampling was done by tube (PVC) and passing through of 30 micron plankton net. The samples were identified and counted by inverted microscope. According to the results, 60 Genus and 6 phylum (11, 31, 10, 2, 1, 1, 1, 2 genus of phylum Protozoa, Rotatoria, Arthropoda, Gastrotricha, Mollusca, Tardigrada, Nematoda, Porifera, Annelida) respectively were identified. The results showed that the maximum annual average density of zooplankton was observed with 2497±687number per litre in Karkan station and the population was more in the summer than in other seasons. Density of Rotatoria, protozoa and superclass Copepoda were 48%, 45% and 6% respectively. Results showed the population structure of zooplankton did not change much compared to past studies (due to improper environmental conditions), excluding Protozoa but the diversity of all zooplankton group is extremely declined. Kruskal Wallis test showed there was not significant difference between density of zooplankton in different stations, months and seasons (p>0.05), but significant differences were found between densities of different zooplankton phylum (p<0.05).

The aim of this study was to evaluate two heavy metals (Cd and Cr) concentrations in different tissues including muscle, gill, kidney and intestine of Zayandehrood chub, Petroleuciscus esfahani in different stations along the Zayandehrood River. For this purpose, 80 specimens of the fish were collected from 4 different stations including Cheshmeh-dimeh, Khersoonak, Chamgordan and Pol-e-Safaiyeh (each 20 fish) in autumn 2011. The metals were extracted using dry digestion method and measured by Atomic Absorption. The results showed that the concentration of heavy metals increased significantly from up to downstream of the River, with the highest level was observed in Chamgordan station (p<0.05). The highest concentrations of Cd (22.7±0.55) and Cr (50.69±22.78) mg/g dry weight (DW) were measured in the kidney of the fish collected from Pol-e-Safaiyeh and Chamgordan stations respectively (p<0.05). While, the lowest level of Cd (0.8±0.11) and Cr (1.30±0.19) mg/gDW were determined in the muscle of the fish from Cheshmeh-dimeh station located at upstream. The metals concentrations in the muscle were increased significantly from upstream to the downstream (p<0.05). In general, in all studied stations, the highest levels of Cd and Cr were observed in the kidney while, the lowest levels were measured in the muscle. By comparison between the results obtained from this study to the international standards defined by WHO or FAO, it was cleared that the concentrations of both metals in Zayandehrood chub (even at the lowest levels in the muscle) were much higher than permitted levels. The results of this study could show inappropriate environmental conditions of the Zayandehrood River, even in the upstream stations.

The purpose of study was to evaluate the anti-oxidant and anti-bacterial activities of three species of green, brown and red algae from northern coast of the Persian Gulf, The study was performed using DPPH, FRAP, PMD and RP tests for anti-oxidant capability and disk diffusion and plate methods of ethanol extraction for anti-bacterial ability. In the current investigation, The best anti-oxidant activity and inhibition potential of DPPH free radicals and RP were shown in ethanol extract of Entromorpha intestinalis green algae and lowest values was detected in Cystoseira myrica brown algae. The highest anti-oxidant activity was measured by FRAP test in green algae E. intestinalis and the lowest anti-oxidant activity was obtained in the red algaeGracilaria corticata. The highest anti-oxidant activity with PMD test was found in the red algae G. corticata. However, anti-oxidant activity of the green algae E. Intestinalis was shown high activity with DPPH, FRAP, RP tests. Hydro-alcohol extraction of sea weed did not show any anti-bacterial properties.

Rectal gland is an important organ for osmoregulation in the sharks, and has species-specific features which are dependent on fish size. In this investigation, 36 individual of Brown banded Bamboo sharks (Chiloscyllium punctatum) were caught from Dervish's Creek located at the northern of Persian Gulf in both autumn and spring seasons. After weighting, biometry, sex determination and the numbering of sharks, the rectal gland were removed and weight were measured and then immediately fixed in Bouin’s solution. Histological sections of 5 micrometers were prepared and stained with Hematoxylin and eosin and then studied by using light microscope. The morphological results showed that about the size of the rectal gland, there was no significant difference between males and females (p>0.05) but the smaller sharks have larger rectal glands in proportion to their body size comperated to larger sharks (p<0.05). Also, it seems that the weight of rectal gland is not dependent upon sex and reproductive season. In addition, considering to the results of both seasons, we can conclude that the rectal gland weight of this species was independent of sex and breeding season. Microscopic results indicated that rectal gland had four structural regions: The capsule, outer parenchyma, inner parenchyma and central canal.

The effects of using n-3 LC-PUFA -enriched Artemia nauplii and newly hatched Artemia on survival and resistance to pH stress in larvae of angel fish (Peterophylum scalar) were examined In tow 20 days period. In the first step of the experiment the larvae with an average weight of 0.86±0.03mg were fed with tow diets (enriched Artemia nauplii and newly hatched Artemia) for 20 days. At the end of the first step of the experiment, the significantly (p<0.05) higher survival rate was observed in larvae fed with enriched Artemia (90.66%) than the larvae fed with newly hatched Artemia (83.66%). In the second step of the experiment the larvae with an average weight of 20.03±3.73mg were fed only with commercial diet for 20 days. At the end of the second 20th days of the experiment, larvae exposed at pH stress (including 5.5, 6.5, 8.8 and 9.5) for 96 hours. The Result showed that the larvae were fed with n-3 LC-PUFA-enriched Artemia have a higher significant survival rate than other group in the period of the experiment and pH stress (p<0.05). Therefore, using of n-3 LC-PUFA-enriched Artemia recommended for increasing survival rate and the resistance to pH stress.

The current study was done with the aim of identification of ectoparasites of some aquarium fish including Carassius auratus auratus, Poecilia reticulata, Pterophyllum scalar and Colisa lalia. A total of 140 fish were randomly collected from Isfahan city in 2013, and were transported alive in appropriate condition to Fishery Reserch Center, Islamic Azad University, Shahrekord. Fish were kept in separate aquariums and were individually studied. The obtained results revealed that the studied fish were infested by Ichthyophthirius multifiliis, Trichodina sp., Dactylogyrus anchoratus, Dactylogyrus spiralis, Dactylogyrus sp1, Dactylogyrus sp2, Trianchoratus sp., Ancyrocephalus pseudorasbora and Gyrodactyrus sp. Overall, 64 0f 140 studied fish (46%) were found to be infested by parasites and the remaining were not infested. The highest infestation rate was found in gold fish (75%) and the lowest was observed in guppy (2.5%). A. pseudorasborae and Trianchoratus sp. are reported for the first time in Iran which were collected from gold fish and dwarf gourami, respectively. Gold fish is also reported as new host for D. spiralis.

This study was conducted to evaluate the effect of probiotic supplementation of Primalac on growth performance, some blood biochemical parameters, survival and salinity tolerance of the Caspian kutum fry. Fish (1.002±0.001 g) were classified to four groups fed on diets containing Primalac in different levels: 0 (control), 0.05, 0.10 and 0.15 % for 45 days. The results showed that there was a significant increase in final weight, weight gain and specific growth rate in those fish fed 0.10% Primalac diets (p<0.05). In addition, food conversion ratio of fish fed Primalac diets was significantly (p<0.05) lower than those fed the control group. However, there was no significant differences in condition factor, blood glucose and blood total protein content between fish fed different experimental diets (p>0.05). On the other hand, blood cholesterol of the Caspian kutum was significantly increased in control group in comparison with Primalac treatments (p<0.05). Survival and tolerance to salinity stress challenge remained unaffected by dietary supplementation of Primalac (p>0.05). The results of the present study indicate that the supplement of 0.10% Primalac have a positive effect on the growth performance and blood biochemical parameters of the Caspian kutum fry.

This study was conducted to evaluate the possible conservation of freshwater green algae using the freeze-drying and cryopreservation methods and comparative of their growth potential. Three experimental algae including Chlamydomonas moewusii, Scenedesmus obliquus, and Chlorococcum olefaciens were cultured for 20 days in 6 Erlenmeyer flasks after preparation of Zinder growth medium. Each algal strain was preserved according to freeze-drying and cryopreservation protocols with 9 replications (3 replications for the days of 1, 5, and 10). Algae were then re-incubated and their growth was evaluated in 1, 5, and 10 days after preservation. Another 9 Erlenmeyer flasks for each algal species were prepared as control treatment by adding the respective growth medium to consider the growth of algae in the same days with similar scale. Highest growth of all experimental algae was obtained after 10 days which was significantly higher than the corresponding control treatments (p<0.05). However, no significant difference was observed in the growth of Scenedesmus obliquus and and Chlorococcum olefaciens after freeze-drying and cryopreservation (p>0.05). Results of the present study illustrated that both preservative methods are suitable for maintenance of experimental algae, although freeze-drying provided better results in Chlamydomonas moewusii.

This study was conducted to compare heavy metal concentrations including lead and cadmium in liver and muscle tissues of Indian mackerel (Rastrelliiger Kanagurta) in Bandar Lengeh, Hormoz island, Hengam island and Kolahi regions. In current research, the influence of season, sex and size (length and weight) on Pb and Cd concentrations in Indian mackerel was investigated in these areas. Then Lead and cadmium concentrations in muscle tissues were compared with international standards for human consumption. Sampling was performed in summer and winter. Metal concentrations of organs were assessed by dry digestion method and atomic absorption spectrometer (AAS). Results showed that there are statistically significant differences between concentrations of lead and cadmium in liver and tissues of the fish in these regions (Bandar Lengeh, Hormoz, Hengam and Kolahi) (p<0.05), also concentrations of lead and cadmium have significant differences in summer and winter (p<0.05). The comparison of results of heavy metal concentrations with international standards including NHMRC, MAFF and WHO demonstrated that the amount of lead and cadmium is lower than allowable limits and doesn't have any problem for human consumption. Concentrations of Pb and Cd in both sexes of Indian mackerel have no significant differences (p>0.05). In addition, there is no correlation between lead and cadmium concentrations in muscle and liver of Indian mackerel with size (length and weight) (p>0.05).

Marine algal toxins have drawn worldwide attention because of their involvement in human intoxication and the socio-economic impacts. Marine biotoxins have been produced by harmful bloom algae, known as dinoflagellate. In the present study, two groups of toxins, i.e. PSP, ASP analyzed in the muscle of shellfish caught from the north parts of the Persian Gulf (Bandar Abbas, Bandar Lengeh, Boushehr) and Oman Sea (Chabahar). Sample preparation and extraction were done according to AOAC methods and by ELISA. PSP amounts in the shellfish samples ranged from ND-3.962 and ND-1.477 ng/g muscle. The results showed all samples were safe.

Microalgae nutritional value during the larviculture has many important roles can be affected on increasing quantity and quality production. The deficiency of some fatty acids especially HUFA in formulation feed which is normally used in aquaculture, is one of the most important problem in feeding, which using the marine sources oil can solve that. In this study, standard method used in culture of two important species of microalgae in aquaculture (Nannochloropsis oculata and Isochrysis galbana) then comparative survey of their nutritional values with emphasize on DHA, EPA and ARA were done, statistically.Microalgae brought from Persian Gulf and Oman Sea Ecological Research Center- Bandar Abbas and cultured in F2 media, counted by Neobar lam and finally their fatty acids identified with Gas Chromatograph DANI-1000. Statistical analysis was done on treatments average data each with three replications by SPSS V.14 (p<0.05). Fatty acid contents T- Test revealed that there are statistical differences (f=182.16, p<0.05, sig.=0.000) between two microalgae species N. oculata and I.galbana. Results showed that total FA (31.8±1.4 and 39.8±2.0) without any difference significantly (p>0.05), total unsaturated FA-omega 3 (9.4±0.5 and 30.2±0.5), total unsaturated FA-omega 6 (19.5±0.2 and 4.7±0.6) and EPA/DHA ratio (4.38±0.6 and 0.032±0.08) with statistical difference (p<0.05) in N. oculata and I.galbana respectively.

This study was carried out in three farmed rainbow trout (Oncorhynchus mykiss) of Guilan Province. Heavy metals (Iron and Lead) were measured using Atomic absorption spectrometry in food, water and fish muscles of farms. The amounts of Iron and Lead (Mean±SD) in all water samples from studied farms were 55.29±2.71 and 2.066±0.714 mg/L, respectively. The amounts of Iron and Lead (Mean±SD) in consumed feed of studied farms were 494.51±89.18 and 3.494±1.462 mg/kg, respectively. Also, the amounts of Iron and lead in fish muscle of studied farms were measured as 7.715±1.050 and 0.39970±0.073 mg/kg, respectively. The obtained results revealed the existence of higher amounts of iron in fish muscle above Codex standard, 2001 and lower amounts of lead levels from the mentioned standard in studied farms. The obtained data showed no significant differences in water, food and muscle of fish in studied areas (p>0.05).