Fishes exposed to different dissolved oxygen concentrations over prolonged time periods have different susceptibility and adaptation mechanisms.In this study,healthy grass carp with an average weight of 214.6±18....Fishes exposed to different dissolved oxygen concentrations over prolonged time periods have different susceptibility and adaptation mechanisms.In this study,healthy grass carp with an average weight of 214.6±18.7 g were selected for long-term culture in recirculating aquaculture systems at three different dissolved oxygen concentrations,i.e.,3.00 mg/L[(2.57±0.33)mg/L,DO_(2.57)),5.00 mg/L[(4.61±0.11)mg/L,DO_(4.61)],which was the control group,and 7.00 mg/L[(6.50±0.48)mg/L,DO_(6.50)].Blood,gill,muscle,and liver samples were collected after 60 days.Using hematoxylin-eosin(HE),alcian blue periodic acid Schiff(AB-PAS)staining,determination of respiratory metabolism enzyme activity,and fluorescent quantitative PCR,the adaptability of juvenile grass carp facing different dissolved oxygen levels were explored.The results showed that the respiration rate increased,and hemoconcentration and hemoglobin(Hb),electrolyte and pH changed at DO2.57.Furthermore,gill lamellae became thinner and longer,the distance between them increased,the mucus on them decreased and the interstitial cell mass decreased.In addition,the relative expression of apoptosis-related genes bcl-2 and bcl-xl in gill tissue decreased,while caspase-3 and bax increased.In muscles and liver tissues,lactate dehydrogenase(LDH)activity and lactic acid content(LA)increased,pyruvate dehydrogenase(PDH)activity decreased,and genes related to the respiratory metabolic enzymes PDH-A4 and PDH-E1α also changed accordingly.The oxygen consumption rate decreased significantly(P<0.05).At DO_(6.50),the distance between gill lamellae,numbers of red blood cells(RBC)and the content of hemoglobin decreased wheras the mucus on gill lamellae increased.The activity of PDH,the expression of PDH-E1a in liver and oxygen consumption rate increased.Different dissolved oxygen concentrations affected the respiratory behavior,gill tissue structure,blood transport capacity and tissue enzyme activity of juvenile grass carp.In summary,juvenile grass carp showed different adaptation strategies when facing different dissolved oxygen concentrations over prolonged periods in recirculating aquaculture systems.展开更多
Fish skin acts as the first immune barrier against pathogens from external environments.Recently,fish skin immunity research has gradually become a hot topic in aquaculture disease control.Interestingly,the skin can d...Fish skin acts as the first immune barrier against pathogens from external environments.Recently,fish skin immunity research has gradually become a hot topic in aquaculture disease control.Interestingly,the skin can do air-breathing in some bimodal respiration fish.However,there is no comprehensive understanding of these two functions.In this study,the skin regeneration of loach(Paramisgurnus dabryanus)was investigated through morphological and histological observations.Then,original skins(OS)and the regenerated skins(RS)when their capillaries were the most abundant during healing,were collected for transcriptomic analysis.285,899,386 clean reads with a total length of 42.34 Gb were obtained.A total of 1282 differentially expressed genes(DEGs)were detected,including 1030 DEGs up-regulated and 252 DEGs down-regulated in the comparison of RS vs.OS.Fc gamma R-mediated phagocytosis(containing gelsolin(Gsn)),chemokine signaling pathway(containing C-C motif chemokine ligand 28(Ccl28)),and B cell receptor signaling pathway(containing CD80 molecule(Cd81))were closely related to skin immune response of the loach.PI3K-Akt signaling pathway[containing fibronectin 1(Fn1)and lysyl oxidase-like 2b(Loxl2b)],TGF-beta signaling pathway[containing thrombospondin 1(Thbs1)],ECM-receptor interaction[containing integrin alpha 7(Itga7),Itgb8,Itgb10 and Itgb5],and dilated cardiomyopathy[containing laminin subunit alpha1(Lama1)]were closely associated with skin air-breathing of the loach.This study is conducive to explore the molecular mechanisms of skin immune response during its regeneration and air-breathing of bimodal respiration fish.This study will benefit for the aquaculture of P.dabryanus and its related species.展开更多
Bacillus subtilis is widely used in aquaculture as a probiotic.However,few studies have been conducted to examine the effect of B.subtilis on liver lipid metabolism.A total of 135 healthy grass carp(50.24±1.38 g)...Bacillus subtilis is widely used in aquaculture as a probiotic.However,few studies have been conducted to examine the effect of B.subtilis on liver lipid metabolism.A total of 135 healthy grass carp(50.24±1.38 g)were randomly divided into three groups:control(Con),high-fat diet(HF),and high-fat diet+B.subtilis(HF4-B.subtilis),and fed for 8 weeks.The results showed that compared with the HF group,the weight gain rate(WGR)significantly increased(Pc0.05)and the hepatic lipid content,serum low-density lipoprotein cholesterol(LDL-C),and aspartate aminotransferase(AST)decreased in the group supplemented with B.subtilis(P<0.05).Moreover,the hepatic mRNA expression of fatty acid synthase(FAS)was significantly down-regulated and the carnitine palmitoyl transferases(CPTlala)were up-regulated in the HF+B.subtilis group compared to the HF group(P<0.05),respectively.Additionally,in the HF+B.subtilis group,glutathione(GSH)significantly increased(Pv 0.()5),while hydrogen peroxide(H2O2)and malondialdehyde(MDA)contents significantly decreased compared to the HF group(P v0.05).B.subtilis may reduce the hepatic lipid content by inhibiting its synthesis and promoting p-oxidation of fatty acids.B.subtilis may also alleviate dyslipidaemia and prevent oxidative damage in the liver caused by the high-fat diet of grass carp.Hence,dietary supplementation with B.subtilis shows promise as a therapeutic or preventive tool against fatty liver disease.展开更多
The core ecosystem functioning(e.g.trophic transfer efficiency)is at risk of being disrupted by the growing mismatch between nutrient content of primary producers and nutrient demand of grazing consumers.Ecological st...The core ecosystem functioning(e.g.trophic transfer efficiency)is at risk of being disrupted by the growing mismatch between nutrient content of primary producers and nutrient demand of grazing consumers.Ecological stoichiometry provides a conceptual framework that explains this trophic interaction using C,N and P elemental composition across trophic levels.In light of ongoing climate change and eutrophication,previous studies have raised concerns regarding the growing stoichiometric mismatch between phytoplankton and zooplankton,given the stoichiometric plasticity of phytoplankton.However,there is currently little conclusive evidence on the stoichiometric mismatch from a dual perspective of phytoplankton and zooplankton.To address this,we conducted a mesocosm experiment to investigate the separate and combined effects of climate warming(a constant increase of t3.5C plus heat waves)and eutrophication(nutrient addition)on stoichiometric mismatch between phytoplankton and zooplankton by examining stoichiometric changes in both communities.We observed a growing trend in stoichiometric mismatches when warming or nutrient addition acted individually,which was mediated by the increase in nutrient demand(N,P elements)of zooplankton growth.However,when these stressors acted jointly,the mismatches were reversed.This could be because climate warming and eutrophication combined would lead to changes in species composition,which accordingly reshaped the stoichiometric composition at the community level.These results illustrate the need of stoichiometric mismatches for understanding the implication of global change on trophic interactions and ecosystem functioning,requiring consideration not only of cross-trophic levels but also of compositional changes within communities.展开更多
基金supported by the earmarked fund for CARS(CARS-45)the Fundamental Research Funds for the Central Universities(No.2662022SCYJ001)the National Key R&D Program of China(No.2019YFD0900303).
文摘Fishes exposed to different dissolved oxygen concentrations over prolonged time periods have different susceptibility and adaptation mechanisms.In this study,healthy grass carp with an average weight of 214.6±18.7 g were selected for long-term culture in recirculating aquaculture systems at three different dissolved oxygen concentrations,i.e.,3.00 mg/L[(2.57±0.33)mg/L,DO_(2.57)),5.00 mg/L[(4.61±0.11)mg/L,DO_(4.61)],which was the control group,and 7.00 mg/L[(6.50±0.48)mg/L,DO_(6.50)].Blood,gill,muscle,and liver samples were collected after 60 days.Using hematoxylin-eosin(HE),alcian blue periodic acid Schiff(AB-PAS)staining,determination of respiratory metabolism enzyme activity,and fluorescent quantitative PCR,the adaptability of juvenile grass carp facing different dissolved oxygen levels were explored.The results showed that the respiration rate increased,and hemoconcentration and hemoglobin(Hb),electrolyte and pH changed at DO2.57.Furthermore,gill lamellae became thinner and longer,the distance between them increased,the mucus on them decreased and the interstitial cell mass decreased.In addition,the relative expression of apoptosis-related genes bcl-2 and bcl-xl in gill tissue decreased,while caspase-3 and bax increased.In muscles and liver tissues,lactate dehydrogenase(LDH)activity and lactic acid content(LA)increased,pyruvate dehydrogenase(PDH)activity decreased,and genes related to the respiratory metabolic enzymes PDH-A4 and PDH-E1α also changed accordingly.The oxygen consumption rate decreased significantly(P<0.05).At DO_(6.50),the distance between gill lamellae,numbers of red blood cells(RBC)and the content of hemoglobin decreased wheras the mucus on gill lamellae increased.The activity of PDH,the expression of PDH-E1a in liver and oxygen consumption rate increased.Different dissolved oxygen concentrations affected the respiratory behavior,gill tissue structure,blood transport capacity and tissue enzyme activity of juvenile grass carp.In summary,juvenile grass carp showed different adaptation strategies when facing different dissolved oxygen concentrations over prolonged periods in recirculating aquaculture systems.
基金supported by the National Natural Science Foundation of China (32172962 and 31872579)the Fundamental Research Funds for the Central Universities of China (Project Number:2662020SCPY002).
文摘Fish skin acts as the first immune barrier against pathogens from external environments.Recently,fish skin immunity research has gradually become a hot topic in aquaculture disease control.Interestingly,the skin can do air-breathing in some bimodal respiration fish.However,there is no comprehensive understanding of these two functions.In this study,the skin regeneration of loach(Paramisgurnus dabryanus)was investigated through morphological and histological observations.Then,original skins(OS)and the regenerated skins(RS)when their capillaries were the most abundant during healing,were collected for transcriptomic analysis.285,899,386 clean reads with a total length of 42.34 Gb were obtained.A total of 1282 differentially expressed genes(DEGs)were detected,including 1030 DEGs up-regulated and 252 DEGs down-regulated in the comparison of RS vs.OS.Fc gamma R-mediated phagocytosis(containing gelsolin(Gsn)),chemokine signaling pathway(containing C-C motif chemokine ligand 28(Ccl28)),and B cell receptor signaling pathway(containing CD80 molecule(Cd81))were closely related to skin immune response of the loach.PI3K-Akt signaling pathway[containing fibronectin 1(Fn1)and lysyl oxidase-like 2b(Loxl2b)],TGF-beta signaling pathway[containing thrombospondin 1(Thbs1)],ECM-receptor interaction[containing integrin alpha 7(Itga7),Itgb8,Itgb10 and Itgb5],and dilated cardiomyopathy[containing laminin subunit alpha1(Lama1)]were closely associated with skin air-breathing of the loach.This study is conducive to explore the molecular mechanisms of skin immune response during its regeneration and air-breathing of bimodal respiration fish.This study will benefit for the aquaculture of P.dabryanus and its related species.
基金the National Natural Science Foundation of China(Grant nos.31472310 and 31672683)the Technical Innovation Project of Hubei Province(Grant No.2018ABA103).
文摘Bacillus subtilis is widely used in aquaculture as a probiotic.However,few studies have been conducted to examine the effect of B.subtilis on liver lipid metabolism.A total of 135 healthy grass carp(50.24±1.38 g)were randomly divided into three groups:control(Con),high-fat diet(HF),and high-fat diet+B.subtilis(HF4-B.subtilis),and fed for 8 weeks.The results showed that compared with the HF group,the weight gain rate(WGR)significantly increased(Pc0.05)and the hepatic lipid content,serum low-density lipoprotein cholesterol(LDL-C),and aspartate aminotransferase(AST)decreased in the group supplemented with B.subtilis(P<0.05).Moreover,the hepatic mRNA expression of fatty acid synthase(FAS)was significantly down-regulated and the carnitine palmitoyl transferases(CPTlala)were up-regulated in the HF+B.subtilis group compared to the HF group(P<0.05),respectively.Additionally,in the HF+B.subtilis group,glutathione(GSH)significantly increased(Pv 0.()5),while hydrogen peroxide(H2O2)and malondialdehyde(MDA)contents significantly decreased compared to the HF group(P v0.05).B.subtilis may reduce the hepatic lipid content by inhibiting its synthesis and promoting p-oxidation of fatty acids.B.subtilis may also alleviate dyslipidaemia and prevent oxidative damage in the liver caused by the high-fat diet of grass carp.Hence,dietary supplementation with B.subtilis shows promise as a therapeutic or preventive tool against fatty liver disease.
基金supported by the National Natural Science Foundation of China[grant numbers 32171515,31800389]the Hundred-Talent Program of the Chinese Academy of Sciencesthe International Cooperation Project of the Chinese Academy of Sciences[grant numbers 152342KYSB20190025].
文摘The core ecosystem functioning(e.g.trophic transfer efficiency)is at risk of being disrupted by the growing mismatch between nutrient content of primary producers and nutrient demand of grazing consumers.Ecological stoichiometry provides a conceptual framework that explains this trophic interaction using C,N and P elemental composition across trophic levels.In light of ongoing climate change and eutrophication,previous studies have raised concerns regarding the growing stoichiometric mismatch between phytoplankton and zooplankton,given the stoichiometric plasticity of phytoplankton.However,there is currently little conclusive evidence on the stoichiometric mismatch from a dual perspective of phytoplankton and zooplankton.To address this,we conducted a mesocosm experiment to investigate the separate and combined effects of climate warming(a constant increase of t3.5C plus heat waves)and eutrophication(nutrient addition)on stoichiometric mismatch between phytoplankton and zooplankton by examining stoichiometric changes in both communities.We observed a growing trend in stoichiometric mismatches when warming or nutrient addition acted individually,which was mediated by the increase in nutrient demand(N,P elements)of zooplankton growth.However,when these stressors acted jointly,the mismatches were reversed.This could be because climate warming and eutrophication combined would lead to changes in species composition,which accordingly reshaped the stoichiometric composition at the community level.These results illustrate the need of stoichiometric mismatches for understanding the implication of global change on trophic interactions and ecosystem functioning,requiring consideration not only of cross-trophic levels but also of compositional changes within communities.
