Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were expose...Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).展开更多
Salinity is recognized as a pivotal factor limiting the migration of freshwater fish to brackish environments.The largemouth bass(LMB,Micropterus salmoides),a globally translocated freshwater fish,exhibits estuarine d...Salinity is recognized as a pivotal factor limiting the migration of freshwater fish to brackish environments.The largemouth bass(LMB,Micropterus salmoides),a globally translocated freshwater fish,exhibits estuarine distribution,yet its hyperosmoregulatory capacity during early ontogenetic stages remains inadequately understood.To investigate the impact of freshwater salinization,a series of experiments were conducted in Guangzhou and Foshan,China.Results reveal that freshwater-activated mature eggs and naturally fertilized oocytes maintained nearly identical osmotic homeostasis,with diameters of 1.38±0.07 mm and 1.37±0.05 mm,respectively.Furthermore,both exhibited peak water excretion at a salinity of 15.0.Remarkably,a reduction in water permeability was observed in hyperosmotic environments.Spontaneous hatching rates increased from 27.5%±14.4%in the 1.0 group to 75.1%±12.0%in the 6.0 group under fluctuating temperature conditions.Yolk-sac LMB larvae consistently reduced survival time from 12.5 d at 1.0 to 50.7±2.1 min at salinity of 35.0.Similarly,more developed larvae also experienced a decrease in survival time.Logistic regression models fitting lethal time with salinity indicated a sharp decrease between 10.0 and 20.0.These findings offer practical insights for predicting distribution patterns and enhancing aquaculture technology for LMB.Moreover,they may contribute theoretically to the broader understanding of the osmoregulatory mechanisms of freshwater fish.展开更多
This study was carried out to evaluate the response of Nile tilapia(Oreochromis niloticus)fingerlings to acute copper sulphate and ferrocene toxicity.Nile tilapia fingerlings weighing 2.3±0.2 g were acclimated an...This study was carried out to evaluate the response of Nile tilapia(Oreochromis niloticus)fingerlings to acute copper sulphate and ferrocene toxicity.Nile tilapia fingerlings weighing 2.3±0.2 g were acclimated and randomly distributed at a rate of 10 fish per 30 L aquarium.Fish were exposed to a range of copper sulphate and ferrocene concentrations of 4 mg/L,8 mg/L,12 mg/L,16 mg/L and 2.5 mg/L,5 mg/L,7.5 mg/L,10 mg/L respectively.Fish not exposed to any toxicant served as control.Mortality was assessed and median lethal concentration(LC_(50))and median lethal time(LT_(50))were calculated.The 96-h LC50 values obtained for copper sulphate and ferrocene were 7.49 mg/L(confidence interval CI:6.35 to 8.57 mg/L)and 3.55 mg/L(CI:0.98 to 5.17 mg/L)respectively.The LC_(50) decreased with time of exposure implying that toxicity increased over time,however,LT50 decreased as concentration increased.The safe concentration for copper sulphate derived was 1.913 mg/L and 1.196 mg/L for ferrocene.Histological analyses were carried out on fish gills and skin.The skin histomorphology showed marked and widespread epidermal loss and widespread mycocytic degeneration in treatments with high concentration for both toxicants.The gill morphology showed moderate to severe hyperplasia of the primary gill epithelia leading to partial or complete loss of the secondary lamellae.展开更多
The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rat...The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena.展开更多
基金Project supported by the National Natural Science Foundation ofChina (No. 50979063)the Scientific Research Foundation for Young Teachers of Xihua University (No. Z1120412),China
文摘Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).
基金the Natural Science Foundation of Guangdong Province(No.2016A030313145)the National Key R&D Program of China(No.2018YFD0900901)the Central Public-interest Scientific Institution Basal Research Fund,Chinese Academy of Fishery Sciences(No.2024SJRC9)。
文摘Salinity is recognized as a pivotal factor limiting the migration of freshwater fish to brackish environments.The largemouth bass(LMB,Micropterus salmoides),a globally translocated freshwater fish,exhibits estuarine distribution,yet its hyperosmoregulatory capacity during early ontogenetic stages remains inadequately understood.To investigate the impact of freshwater salinization,a series of experiments were conducted in Guangzhou and Foshan,China.Results reveal that freshwater-activated mature eggs and naturally fertilized oocytes maintained nearly identical osmotic homeostasis,with diameters of 1.38±0.07 mm and 1.37±0.05 mm,respectively.Furthermore,both exhibited peak water excretion at a salinity of 15.0.Remarkably,a reduction in water permeability was observed in hyperosmotic environments.Spontaneous hatching rates increased from 27.5%±14.4%in the 1.0 group to 75.1%±12.0%in the 6.0 group under fluctuating temperature conditions.Yolk-sac LMB larvae consistently reduced survival time from 12.5 d at 1.0 to 50.7±2.1 min at salinity of 35.0.Similarly,more developed larvae also experienced a decrease in survival time.Logistic regression models fitting lethal time with salinity indicated a sharp decrease between 10.0 and 20.0.These findings offer practical insights for predicting distribution patterns and enhancing aquaculture technology for LMB.Moreover,they may contribute theoretically to the broader understanding of the osmoregulatory mechanisms of freshwater fish.
文摘This study was carried out to evaluate the response of Nile tilapia(Oreochromis niloticus)fingerlings to acute copper sulphate and ferrocene toxicity.Nile tilapia fingerlings weighing 2.3±0.2 g were acclimated and randomly distributed at a rate of 10 fish per 30 L aquarium.Fish were exposed to a range of copper sulphate and ferrocene concentrations of 4 mg/L,8 mg/L,12 mg/L,16 mg/L and 2.5 mg/L,5 mg/L,7.5 mg/L,10 mg/L respectively.Fish not exposed to any toxicant served as control.Mortality was assessed and median lethal concentration(LC_(50))and median lethal time(LT_(50))were calculated.The 96-h LC50 values obtained for copper sulphate and ferrocene were 7.49 mg/L(confidence interval CI:6.35 to 8.57 mg/L)and 3.55 mg/L(CI:0.98 to 5.17 mg/L)respectively.The LC_(50) decreased with time of exposure implying that toxicity increased over time,however,LT50 decreased as concentration increased.The safe concentration for copper sulphate derived was 1.913 mg/L and 1.196 mg/L for ferrocene.Histological analyses were carried out on fish gills and skin.The skin histomorphology showed marked and widespread epidermal loss and widespread mycocytic degeneration in treatments with high concentration for both toxicants.The gill morphology showed moderate to severe hyperplasia of the primary gill epithelia leading to partial or complete loss of the secondary lamellae.
文摘The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena.
