University of GuilanAquatic Physiology and Biotechnology2345-39666220180823Effect of feeding strategies on growth performance and hematological indices of Siberian sturgeon Acipenser baerii (Brandt, 1869) at different sizesEffect of feeding strategies on growth performance and hematological indices of Siberian sturgeon Acipenser baerii (Brandt, 1869) at different sizes122301610.22124/japb.2018.7314.1161FANaqmeJafary PastakyM.Sc. Student in Aquaculture, Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, IranBahramFalahatkarProfessor in Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, IranProfessor in Department of Marine Sciences, The Caspian Sea Basin Research Center, University of Guilan, Rasht, IranMir MasoudSajjadiProfessor in Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, IranJournal Article20170424This study was conducted to investigate the effect of feeding strategies on growth performance and hematological parameters of Siberian sturgeon (<em>Acipenser baerii</em>) at different sizes for 45 days. Experimental treatments were including large fish with satiation feeding (LA); small fish with satiation feeding (SA); large fish with restricted feeding (LR); small fish with restricted feeding (SR); large starved fish (LS) and small starved fish (SS). Mean weights in large and small fish were 465.75±11.18g and 250.40±12g, respectively. Final weight in the LS and SS groups were significantly lower than the other groups (P<0.05). Hematological indices showed no interaction between feeding strategy and fish size (P>0.05), but monocyte values were significantly higher in LA treatment compared to the LR treatment (P<0.05). The present study revealed that feed deprivation has severe negative impacts on small fish while in restricted feeding treatments, these negative impacts were lower and the fish adapted to feed restriction period. Furthermore, the result of the present study indicated that various feeding strategies in both sizes had no adverse impact on hematological indices in Siberian sturgeon.This study was conducted to investigate the effect of feeding strategies on growth performance and hematological parameters of Siberian sturgeon (<em>Acipenser baerii</em>) at different sizes for 45 days. Experimental treatments were including large fish with satiation feeding (LA); small fish with satiation feeding (SA); large fish with restricted feeding (LR); small fish with restricted feeding (SR); large starved fish (LS) and small starved fish (SS). Mean weights in large and small fish were 465.75±11.18g and 250.40±12g, respectively. Final weight in the LS and SS groups were significantly lower than the other groups (P<0.05). Hematological indices showed no interaction between feeding strategy and fish size (P>0.05), but monocyte values were significantly higher in LA treatment compared to the LR treatment (P<0.05). The present study revealed that feed deprivation has severe negative impacts on small fish while in restricted feeding treatments, these negative impacts were lower and the fish adapted to feed restriction period. Furthermore, the result of the present study indicated that various feeding strategies in both sizes had no adverse impact on hematological indices in Siberian sturgeon.https://japb.guilan.ac.ir/article_3016_6ae39eede88cbc238078e85930cc3087.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180922The effect of monsoon on physiological stress indicators of Chabahar bay (Oman Sea) Bivalvia Azumapecten ruschenbergerii (Tryon, 1869) under laboratory conditionThe effect of monsoon on physiological stress indicators of Chabahar bay (Oman Sea) Bivalvia Azumapecten ruschenbergerii (Tryon, 1869) under laboratory condition2344302810.22124/japb.2018.6630.1137FAMohammad MansourToutouniAssistant Professor in Marine Biology Department, Faculty of Marine Science, Chabahar Maritime University, Chabahar, IranAhmadSavariProfessor in Marine Biology Department, Faculty of Marine and Ocean Science, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranBabakDoustshenasAssociate Professor in Marine Biology Department, Faculty of Marine and Ocean Science, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranNasrinSakhaeiAssociate Professor in Marine Biology Department, Faculty of Marine and Ocean Science, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranDanialAzhdariAssistant Professor of Iranian Fisheries Science Research Institute, Chabahar, IranJournal Article20171011Environmental quality assessments recommend use of sessile invertebrates. Because, they are unable to escape from environmental deterioration. In addition, the ability of adaptive responses to such environmental change, would determine its survival and reproduction potential. The organism adaptability may therefore be defined by its capacity to adjust the physiology to operate with optimal efficiency in a variable environment. Indicators that are discussed in this field for <em>Azumapecten ruschenbergerii</em>, at the Chabahar Bay and in the time before and after the monsoon, include: the ratio of consumed oxygen to excreted nitrogen and body condition index. The first is widely used to study the metabolism of animals. The second is the occupied space of internal volume of the shell by the body. Accordingly, stress indices were determined and statistically evaluated. The average of both indices was associated with significant changes (increase for the first and decrease for the second one) in relation to pre- and post-monsoon period (P<0.05). Evaluating both indicators suggests less environmental stress in the post-monsoon period to this bivalve living in sampling sitesEnvironmental quality assessments recommend use of sessile invertebrates. Because, they are unable to escape from environmental deterioration. In addition, the ability of adaptive responses to such environmental change, would determine its survival and reproduction potential. The organism adaptability may therefore be defined by its capacity to adjust the physiology to operate with optimal efficiency in a variable environment. Indicators that are discussed in this field for <em>Azumapecten ruschenbergerii</em>, at the Chabahar Bay and in the time before and after the monsoon, include: the ratio of consumed oxygen to excreted nitrogen and body condition index. The first is widely used to study the metabolism of animals. The second is the occupied space of internal volume of the shell by the body. Accordingly, stress indices were determined and statistically evaluated. The average of both indices was associated with significant changes (increase for the first and decrease for the second one) in relation to pre- and post-monsoon period (P<0.05). Evaluating both indicators suggests less environmental stress in the post-monsoon period to this bivalve living in sampling siteshttps://japb.guilan.ac.ir/article_3028_abfd5e13019bc29180d61f3380298493.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180823Effects of vitamin B2 and E on performance of growth, hematological and immunology indices in Caspian Sea salmon (Salmo trutta caspius)Effects of vitamin B2 and E on performance of growth, hematological and immunology indices in Caspian Sea salmon (Salmo trutta caspius)4564304710.22124/japb.2018.7532.1167FAAfshinAshouriM.Sc. in Fisheries, Lahijan Branch, Islamic Azad University, Lahijan, IranHosseinKharaAssociate Professor in Department of Fisheries, Lahijan Branch, Islamic Azad University, Lahijan, IranMohaddesehAhmadnezhadAssistant Professor in Inland Waters Aquaculture Research Center, Iranian Fisheries Science Research Institute, Agricultural Research Education and Extension Organization (AREEO), Bandar Anzali, IranJournal Article20170516The Caspian Sea salmon (<em>Salmo trutta caspius</em>) is anadromous fish which has economic value and high popularity. In this study, the effects of vitamin E and B<sub>2</sub> were investigated on growth performance, hematological and immunology parameters. This study does on 750 fish. Fishes with an initial weight of 20±3g were divided into 10 groups, one was the control group and other groups received different doses of vitamin E and B<sub>2</sub>. 15, 20, 25 mg/Kg vitamin B<sub>2</sub>, 100, 200 300 mg/Kg vitamin E and 15+100, 20+200 and 25+300 mg/Kg mixture of vitamin B<sub>2</sub>+E in T1 to T9, respectively. Significant differences were observed in final weight and length of different treatments (P<0.05). The lowest weight and length increment was seen in the control group. Also, the best FCR and the highest SGR, GR, BWI, and CF were observed in T8, the largest WBC, RBC, IgM, and lysozyme were measured in T9 and the largest MCHC, MCH, MCV, Hb and total immunoglobulin were recorded in control group. The best performance was obtained in T8 (20B<sub>2</sub>+200E). Overall results showed that adding the mixture of 2 vitamins improve growth and performances of the immune system and has larger effects on growth.The Caspian Sea salmon (<em>Salmo trutta caspius</em>) is anadromous fish which has economic value and high popularity. In this study, the effects of vitamin E and B<sub>2</sub> were investigated on growth performance, hematological and immunology parameters. This study does on 750 fish. Fishes with an initial weight of 20±3g were divided into 10 groups, one was the control group and other groups received different doses of vitamin E and B<sub>2</sub>. 15, 20, 25 mg/Kg vitamin B<sub>2</sub>, 100, 200 300 mg/Kg vitamin E and 15+100, 20+200 and 25+300 mg/Kg mixture of vitamin B<sub>2</sub>+E in T1 to T9, respectively. Significant differences were observed in final weight and length of different treatments (P<0.05). The lowest weight and length increment was seen in the control group. Also, the best FCR and the highest SGR, GR, BWI, and CF were observed in T8, the largest WBC, RBC, IgM, and lysozyme were measured in T9 and the largest MCHC, MCH, MCV, Hb and total immunoglobulin were recorded in control group. The best performance was obtained in T8 (20B<sub>2</sub>+200E). Overall results showed that adding the mixture of 2 vitamins improve growth and performances of the immune system and has larger effects on growth.https://japb.guilan.ac.ir/article_3047_4000e0702d32d1bdc5ea5e91aa81ebbf.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180922Effects of dietary supplementation of synthetic astaxanthin on reproductive performance of giant freshwater prawn (Macrobrachium rosenbergii)Effects of dietary supplementation of synthetic astaxanthin on reproductive performance of giant freshwater prawn (Macrobrachium rosenbergii)6586305010.22124/japb.2018.8286.1186FAGhasemRashidiyanM.Sc. in Fisheries, Fisheries Department, Natural Resources Faculty, University of Tehran, Karaj, IranGholamrezaRafieeProfessor in Fisheries Department, Natural Resources Faculty, University of Tehran, Karaj, IranMohammad AliNematollahiAssociate Professor in Fisheries Department, Natural Resources Faculty, University of Tehran, Karaj, IranKamranRezaei TavabeAssistant Professor in Fisheries Department, Natural Resources Faculty, University of Tehran, Karaj, IranJournal Article20170715The present study was carried out to investigate the dietary effects of different levels of synthetic astaxanthin on reproductive performance of giant freshwater prawn (<em>Macrobrachium rosenbergii</em>). 24 broodstock prawns were randomly distributed into 3 treatments considering male to female ratio as 1:3 in duplicates. Experimental diets were supplemented with an amount of 0 (as control), 50 and 100 mg.Kg<sup>-1</sup> astaxanthin. Prawns were fed on experimental diets in a ratio of 2% biomass for a period of 45 days. Total carotenoid, number of eggs per gram, eggs diameter, hatching rate and number of larvae after hatching as broodstock reproductive performance indices while larval somatic index (LSI) and larval length were measured to assess larval quality. Results showed that diet supplementation with synthetic astaxanthin significantly affects the number of eggs and number of larvae after hatch (P<0.05). Also, a significant difference was observed in total carotenoid, eggs diameter, LSI and larval length (P<0.05). Thus, based on these results and being more cost-effective 50 mg.Kg<sup>-1</sup> supplementation level is recommended to improve giant freshwater prawn reproductive performance.
The present study was carried out to investigate the dietary effects of different levels of synthetic astaxanthin on reproductive performance of giant freshwater prawn (<em>Macrobrachium rosenbergii</em>). 24 broodstock prawns were randomly distributed into 3 treatments considering male to female ratio as 1:3 in duplicates. Experimental diets were supplemented with an amount of 0 (as control), 50 and 100 mg.Kg<sup>-1</sup> astaxanthin. Prawns were fed on experimental diets in a ratio of 2% biomass for a period of 45 days. Total carotenoid, number of eggs per gram, eggs diameter, hatching rate and number of larvae after hatching as broodstock reproductive performance indices while larval somatic index (LSI) and larval length were measured to assess larval quality. Results showed that diet supplementation with synthetic astaxanthin significantly affects the number of eggs and number of larvae after hatch (P<0.05). Also, a significant difference was observed in total carotenoid, eggs diameter, LSI and larval length (P<0.05). Thus, based on these results and being more cost-effective 50 mg.Kg<sup>-1</sup> supplementation level is recommended to improve giant freshwater prawn reproductive performance.
https://japb.guilan.ac.ir/article_3050_91ebbd218413b13243cde90694321057.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180922Effects of fish meal replacement with poultry by-product meal on growth performance, hematological indices and serum biochemical parameters in sobaity sea bream (Sparidentex hasta, Valenciennes 1830) juvenilesEffects of fish meal replacement with poultry by-product meal on growth performance, hematological indices and serum biochemical parameters in sobaity sea bream (Sparidentex hasta, Valenciennes 1830) juveniles87114306910.22124/japb.2018.7731.1171FAFetemehHekmatpourPh.D. in Aquaculture Science, Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranPreetaKochanianAssociate Professor in Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranJasemGhafle MarammaziProfessor in South Iranian Aquaculture Research Center, Iranian Fisheries Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Ahwaz, IranMohammadZakeriAssociate Professor in Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranSeyed MohammadMousaviAssociate Professor in Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, IranJournal Article20170610Finding economically viable and environmentally friendly protein sources to fish meal (FM) replacement in carnivorous fish feeds is one of the main challenges for the sustainability of the aquaculture industry. In this study, FM was replaced by Poultry by-product meal (PBM) levels of 0 (control), 15, 25, 35, 45 and 55% in <em>Sparidentex hasta</em> formulated diets. Sobaity sea-bream with an average initial weight of 29.27±0.06g and standard length of 8.7±0.36cm were randomly assigned to 18 tanks (300L) at stocking density of 20 fish per tank (6 treatments, triplicate) and were fed with experimental diets for 60 days. At the end of feeding trial, no significant reduction were observed in growth indices between the control and the fish fed up to 55% replacement. Hematocrit, hemoglobin, MCHC and serum albumin, globulin, total protein, glucose, urea and acid uric, aspartate aminotransferase had no significant differences between fish fed the PBM based diets and control diet (P>0.05). Serum alkaline phosphatase, cholesterol and calcium showed higher value in PBM diets than control, although triglyceride was higher in control diet than PBM diets. The results indicated that FM can be substituted successfully by PBM in the diet of <em>S. hasta</em> juveniles up to 45% without adverse effects on serum biochemical parameters.Finding economically viable and environmentally friendly protein sources to fish meal (FM) replacement in carnivorous fish feeds is one of the main challenges for the sustainability of the aquaculture industry. In this study, FM was replaced by Poultry by-product meal (PBM) levels of 0 (control), 15, 25, 35, 45 and 55% in <em>Sparidentex hasta</em> formulated diets. Sobaity sea-bream with an average initial weight of 29.27±0.06g and standard length of 8.7±0.36cm were randomly assigned to 18 tanks (300L) at stocking density of 20 fish per tank (6 treatments, triplicate) and were fed with experimental diets for 60 days. At the end of feeding trial, no significant reduction were observed in growth indices between the control and the fish fed up to 55% replacement. Hematocrit, hemoglobin, MCHC and serum albumin, globulin, total protein, glucose, urea and acid uric, aspartate aminotransferase had no significant differences between fish fed the PBM based diets and control diet (P>0.05). Serum alkaline phosphatase, cholesterol and calcium showed higher value in PBM diets than control, although triglyceride was higher in control diet than PBM diets. The results indicated that FM can be substituted successfully by PBM in the diet of <em>S. hasta</em> juveniles up to 45% without adverse effects on serum biochemical parameters.https://japb.guilan.ac.ir/article_3069_8cba770b8583e1f6a79e3183fa4dad0c.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180922Chromosomal location of HindIII Satellite DNA in Acipenser persicus and Acipenser gueldenstaedtii by using of fluorescent in situ hybridization (FISH)Chromosomal location of HindIII Satellite DNA in Acipenser persicus and Acipenser gueldenstaedtii by using of fluorescent in situ hybridization (FISH)115134307010.22124/japb.2018.7897.1181FAMohammad RezaNowruzfashkhamiAssistant Professor in Genetic and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Rasht, IranBahramKazemiProfessor in Biotechnology Department, Cellular and Molecular Biology Research Center, Shahid Beheshti Medical Sciences University, Tehran, IranLilaAzizzadeh PormehrPh.D. Student in Biochemistry, Biochemistry Department, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, IranHamedVazirinasabM.Sc. in Cell and Molecular Biology, Royan Institute, Tehran, IranMohammadPourkazemiProfessor in Iranian Fisheries Research Organization, Agricultural Research, Education and Extension Organization (AREEO), Tehran, IranMahtabYarmohhammadiAssistant Professor in Genetic and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Rasht, IranMohammadHassanzadeh SaberScientific Member in Genetic and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Rasht, IranJournal Article20170706In this study, a <em>Hind</em>III Satellite DNA (168bp) was isolated from Russian sturgeon, <em>Acipenser gueldenstaedtii</em> and was used as a probe for fluorescent in situ hybridization (FISH) with the chromosomes of Persian sturgeon, <em>Acipenser persicus</em> and Russian sturgeon. After obtaining suitable chromosomal preparations from the fishes through leukocyte culture and labeling the probe with Spectrum orange (Orange-dUTP) through Nick translation method, the probe was hybridized with chromosomes of the fishes on the microscopic slide. In the studied chromosomal preparations, the hybridization colored signals were clearly visible. Counting the produced signals in twelve chromosomal preparations of three fishes from each species showed that the mean number of the signals in the chromosomal preparations of the Persian sturgeon and Russian sturgeon were 66±4 and 68±3 respectively. In this study, accurate kind determining of chromosomes and <em>Hind</em>III SatDNA site on the chromosomes were impossible due to the presence of microchromosomes and heterogeneity of shapes and sizes of colored signals.In this study, a <em>Hind</em>III Satellite DNA (168bp) was isolated from Russian sturgeon, <em>Acipenser gueldenstaedtii</em> and was used as a probe for fluorescent in situ hybridization (FISH) with the chromosomes of Persian sturgeon, <em>Acipenser persicus</em> and Russian sturgeon. After obtaining suitable chromosomal preparations from the fishes through leukocyte culture and labeling the probe with Spectrum orange (Orange-dUTP) through Nick translation method, the probe was hybridized with chromosomes of the fishes on the microscopic slide. In the studied chromosomal preparations, the hybridization colored signals were clearly visible. Counting the produced signals in twelve chromosomal preparations of three fishes from each species showed that the mean number of the signals in the chromosomal preparations of the Persian sturgeon and Russian sturgeon were 66±4 and 68±3 respectively. In this study, accurate kind determining of chromosomes and <em>Hind</em>III SatDNA site on the chromosomes were impossible due to the presence of microchromosomes and heterogeneity of shapes and sizes of colored signals.https://japb.guilan.ac.ir/article_3070_9ca3f3997c4c215dfc74c0bdde9b3f2e.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180922Effects of ethanolic extract of Aloe vera leaf on growth factors and reproductive performance in swordtail (Xiphophorus helleri)Effects of ethanolic extract of Aloe vera leaf on growth factors and reproductive performance in swordtail (Xiphophorus helleri)135150308110.22124/japb.2018.7770.1173FANiloufarMahigirM.Sc. Student in Aquaculture, Faculty of Fisheries and Environment, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, IranMohammadSudagarAssociate Professor in Department of Aquaculture, Faculty of Fisheries and Environment, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, IranAbbasaliHajibegloAssistant Professor in Department of Aquaculture, Faculty of Fisheries and Environment, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, IranShahramDadgarAssistant Professor in Fisheries Research Institute, Tehran, IranJournal Article20170613<em>Aloe vera</em> is a rich resource of antioxidants, vitamins, minerals, mineral acids and enzymes. Studies showed that <em>Aloe vera</em> can affect the physiology of reproduction in animals. The aim of this trial was to evaluate the effect of different levels of the ethanol extract of the <em>Aloe vera</em> plant on reproduction and growth performance in <em>Xiphophorus helleri</em>. Powder extract was added to the diet in 4 levels: 200, 400, 800 and 1600 mg/Kg and control group without any extract. At the end of the experiment the results showed that there were significant differences in final weight, final length, weight gain, weight gain percentage and SGR in fish fed 800 mg/Kg compare to control group. Also, there were remarkable differences in the gonadosomatic index in treatment 4 and 5 than 1, 2 and 3. In conclusion, <em>Aloe vera</em> extract can improve the growth performance, fecundity and gonadosomatic index in <em>Xiphophorus helleri</em>.<em>Aloe vera</em> is a rich resource of antioxidants, vitamins, minerals, mineral acids and enzymes. Studies showed that <em>Aloe vera</em> can affect the physiology of reproduction in animals. The aim of this trial was to evaluate the effect of different levels of the ethanol extract of the <em>Aloe vera</em> plant on reproduction and growth performance in <em>Xiphophorus helleri</em>. Powder extract was added to the diet in 4 levels: 200, 400, 800 and 1600 mg/Kg and control group without any extract. At the end of the experiment the results showed that there were significant differences in final weight, final length, weight gain, weight gain percentage and SGR in fish fed 800 mg/Kg compare to control group. Also, there were remarkable differences in the gonadosomatic index in treatment 4 and 5 than 1, 2 and 3. In conclusion, <em>Aloe vera</em> extract can improve the growth performance, fecundity and gonadosomatic index in <em>Xiphophorus helleri</em>.https://japb.guilan.ac.ir/article_3081_b398ec6e2476cf55db8667e580788af2.pdfUniversity of GuilanAquatic Physiology and Biotechnology2345-39666220180922Histopathological study and heavy metal lead and chromium bioaccumulation in gills and liver of tigertooth croaker (Otolithes ruber) in the Gulf of OmanHistopathological study and heavy metal lead and chromium bioaccumulation in gills and liver of tigertooth croaker (Otolithes ruber) in the Gulf of Oman151175308210.22124/japb.2018.7855.1175FAParvinSadeghiAssistant Professor in Department of Marine Biology, Faculty of Marine Sciences, Chabahar Maritime and Marine Science University, Chabahar, IranOmidKoohkanScientific Member in Department of Marine Biology, Faculty of Marine Sciences, Chabahar Maritime and Marine Science University, Chabahar, IranFatemehKhonyagarM.Sc. Student in Marine Biology, Marine Biology Department, Faculty of Marine Sciences, Chabahar Maritime and Marine Science University, Chabahar, IranJournal Article20170624<span>The aim of this study was investigated the accumulation of lead and chromium in liver and gills of tigertooth croaker (</span><em>Otolithes ruber</em><span>) and use of histopathological changes of gills and liver to evaluate the effects of Oman Sea pollutants. Tigertooth croakers with an average weight of 382.5±1.93g were collected from four stations include: Konarak desalination, Beris, Pasabandar and Gowatr and samples of liver and gill tissues were studied based on the routine histological methods. Chromium and lead concentrations in liver and gill tissues were measured by atomic absorption spectrophotometer. Most of the observed changes in liver tissue were destruction, vacuolation of hepatocytes, expansion of disk space, recession bile, hyperemia and hemorrhage, melanomacrophage centers, fat accumulation, pyknosis and necrosis. Also, in the gills, lifting epithelium, clubbing, hyperplasia and hypertrophy of chloride cells, mucus secretion, shorter blade and necrosis were recorded. The results showed that the Pasabandar station had the highest severity of tissue lesions and the highest bioaccumulation of metals in liver and gill tissues. Histopathological lesions of the tissue in tigertooth croaker can be considered as a bioindicator of the negative effects of contamination in the studied area. </span><span>The aim of this study was investigated the accumulation of lead and chromium in liver and gills of tigertooth croaker (</span><em>Otolithes ruber</em><span>) and use of histopathological changes of gills and liver to evaluate the effects of Oman Sea pollutants. Tigertooth croakers with an average weight of 382.5±1.93g were collected from four stations include: Konarak desalination, Beris, Pasabandar and Gowatr and samples of liver and gill tissues were studied based on the routine histological methods. Chromium and lead concentrations in liver and gill tissues were measured by atomic absorption spectrophotometer. Most of the observed changes in liver tissue were destruction, vacuolation of hepatocytes, expansion of disk space, recession bile, hyperemia and hemorrhage, melanomacrophage centers, fat accumulation, pyknosis and necrosis. Also, in the gills, lifting epithelium, clubbing, hyperplasia and hypertrophy of chloride cells, mucus secretion, shorter blade and necrosis were recorded. The results showed that the Pasabandar station had the highest severity of tissue lesions and the highest bioaccumulation of metals in liver and gill tissues. Histopathological lesions of the tissue in tigertooth croaker can be considered as a bioindicator of the negative effects of contamination in the studied area. </span>https://japb.guilan.ac.ir/article_3082_621d57a23e0354464db4ad48970d127a.pdf