Iranian Scientific Fisheries Journal
Year:2015 | Volume:24 | Issue:1|Papers Count:20

The monitoring of the harmful Alga blooms (Red tide) in the the Khuzestan coastal waters Provinces was carried out monthly at 5 stations during 2010 to 2011. The results revealed that, Coclodinum polykrikoides blooms was not occurred during investigation times, Phytoplankton composition species were included of 45 species of diatoms (%91), 9 species of Dinoflgellates (7.52%) and Cyanophytes with one species (1.88%). Furthermore significant different values of nutrients were recorded. Different values of NH4 were measured for different months. In total, the measured ratio of N: P in all months were lower than Redfield Ratio (16:1) in which subsequently the environmental condition was not suitable for bloom of C. polykrikoides.

Carotenoid pigments are responsible for pigmentation of edible fish muscle and skin of ornamental fishes. Accumulation of this colorful substance is important in fish marketing and there is a need to add carotenoids in cultured fish. In this study, Carassius auratus feeding was undertaken with 3 treatments including concentrate, freezed fairy shrimps (Phallocryptus spinosa) and concentrate with the same ratio and freezed Artemia urmiana and concentrate with the same ratio for 90 days. The amounts of total carotenoids were determined in the skin of different treatments at the end of the experiment using spectrophotometer model WPA, UK, astaxantin, canthaxantin and beta-carotene using HPLC model Younglin, UK. The results revealed that the most skin pigmentation obtained from the diet contained fairy shrimp. Also, carotenoid pigments were significantly higher in goldfish fed with live food supplement comparing concentrate one. The results showed a significant difference among different diets as in concentrate, concentrate and freezed fairy shrimps, concentrate and freezed artemia diets. Amounts of Mean (±SD) total carotenoids were 1.09±0.3, 3.90±0.021 and 2.07±0.05mg/100, astaxantin were 84.57±0.23, 205.82±0.40 and 102.24±0.63 ng/g and canthaxanthin were 0.24±0.01, 35.79±0.17 and 30.64±0.2 ng/g and beta carotene were 34.73±0.11, 138.78±0.2 and 69.77±0.15 ng/g of fish skin, respectively. Therefore, Fairy shrimps can be used as a suitable replacement for artemia to enhance color of ornamental fish. This is an environmental friendly food with the lower cost compared to high cost synthetic pigments.

This study investigated the composition and functional properties of isolated fish protein from Lanternfish (Benthosema pterotum). The proteins were isolated by using pH shift method. Basic pHs (10 and 12) were used to produce fish protein isolate. Fat contents of samples revealed that alkaline had a significant effect on reduction of fat in fish protein isolate. The lipid content decreased significantly by increasing the pH. Furthermore, the results showed that the functional properties including water holding capacity, oil holding capacity, emulsifying capacity, foaming and solubility were improved with increasing the pH and the fish protein produced at pH 12 had higher functional properties than the protein isolated at pH 10. Investigation and comparison of the color characteristics (L, a and b) attributed to the samples demonstrated that fish protein isolated at pH 12 was lighter (higher L) than that isolated at pH 10. In addition, redness (a) and yellowness (b) of protein isolates declined with increasing the pH. As a result, fish protein isolate from Lantrnfish produced using alkaline pH showed appropriate functional properties and alkaline led to improvement of the functionality and color characteristics of the protein isolate.

Due to the increased bacterial resistance to common antibiotics, there is tendency towards using herbal extracts in order to increase the non-specific immune system. This study was conducted to evaluate the effects of different levels of Mentha piperita extract on hematological, biochemical and immune parameters of Oncorhynchus mykiss. For this purpose, fish with mean (±SD) weight of 32.2±0.12 g were raised for 8 weeks in Vniro tanks (1800 1 water), 80 fish to each tank and feeding with different levels of M. piperita (with concentrations of %0, %1, %2.0 and %3.0, three replicates were used for each concentration). At the end of the trial, blood samples were collected to determine some hematological, biochemical and immunity parameters in different groups and compared to one another. Results showed significant differences in RBC and WBC count, neutrophil percentage, haemoglobin (Hb), haematocrit (HCT) value, total protein (TP), IgM and lysozyme activity in fish fed M. piperita (especially with 2 and 3.0% concentrations) when compared with control group. The results suggest that M. piperita extract may enhance the non-specific immune system of O. mykiss. Thus, using this supplement especially at of 3.0% level as immunostimulants was recommended in O. mykiss diet.

After the arrival of the invasive species (Mnemiopsis leidyi) in the Caspian Sea (in 1999) significant changes have been occurred in the ecosystem. In the present study, the data concerning the period 1996 to 2010 (extracted from the relevant research projects) were analyzed. The period was classified into two phases, before and after the species invasion (1996 and 2001-2010). In our study, the impact of the invasive species on the structure of southern Caspian zooplankton communities was assessed during the period 2001-2010, quantitatively.The combination of abundance and distribution range of the species (ADR) during the period 2001-2009 and the year 2010 were evaluated as E (occurrence in high numbers in all localities) and D (occurrence in moderate numbers in all localities), respectively. Considering the obtained results, the year 2001, in which the relative biomass was more than 90 percent, could be considered as the expansion phase and the following years (2002-2010) as the adjustment phase. With regards to the loss of the keystone and some other native species after the invasion of M. leidyi (2001 to 2010), the impact of the invasive species on the structure of southern Caspian zooplankton communities was assessed as massive (C4).

This study was carried out to find the effects of 17-b estradiol (E2) on biochemical parameters, sex steroids and carcass composition in juvenile stellate sturgeon (Acipenser stellatus). One hundred and eighty 5-month stellate sturgeon with an average weight of 11.7±0.2 g were divided into 3 treatments with 3 replicates each with 20 fish per tank. The treatments were included 0, 25 and 50 mg E2/kg diet. At the termination of 7 months feeding trial with different levels of E2, blood biochemical parameters, sex steroids and carcass composition were measured. The results of biochemical parameters including plasma glucose, total protein, cholesterol, triglyceride, calcium and phosphorus showed dose-dependent manner. The lowest and highest levels of all biochemical parameters were observed in fish fed control and 50 mg E2/kg diet, respectively (p<0.05). Plasma sex steroids concentrations showed the lowest level of E2 in fish fed control diet, while the highest levels of testosterone and progesterone were observed in this treatment (p<0.05). Proximate carcass analysis showed no significant difference in moisture, crude protein, crude fat and ash contents among the treatments (p>0.05). Final weight, total length, hepatosomatic and viscerosomatic indices were also affected by different levels of E2 (p<0.05). The results of present study demonstrated that using E2 in the diet of juvenile stellate sturgeon can influence most of biochemical indices and sex steroids which seems that those were related to the changes of sex ratio and some physiological parameters.

Pike (Esox lucius) is a native species in Anzali Wetland and has been considered for its flesh. This study was carried out to compare the rate of accumulation and concentration of heavy metals such as cadmium, nickel and zinc in edible muscle tissue of pike at three stations (west, center and east) of Anzali wetland in 2012.Ten fishes were randomly caught by gillnet from different stations in standard weights. After removal of the tissue samples, for chemical digestion through mixed acid digestion (HNO3/HClO4) was performed on samples. Heavy metal concentrations were measured using flame atomic absorption spectrophotometer. The average concentration of cadmium in pike in western station was 0.05 and in eastern and central part of wetland was 0.09 (mg/g dry weight), Mean concentrations of nickel metal in west, center and east, were 0.44, 0.37 and 0.22 (mg/g dry weight), Average concentrations of zinc in western, central and eastern part of wetland were 28, 25.55 and 13.55 (mg/g dry weight) respectively. In this study, concentrations of cadmium, nickel and zinc in edible muscle tissue of pike did not show significant differences between stations (P>0.05). The cadmium, nickel and zinc standards in American Food and Drug Administration (FDA), World Health Organization (WHO) were compared. The results showed that toxicity of nickel in samples of central was near but in western part was more than the permissible limit compared with the standard WHO=0.38, therefore consumption of this fish could be a warning of a threat to the health of these fish in vulnerable groups of society.

This research was carried out in order to identify the effects of different feeding frequency on growth indices, feed conversion ratio, survival and body composition of oriental river prawn (Macrobrachium nipponense) during 56 days. 180 oriental river prawns, with mean (±SE) weight 1.40±0.11g were counted and distributed randomly in twelve 70-liter glass tanks with 60 l water in 4 treatments each with 3 replicates cultured in same conditions (dietary feeding, dissolved oxygen, photoperiod, density, 2% feeding rate). Feeding were done 3, 4, 5 and 6 times/day with a constant commercial diet (50% protein, 13% fat, 12% ash, moisture 10-12 %). At the end of experiment, growth indices, feed conversion ratio, body composition ratio were measured for each treatment. Mean final weight, weight gain and specific growth rate in the treatment feeding 5 times/day was higher than the other treatments (p<0.05) but there was no significant difference in condition factor between treatments (p>0.05).The lowest feed conversion ratio was obtained in 5 times/day feeding and feeding 4 and 5 times/day treatments (68.80±1.8 and 77.60±2.5 %, respectively) had the highest survival rate. The highest body protein content (12.86±0.07 %) and fat content (3.46±0.02%) were obtained from the 5 times/day feeding. Results indicate that 5 times/day feeding has a significant difference in the increase of growth indices, survival rate, reduced feed conversion ratio, increased carcass protein and fat content, with other treatments (p<0.05).

The purpose of this study was to evaluate the effect of Fructo-oligosaccharide (FOS) on growth and survival performances of sturgeon juvenile fish (Acipenser stellatus). 90 sturgeon fry fishes (average weight 30.16±0/14 gram) has been brought from Sturgeon International, Research Institute and stored in fiberglass tanks using randomize design with 3 treatments each with 3 replicates in relative constant physico-chemical water parameters(P>0.05) then fed with basal adaptive food for two weeks. Fry fed 11 weeks with diets containing 0% (Basal food), 1% and 2% oligofructose (Raftilose p95, Sigma Co.) added to the basal food. The results revealed that 1% pribiotic compare to other treatments caused increasing weight gain, specific growth rate, feed conversion, feed efficiency, protein efficiency ratio and liver indices significantly (p<0.05) but there is no any significant difference between treatment's survival rates (p> 0.05). At the end of experiment, after bleeding from sample fries, the hematological characters showed that there are no any differences between hemoglobin, WBC and RBC numbers, hematocrit, MCV, MCH and MCHC between treatments(P>0.05) although the number of WBC in 1% and numbers of neutrophils in 1 and 2% prebiotic had differences with zero% significantly (P<0.05). Based on these results good influence on the improving growth and feeding performances by oligofroctose as prebiotic was proved in Acipenser stellatus fries and 1% level was the best.

An experiment was conducted to study the effects of oil source, L- carnitine and ractopamine supplements on growth performance and blood biochemical parameters of rainbow trout. With 2´2´2 factorial experimental design, 288 fish with 90±5 g initial weight were randomly distributed to 32 fiber glass thanks and fed two times a day at ad libitum by eight dietary treatments during 8 weeks. The experimental diets were containing two supplemental dietaries L- carnitine levels (0 and 1 g.kg-1), two levels of ractopamine (0 and 10 mg.kg-1) and two dietary oil sources (fish and soybean oil). Feed conversion ratio (FCR), specific growth rate (SGR), feed intake, body weight gain and biochemical parameter of blood serum in fish such as albumin, total protein, triglyceride, cholesterol and high density lipoprotein (HDL) were measured at the end of experiment. Results showed that feed conversion ratio of fish was not affected by dietary oil sources and ractopamanie supplements but addition of L- carnitine to diet reduced it significantly. Addition of L-carnitine and ractopamine to diet which contain fish oil improved significantly FCR of fish. Fish oil increased fish SGR and its highest level was seen at fish oil plus ractopamine dietary treatment. Feed intake was affected by fish oil and L- carnitine supplement which is increased and reduced it, respectively. Addition of L- carnitine to diet containing fish oil with ractopamine, significantly reduced feed intake of fish. Body weight gain of fish were not affected by dietary oil sources, L-carnitine and ractopmanine supplement; however, addition of ractopamine to diet containing fish oil improved it. Ractopamine supplement significantly reduced level of triglyceride and L-carnitine increased albumin and HDL of blood serum of fish. Interaction between oil sources and addition of L- carnitine and ractopamine supplements were seen on biochemical blood serum of fish except HDL. The highest level of albumin and triglyceride in blood serum were seen in fish fed by soybean oil plus L- carnitine, and also the highest level of total protein and globulin in serum were in fish fed by soybean oil plus ractopamine. Overall, results of this experiment showed that physiological and growth responses of rainbow trout to dietary L- carnitine and ractopamine supplements were affected by dietary oil sources.

Big-scale sand smelt is one of the fishes with high ecological value, which consume by fishes such as sturgeon in the Caspian Sea. In this study, 191 samples of Big-scale sand smelt from southeast coast of the Caspian Sea were collected seasonally from December 2013 to September 2014. In the present study, food items and the relative index of gastrointestinal (RLG), stomach emptiness index (VI) and feeding intensity (IF) were determined. The fork length, weight and age (mean±SD) were 7.70±1.09 cm, 3.64±1.49 g and 2.00±0.81 year, respectively. This fish with a relative gastrointestinal tract length of 0.46±0.06 (mean±Standard Deviation) can be considered as a carnivorous fish. The average of empty stomach was 45% showing big-scale sand smelt is a relatively voracious feeder. The average intensity of feeding (mean±Standard Deviation) 535±221.21, as a moderate level for this fish in the region. Gammarus (benthos) and Daphnia (zooplankton) were the favored food for this fish. This study also showed opportunistic hunting activities of this fish.

An unknown mortality was occurred in some ponds of a farm in an area of Kohgiloyeh-&-Boyerahmad province. Three ponds showed the highest mortality rate, about 5 to 20 dead fish were reported daily for 45 days. Afflicted fish have darkening in the skin and swimming near surface or at the floor of pond and swam unmatched with flock. Some fish showed hemorrhages around and within the oral cavity and exophthalmia occasionally. About 45 moribund rainbow trout were sampled for dissection and bacteriological examination. Kidney, liver and spleen of the fishes were examined for the detection and identification of bacteria causative agent of disease in rainbow trout. They cultivated aseptically on different media (Blood Agar, Tryptic soy Agar, TCBS Agar and MacConkey Agar). All fish have been infected and suffered septicemia. A type of gram's negative bacteria was responsible of infection and mix infection was not confirmed. The bacterium was being able to grow on Mac Conkey agar. It was a bacterium very similar with Yersinia ruckeri which induced infection. Detection was based on clinical finding and bacteriological laboratory results so using of some confirmation methods such as FAT or PCR would be recommended strongly.

Acipenser persicus is the most important sturgeon species in the south Caspian Sea, showing high mortality during larval culture. The aim of this study was to use the freshwater rotifer, Brachionus calyciflorus to feed A. persicus larvae to improve survival rates and enhance resistance. Three experimental treatments were used in this study; Treatment 1, similar to the feeding protocol of the hatchery was initially fed decapsulated cysts of artemia and then fed daphnia; Treatment 2, was fed a mixed diet of decapsulated artemia cysts, daphnia and freshwater rotifers and Treatment 3, was fed freshwater rotifers enriched with vitamin C (ascorbic acid 6- palmitate). A total of 45 larvae were stocked in each experimental tank (100 1 capacity) filled with 30 1 of water. Three replicates were used for each experimental group. Larvae were fed at the rate of 30% of body weight per day for 8 days. Mean dissolved oxygen, pH and water temperature throughout the experimental period were 9.58±0.2 mg/l, 8.5±0.1 and 22.5±0.5oC, respectively. Results showed significant differences in specific growth rate (SGR), percentage weight gain (WG), feed conversion ratio (FCR), and condition factor (CF) of experiment treatment 1 and treatment 3 and survival ratio were significantly different among treatment 3 and other treatments .This study demonstrated that Brachionus calyciflorus is a suitable live food for larval feeding.

The aim of this study was measuring the accumulation of heavy metals (Co and Ni) in the edible tissues of silver Carp and their comparison with international standards of FAO and FDA. Treatments were Carp fish caught from the West, Central and East Anzali wetland in autumn of 2012. Accumulation of heavy metals were measured by flame atomic absorption spectrophotometer. The level of nickel in the West, Central and East wetland was in permissible range. Cobalt no observed in western wetland Carp fish. But, concentrations of Cobalt were not significant increase (p>0.05) compared with standards levels of FDA and FAO in East and Central wetland. The results showed that there were not significant differences (p>0.05) amoung stations about the Cobalt and Nickel in the tissues of Carp fish. According to the results Carp fish caught from Anzali wetland in Western, Central and Eastern in terms of health food is suitable for human consumption and it has no side effects for human.

The aim of this study was to evaluate of zooplankton communities as bioindicator of water quality and saprobi index at six Chinese carp ponds at East of Golestan province, Gonbade Kavous city. Zooplankton sampling was done monthly during one culture period from June to November 2011. Finally, 27 genus from 4 class were identified. Between these groups, 12 genus belong to Protozoa, 8 genus from Rotatoria, 4 genus from Copepoda and 3 genus from Cladocera were recorded. The highest and lowest frequency percentage were belongs to Rotatoria and Protozoa with 46 and 3 percent, respectively. The results show that, there is no significant differences between saprobi index of six ponds (p>0.05). During the whole period of study, the saprobi index indicated Class ß-mesosaprob as water quality. There was significant general tends of decrease in the saprobi index from the beginning to end of the culture period (p<0.05), its value ranged was 1.52 to 1.70. Also, gradual improvement of water quality observed toward the end of culture period and these reasons are partly a result of natural and management processed such as seasons changes (climate), water exchange (replacement of water) and pause of introduce of fertilizer materials to the ponds.