Commensalism and parasitic infestation in crayfish (Astacus leptodactylus Eschscholtz, 1823) of Aras Dam Reservoir, Iran

The freshwater crayfish of the Aras Reservoir is an important economic fisheries resource of West Azarbaijan, Iran. This study was conducted to evaluate the prevalence of parasitic infestation of Crayfish seasonally in this area in 2010. Among 390 different sizes of Astacus leptodactylus which were examined, a range of ectocommensals or ectosymbionts from a number of different phyla including 9 orders and 11 classes infested the different anatomic units of the surface and appendages such as gills, head, thorax, abdomen, walking legs, uropod, telson, antennae and antennulae of freshwater crayfish. Common groups such as peritrich ciliates, suctorian ciliates, free living nematodes, branchiobdellids, and algae, copepods, rotifers and oligochaetes have also been observed in association with freshwater crayfish

Proximate composition and fatty acids profiles of Artemia cysts and nauplii from different geographical regions of Iran

Artemia has been widely used in aquaculture as a suitable live food. The presence of highly unsaturated fatty acids is a key factor that determines the nutritional value and marketing of Artemia for shrimp, marine larvae, sturgeon and ornamental fish industries. To determine the variation in nutritional content in cysts, decapsulated cysts and nauplii of Artemia from three different biotopes of Iran, were tested for their protein, lipid, energy, and fatty acid profiles, particularly essential fatty acids. The cysts collected from Urmia, Maharlou and Meighan lakes, were rinsed, processed, decapsulated, hatched and then analyzed for proximate and fatty acid composition using standard methods. Statistical comparisons of the results revealed significant differences not only in proximate composition but also in fatty acid contents (p<0.05). The highest mean (±SD) level of protein (60.5±3.3%), lipid (18.60±1.1%) and energy contents (5448.3±10.4 Kcal/kg) were observed in Instar I nauplii hatched from Urmia Lake cysts, Instar I nauplii hatched from Maharlou Lake cyst and Instar I nauplii hatched from Urmia Lake decapsulated cyst, respectively. The highest content of DHA (0.78 mg/g DW) was observed in nauplii of cysts from Urmia Lake whereas it was around zero in other samples. The highest level of EPA (24.24 mg/g DW) was measured in nauplii from Maharlou Lake decapsulated cysts and the lowest (0.24 mg/g DW) was observed in Urmia lake cysts. The results revealed that the nauplii from decapsulated cysts of Maharlou Lake Artemia contained significantly higher levels of EPA and n-3 HUFA compared to others. Therefore, it is recommended to use it in aquatic larviculture

The growth, survival rate and reproductive characteristics of Artemia urmiana fed by Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp., Chlorella sp. and Spirolina sp. as feeding microalgae

This study was performed to compare the efficiency of six microalgae namely Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp., Chlorella sp. and Spirolina sp. on the growth, survival rate and reproduction efficacy in Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to the standard method. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. A highly significant difference (p<0.01) were found among three microalgae in terms of length growth, survival rates and reproduction characteristics in A. urmiana. In spite of higher length growth of A.urmiana fed on N. oculata than A. urmiana fed by T. suecica but survival and reproduction in the latter was better than the first treatment. In general, D. tertiolecta was more efficient than other microalgae examined in the present study on A. urmiana concerning not only to growth and survival but also to reproduction mode. So, it is preferred to feed A. urmiana

Protozoan epibionts on Astacus leptodactylus (Eschscholtz, 1823) from Aras Reservoir, northwest Iran

The Astacus leptodactylus specimens were collected from four sites of Aras reservoir, North-West of Iran and examined for the epibionts during 2009. Protozoan epibionts from ciliophora (one genus and seven species) and tracheophyta were isolated from the cuticular surface of different body parts of narrow-claw crayfish, A. leptodactylus. Seasonal prevalence of infestation was determined in 394 individuals of A. leptodactylus. The facultative ciliate Tetrahymena pyriformis was identified on the gills and gill haemocoel with 0.5% prevalence. Furthermore, epibiont fouling organisms such as Epistylis chrysemidis (52.3%); Vorticella similis (45.9%); Cothurnia sieboldii (68.5%); Pyxicola annulata (66%); Chilodonella spp. (0.5%); Zoothamnium intermedium (57.1%); Opercularia articulate (20.6%) and Podophrya fixa (8.6%) were also isolated from 13 body parts of A. leptodactylus. The presence of Chilodonella infestation is the first record of this genus on freshwater crayfish species. The comparison of biometrical data of the epibionts showed no significant differences in prevalence of seasonal infestation between sampling sites. The current work represents the first documentation for the presence of protozoan epibionts on A. leptodactylus in Aras Reservoir, Iran

The study of heavy metals (Lead and Iron) contamination in cultured Oncorhynchus mykiss of Guilan province

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 µg/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)

The Effects of Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata as Food on the Growth, Survival and Reproductive Characteristics of Artemia urmiana

Abstract Artemia is the most widespread live food used in the production of different stages of many aquaculture organisms. It is a non-selective filter feeding organism. Generally, microalgae are the most favorable feeds for Artemia, particularly when the algal species have suitable size, digestibility and nutrient values. This study was performed to compare the efficiency of three microalgae namely Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata for growth, survival and reproduction efficiency of Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to standard methods. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. The results indicated a significant difference (P&lt;0.01) among three microalgae in terms of growth, survival rates and reproduction characteristics in A.urmiana. In spite of higher length growth of A.urmiana fed on N.oculata than T.suecica but survival and reproduction in A.urmiana fed on T.suecica was better than the first treatment. In general, D.tertiolecta was more efficient than T.suecica and N.oculata on A.urmiana, hence, it is preferred for feeding A.urmiana

The study of cyst formation in bisexual strains of A. urmiana, A. franciscana and parthenogenetic strians of A. pakistan, A. turkmenistan in laboratory conditions

The study was conducted to achieve growth, survival and reproductive characteristics of four Artemia populations (A.urmiana , A.franciscana , Pakistan strain and Turkmanestan strain). In this study, The strains were cultured under the same and static environment in laboratory condition. All cysts strains were hatched using the standard methods and the nauplii from the populations were cultured in laboratory condition using 80 g/L salinity, 25±1ºC with photoperiod (12L:12D) and Dunalliella tertiolecta were fed. The growth and survival of artemia were determined on days 8, 11, 14, 17 and 20 of culture. Randomly, The adult population were placed in 50 ml conical falcons and reproductive characteristics were determined. The results revealed that the survivorship A. franciscana had the highest survival (%99.8) and A. turkmanestan lowest survival (%92.1) The results revealed that the in growth rate while pakistanian strain had the highest growth rate(8554 micron). The results revealed that the reproductive characteristics in each population of species , the highest cyst production were observed in A. urmiana, A. franciscana and A. turkmanestan strains and the highest nauplii production was due to pakistanian strain. The highest production were observed in A. franciscana and lowest production were observed in turkmanestan strain

Comparative study of goldfish growth and survival rate feeding by fairy shrimp (Phallocryptus spinosa), Artemia and concentrate diet

The diet quality and type has a great role in aquatic animals and leads to increase of resistance against diseases and good growth. Cultured andornamental fish do not access to live and selected food due to captivity condition. Threfore, they should be provided with complete diet similar to natural food in captive condition. Carotenoid pigments are responsible of flesh pigmentation of edible fish and skin color of ornamental fish. The accumulation of this pigments in fish tissue has a greate importance in marketing and hence due to lack of its synthesis, carotenoids shoud be added to diet of cultured fish. As the synthetic carotenoids are harmful to the environment , there is a greate interest to use natural carotenoids in ornamental fish diets to obtain bright color. This study was carried out to compare the effects of diets containing Artemia urmiana and Phallocryptus spinosa supplements and commercial feed on growth and survival of goldfish fingerlings, quality of skin color, amounts of total carotenoids, Astaxantin, Canthaxantin and beta-carotene inCultured Carassius auratus during 90 days. The culture medium were contained glass aquaria in controlled condition and suitable for goldfish growth with 12 L: 12 D photoperiod and water temperature of 28±1 oC 3 test groups were included: treatment 1 fed with concentrate diet , treatment 2 fed with concentrate and frizzed Phallocryptus spinosa with tha same concentrations and treatment 3 fed with concentrate and frizzed Artemia urmiana with the same concentrations . Each treatment contains 2 replications and each replication consisted of 30 goldfish. In this study, The amounts of total carotenoids using spectrophotometer modelWPA, astaxantin, canthaxantin and beta-carotene using HPLC model Younglin, UK, were determined in the skin of Carassius auratus at the end of the exprement period. The results revealed that the most growth rate (GR), specific growth rate and condition factor (CF) were 0.11 ±0.006, 0.34 ± 0.015 and 3.96 ± 0.10, respectively which due to treatment 3 and the most weight gain and length gain including 8.57± 1.18g and 31.54± 3.33 mm, respectively due to treatment 2 .During rearing period, there was not any significant difference among treatments (p>0.05). The analysis of obtained data showed that there was a significant difference between diets containing live food and concentrate diet (p<0.05). The results revealed that live food enhanced skin color of Carassius auratus compared to concentrate diet. Also, the most pigmentation obtained from the diet contained fairy shrimp. As, in concentrate, concentrate and fairy shrimps, concentrate and Artemia diets amounts of total carotenoids at 450 nm wave length were 1.09, 3.90 and 2.07 mg/100, asthaxantin were 84.57, 205.82 and 102.24 ng/g and canthaxanthin were 0.24, 35.79 and 30.64 ng/g and carotenoid were 34.73, 138.78 and 69.77 ng/g, respectively. The use of fairy shrimp compared to Artemia in the diet can be significantly increased the amounts of carotenoids especially asthaxanthin in the skin of goldfish (p<0.05). Therefore fairy shrimps can be used as a suitable for artemia and high cost synthetic pigments to enhance color of ornamental fish

Hygienic monitoring of freshwater crayfish (Astacus leptodactylus) on Aras Lake reservoir

Aras dam reservoir situated in the northwest of Iran, west Azarbaijan province, is the only water resource of Astacus leptodactylus harvest in the country that more than 250tons of this species were exported to different countries all over the world, annually. On the other hand, one of the polices of Iranian Science Fisheries Institute is the release of this species into other water resources in the country and for this purpose, the study of risky diseases such as Crayfish pest (Aphanomysis astasi) and other zoonotic diseases are considered as the research priorities of aquaculture development of the country. This study was carried out to health screening of Astacus leptodactylus at Aras dam reservoir from winter 2013 to fall 2014. In this regard, A total of 394 harvested livefreshwater crayfish Astacus leptodactylus (255males, 139females) weretested. 9 epibionts and parasites peritrich protozoans were identified. From Metazoan parasites group, Branchiobdella kozarovi with incidence rate of (100%) in obtained samples was the only isolated organism from this group that identified up to species level. There was a heavy damage in gills of samples with Aeolosoma hemprichi (Annelid) in winter with90% prevalence. Furthermore, Other Epibiont fouling organisms such as Rotatoria; free living nematods and suctoria were observed in this survey. The fungi study of the lesions and melanized spots of mentioned samples revealed their infection to Penicillium expansum; Aspergillus flavus; Alternaria sp. ; Fusarium sp. and Saprolegnia sp. The results of bacterial study confirmed the presence of pathogen bacteria in Astacus leptodactylus. The most frequency percentage (15.16%) in hepatopancrease were related to Aeromonas hydrophila and the least one (1.37%) were due to Yersinia bacteria. Also, only Aeromonas hydrophila and Staphylococcus aureus were isolated and identified from heamolymph, respectively. The results revealed that the combination of Salmonella typhi, Escherichia coli and Staphylococcus sp. has caused the most infection rate while. Yersinia ruckeri and Salmonella typhi has caused the least infections in Astacus leptodactylus. According to the isolation of 6 bacteria species from hepatopancreas and 2 species from heamplymph , it can be concluded that hepatopancreas enjoyed the higher infection rate compared to haemolymph in the obtained samples

Molecular barcoding of the Aras reservoir alga Microcystis aeruginosa (Kützing) Kützing 1846 by ITS-2 gene

Today, due to population increase and anthropogenic activities together with sewage and agricultural waste water entrance, aquatic ecosystems have been exposed to high pollutions. Phytoplankton is a group of water floating algae that have crucial roles in providing nutrients and oxygen for other organisms, nitrogen and CO_2 fixation. These organisms are considered as primary producers in aquatic ecosystems. They are found in various water habitats all over the world, affected by environmental variables such as pH, light and temperature and used for determination of water pollution degree and quality. Phytoplankton composition and density may be used as a complementary indicator of water trophy state. Phytoplankton communities indicate short and long term variations of aquatic systems. One of the most obvious problems in freshwater ecosystems is algal bloom or over growth of some blue- green algae which can decrease oxygen, and in some cases bring about toxin excretion and fish and human kills. In addition, many of bloom forming cyanobacteria produce secondary metabolites which can create sever poisoning in mammals including human. The genus Microcystis is a key bloom forming cyanobacteria in aquatic ecosystems. Populations of this genus form intense blooms in water bodies that has attracted more attentions in recent years. Various species of this alga have been distributed in stagnant and eutroph freshwater around the world. Microcystis has been defined by genetic criteria such as 16S rRNA molecular sequencing, but its classification in levels lower than genus is unclear and the presence of its classical morphospecies is doubtful. However, this genus creates sever blooms in eutrophic waters all over the world and many species produce toxins. Therefore, identification of its natural diversity in the levels lower than genus has high importance. However, several characteristics of Microcystis morphotypes which are classified a traditional species, actually are present and observed in different regions of the world. At present, they can be considered as morphospecies that belong to one genotype and have similar ecology. These traditional species with definite phenotypic and ecophysiological characteristics cannot be eliminated completely. Their identification is essential for ecological and ecotoxicological studies. Interistic transcribed separator (ITS) gene is a section of genome which is located between 16s rRNA and 23s genes. This gene has more heterogeneity than 16s rRNA; so it is used to identify many genera of cyanobacteria. The Aras reservoir located in the north-west of Iran plays important roles as fisheries, drinking and agricultural water supply and recreational activities in the region. The present thesis was undertaken to: analyze the Microcystis sp. populations by molecular methods such as ITS in Aras Reservoir. Samples for molecular analysis were collected from 10 sampling sites on 18 August 2013. Samples for molecular study of Microcystis were collected from two different depths (surface and 1 m depth) and transferred to laboratory without any treatments. Microscopic images of Microcystis were sent to professor Komárek and was confirmed