Study on the potency of domperidone and metoclopramide for spawning induction in kutum (Rutilus frisii kutum)

The effectiveness of two kinds of dopamine antagonist (DA), metoclopramide (Met) and domperidone (Dom) combined with the gonadotropin releasing hormone analogue (D-Ala6, Des Gly10 ethylamide) GnRHa was assayed on the ovulation success, latency period, ovulation index (OI) and fertilization success of kutum, Rutilus frisii kutum (Kamenskii, 1901). Brood fish were injected intra-peritoneally as follows: 2 mg/kg b.w. of carp pituitary extract (CPE) as a control, 5μg + 2.5mg, 10μg + 5mg and 20μg + 10mg/kg b.w. of GnRHa + Met or Dom in a single injection. Based on the ovulation and fertilization success, no significant differences between similar doses of Dom and Met when combined with similar doses of GnRHa were found (p>0.05). However, in some groups, the OI and latency period were greater when Dom was used as a DA instead of Met (p<0.05). In general, the results of this study showed that the potency of Dom was nearly same as Met when combined with GnRHa and used as a DA in kutum. It is strongly recommended to repeat the experiment under different conditions to find out definite conclusion

A study on genetic differentiation in two species of Iranian bleaks, Alburnus mossulensis and Alburnus caeruleus (Teleostei, Cyprinidae) using simple sequence repeats

The genetic structure of the genus Alburnus is not well known and the phylogenetic relationships among its species are uncertain. In the present study, simple sequence repeats (SSRs or microsatellites) were used to evaluate genetic diversity and genetic differentiation between Alburnus mossulensis Heckel, 1843 from Kashgan River in Lorestan province and A. caeruleus Heckel, 1843 from Gamasiab River in Kermanshah province. Thirty specimens from each species were collected and their genomic DNA was extracted. Polymerase chain reaction was performed using four pairs of SSR markers, including CypG24, BL1-2b, BL1-98 and Rser10, from which a total of 480 bands were amplified. The average observed and expected heterozygosities for both species were similar. In both species, except for Rser10 locus, all loci deviated from the Hardy-Weinberg equilibrium (P <0.05). Average genetic distance and Fst values between the two species were 0.361 and 0.04, respectively. Analysis of molecular variance (AMOVA) revealed more interspecific (94%) than intraspecific (4%) genetic variation. Although four sets of SSR markers developed for other cyprinids showed high level of polymorphisms in the Iranian bleaks, they showed low genetic differentiation between them. Study on the possibility of genetic differentiation of the examined species by more microsatellite loci or other molecular markers such as amplified fragment length polymorphisms (AFLP) are recommended

Microsatellite polymorphism reveals low genetic differentiation between fall and spring migratory forms of endangered Caspian trout, Salmo trutta caspius (Kessler, 1870)

The main objective of this study was to assess genetic comparison of two migratory forms of Caspian trout Salmo trutta caspius namely fall-run and spring-run. Owing to the lack of information on its genetic differences, 5 microsatellite loci were used for 58 sample analyses. Genomic DNA was extracted from caudal fin using Roche DNA extraction kit and each PCR reaction was performed in a 25 µl reaction volume. Results revealed that the most allelic frequencies were observed in fall-runs of Caspian trout. The average observed and expected heterozygosity in fall-runs and spring-runs were 0.7719, 0.6108 and 0.4435, 0.5911, respectively. In both groups except Str543INRA in spring runs, all loci had deviation from Hardy Weinberg equilibrium. Furthermore except Str543INRA in spring runs, expected heterozygosity in all loci was more than observed heterozygosity. In conclusion microsatellite loci polymorphism in this study reveals low genetic differentiation between fall-runs and spring-runs. In order to increase gene flow between Caspian trout populations of different rivers and to increase the production of these fishes, restoration of rivers habitats, as well as using more breeders originating from various rivers is highly recommended

Karyological analysis of Cyprinion macrostomum Heckel, 1843, from Godarkhosh River, Ilam Province, Iran

In this study, for the first time in Iran, the karyotype of bigmouth Lotak, Cyprinion macrostomum Heckel, 1843, was investigated through examining metaphase chromosomes of seven fish with mean weight 30±5g caught by electrofishing from Godarkhosh River in Ilam Province. To stimulate cell divisions, fish were injected intraperitoneally two times by phytohemagglutinin (PHA). The cell divisions were arrested in metaphase stage by intraperitoneal injection of colchicine. Well-separated cells were obtained from kidney and gill filament and chromosome spreads were prepared and stained with giemsa. Karyotype was obtained as 2n=50. The karyotype consisted of 5 metacentric, 12 submetacentric and 8 telocentric chromosome pairs. Centromeric index, arm ratio and Fundamental Number (FN) were determined as 0-50, 1-∞, and 84, respectively

Genetic structure of Spanish and American stocks of cultivated rainbow trout, (Oncorhynchus mykiss)

Rainbow trout, Oncorhynchus mykiss is the most important cold water farmed fish in Iran. Several cultivated stocks have been imported to Iran and some fish farms have focuesd on the culture and breeding of these stocks all around the country. In this study, the genetic structure of Spanish and American stocks of rainbow trout was investigated using 4 pairs of microsatellite markers and 30 specimens of fish from each stock. Allele sizes at OMY77, OMY325, OMM1329 and OMM1332 loci were in the range of 102-178, 100-150, 122-198, 172-204 bps respectively. Average number of observed alleles in American and Spanish stocks was 11 and 11.5, respectively. Average number of effective alleles in Spanish and American stock was 8.65 and 8.03, respectively. The mean of observed heterozygosity for American and Spanish stocks were calculated as 0.59 and 0.63, respectively. The mean of expected heterozygosity for both stocks was very similar (around 0.86). The results showed a significant deviation from Hardy-Weinberg equilibrium at seven out of eight loci × stock. AMOVA test showed low (7%) genetic diversity between stocks, while the most (93%) genetic diversity was observed within stocks. Genetic identity and genetic distance between stocks were 0.831 and 0.186, respectively. Fixation index FST was calculated based on allelic frequency between two stocks was 0.012 with no significant difference between 2 stocks. The results of this study showed that while there was considerable genetic diversity within Spanish and American stocks, two stocks were very similar and showed very insignificant genetic differentiation based on 4 microsatellite studied loci

Sperm fertilization capacity of Caspian salmon, Salmo trutta caspius under ultraviolet irradiation

The optimum dose of ultraviolet (UV) irradiation to produce gynogenetic Caspian salmon, Salmo trutta caspius, with emphasis on the "Hertwig effect" and photoreactivation (PR) were investigated. The sperm of Caspian salmon was irradiated with UV at 2010 ± 200 µw.cm-2 in different times including 0, 1, 3, 5, 8, 10, 15, 20, 25, 35 and 45 min and was allowed to fertilize normal ova; the fertilization, eyed and hatching rates were calculated to assess the performance. Using the irradiated sperm decreased the fertilization, eyed as well as hatching rates and the so-called "Hertwig effect" was observed, with the time-dependent decrease in the hatching rates at 0+ to 3 min irradiation, but better hatching rates were observed at more prolonged irradiation times. The best hatching rate was achieved at 25 min of UV irradiation; after that the survival rates rapidly declined to near zero. For PR studies, the semen was irradiated with UV (5, 30 and 120s) and untreated semen (0s) was used as control. Irradiated semen and/or fertilized eggs by treated semen were exposed to visible light (60 W) at a distance of 30 cm for 10 min; the eyed and hatching rates were measured. UV irradiation as low dose as 5s, significantly decreased the hatching rate (P 0.05). So, based on the results of this study, it was impossible to detect any PR mechanism in Caspian salmon

Optimization of UV irradiation for production of gynogenetic rainbow trout, Oncorhynchus mykiss: emphasising Hertwig effect and photoreactivation

The optimum dose of UV irradiation to produce gynogenesis rainbow trout, Oncorhynchus mykiss with emphasis of Hertwig effect and photoreactivation (PR) was investigated. For this purpose, the sperm of rainbow trout were irradiated with UV at 2010±200 µw.cm-2intensity in different alternatives of 0, 1, 3, 5, 8, 10, 15, 20, 25, 35 and 45 minutes and allowed to fertilize normal ova; the fertilization, eyed and hatching rate were calculated to assess the performance. Using the irradiated sperm decreased the fertilization, eyed as well as hatching rates and the so-called "Hertwig effect" was observed, with the time-dependent decrease in hatching rate at 0+to 10 min of irradiation, but a better hatching rate at greater time of irradiation was observed. The highest hatching rate was observed in 20 min of UV irradiation; after that the survival rate decreased rapidly. Interestingly, irradiation even up to 45 min could not eradicate sperm fertility and a hatching rate above zero was observed at this treatment. For PR studies the semen was irradiated with UV for 5, 30 and 120 seconds and untreated semen (Os) was used as control. Irradiated semen and/or fertilized eggs by treated semen were exposed to visible light (60 W) at a distance of 30 cm for 10 min; the eyed and hatching rates were measured. The results showed that UV irradiation in as low as 5s could cause deleterious effect on semen chromatin and decrease the eyed and hatching rates (p<0.05). Illumination of semen and\or eggs with visible light resulted in PR in rainbow trout when sperm was irradiated by UV at 120s. We could conclude that the best UV irradiation time for production of gynogenesis rainbow trout was 20 min and UV irradiation, fertilization and egg hardening must be done far from visible light to eliminate the PR mechanism

The sub-lethal effects of cadmium on some gill histopathology in the cultivated Sterlet (Acipenser ruthenus)

The sub-lethal effects of water-born Cadmium (Cd) on histopathological changes of gill tissues were investigated on Sterlet, Acipenser ruthenus. In this research, 60 fish (41.69 ± 0.95 g and 23.98 ± 0.14 cm) were randomly distributed in 4 experimental groups, each with 3 replicates. The fish were exposed to different concentrations of Cd for 21 days under semistatic experimental condition as: 0, 16, 32 and 64 µg/L Cd. At the end of the experiment, the gill tissues were fixed in Bouin's solution for histopathological studies. Qualitative and quantitative changes of the gill tissues were analyzed. Several qualitative changes including hyperplasia, hypertrophy of epithelial cells and epithelial edema as well as necrosis, rings and fusion of gill filaments and secondary lamellae were observed in all treated fish including control group. Quantitative analysis based on organ index (Iorg) showed significant increase in histopathological changes in the gill tissues coincided by elevation of Cd concentration in the water. However, there was no significant differences in the organ index between control and 16Cd group.The results of this study demonstrate severe histopathological changes in the gill tissues after exposing to sub-lethal concentration of water-born Cd under experimental condition. The results of this study might be used as a guildline for evaluation of histopahological changes being induced by heavy metals in natural or cultivated environment for sturgeon fish

Histopathological effects of cadmium chloride on liver and gill of Chondrostoma regium

Aquatic environments received huge amount of pollutants such as heavy metals, hydrocarbons, pesticides and organic materials every day. In this study, the effect of dissolved cadmium chloride on liver and gill in Chondrostoma regium was investigated. For this purpose, one hundred fishes were caught by sein net from one of the branches of Zayandeh Roud and transferred to the laboratory. The experiments consist of four treatments including: control group (without cadmium), 0.5, 2.5 and 7.5 µg/l cadmium concentrations. For histopathological studies liver and gill were performed at the end of experiment the samples were fixed in 10% formalin.The highest rate of cadmium concentration was observed in gill at 7.5 µg/l of cadmium equivalent. Hyperplasia, clubbing and fusion were the main gill histopathological changes. Congestion, nuclear psychosis and necrosis were the main liver histopathological signs. Intensity of gill and liver damages showed increased trend in a dose dependent manner

Genetic analysis of wild common carp, Cyprinus carpio L. in the Anzali wetland, the Caspian Sea

The Caspian Sea and its basin (e.g. Anzali wetland) is one of the natural habitats of wild common carp Cyprinus carpio. In this study the genetic structure of this species in the south-west of Caspian Sea (the Anzali wetland) was investigated using PCR-RFLP analysis of D-loop region. Two hundred of mature fish were collected from 5 stations (40 individuals from each station) including Siahkeshim protected area (SK), Selke wild refuge (S), Sorkhankol wild refuge (SO), Abkenar (A) and the Anzali wetland estuary (E) during spawning season. A 420bp fragment of D-loop was amplified and the PCR products were digested with forty endonuclease enzymes. Four out of them: TasI, SmaI, SspI and ApoI showed polymorphism. Seven different composite haplotypes were detected among 5 stations and AAAA was the most frequent. FST ranged from 0.003-0.99. Over all stations, average haplotype and nucleotide diversity were 0.13 and 0.01, respectively. The highest haplotype (0.42) and nucleotide (0.06) diversities were found in (SO) station. AMOVA test showed that the Anzali wetland probably consists of two different populations of wild common carp which are distributed in SK, A-SO-S-E stations. The results of this study will be useful as a guideline for conservation, restocking as well as cultivation purposes of wild common carp in the Caspian Sea