Feeding regime of Persian sturgeon (Acipenser persicus) in the south Caspian Sea

Feeding regime of the Persian sturgeon in the southern basins of the Caspian Sea was studied in summer and winter 2006 in three provinces Guilan, Mazandaran and Golestan. We caught 52 fish specimens in 85 sampling sites varying in depths from 2-100 m using bottom trawls. The average weight and length of fish specimens were 332.81+1 g and 37.69±1 cm, respectively. The alimentary tract of fishes were analyzed and 11 food items including Gobiidae, Gammaridae, Mysidae, Nereidae, Ampharetidae, Pseudocumidae, Clupeidae, Syngnathidae, Scrobicularidae, insects and Cardiidae were identified. The highest feed diversity was observed in Mazandaran province (9 items) and the lowest in the Golestan province (4 items). Although Nereids showed the highest percentage of benthic organisms (49%) but they were of secondary and tertiary importance in the fish diet qualitatively. Comparison of Fulton's condition factor of fishes in the three provinces showed a similar pattern (0.3<1(<0.4). A tukey test revealed that there were no statistically significant differences between condition factor and gastrosomatic index in the three provinces while Vacuity index (CV) showed significant statistical differences among the provinces

Seasonal variation of chemical composition and fatty acid profile of ovary in wild common carp (Cyprinus carpio) of southeastern Caspian Sea

Chemical composition and fatty acid profile of common carp's gonad (ovary) were assessed. Protein, lipid, fatty acid profile and moisture content were determined during 4 seasons’ summer, autumn, winter in 2007 and spring in 2008. For each season 10 samples were examined. Average of gonadosomatic index in wild common carp was 7.53 ±5.02. Proximate composition of ovary during the study period showed the lipid at 8.06 ±2.20; protein at 23.26 ±4.85; and moisture at 67.12 ±3.85. The results showed lipid content of wild fish ovary increased from summer to spring (summer 6.875 ±0.53; autumn 7.07 ±2.12; winter 7.96 ±1.22; spring 9.44 ±3.62), protein content also increased from summer to spring (summer 12.920.09; autumn 23 ±1.32; winter 25.16 ±0.63; spring 27.11 ±0.63), moisture content decreased in this period (summer 75.235 ±1.75; autumn 68.25 ±2.28; winter 65.685 ±0.40; spring 63.43 ±0.11). Significant differences (P0.05). Saturated and polyunsaturated fatty acids increased from summer to spring (spawning season). The major fatty acids identified in common carp ovary were Oleic (C18:1), palmitic (C16:0), Docosahexanoic acid (C22:6 DHA), Palmitoleic (C16:1), Arachidonic, AA (C20:4), Stearic (C18:0), Eicosapentaenoic acid (C20:5 EPA) and Linoleic (C18:2) in all seasons. Lipid, protein and omega 3 PUFA increased during gonad maturation. It seems that these resources of energy are necessary for embryogenesis

Isolation and long-term culture of neural stem cells from Acipenser persicus (Borodin, 1897)

In the present study, an in vitro brain cell culture was developed from neural cells of Persian sturgeon (Acipenser persicus). The tissue samples collected from the anterior, middle and posterior regions of the brain were cultivated separately in DMEM/F12 medium supplemented with 15 fetal bovine serum, antibiotic and antimycotic. The medium was refreshed every 3 days. The cells became confluent after about 3 weeks from the initial time of seeding. The cultured cells from the posterior part of the brain showed high potential of proliferation as they had been passaged 16 times in more than 11 months. To determine optimal temperature, the brain cells were incubated at four temperatures including; 20, 22, 25 and 28°C. The best cultivation temperature was obtained at 25°C. The cultured cells from posterior part of the brain were cryopreserved successfully and the survival rate was 70 after thawing. Immunocytochemistry using antibody against nesting showed that some cells were immunopositive for nesting. Finally, these results suggested that cell cultures from posterior part of the Persian sturgeon brain with high proliferation capacity can be useful for research on brain cells in A. persicus in the future. © 2018 Iranian Fisheries Research Organization. All rights reserved

Effects of starvation and re-feeding on compensatory growth performance, plasma metabolites and IGF-I gene expression of Persian sturgeon (Acipenser persicus, Borodin 1897)

The effects of starvation and subsequent re-feeding on compensatory growth performance, blood serum metabolites and IGF-ImRNA expression in liver and muscle were investigated in juvenile Persian sturgeon. Growth indices including body weight, SGR, CF, and HSI significantly decreased after starvation. However, after re-feeding sturgeons that were starved for 1 week reached the same weight as the control, indicating that complete compensatory growth had occurred. Conversely, sturgeon in longer periods of starvation showed only partial growth compensation. HSI values decreased significantly during starvation, although they returned to the control fish levels after re-feeding. Plasma levels of glucose and insulin during starvation and re-feeding did not significantly change. This suggests that sturgeon is able to maintain glycaemia during starvation, probably due to their non-carbohydrates source dietary. Plasma total lipid level in un-fed treatments, however, was found to increase, possibly as a mechanism to utilise lipids as a fuel during starvation. IGF-I mRNA expression in liver and muscle increased during starvation and decreased after re-feeding. However, changes in the IGF-ImRNA expression were not significantly different among treatments. These results indicate that a periodic short-term starvation in Persian sturgeon does not adversely sacrifice overall fish weight gain and sturgeon can realise compensatory growth

Diversity and distribution of Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae) in Iran, with descriptions of three new species

Combining morphological and molecular data in an integrative approach, three new mayfly species of Epeorus (Caucasiron) are described. These include Epeorus (Caucasiron) alborzicus Hrivniak & Sroka, sp. nov. and Epeorus (Caucasiron) shargi Hrivniak & Sroka, sp. nov. from northern Iran, and Epeorus (Caucasiron) zagrosicus Hrivniak & Sroka, sp. nov. from central Iran. They are unambiguously delimited using both distance-based and likelihood-based approaches in the analyses of barcode COI sequences. Each new species is compared with other species of the subgenus and morphological diagnostic characters are provided. Based on extensive sampling of streams throughout the country, the distribution and habitat preferences of all Caucasiron species in Iran are assessed. Altogether, there are now six species recorded, among them also E. (C.) nigripilosus Sinitshenkova, 1976 is reported for the first time in Iran. Five species are distributed in the Alborz Mts. in northern Iran, one species was found in the Zagros Mts. in central Iran

Initial commented checklist of Iranian mayflies, with new area records and description of Procloeon caspicum sp. n. (Insecta, Ephemeroptera, Baetidae)

An initial checklist of mayflies (Ephemeroptera) of Iran is compiled based on critical review of available literature data, complemented with new data from 38 localities of Gilan and Ardabil provinces. At present, altogether only 46 species and 25 genera are known from Iran, 18 species are reported as new to Iran in this study. Some previously published data are critically evaluated and doubtful taxa are excluded from the list. Basic analysis of the distribution and biogeography of recorded species is given. Procloeon (Pseudocentroptilum) caspicum Sroka, sp. n. is described based on mature larva and egg. Critical differential diagnostic characters distinguishing the species from related taxa are discussed in detail