فهرست مطالب امیررضا عابد علم دوست

Despite the development of polystyrene nanoplastics (PSNPs) in different fields, including nanotechnology, environment, industries, and their possible approach to aquatic ecosystems, a few studies have been conducted on nanoecotoxicology in aquatic animals. Therefore, this study was designed and conducted to measure the effect of toxicity of the PSNPs while transferring from the diet to the body of the fish (food concentrations= 0.1, 10, and 100 mg/kg) on juvenile rainbow trout (Oncorhynchus mykiss) in a 28-day chronic treatment and the control group (food concentration = 0 mg/kg) after the 7-day adaptation period, in three repetitions (15 juvenile trout were included in each repetition per concentration). Depending on the target test, fish sampling in the treatment group was taken after 24 h without food. According to the results, the survival rate (SR) (84.44 ± 3.14%) was significantly reduced with the highest dose of PSNPs compared to other treatments (P<0.05). But other growth indices did not show statistically significant difference (P>0.05). From the point of view of tissue pathology of polystyrene nanoplastic in the liver tissue in treatment 3 and 4, injuries such as vacuolation, necrosis, sinusoidal expansion and pyknotic nucleus were observed in rainbow trout. Based on the obtained results, the negative effects of polystyrene nanoplastic release on health and immunity at the cellular level were seen in liver histology in the studied aquatic sample. In general, this study showed that the entry of nanoplastic particles through the digestive tract causes changes in the histological parameters of the liver. However, more comprehensive studies are needed in this field.

This study was conducted in order to investigate and compare the effect of cloves, propofol and electrical methods on the duration and recovery from anesthesia and their effects on some immune and physiological responses in beluga (Huso huso). The 270 beluga fish were randomly stored in 12 tanks. To induce anesthesia, a bath of 300 mg/L of clove powder, 5mg/L of propofol and an electroshock device were used as experimental treatments. In each treatment, immediately after the fish reached the stage of anesthesia, the duration of anesthesia and the recovery time were recorded separately and compared. The treatments were also evaluated for the anesthetic effects on the blood indices (red blood cell count, white blood cell count, hemoglobin concentration and hematocrit percentage), immune parameters (lysozyme and ACH50) and stress parameters (glucose and cortisol). In the examination of hematological indices, the highest level of hemoglobin was obtained in the electroshock treatment, which was significantly different from other treatments, and the lowest was related to clove powder treatment (P<0.05). The highest content of hematocrit was observed in the electroshock treatment and the lowest value was measured in the propofol and clove powder treatments (P<0.05). The results of immune parameters showed that the highest levels of lysozyme and ACH50 were in the electroshock treatment and the lowest values were in the clove powder treatment (P<0.05). Also, the results of stress indicators showed that the highest levels of glucose and cortisol were detected in the clove treatment and the lowest values were in the electroshock treatment. The results of this study revealed that the immune and stress indicators of the fish that underwent electrical anesthesia were better than the clove and propofol methods. Therefore, electrical anesthesia is a fast, cheap, eco-friendly method that can be a potential alternative to chemical anesthesia agents.

Most of the plastic materials used for food packaging are non-biodegradable, resulting in more environmental pollution. Hence, this study was designed and conducted to measure the effect of toxicity of the PSNPs while transferring from the diet to the body of the fish (food concentrations = 0, 0.1, 10, and 100 mg/kg) on juvenile rainbow trout (Oncorhynchus mykiss) in a 28-day chronic treatment and the control group (food concentration= 0mg/kg) after the 7-day adaptation period, in three repetitions (15 juvenile trout were included in each repetition per concentration). In addition, changes in two genetic biomarkers of the immune system and stress in the expression profile of the liver and spleen tissues indicated that following the increase in the concentration of PSNPs, the tumor necrosis factor-alpha (TNF-α) and expression level of heat shock protein 70 (HSP70) in both liver and spleen tissues significantly increased with the increase of mRNA transcription (P<0.05). Based on the obtained results, the release of NPsPS was confirmed for health and safety at the cellular-molecular level in the aquatic sample under study, and it is likely that if this nanomaterial is released in the aquatic environment, it will induce adverse environmental effects.

In this study, the effect of different amounts of rainbow trout bone micropowder (concentrations of 0.5, 1 and 2%) on the shelf life (the rate of formation of secondary fat oxidation compounds, total volatile nitrogen compounds, water holding capacity, color parameters) and the gel quality (hardness, chewing, cohesiveness and folding characteristics) of the largehead hairtail (Trichiurus lepturus) were examined during 15 days of refrigeration. Addition of bone micropowder to the gels prepared from hairtail fish, affected some of the gels properties. The results showed that with increasing the amount of bone micropowder in surimi gels, the amount of thiobarbituric acid (as the most important indicator of advanced degradation due to fat oxidation) was lower than to control group, which indicates the inhibitory effect of micropowder on lipid oxidation in the prepared surimi. In terms of color parameters, the results showed that horsetail fish gels containing bone micropowder had a darker color than the control. In the Folding Test, the horsetail gel containing bone micropowder with a concentration of 2% received the highest score. In the characteristics of texture profile (hardness, chewiness and cohesion indices), it was found that with increasing the amount of bone micropowder, the texture properties in the prepared surimi were significantly improved (p <0.05). Findings from the present study showed that bone micropowder due to its positive effect on the main indicators can be used to improve the texture properties of horsetail fish surimi gel.

Luciobarbus is one of the most important and economical genus of the Cyprinidae family, most of them are similar in appearance, making it difficult to identify species. In the present study, 519 stations in seven basins, including: Caspian, Namak, Urmia, Hari, Tigris, Persis and Hormuz basins were sampled using nets, electro fisher and jigging, during the years 2011-2011. In total, the presence of nine species including L. barbulus, L. brachycephalus, L. capito, L. conocephalus, L. esocinus, L. kersin, L. mursa, L. subquincunciatus and L. xanthopterus was confirmed in Iran's inland waters. For the approved members of this genus in Iran, the identification key were presented and their distribution map were prepared. Also, after examining the conservation status of the members of this genus, it was suggested that a well-codified, principled and scientific program be considered to identify populations, suitable places for reproduction and release of larvae from reproduction in captivity.

Southern Caspian Kutum, Rutilus frisii kutum (Kamensky, 1901) is an important economic species in north of Iran. This study was conducted in order to identifying QTLs associated with growth traits, body weight and total length, in Caspian Kutum (R. frisii kutum) using microsatellites from close species, Common Carp (cyprinus carpio). The eleven full-sibs family were produced by mating between eleven male and eleven female that were collected from Sefid Rood river. Sampling was accomplished from broodstock caudal fin. Three month after hatch the offspring were collected and stored in alcohol 96%. Altogether 75 offspring were sampled. Genomic DNA was isolated from broodstock and offspring according to the protocol. With applying four microsatellite markers (HLJ2225, HLJ3366, HLJ3988, and HLJ2316) related to growth traits, altogether 10 loci, 13 genotype, were selected for performing statistical analyses. Genotyping was accomplished using AlphaEaseFC software. Statistical analyses were performed by GenAlEx 6.1, Arlequin ver. 3.5.2 and Excel 2013 softwares. Investigating the number of alleles per locus, effective number of alleles per locus, expected heterozygosity, observed heterozygosity, fixation index, polymorphic information content, R and F statistics, Hardy-Weinberg equilibrium showed that these loci, HL1, HL2, HL3, HL4, HL5, HL6, HL7, HL8, HL9 and HL10, were suitable for applying in marker-assisted-selection (MAS) program for Caspian Kutum (R. frisii kutum). The heritability was calculated for each locus, for total length and total weight. Then based on linkage disequilibrium five heritable linkage group, LG1, LG2, LG3, LG4 and LG5, were constructed for total length in Caspian Kutum (R. frisii kutum). The LG4 with eight loci (nine genotype), including loci HL3, HL4, HL5, HL6, HL7, HL8, HL9 and HL10, was selected for family linkage group selection (LGS). The LG4 had a relatively average heritability ( = 0/432). Altogether, six family based on LG4 were selected to use in R. frisii kutum selective breeding program. This study showed that using microsatellite markers related to growth traits in close species to Caspian Kutum (R. frisii kutum) can aid to identifying QTLs associated with growth traits in Caspian Kutum, an important commercial species.

Nowadays, the presence of microplastics in aquatic ecosystems is a serious challenge for aquatic animals. In this study, the accumulation of polystyrene microplastic (PS-MPs) and its toxic effects on histology of liver and intestines of goldfish was investigated. A total of 231 healthy fish with an average weight of 18.55±2.41 g was selected in the spring of 2019. Microplastic were synthesized in two size ranges (0.25 and 8 μm) with two different functions (fluorescent and non-fluorescent). The experiments were performed in two stages. Initially, after the adaptation period, 68 fish were exposed to a constant concentration (PS-MPs) of 300 µg/L of both 0.25 and 8 μm PS-MPs. Liver and intestinal tissue were sampled for 7 days and the samples were imaged using a fluorescent microscope. Then, 168 fish were exposed to non-fluorescent microplastics with different concentrations (0, 5, 0.5, 0.05 ppm) for 28 days to determine histopathological lesions. The results showed that both sizes can accumulate in liver and intestinal tissues. Examination of liver histopathology showed different complications such as bleeding, necrosis, cell swelling, bile stasis, thinning of the sinusoidal space and accumulation of blood compared to the control group, the severity of lesions increased with increasing concentrations in a group of size. There was no predictable trend, but the intensity of destruction was greater at 0.25 μm. Examination of intestinal tissue lesions showed different complications such as necrosis, loss of intestinal villi, vacuolation, villi decay and degeneration of epithelium in both size groups compared to the control group. In general, microplastics have destructive tissue effects on goldfish. Most tissue lesions were observed at the highest concentration (5 mg/l). The severity of particles with a size of 0.25 μm was higher than the size of 8 μm, with destructive effects observed first in the intestine and then in the liver.   

Nanotechnology is the exploitation of physical, chemical, and biological characteristics of the particles with less than 100 nanometers in size. The most of the produced nanoparticles (56%) are composed of silver. The high consumption of these materials in industry and household products has led to their frequent release in aquatic ecosystems. The median lethal concentration (LC50) and the impact of silver nanoparticles on liver enzymes (ALP, LDH, AST, ALT) and thyroid hormones (T4 and T3) in Pangasius hypophthalamus wereinvestigated in the present study in three steps: At first, OECD (The Organization for Economic Cooperation and Development) protocols were used to determine the fatal levels of the silver nanoparticles (Ag NPs) in striped catfish. Second, semi-lethal concentration was found as 37.32 µg L-1 via regression test. In the last step, 168 fish received 0, 3.37, 7.46, 18.66 µg l-1  Ag NPs with three replicate.  Six fish were randomly selected after 14 days from each replicate. Whole fish body extraction was used to measure the liver enzymes and thyroid hormones. The results suggested that due to the lower LC50 of Ag NPs in striped catfish, this species is more susceptible compared to various other fish species. Exposure to the silver nanoparticles with different concentrations significantly increased the levels of liver enzymes (ALP, LDH, AST, ALT) and also significantly decreased the T3, but no effect on T4.

In order to increase the knowledge of the probiotic effects on reproductive indices of fish, this study was conducted to investigate the effects of different levels of probiotic Lactobacillus plantarum on gonadal development and sexual maturation in zebrafish (Danio rerio). Some 720 zebrafish were fed the experimental diets in four treatments such as: 0%, 0.5%, 1.5% and 3% probiotic diets for 40 days. Based on the measurement of reproductive indices in this species, the maximum absolute fecundity was observed in the diet containing 3% probiotic, which was significantly different from the control treatment and the diet containing 0.5% probiotic. Based on relative fecundity index, the control treatment showed the lowest fecundity rate compared to the other treatments. The gonadosomatic index data showed the utmost gonadal index in the diet containing 3% probiotic compared to the other treatments, which was significantly higher than the control and 0.5% probiotic treated diets, but it did not show any significant difference with the diet fed 1.5% probiotic. Histological examination of gonads in males and females showed gonads development and complete sexual maturity in treatments fed 3% and 1.5% probiotic levels. The present study indicates that probiotic Lactobacillus plantarum at 3% level will have the best effect on reproductive and gonadal development parameters in zebrafish.

Caspian lamprey (Caspiomyzon wagneri), a native species of the Caspian Sea, is under threatened by destruction of its habitats. The present study was carried out to investigate the possibility of separation between fall and spring run populations of Caspian lamprey in Shirud River due to different migration time using microsatellite markers. For this purpose, Caspian lampreys were sampled in fall and spring during their reproductive migrations at the Shirud River Bridge. After extraction of DNA from 46 fish, 4 primer pairs were used for polymerase chain reaction for selective proliferation. In this study, a total of 3 specific alleles were identified, one for fall autumn population in Locus Lun3 and two others for spring population in Lun5. The results showed no significant difference between the fall and spring immigrant populations, and the genetic distances of Fst (0.76) and Nei (0.206) indicated they belong to one population Units. Therefore, it can be concluded that the rate of homing behavior in the Caspian lamprey is very low preventing the formation of a separate populations.