Background: The homeobox containing transcription factor Nanog plays crucial roles in embryonic development/proliferation and/or maintenance of spermatogonial stem cells(SSCs) via interacting with transcription factor...Background: The homeobox containing transcription factor Nanog plays crucial roles in embryonic development/proliferation and/or maintenance of spermatogonial stem cells(SSCs) via interacting with transcription factors such as Oct4 and Sox2 in mammals. However, knowledge of its exact mechanistic pathways remains unexploited. Very little is known about teleost Nanog. Information on the Nanog gene of farmed rohu carp(Labeo rohita) is lacking. We cloned and characterized the Nanog gene of rohu carp to understand the expression pattern in early developmental stages and also deduced the genomic organization including promoter elements.Results: Rohu Nanog(LrNanog) cDNA comprised an open reading frame of 1,161 nucleotides bearing a structural homeodomain; whereas, the genomic structure contained four exons and three introns suggesting that it is homologous to mammalian counterparts. Phylogenetical y, it was closely related to freshwater counterparts. Protein sequence(386 AA of42.65 kDa) comparison revealed its low similarity with other vertebrate counterparts except that of the conserved homeodomain. Tissue distribution analysis revealed the existence of LrNanog transcripts only in adult gonads. The heightened abundances in the ovary and proliferating spermatogonia suggested its participations in maternal inheritance and male germ cell development. The potentiating abundances from fertilized egg onwards peaking at blastula stage vis-à-vis decreasing levels from gastrula stage onwards demonstrated its role in embryonic stem cell development. We also provided evidence of its presence in SSCs by western blotting analysis. Further, the promoter region was characterized, predicting a basal core promoter and other consensus elements.Conclusion: The molecular characterization of LrNanog and its documented expression profiling at transcript and protein levels are indicative of its functional linkage with embryonic/spermatogonial stem cell maintenance. This is the first report of LrNanog genomic organization including its promoter sequence information with predicted regulatory elements of a large-bodied carp species. This will be useful for elucidating its mechanism expression in future. Nanog could be used as a potential biomarker for proliferating carp SSCs.展开更多
ATPase 6/8 gene （842 bp） of mitochondrial DNA was sequenced in Labeo rohita samples （n = 253） collected from nine rivers belonging to four river basins; Indus, Ganges, Brahmaputra and Mahanadi. Analysis revealed 4...ATPase 6/8 gene （842 bp） of mitochondrial DNA was sequenced in Labeo rohita samples （n = 253） collected from nine rivers belonging to four river basins; Indus, Ganges, Brahmaputra and Mahanadi. Analysis revealed 44 haplotypes with high haplotype diversity （Hd） 0.694 and low nucleotide diversity （π） 0.001. The within population variation was larger （83.44%） than among population differences （16.56%）. The mean Fsv value （0.166; P 〈 0.05） for overall populations revealed moderate level of genetic structuring in the wild L. rohita populations. The haplotype network presented a single clade for wild L. rohita population, from different rivers. Negative values for Fu＇s index （Fs）, mismatch distribution analysis indicated period of expansion in L. rohita population. The time after recent expansion was estimated for each population, between 0.042 to 0.167 mya. The pattern of Isolation by Distance （IBD） was not significant （r = -0.113, P 〈 0.287）, when all the sampling locations were compared （Mantel test）, however, when an outlier （Indus, Brahmaputra and Mahanadi） was removed from the whole population set, a clear positive correlation between pairwise Fsv and geographic distance （Km） was seen. The analysis of data demonstrated that ATPase6/8 gene polymorphism is a potential marker to understand genetic population structure of wild L. rohita existing in different rivers. The study identified population substructure in wild L. rohita with common ancestral origin [Current Zoology 60 （4）： 460--471, 2014].展开更多
The Labeo dyocheilus(family Cyprinidae)in-habits fresh water streams at the fo thill regions and is a commercially important food fish.It is native to Afganistan,Pakistan,India,Nepal,Bhutan,Bangladesh,M yanmnar,Cambod...The Labeo dyocheilus(family Cyprinidae)in-habits fresh water streams at the fo thill regions and is a commercially important food fish.It is native to Afganistan,Pakistan,India,Nepal,Bhutan,Bangladesh,M yanmnar,Cambodia and Thailand(Froese and Pauly,2003).In India,the species in-habits the Indus,Ganges and Mahanadi river sys-terns.It is identified as a potential cultivable species and has considerable significance for the fishery of these regions.L.dyocheilus has been categorized as a vulnerable fish due to declining commercial catches in India(Mahanta et a1.,1994).At present the fishery is supported through capture from natural sources.To achieve domestication,various aspects of captive breeding and propagation are being studied.展开更多
Unwarranted accumulation of halogenated compounds in the rivers and streams has in recent years emerged due to the widespread use agricultural pesticides. The presence of these halogenated compounds in the water does ...Unwarranted accumulation of halogenated compounds in the rivers and streams has in recent years emerged due to the widespread use agricultural pesticides. The presence of these halogenated compounds in the water does not only suppress the immune system of fish but adversely induce serious morbidity and mortality among cultured stocks. Importantly, gradual accumulation of these compounds in the system of cultured and wild freshwater fish species cultured in ponds and floating net-cages in dams and rivers, respectively, poses some risks to humans, the end users. In this study, we attempted to isolate bacteria from the gut of pond-reared rohu (Labeo rohita) in Myanmar, screened the isolated bacteria for dehalogenase gene using molecular technique and tested the ability of these bacteria to degrade halogenated compounds in vitro. The eight bacterial strains studied were identified as Enterobacter mori strain MK- 121001, Enterobacter cloacae strains MK121003, MK-121004, MK121010, Ralstonia solanacearum strain 121002, Acinetobacter baumannii strain MK121007, Chromobacterium violaceum strain MK121009 and Pantoea vagans strain 121011. Only three bacterial strains (MK121002, MK121007 and MK121009) were capable of degrading 2,2-dichloropropionic acid (2,2-DCP) as the sole carbon source up to a final substrate concentration of 20 mM. Their mean growth doubling time ranging from 6-23 hours with the maximum of chloride ion released of 85%. PCR amplifica- tion with oligonucleotide primers designed from group I dehalogenase revealed the presence of deha- logenase genes in all isolates suggesting dehalogenase gene in strains 121001, 121003, 121004, 121010 and 121011 were silenced. In contrast, group II dehalogenase primers did not show any PCR amplification. These results suggest that MK121002, MK121007 and MK121009 only encode a group I dehalogenase and its non-stereoselectivity is in agreement with previoulsly described group I haloacid dehalogenase. The partial gene sequences were blasted but no significant sequence identity was observed. Therefore, it suggest the 2-haloacid dehalogenase of MK121002, MK12-1007 and MK121009 might be a novel group I 2-haloacid dehalogenase. The results indicated a broad distribution of dehalogenation genes in many micro- bial genomes that harbor dehalogenase(s) due to the exposure of the microorganisms to the naturally occurring or man-made halogenated compounds in the environmental systems. So far, microorganisms capable of producing dehalogenases were mainly isolated from soil and scarcely from aquatic animals and their environments. To the authors’ knowledge, this is the first report on the isolation of dehalogenase-producing bacteria from the gut of pond-reared freshwater fish, Labeo rohita, in Myanmar.展开更多
Optimum conditions for in vitro production of interleukin 2 （IL 2） like activity from the Peripheral blood lymphocytes （PBL） of an Indian major carp, Labeo rohita were studied. Culture supernatants were generated ...Optimum conditions for in vitro production of interleukin 2 （IL 2） like activity from the Peripheral blood lymphocytes （PBL） of an Indian major carp, Labeo rohita were studied. Culture supernatants were generated by culturing the PBL in RPMI-1640 media supplemented with Glutamine and 10% fetal bovine serum （FBS） and stimulating with two different mitogens： concanavalin A （Con A） and Phytohaemagglutinin （PHA） at different concentrations separately. Significantly （P 〈 0.01） higher proliferation response was obtained from the culture supematant stimulated with concanavalin A （Con A） at a concentration of 10 lag mLl. The effect of phorbol myristate acetate （PMA） was also studied by co-stimulating PBL with Con A and PHA separately and it was found to synergistically enhancing the stimulation index with Con A whereas the stimulation index remain unchanged with PHA. The Con A （10 μg mLl） stimulated PBL were also cultured at different cell density, incubation period and incubation temperature in order to optimize the in vitro L. rohita IL2 production. The IL2 like activity was studied by lymphocyte proliferation assay on 72 h Con A blasts using WST based assay technique. Significantly （P 〈 0.01） higher stimulation indices were obtained when the PBL were cultured at a cell density of 1 × 10^6 cells mL^-1 for 30-36 h at an incubation temperature of 30 ℃. The IL2 like activity was purified by DEAE-Sepharose anion exchange chromatography and recorded between 70-130 mM NaCI with peak activity at 110 Mm NaCI. The molecular weight of the factor responsible for IL2 like activity was found to be 15-17 KD.展开更多
The present work reports the length–weight relationships(LWR)and condition factor relationships for Labeo calbasu collected from Upstream(Matyari)Kotri barrage at,River Indus,Pakistan,because stock assessment helps t...The present work reports the length–weight relationships(LWR)and condition factor relationships for Labeo calbasu collected from Upstream(Matyari)Kotri barrage at,River Indus,Pakistan,because stock assessment helps the fisheries managers to conserve the commercially important fish.Morphological characters of fish as well as Length-weight relationship are an important tool for fishery management.The results of LWR(W=aLb),for L calbasu.Representing negative allometric growth pattern.LWRs and condition factor relationships were found significantly correlated.A total of 200 and 190 specimens from upstream and downstream were collected,respectively.The assessed values of length-weight correlation and condition factor were calculated as Kn=39.663(LeCren),and K=11.915(Fulton)for upstream and Kn=44.066 and K=13.872 for downstream.Length-weight was found with a strong correlation of n=2.892,a=0.0235 with r2=0.934 for upstream population then the downstream population.The results of this work would be beneficial for sustainable management as well as fishery managers.展开更多
Multi-strain probiotics provide the most dependable approaches to improve health,immune response,and disease resistance in farmed fishes.In the present study,we examined the effects of multi-species probiotics on the ...Multi-strain probiotics provide the most dependable approaches to improve health,immune response,and disease resistance in farmed fishes.In the present study,we examined the effects of multi-species probiotics on the survival,growth,immune response,and disease resistance of rohu(Labeo rohita)larvae.Newly hatched larvae from the day of first feeding(average weight of 0.003 g)were reared with multi-species probiotics having a combination of Bacillus subtilis(109 colony forming units(cfu)/mL)and Lactobacillus spp.(Lactobacillus plantarum,Lactobacillus buchneri-1011 cfu/mL)in water containing doses of 0(control-C),0.5 mL/L(treatment 1-T1),and 1.0 mL/L(treatment 2-T2)in triplicates for 90 days.After the experiment,a challenge test was performed to assess the fish's resistance to pathogenic Aeromonas veronii.Significantly higher survival was recorded in larvae of treated groups(87%in T2 and 79%in T1)compared to the control(62%).Significantly higher growth performance(weight gain and specific growth rate—SGR)was shown by the probiotic-treated larval groups compared to the control.Probiotic supplementation resulted in significantly higher counts of total viable colony(TVC)and lactic acid bacteria(LAB)in the intestine.Some immunological parameters(mucosal fold fattening,goblet cell abundance,expansion of lamina propria and enterocytes)of the gut were significantly better in probiotic-treated fish.The liver of treated fish showed irregular shape nuclei turning into regular shape and reducing spaces between the hepatic cells.Probiotic-treated fish had the highest post-challenge survival rate(90%)against A.veronii infection.The erythrocytes of challenged fish treated with probiotics had significantly lower frequencies of various nuclear and cellular abnormalities.These findings suggest that multi-species probiotic supplements could improve the survival,growth,health status,and immune response of rohu in the early stages of its development.展开更多
Epizoic algae growing upon molluscs and turtles were earlier reported by Hutchinson and La Rivers. Recently Leghari (1983) has reported epizoic algae from some molluscs of Sind. Many species of green and blue-green al...Epizoic algae growing upon molluscs and turtles were earlier reported by Hutchinson and La Rivers. Recently Leghari (1983) has reported epizoic algae from some molluscs of Sind. Many species of green and blue-green algae have been recorded as growing upon the body of fish. Vinyard found that Cladophora sp. occurred on the operculum of Ictiobus bubalus from lake Texoma, USA. In 1960 Hoffman et al. re-展开更多
Aquatic environment gets highly polluted due to the presence of heavy metals,which are usually discharged into water bodies because of rapid industrialization.The main purpose of this study is to evaluate the effects ...Aquatic environment gets highly polluted due to the presence of heavy metals,which are usually discharged into water bodies because of rapid industrialization.The main purpose of this study is to evaluate the effects of chromium toxicity on histo-biochemical biomarkers of Labeo rohita.A total of 240 randomly selected fish were distributed into four aquaria(n=20).Three groups designated as T_(1),T_(2) and T_(3) were exposed with 1/3rd,1/5th and 1/10th of LC_(50) of chromium chloride,and the fourth group was chromium-free control(T0).Results showed a significant(p<0.05)decrease in blood parameters such as hematocrit,red blood cells,hemoglobin,mean cell hemoglobin and platelets.In contrast,mean cell volume and white blood cell values increased significantly.The results obtained by comet assay showed that DNA damage was increased significantly(p<0.05)in chromium-exposed groups compared to the control.At the histopathological level,observed alterations in the gill tissues are degeneration of epithelium,fusion of secondary lamellae,lamellar curling,hypertrophy,telangiectasis and oedema,while in the liver is necrosis,dilation of the vein,congestion of blood vessels,hepatocytes degeneration,melano-macrophage centers,pigmentation and hemorrhage.In the kidney,histological alterations such as glomerular destruction,necrosis,damaged blood vessels,oedema and pigmentation were seen.Those results suggest that chromium has the ability to bring variations DNA integrity,histopathology and blood of Labeo rohita.展开更多
Objective:To conduct on sustainable fingerling production technique of endangered Labeo calbasu (Hamilton, 1822) (L. calbasu) based on different protein levels in ponds. Methods: The experiment was carried out under r...Objective:To conduct on sustainable fingerling production technique of endangered Labeo calbasu (Hamilton, 1822) (L. calbasu) based on different protein levels in ponds. Methods: The experiment was carried out under rearing pond in fish hatchery complex with three treatments group each having three replicates under department of fisheries, University of Rajshahi.L. calbasu were stocked at 41990/ha in T1, T2 and T3, respectively. The initial length ofL. calbasu in three treatments were (4.60 ± 0.10) cm and initial weights were (3.48 ± 0.01) g. Fishes were fed with 28%, 30%, 32% protein supplement for T1, T2, T3, respectively. The fishes were initially fed at 10% of body weight on 1st and 2nd fortnight. Then it was decreased at 8% of body weight on 3rd and 4th fortnight. Finally in 5th fortnight they were fed 5% of body weight. The physico-chemical characteristics of pond water were measured fortnightly. Results: The mean final weight gain was found highest in T3 (40.87 ± 0.01) g which was significant compared to T1 and T2. SGR (% bwd–1) was found 2.83 ± 0.02 (T1), 3.04 ± 0.01 (T2) and 3.39 ± 0.01 (T3). The highest survival rate ofL. calbasu was found in T3 (90.00 ± 1.00) and the lowest was found in T1 (87.00 ± 1.00). The best FCR (1.54 ± 0.01) was observed in T3 fed with 32% protein supplement. The highest production was observed in T3 (1672.20 ± 16.96 kg/ha/75 days) and lowest was observed in T1(1055.50 ± 29.04 kg/ha/75 days). The highest net benefit was calculated in T3 (260663.00 ± 4326.88 tk.) and lowest was found in T1 (112831.00 ± 7383.66 tk.). The CBR was found 0.60 ± 0.04, 0.80 ± 0.02 and 1.16 ± 0.02 in T1, T2 and T3, respectively. There were significant differences in CBR values among the three treatments. Conclutions:In this study, growth parametersi.e., weight gain, SGR (% bwd–1), length gain, total yield were significantly (P < 0.05) improved in T3 treatment fed with 32% protein supplemented diets.展开更多
Labeo victorianus(Boulenger,1901)is one of the endemic fishes in Lake Victoria Basin(LVB)but is now threatened by multiple stressors caused by human activities.We investigated spatial and temporal variability in food ...Labeo victorianus(Boulenger,1901)is one of the endemic fishes in Lake Victoria Basin(LVB)but is now threatened by multiple stressors caused by human activities.We investigated spatial and temporal variability in food composition and condition of L.victorianus in influent rivers of Lake Victoria,Kenya.Sampling was done during the dry and wet seasons by electrofishing.Food composition analysis showed that L.victorianus is a benthophagus and omnivorous species whose diet is dominated by detritus,periphyton and insects.There were differences in food composition among rivers,with significant river X season interactions(PERMANOVA F=11.6,df=4,p=0.001),suggesting that the diet depended on prevailing environmental conditions.In turbid rivers,the diet was dominated by detritus while in less turbid rivers it was dominated by insects and periphyton.Sand and mud also formed a significant part of the diet,which was an indication of a limited occurrence of preferable food items.There were ontogenetic shifts in food composition(PERMANOVA F=4.6,df=3,p=0.001),but also with a spatial interaction(PERMANOVA F=5.6,df=7,p=0.001),further indicating the role of environmental conditions in determining the diet for different size classes.Interestingly,the fish condition did not differ among rivers.This study shows that turbidity and organic matter and nutrient loading determine the diet of L.victorianus in LVB rivers,and provides further justification for the maintenance of water quality as a conservation measure for threatened species.展开更多
There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas(Hemibarbus labeo)egg.From the outer to the inner of the cortex,the diameter of the cortical alveoli decreases gradually.We found a n...There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas(Hemibarbus labeo)egg.From the outer to the inner of the cortex,the diameter of the cortical alveoli decreases gradually.We found a new structure named solicitation speckle at the low latitude of the animal pole and near the micropylar apparatus between the ovum envelope and cell membrane in the zygote of fish.The solicitation speckle similar to type I cortical alveoli was very purple in H.E chromosome,and it had no obvious boundary with the ovum envelope and membrane.Moreover,no membrane around the solicitation speckle in TEM was found.In SEM,the solicitation speckle looked flocculent.During cortical reaction,the solicitation speckle played a very important function in arousing cortical reaction.Thirty-five seconds after fertilization,cortical alveoli began to break down near the low latitude of the animal pole.At the same time,the same thing happened near the micropylar apparatus before cortical reaction.Both starting points encountered and healed up at the vestibule of the micropylar apparatus.The cortical reaction that happened near the low latitude of the animal pole was another new pattern.The cortical reaction was divided into four parts that included latent period,developmental period,climactic period and declining period.In the latent period,no cortical alveoli were released.In the developmental period,a few cortical alveoli were released outside the cortex.In the climactic period,several cortical alveoli were inosculated into a big vesicle and released intensely.In the declining period,the type V cortical alveoli and the other remnant cortical alveoli were released.Five minutes after fertilization,cortical alveoli were released entirely in the animal pole.Five minutes after fertilization,all of the remnant cortical alveoli were released.This leads us to conclude that cortical reaction is induced by type I cortical alveoli,and the solicitation speckle is a volcanic chain reaction under water or the other lower osmotic pressure of fluids.The outer cortical reaction can accelerate the inner cortical reaction.While cortical alveoli releases in batches,the cell plasma membrane is reorganized over and over.No cortical alveoli were found below the micropylar tube where sperm enters the ovum,which suggests that the cortical reaction prevents polyspermy.展开更多
Objective:To observe the effectiveness of most widely used antibiotic,oxytetracycline(OTC)in reducing the bacterial load in rohu fish under artificial culture condition in the laboratory.Methods:The experiment was con...Objective:To observe the effectiveness of most widely used antibiotic,oxytetracycline(OTC)in reducing the bacterial load in rohu fish under artificial culture condition in the laboratory.Methods:The experiment was conducted in the Faculty Fisheries,Bangladesh Agricultural University,Mymensingh-2202.The fish were reared in 8 aquaria where fish in 5 aquaria were used for replication of the treatment(experimental group)and fish in remaining 3 aquaria were considered as a control(Control group).OTC was fed to the fish in the experimental aquarium at the rate of 2 g/kg through diet twice daily whereas fish reared under control condition was given feed without antibiotic for 20 d and bacterial content in the aquarium water,gills,skin and intestine of fish were estimated at every alternative day after onset of the experiment.Results:Rearing the fish with OTC treated feed resulted in gradual decrease of bacterial load in the aquarium water,gills,intestine and skin of the fish whereas the content remain unchanged Or little increased in the control group.W ater quality parameters such as dissolved oxygen,pH and total hardness were within the suitable range in the experimental aquarium but not in control aquaria throughout the experimental period.Conclusions:These results suggest that OTC could be a potential antibiotic to reduce the bacterial load in fish and can be used commercially for maintaining the fish health in aquarium conditions.展开更多
This study extensively investigated to find out the in-vivo acute toxicity and lethal concentration(LC50)of biosynthesized Ag NPs in Labeo rohita(L.rohita).The haematological studies and antioxidative responses were c...This study extensively investigated to find out the in-vivo acute toxicity and lethal concentration(LC50)of biosynthesized Ag NPs in Labeo rohita(L.rohita).The haematological studies and antioxidative responses were considered in three tissues such as gill,liver and muscle of L.rohita.The results of this study showed that increasing the dose of Ag NPs led to bioaccumulation in the tissues.The haematological analysis showed considerable alterations in the Ag NPs-treated fish.The impact of histological changes induced by Ag NPs were confirmed by the damages in the tissues,primary lamella,blood vessels and formation of vacuolation in liver and muscle when compared with the control L.rohita.展开更多
基金provided by grant from Indian Council of Agricultural Research (ICAR) and Department of Biotechnology(DBT),Government of India
文摘Background: The homeobox containing transcription factor Nanog plays crucial roles in embryonic development/proliferation and/or maintenance of spermatogonial stem cells(SSCs) via interacting with transcription factors such as Oct4 and Sox2 in mammals. However, knowledge of its exact mechanistic pathways remains unexploited. Very little is known about teleost Nanog. Information on the Nanog gene of farmed rohu carp(Labeo rohita) is lacking. We cloned and characterized the Nanog gene of rohu carp to understand the expression pattern in early developmental stages and also deduced the genomic organization including promoter elements.Results: Rohu Nanog(LrNanog) cDNA comprised an open reading frame of 1,161 nucleotides bearing a structural homeodomain; whereas, the genomic structure contained four exons and three introns suggesting that it is homologous to mammalian counterparts. Phylogenetical y, it was closely related to freshwater counterparts. Protein sequence(386 AA of42.65 kDa) comparison revealed its low similarity with other vertebrate counterparts except that of the conserved homeodomain. Tissue distribution analysis revealed the existence of LrNanog transcripts only in adult gonads. The heightened abundances in the ovary and proliferating spermatogonia suggested its participations in maternal inheritance and male germ cell development. The potentiating abundances from fertilized egg onwards peaking at blastula stage vis-à-vis decreasing levels from gastrula stage onwards demonstrated its role in embryonic stem cell development. We also provided evidence of its presence in SSCs by western blotting analysis. Further, the promoter region was characterized, predicting a basal core promoter and other consensus elements.Conclusion: The molecular characterization of LrNanog and its documented expression profiling at transcript and protein levels are indicative of its functional linkage with embryonic/spermatogonial stem cell maintenance. This is the first report of LrNanog genomic organization including its promoter sequence information with predicted regulatory elements of a large-bodied carp species. This will be useful for elucidating its mechanism expression in future. Nanog could be used as a potential biomarker for proliferating carp SSCs.
文摘ATPase 6/8 gene （842 bp） of mitochondrial DNA was sequenced in Labeo rohita samples （n = 253） collected from nine rivers belonging to four river basins; Indus, Ganges, Brahmaputra and Mahanadi. Analysis revealed 44 haplotypes with high haplotype diversity （Hd） 0.694 and low nucleotide diversity （π） 0.001. The within population variation was larger （83.44%） than among population differences （16.56%）. The mean Fsv value （0.166; P 〈 0.05） for overall populations revealed moderate level of genetic structuring in the wild L. rohita populations. The haplotype network presented a single clade for wild L. rohita population, from different rivers. Negative values for Fu＇s index （Fs）, mismatch distribution analysis indicated period of expansion in L. rohita population. The time after recent expansion was estimated for each population, between 0.042 to 0.167 mya. The pattern of Isolation by Distance （IBD） was not significant （r = -0.113, P 〈 0.287）, when all the sampling locations were compared （Mantel test）, however, when an outlier （Indus, Brahmaputra and Mahanadi） was removed from the whole population set, a clear positive correlation between pairwise Fsv and geographic distance （Km） was seen. The analysis of data demonstrated that ATPase6/8 gene polymorphism is a potential marker to understand genetic population structure of wild L. rohita existing in different rivers. The study identified population substructure in wild L. rohita with common ancestral origin [Current Zoology 60 （4）： 460--471, 2014].
基金This research was funded by agrant from ICAR(No NBFGR/DNA25A)
文摘The Labeo dyocheilus(family Cyprinidae)in-habits fresh water streams at the fo thill regions and is a commercially important food fish.It is native to Afganistan,Pakistan,India,Nepal,Bhutan,Bangladesh,M yanmnar,Cambodia and Thailand(Froese and Pauly,2003).In India,the species in-habits the Indus,Ganges and Mahanadi river sys-terns.It is identified as a potential cultivable species and has considerable significance for the fishery of these regions.L.dyocheilus has been categorized as a vulnerable fish due to declining commercial catches in India(Mahanta et a1.,1994).At present the fishery is supported through capture from natural sources.To achieve domestication,various aspects of captive breeding and propagation are being studied.
文摘Unwarranted accumulation of halogenated compounds in the rivers and streams has in recent years emerged due to the widespread use agricultural pesticides. The presence of these halogenated compounds in the water does not only suppress the immune system of fish but adversely induce serious morbidity and mortality among cultured stocks. Importantly, gradual accumulation of these compounds in the system of cultured and wild freshwater fish species cultured in ponds and floating net-cages in dams and rivers, respectively, poses some risks to humans, the end users. In this study, we attempted to isolate bacteria from the gut of pond-reared rohu (Labeo rohita) in Myanmar, screened the isolated bacteria for dehalogenase gene using molecular technique and tested the ability of these bacteria to degrade halogenated compounds in vitro. The eight bacterial strains studied were identified as Enterobacter mori strain MK- 121001, Enterobacter cloacae strains MK121003, MK-121004, MK121010, Ralstonia solanacearum strain 121002, Acinetobacter baumannii strain MK121007, Chromobacterium violaceum strain MK121009 and Pantoea vagans strain 121011. Only three bacterial strains (MK121002, MK121007 and MK121009) were capable of degrading 2,2-dichloropropionic acid (2,2-DCP) as the sole carbon source up to a final substrate concentration of 20 mM. Their mean growth doubling time ranging from 6-23 hours with the maximum of chloride ion released of 85%. PCR amplifica- tion with oligonucleotide primers designed from group I dehalogenase revealed the presence of deha- logenase genes in all isolates suggesting dehalogenase gene in strains 121001, 121003, 121004, 121010 and 121011 were silenced. In contrast, group II dehalogenase primers did not show any PCR amplification. These results suggest that MK121002, MK121007 and MK121009 only encode a group I dehalogenase and its non-stereoselectivity is in agreement with previoulsly described group I haloacid dehalogenase. The partial gene sequences were blasted but no significant sequence identity was observed. Therefore, it suggest the 2-haloacid dehalogenase of MK121002, MK12-1007 and MK121009 might be a novel group I 2-haloacid dehalogenase. The results indicated a broad distribution of dehalogenation genes in many micro- bial genomes that harbor dehalogenase(s) due to the exposure of the microorganisms to the naturally occurring or man-made halogenated compounds in the environmental systems. So far, microorganisms capable of producing dehalogenases were mainly isolated from soil and scarcely from aquatic animals and their environments. To the authors’ knowledge, this is the first report on the isolation of dehalogenase-producing bacteria from the gut of pond-reared freshwater fish, Labeo rohita, in Myanmar.
文摘Optimum conditions for in vitro production of interleukin 2 （IL 2） like activity from the Peripheral blood lymphocytes （PBL） of an Indian major carp, Labeo rohita were studied. Culture supernatants were generated by culturing the PBL in RPMI-1640 media supplemented with Glutamine and 10% fetal bovine serum （FBS） and stimulating with two different mitogens： concanavalin A （Con A） and Phytohaemagglutinin （PHA） at different concentrations separately. Significantly （P 〈 0.01） higher proliferation response was obtained from the culture supematant stimulated with concanavalin A （Con A） at a concentration of 10 lag mLl. The effect of phorbol myristate acetate （PMA） was also studied by co-stimulating PBL with Con A and PHA separately and it was found to synergistically enhancing the stimulation index with Con A whereas the stimulation index remain unchanged with PHA. The Con A （10 μg mLl） stimulated PBL were also cultured at different cell density, incubation period and incubation temperature in order to optimize the in vitro L. rohita IL2 production. The IL2 like activity was studied by lymphocyte proliferation assay on 72 h Con A blasts using WST based assay technique. Significantly （P 〈 0.01） higher stimulation indices were obtained when the PBL were cultured at a cell density of 1 × 10^6 cells mL^-1 for 30-36 h at an incubation temperature of 30 ℃. The IL2 like activity was purified by DEAE-Sepharose anion exchange chromatography and recorded between 70-130 mM NaCI with peak activity at 110 Mm NaCI. The molecular weight of the factor responsible for IL2 like activity was found to be 15-17 KD.
基金The present work is partial work of M.Phil research scholar.
文摘The present work reports the length–weight relationships(LWR)and condition factor relationships for Labeo calbasu collected from Upstream(Matyari)Kotri barrage at,River Indus,Pakistan,because stock assessment helps the fisheries managers to conserve the commercially important fish.Morphological characters of fish as well as Length-weight relationship are an important tool for fishery management.The results of LWR(W=aLb),for L calbasu.Representing negative allometric growth pattern.LWRs and condition factor relationships were found significantly correlated.A total of 200 and 190 specimens from upstream and downstream were collected,respectively.The assessed values of length-weight correlation and condition factor were calculated as Kn=39.663(LeCren),and K=11.915(Fulton)for upstream and Kn=44.066 and K=13.872 for downstream.Length-weight was found with a strong correlation of n=2.892,a=0.0235 with r2=0.934 for upstream population then the downstream population.The results of this work would be beneficial for sustainable management as well as fishery managers.
基金Krishi Gobeshona Foundation,Bangladesh Agricultural Research Council,Dhaka,supported a grant(CGP TF 75-F/20)the corresponding author.Bangladesh Agricultural University Research System(BAURES)is gratefully acknowledged for the financial management of this project(Project No.2020/954/KGF).
文摘Multi-strain probiotics provide the most dependable approaches to improve health,immune response,and disease resistance in farmed fishes.In the present study,we examined the effects of multi-species probiotics on the survival,growth,immune response,and disease resistance of rohu(Labeo rohita)larvae.Newly hatched larvae from the day of first feeding(average weight of 0.003 g)were reared with multi-species probiotics having a combination of Bacillus subtilis(109 colony forming units(cfu)/mL)and Lactobacillus spp.(Lactobacillus plantarum,Lactobacillus buchneri-1011 cfu/mL)in water containing doses of 0(control-C),0.5 mL/L(treatment 1-T1),and 1.0 mL/L(treatment 2-T2)in triplicates for 90 days.After the experiment,a challenge test was performed to assess the fish's resistance to pathogenic Aeromonas veronii.Significantly higher survival was recorded in larvae of treated groups(87%in T2 and 79%in T1)compared to the control(62%).Significantly higher growth performance(weight gain and specific growth rate—SGR)was shown by the probiotic-treated larval groups compared to the control.Probiotic supplementation resulted in significantly higher counts of total viable colony(TVC)and lactic acid bacteria(LAB)in the intestine.Some immunological parameters(mucosal fold fattening,goblet cell abundance,expansion of lamina propria and enterocytes)of the gut were significantly better in probiotic-treated fish.The liver of treated fish showed irregular shape nuclei turning into regular shape and reducing spaces between the hepatic cells.Probiotic-treated fish had the highest post-challenge survival rate(90%)against A.veronii infection.The erythrocytes of challenged fish treated with probiotics had significantly lower frequencies of various nuclear and cellular abnormalities.These findings suggest that multi-species probiotic supplements could improve the survival,growth,health status,and immune response of rohu in the early stages of its development.
文摘Epizoic algae growing upon molluscs and turtles were earlier reported by Hutchinson and La Rivers. Recently Leghari (1983) has reported epizoic algae from some molluscs of Sind. Many species of green and blue-green algae have been recorded as growing upon the body of fish. Vinyard found that Cladophora sp. occurred on the operculum of Ictiobus bubalus from lake Texoma, USA. In 1960 Hoffman et al. re-
文摘Aquatic environment gets highly polluted due to the presence of heavy metals,which are usually discharged into water bodies because of rapid industrialization.The main purpose of this study is to evaluate the effects of chromium toxicity on histo-biochemical biomarkers of Labeo rohita.A total of 240 randomly selected fish were distributed into four aquaria(n=20).Three groups designated as T_(1),T_(2) and T_(3) were exposed with 1/3rd,1/5th and 1/10th of LC_(50) of chromium chloride,and the fourth group was chromium-free control(T0).Results showed a significant(p<0.05)decrease in blood parameters such as hematocrit,red blood cells,hemoglobin,mean cell hemoglobin and platelets.In contrast,mean cell volume and white blood cell values increased significantly.The results obtained by comet assay showed that DNA damage was increased significantly(p<0.05)in chromium-exposed groups compared to the control.At the histopathological level,observed alterations in the gill tissues are degeneration of epithelium,fusion of secondary lamellae,lamellar curling,hypertrophy,telangiectasis and oedema,while in the liver is necrosis,dilation of the vein,congestion of blood vessels,hepatocytes degeneration,melano-macrophage centers,pigmentation and hemorrhage.In the kidney,histological alterations such as glomerular destruction,necrosis,damaged blood vessels,oedema and pigmentation were seen.Those results suggest that chromium has the ability to bring variations DNA integrity,histopathology and blood of Labeo rohita.
文摘Objective:To conduct on sustainable fingerling production technique of endangered Labeo calbasu (Hamilton, 1822) (L. calbasu) based on different protein levels in ponds. Methods: The experiment was carried out under rearing pond in fish hatchery complex with three treatments group each having three replicates under department of fisheries, University of Rajshahi.L. calbasu were stocked at 41990/ha in T1, T2 and T3, respectively. The initial length ofL. calbasu in three treatments were (4.60 ± 0.10) cm and initial weights were (3.48 ± 0.01) g. Fishes were fed with 28%, 30%, 32% protein supplement for T1, T2, T3, respectively. The fishes were initially fed at 10% of body weight on 1st and 2nd fortnight. Then it was decreased at 8% of body weight on 3rd and 4th fortnight. Finally in 5th fortnight they were fed 5% of body weight. The physico-chemical characteristics of pond water were measured fortnightly. Results: The mean final weight gain was found highest in T3 (40.87 ± 0.01) g which was significant compared to T1 and T2. SGR (% bwd–1) was found 2.83 ± 0.02 (T1), 3.04 ± 0.01 (T2) and 3.39 ± 0.01 (T3). The highest survival rate ofL. calbasu was found in T3 (90.00 ± 1.00) and the lowest was found in T1 (87.00 ± 1.00). The best FCR (1.54 ± 0.01) was observed in T3 fed with 32% protein supplement. The highest production was observed in T3 (1672.20 ± 16.96 kg/ha/75 days) and lowest was observed in T1(1055.50 ± 29.04 kg/ha/75 days). The highest net benefit was calculated in T3 (260663.00 ± 4326.88 tk.) and lowest was found in T1 (112831.00 ± 7383.66 tk.). The CBR was found 0.60 ± 0.04, 0.80 ± 0.02 and 1.16 ± 0.02 in T1, T2 and T3, respectively. There were significant differences in CBR values among the three treatments. Conclutions:In this study, growth parametersi.e., weight gain, SGR (% bwd–1), length gain, total yield were significantly (P < 0.05) improved in T3 treatment fed with 32% protein supplemented diets.
基金support was provided by the National Research Fund(NRF),Kenya through the KISS Project.
文摘Labeo victorianus(Boulenger,1901)is one of the endemic fishes in Lake Victoria Basin(LVB)but is now threatened by multiple stressors caused by human activities.We investigated spatial and temporal variability in food composition and condition of L.victorianus in influent rivers of Lake Victoria,Kenya.Sampling was done during the dry and wet seasons by electrofishing.Food composition analysis showed that L.victorianus is a benthophagus and omnivorous species whose diet is dominated by detritus,periphyton and insects.There were differences in food composition among rivers,with significant river X season interactions(PERMANOVA F=11.6,df=4,p=0.001),suggesting that the diet depended on prevailing environmental conditions.In turbid rivers,the diet was dominated by detritus while in less turbid rivers it was dominated by insects and periphyton.Sand and mud also formed a significant part of the diet,which was an indication of a limited occurrence of preferable food items.There were ontogenetic shifts in food composition(PERMANOVA F=4.6,df=3,p=0.001),but also with a spatial interaction(PERMANOVA F=5.6,df=7,p=0.001),further indicating the role of environmental conditions in determining the diet for different size classes.Interestingly,the fish condition did not differ among rivers.This study shows that turbidity and organic matter and nutrient loading determine the diet of L.victorianus in LVB rivers,and provides further justification for the maintenance of water quality as a conservation measure for threatened species.
基金This paper was supported by Chongqing Scien-tific Committee Project(No.2001-6630)Three Gorges Reservoir Area Environmental Key Laboratory of Ministry of Education Fund(No.03121).
文摘There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas(Hemibarbus labeo)egg.From the outer to the inner of the cortex,the diameter of the cortical alveoli decreases gradually.We found a new structure named solicitation speckle at the low latitude of the animal pole and near the micropylar apparatus between the ovum envelope and cell membrane in the zygote of fish.The solicitation speckle similar to type I cortical alveoli was very purple in H.E chromosome,and it had no obvious boundary with the ovum envelope and membrane.Moreover,no membrane around the solicitation speckle in TEM was found.In SEM,the solicitation speckle looked flocculent.During cortical reaction,the solicitation speckle played a very important function in arousing cortical reaction.Thirty-five seconds after fertilization,cortical alveoli began to break down near the low latitude of the animal pole.At the same time,the same thing happened near the micropylar apparatus before cortical reaction.Both starting points encountered and healed up at the vestibule of the micropylar apparatus.The cortical reaction that happened near the low latitude of the animal pole was another new pattern.The cortical reaction was divided into four parts that included latent period,developmental period,climactic period and declining period.In the latent period,no cortical alveoli were released.In the developmental period,a few cortical alveoli were released outside the cortex.In the climactic period,several cortical alveoli were inosculated into a big vesicle and released intensely.In the declining period,the type V cortical alveoli and the other remnant cortical alveoli were released.Five minutes after fertilization,cortical alveoli were released entirely in the animal pole.Five minutes after fertilization,all of the remnant cortical alveoli were released.This leads us to conclude that cortical reaction is induced by type I cortical alveoli,and the solicitation speckle is a volcanic chain reaction under water or the other lower osmotic pressure of fluids.The outer cortical reaction can accelerate the inner cortical reaction.While cortical alveoli releases in batches,the cell plasma membrane is reorganized over and over.No cortical alveoli were found below the micropylar tube where sperm enters the ovum,which suggests that the cortical reaction prevents polyspermy.
基金Supported in part by Bangladesh Fisheries Research Institute(BFRI).
文摘Objective:To observe the effectiveness of most widely used antibiotic,oxytetracycline(OTC)in reducing the bacterial load in rohu fish under artificial culture condition in the laboratory.Methods:The experiment was conducted in the Faculty Fisheries,Bangladesh Agricultural University,Mymensingh-2202.The fish were reared in 8 aquaria where fish in 5 aquaria were used for replication of the treatment(experimental group)and fish in remaining 3 aquaria were considered as a control(Control group).OTC was fed to the fish in the experimental aquarium at the rate of 2 g/kg through diet twice daily whereas fish reared under control condition was given feed without antibiotic for 20 d and bacterial content in the aquarium water,gills,skin and intestine of fish were estimated at every alternative day after onset of the experiment.Results:Rearing the fish with OTC treated feed resulted in gradual decrease of bacterial load in the aquarium water,gills,intestine and skin of the fish whereas the content remain unchanged Or little increased in the control group.W ater quality parameters such as dissolved oxygen,pH and total hardness were within the suitable range in the experimental aquarium but not in control aquaria throughout the experimental period.Conclusions:These results suggest that OTC could be a potential antibiotic to reduce the bacterial load in fish and can be used commercially for maintaining the fish health in aquarium conditions.
文摘This study extensively investigated to find out the in-vivo acute toxicity and lethal concentration(LC50)of biosynthesized Ag NPs in Labeo rohita(L.rohita).The haematological studies and antioxidative responses were considered in three tissues such as gill,liver and muscle of L.rohita.The results of this study showed that increasing the dose of Ag NPs led to bioaccumulation in the tissues.The haematological analysis showed considerable alterations in the Ag NPs-treated fish.The impact of histological changes induced by Ag NPs were confirmed by the damages in the tissues,primary lamella,blood vessels and formation of vacuolation in liver and muscle when compared with the control L.rohita.
