Assessment of population parameters and genetic diversity is critical for the economic and threatened species,including Oreochromis mossambicus.The morphometric and population parameters data for O.mossambicus were ex...Assessment of population parameters and genetic diversity is critical for the economic and threatened species,including Oreochromis mossambicus.The morphometric and population parameters data for O.mossambicus were extracted based on the available literature from various countries.Phylogenetic and genetic diversity were analyzed based on cytochrome c oxidaseⅠ(COⅠ)sequences of the mitochondrial DNA(mtDNA)gene.The population parameters(asymptotic length(L_(∞)),growth constant(K),growth performance index(Ø),approximate maximum age(t_(max)),standard length(L),and weight(W))results revealed a variation among the populations studied.The result categorized the population into two groups:South African populations located close to Zimbabwe,Mozambique,Namibia,Australia,and China,as GroupⅠ,and the Indian population placed close to Thailand,the Philippines,Indonesia,America,and Mexico as GroupⅡ.The meta-regression results reveal that temperature strongly correlated with weight.In contrast,other population factors showed no significant differences.The haplotype analysis based on COI of mtDNA displayed 21 haplotypes,which revealed low nucleotide(π=0.025)diversity.Haplotype diversity(HD)was 0.65.The haplotype analysis showed that Tajima(D)was negative(-0.82)and Fu’s Fs was positive(2.2),and both tests were not significant(P>0.05),whereas the overall F-statistic(F_(st))value was 0.40(P<0.001).In conclusion,population parameters,and genetic analysis indices a high variation among the O.mossambicus from different locations.Additionally,the population parameters for O.mossambicus in America,Asia,and Australia were more influenced by ecological factors.At the same time,the population parameters in the African continent were influenced more by genetic factors.展开更多
Juveniles of Oreochromis mossambicus with initial wet weights of 0.0382±0.0859 g and initial total lengths of 0.735 ±1.425 cm were tested for their salinity tolerance. The juveniles were subjected to five sa...Juveniles of Oreochromis mossambicus with initial wet weights of 0.0382±0.0859 g and initial total lengths of 0.735 ±1.425 cm were tested for their salinity tolerance. The juveniles were subjected to five salinity levels for a period of seventy five days. These salinity levels correspond to the salinities found along the creek and in estuarine regions. Each set of experiments was conducted at a fifteen day intervals. The weight, length and survival rate were calculated. No mortality was observed at salinity levels 0, 5, 10 and 15, while the juveniles faced slight mortality at 20 in the same environmental conditions, including the diet. There was no significant difference in specific growth rate at all salinity levels. The juveniles of O. mossambicus could survive up to 20 salinity. These results suggest that this species can grow and be exploited commercially in brackish waters, rivers and estuarine regions.展开更多
Urotensin-I(UI)is a peptide belonging to the corticotropin-releasing hormone family,produced in the urophysis of teleosts.This investigation was undertaken to examine the effect of UI on the hypothalamo-hypophyseal-ov...Urotensin-I(UI)is a peptide belonging to the corticotropin-releasing hormone family,produced in the urophysis of teleosts.This investigation was undertaken to examine the effect of UI on the hypothalamo-hypophyseal-ovarian axis in the Mozambique tilapia,a cichlid fish.In the first experiment,administration of UI(2μg/100μL saline)for 22 days caused a significant reduction in the number of follicles at stages I,II,III(previtellogenic),IV(vitellogenic),and V(preovulatory),concomitant with a significant increase in the percent atresia of follicles at stages II,III,and IV than in controls.In the pituitary,gonadotropin-releasing hormone(GnRH)-positive fibres were detected in the proximal pars distalis(PPD)in both controls and UI-treated fish;however,there was a significant reduction in the intensity and percent area of GnRH-immunoreactive fibres in fish treated with UI compared with controls.The serum luteinizing hormone(LH)level was significantly lower,whereas a significant rise in the serum level of cortisol was noticed in UI-treated fish compared with controls.In the second experiment,treatment with a low dose of UI(10 mM)did not affect the number of ACTH-secreting cells in vitro,but the number of these cells was significantly higher in high-dose UI(50 mM)-treated pituitaries compared to controls.Together,the present investigation reveals for the first time that the treatment of UI affects the follicular development process through the downregulation of the GnRH-LH axis and activation of the pituitary-interrenal pathway in teleosts.展开更多
To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic species.Adult tilapia （Oreochromis mossambicus） were mai...To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic species.Adult tilapia （Oreochromis mossambicus） were maintained in 10 L glass aquaria,and exposed to a graded series of synthesized silver nanoparticles （Ag-NPs） at 25,50 and 75 mg/L for eight days.The LC 50 value was 12.6 mg/L.Reduced activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with AgNPs,which resulted in heavy accumulation of free radicals.Histopathological results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs exposure.The principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles.展开更多
Objective:To evaluate the larval consumption rate of Danio rerio(D.rerio)and Oreochromis mossambicus(O.mossambicus)for the control of filarial vector mosquito Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fi...Objective:To evaluate the larval consumption rate of Danio rerio(D.rerio)and Oreochromis mossambicus(O.mossambicus)for the control of filarial vector mosquito Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fishes D.rerio and O.mossambicus were tested by feeding assay against Cx.quinquefasciatus for 24 h.Results:After 24 h of feeding assay the fishes D.rerio and O.mossambicus exhibited potential reduction rate of Cx.quinquefasciatus larvae.Conclusions:The present research work demonstrates that the D.rerio and O.mossambicus can be used for integrated mosquito management,which is simple and safe to non target organisms.展开更多
文摘Assessment of population parameters and genetic diversity is critical for the economic and threatened species,including Oreochromis mossambicus.The morphometric and population parameters data for O.mossambicus were extracted based on the available literature from various countries.Phylogenetic and genetic diversity were analyzed based on cytochrome c oxidaseⅠ(COⅠ)sequences of the mitochondrial DNA(mtDNA)gene.The population parameters(asymptotic length(L_(∞)),growth constant(K),growth performance index(Ø),approximate maximum age(t_(max)),standard length(L),and weight(W))results revealed a variation among the populations studied.The result categorized the population into two groups:South African populations located close to Zimbabwe,Mozambique,Namibia,Australia,and China,as GroupⅠ,and the Indian population placed close to Thailand,the Philippines,Indonesia,America,and Mexico as GroupⅡ.The meta-regression results reveal that temperature strongly correlated with weight.In contrast,other population factors showed no significant differences.The haplotype analysis based on COI of mtDNA displayed 21 haplotypes,which revealed low nucleotide(π=0.025)diversity.Haplotype diversity(HD)was 0.65.The haplotype analysis showed that Tajima(D)was negative(-0.82)and Fu’s Fs was positive(2.2),and both tests were not significant(P>0.05),whereas the overall F-statistic(F_(st))value was 0.40(P<0.001).In conclusion,population parameters,and genetic analysis indices a high variation among the O.mossambicus from different locations.Additionally,the population parameters for O.mossambicus in America,Asia,and Australia were more influenced by ecological factors.At the same time,the population parameters in the African continent were influenced more by genetic factors.
文摘Juveniles of Oreochromis mossambicus with initial wet weights of 0.0382±0.0859 g and initial total lengths of 0.735 ±1.425 cm were tested for their salinity tolerance. The juveniles were subjected to five salinity levels for a period of seventy five days. These salinity levels correspond to the salinities found along the creek and in estuarine regions. Each set of experiments was conducted at a fifteen day intervals. The weight, length and survival rate were calculated. No mortality was observed at salinity levels 0, 5, 10 and 15, while the juveniles faced slight mortality at 20 in the same environmental conditions, including the diet. There was no significant difference in specific growth rate at all salinity levels. The juveniles of O. mossambicus could survive up to 20 salinity. These results suggest that this species can grow and be exploited commercially in brackish waters, rivers and estuarine regions.
基金supported by a grant from Science and Engineering Research Board-Department of Science and Technology(No.EEQ/2017/414) and New Delhi,Government of India.
文摘Urotensin-I(UI)is a peptide belonging to the corticotropin-releasing hormone family,produced in the urophysis of teleosts.This investigation was undertaken to examine the effect of UI on the hypothalamo-hypophyseal-ovarian axis in the Mozambique tilapia,a cichlid fish.In the first experiment,administration of UI(2μg/100μL saline)for 22 days caused a significant reduction in the number of follicles at stages I,II,III(previtellogenic),IV(vitellogenic),and V(preovulatory),concomitant with a significant increase in the percent atresia of follicles at stages II,III,and IV than in controls.In the pituitary,gonadotropin-releasing hormone(GnRH)-positive fibres were detected in the proximal pars distalis(PPD)in both controls and UI-treated fish;however,there was a significant reduction in the intensity and percent area of GnRH-immunoreactive fibres in fish treated with UI compared with controls.The serum luteinizing hormone(LH)level was significantly lower,whereas a significant rise in the serum level of cortisol was noticed in UI-treated fish compared with controls.In the second experiment,treatment with a low dose of UI(10 mM)did not affect the number of ACTH-secreting cells in vitro,but the number of these cells was significantly higher in high-dose UI(50 mM)-treated pituitaries compared to controls.Together,the present investigation reveals for the first time that the treatment of UI affects the follicular development process through the downregulation of the GnRH-LH axis and activation of the pituitary-interrenal pathway in teleosts.
文摘To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic species.Adult tilapia （Oreochromis mossambicus） were maintained in 10 L glass aquaria,and exposed to a graded series of synthesized silver nanoparticles （Ag-NPs） at 25,50 and 75 mg/L for eight days.The LC 50 value was 12.6 mg/L.Reduced activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with AgNPs,which resulted in heavy accumulation of free radicals.Histopathological results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs exposure.The principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles.
文摘Objective:To evaluate the larval consumption rate of Danio rerio(D.rerio)and Oreochromis mossambicus(O.mossambicus)for the control of filarial vector mosquito Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fishes D.rerio and O.mossambicus were tested by feeding assay against Cx.quinquefasciatus for 24 h.Results:After 24 h of feeding assay the fishes D.rerio and O.mossambicus exhibited potential reduction rate of Cx.quinquefasciatus larvae.Conclusions:The present research work demonstrates that the D.rerio and O.mossambicus can be used for integrated mosquito management,which is simple and safe to non target organisms.
