The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from t...The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from the Yangtze River estuary to the upper Jinsha River,which extend to nearly 3 000 km.However,their migration behaviors remain relatively unknown.We analyzed the biological characteristics of 153 specimens of silver eels collected from the Jingjiang section of Yangtze River（31o30＇N,120o42＇E） between September and November,2008,and tested the sagittal Sr/Ca ratios of 27 specimens.Among the 153 specimens examined,85 were female and 68 were male,which translated to a female-male ratio of 1：0.8.The ages of the female specimens ranged from 3 to 7 a（average 5.52） with an average total length（TL） of（669±80） mm,average body weight（BW） of（555±229）g,average condition factor of 1.77±0.22,and average gonad somatic index（GSI） of 1.32±0.31.The ages of the males ranged from 3 to 5 a（average：4.38） with an average TL of（518±51） mm,average BW of（234±76） g,average condition factor of 1.62±0.18,and average GSI of 0.21±0.11.All biological parameters of females were significantly larger than those of the male specimens（P0.05）.According to the average Sr/Ca ratio（7.99±1.05） ×10-3 of the elver mark of sagitta,17 individuals（62.96%） were river eels and 10 individuals（37.04%） were estuarine eels.Of 16 females,13 individuals（81.25%） were river eels and 3 were estuarine eels,while of 11 males,36.36% were river eels and 63.64% were estuarine eels.The analysis on Sr/Ca ratios for every growth layer group（GLG） indicated there were no significant differences between second-age males and females.However,significant differences were observed between the third-age,fourth-age,and migration-age male and female specimens.This was likely related to the fact that second-age eels of both sexes stay in the same inhabitation waters;however,as they grow older,they move to different areas.展开更多
As a potent pleiotropic cytokine, tumor necrosis factor-alpha （TNF-ct） plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene （AjTNF-c0 in the Japanese eel （...As a potent pleiotropic cytokine, tumor necrosis factor-alpha （TNF-ct） plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene （AjTNF-c0 in the Japanese eel （Anguilla japonica） were identified and characterized. The full-length AjTNF-α cDNA was 1 546 bp, including a 5＇-untranslated region （UTR） of 13 bp, a 3＇-UTR of 879 bp and an open reading frame of 654 bp encoding a protein of 218 amino acids. The full-length genomic sequence of AjTNF-ct was 2 392 bp and included four exons and three introns. The putative AjTNF-α protein contained TNF family signature motifs, including a protease cleavage site, a transmembrane domain and two conserved cysteine residues. Quantitative real-time reverse transcription PCR analysis revealed AjTNF-α expression in a wide range of tissues, with predominant expression in blood and liver. Lower levels of expression were seen in spleen, gills, kidney, intestine, heart, and skin, with very low levels in muscle. The modulation of AjTNF-ct expression after injection of eels with lipopolysaccharide （LPS）, the viral mimic, poly I：C, or Aeromonas hydrophila was assessed in blood, liver, and kidney. In blood, TNF-α mRNA levels increased rapidly and then rapidly decreased after stimulation with LPS, poly I：C or A. hydrophila. However, the response to LPS and A. hydrophila peaked at 6 h while for poly I：C the peak was at 12 h. In liver, after injection with A. hydrophila, an up- and down-regulation of AjTNF-ct expression occurred twice, peaking at 6 h and 24 h, respectively. No remarkable increase of AjTNF-α expression appeared in liver until 72 h after LPS or poly I：C treatment. In kidney, ApiNF-α expression increased significantly only at 72 h post-stimulation with LPS orA. hydrophila. Our results suggest that AjTNF-α plays an important role in fish in the defense against viral and bacterial infection.展开更多
Methylene blue(MB) is commonly used in aquaculture as a fungicide and antidotes. This study was designed to explore the pharmacokinetics of MB in Japanese eel(Anguilla Japonica) immersed in 10 mg L^-1 and 20 mg L^-1 M...Methylene blue(MB) is commonly used in aquaculture as a fungicide and antidotes. This study was designed to explore the pharmacokinetics of MB in Japanese eel(Anguilla Japonica) immersed in 10 mg L^-1 and 20 mg L^-1 MB for 0.5 h. The concentrations of MB and its derivatives in the blood, liver, kidney, skin and muscle were determined by HPLC after immersion. The results showed that the changes of drug concentrations in Japanese eel were basically the same in different dose groups, showing a general trend of increasing at first and then decreasing, but the peak time was slightly different. The peak concentration of the drug was positively correlated with the dose level. The peak concentrations of MB in MB(20 mg L^-1) group, MB, azure A and azure B in the tissues of Japanese eel were significantly higher than those in MB(10 mg L^-1) group. Moreover, MB, azure A and azure B remained for a long time and could still be detected at 64 days, and azure C was not detected in tissues.展开更多
The Japanese eel(Anguilla japonica)is a commercially important fi sh species in East Asia and its recruitment has been rapidly declining since 1990s.Clarifying the genetic population structure of A.japonica is the bas...The Japanese eel(Anguilla japonica)is a commercially important fi sh species in East Asia and its recruitment has been rapidly declining since 1990s.Clarifying the genetic population structure of A.japonica is the basis of multinational cooperation on its management and protection,due to its large distribution range.Gene-associated markers have been proved powerful in delineating fi ne-scale population genetic structure and spatially varying selection.In the present study,we developed 24 polymorphic gene-associated microsatellite markers including 18 loci associated with the genes under selection in the two North Atlantic eel species(Anguilla anguilla and Anguilla rostrata)and 6 loci based on transcript sequences.A total of 13 geographic populations were sampled across its distribution range,including 11 samples from China(9 from China’s mainland and 2 from Taiwan region),and 2 samples from Japan.A total of 416 individuals(mostly glass eels)were collected and genotyped at the 24 microsatellites.All measures of diff erentiation were accordant with a panmictic scenario(F ST=-0.001)in A.japonica.No footprints of spatially varying selection were found,indicating that the selection pattern in A.japonica might be diff erent from that in the two North Atlantic eel species.We suggest that A.japonica should be managed as a single unit and management and conservation eff orts must be coordinated at the international level,as overexploitation in any region will decrease its recruitment across the whole distributional range.展开更多
[Objective] The aim was to find a suitable weaning regime, including weaning period and weaning feed, for Angui//a mormorata glass eels. [Method] A weaning processing experiment was conducted indoor in fiberglass tank...[Objective] The aim was to find a suitable weaning regime, including weaning period and weaning feed, for Angui//a mormorata glass eels. [Method] A weaning processing experiment was conducted indoor in fiberglass tanks, two kinds of artificial feeds （eel grower powder feed and eel grower piece feed） were selected as weaning diets against a control group fed on natural food （minced octopus flesh）, two weaning periods, 5 and 15 d, were introduced in weaning experiment. [Result] The growth rate and survival rate of the groups with 15-day＇s weaning period were higher than that of the groups with 5-day＇s weaning period, revealing that a 20% increase every 3 d from 0% to 100% in the proportion of grower paste in the minced octopus flesh during weaning is suitable for A. mormorata glass eels. [Conclusion] A. mormorata glass eels can be weaned from natural food to the commer- cially available eel grower feeds over a certain weaning period, and of the artificial feeds with same ingredients and nutrient, A. mormorata glass eels accepted powder feed more readily over 28 d than piece feed.展开更多
[ Objective] To find a suital;）le food for initial feeding of Anguilla mormorata glass eels. [ Method] A pre -weaning feeding experiment was conducted indoor in fiberglass tanks, three different diets, Tubifex, mince...[ Objective] To find a suital;）le food for initial feeding of Anguilla mormorata glass eels. [ Method] A pre -weaning feeding experiment was conducted indoor in fiberglass tanks, three different diets, Tubifex, minced octopus flesh and 1：1 mixture （ by weight ） of Tubffex and minced octo- pus flesh were introduced, r Result] All three kinds of diets were acceptable to A. morrnorata glass eels, and of three diets, the minced octopus flesh could serve as the best food for initial feeding of A. mormorata glass eels, which contributed 93% survival at the termination of the 21 - day＇s exped- ment and provided with relatively fast growth and homogeneous size variation. [ Conclusion] The minced octopus flesh can serve as a suitable food to replace Tubifex for the initial feeding of anguilla glass eels.展开更多
[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 nor...[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 normal Japanese eels （Weight from 126.4 to 140.2 g per eel） and 20 growth retarded eels （Weight from 3.5 to 8.6 g per eel） were selected, then, the protease, amylase, lipase activities in hepatopancreas, intestine and stomach under the reaction temperature 5, 10, 15, 25, 30, 35, 40, 45 and 55℃ were measured. [ Result] The protease activities in hepatopancreas, intestine and stomach all reached the highest value for both normal eels and growth retarded eels, and the order of protease activities was intestine 〉 stomach 〉 hepatopancreas except the protease activities of growth retarded eels at the temperature of 5, 15, 55℃ The protease activities in hepatopancreas, intestine and stomach of growth retarded eels were 29.5%, 15.7% and 25.2% of those of normal eels（ P 〈0. 05）. The amylase activities of both normal and growth retarded eels reached the highest value at the temperature of 30 ~C. The amylase activity or- der of normal eels was hepatopancreas 〉 intestine 〉 stomach expect the amylase activity at the temperature of 5 ~C, while the amylase activity order of growth retarded eels is intestine 〉 hepatopancreas 〉 stomach. The amylase activities in hepatopancreas, intestine and stomach of growth retarded eels were 42.4%, 73.7% and 43.8% of those of normal eels （ P 〈 0.05）. The lipase activities of both normal and growth retarded eels reached the highest value at the temperature of 35 ~C. The lipase activity order of normal eels was hepatopancreas 〉 stomach 〉 intestine, while the lipase activity order of growth retarded eels was hepatopancreas 〉 intestine 〉 stomach expect the lipase activity at the temperature of 35 ~C. The lipase activities in hepatopancreas, intestine and stomach of growth retarded eels were 41.5%, 45.6% and 23.2% of those of normal eels（ P 〈0.05）. [ Conclusion] The protease, amylase, lipase activities in hepatopancreas, intestine and stomach of growth retarded Japanese eels were significantly lower than those of normal Japanese eels, therefore, its growth was affected directly.展开更多
基金supported by the Chinese National Science Foundation under the Grant(30771650)the Key Programs of Science and Technology Commission Foundation of Shanghai(08391910200)+3 种基金Special Fund for Agroscientific Research in the Public Interest(201203065)Research Fund for the Doctoral Program of Higher Education of China(20070264001)E-class Programs of Shanghai Municipal Education Commission(E03009)the Key Subject Construction of Shanghai(S30701)
文摘The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from the Yangtze River estuary to the upper Jinsha River,which extend to nearly 3 000 km.However,their migration behaviors remain relatively unknown.We analyzed the biological characteristics of 153 specimens of silver eels collected from the Jingjiang section of Yangtze River（31o30＇N,120o42＇E） between September and November,2008,and tested the sagittal Sr/Ca ratios of 27 specimens.Among the 153 specimens examined,85 were female and 68 were male,which translated to a female-male ratio of 1：0.8.The ages of the female specimens ranged from 3 to 7 a（average 5.52） with an average total length（TL） of（669±80） mm,average body weight（BW） of（555±229）g,average condition factor of 1.77±0.22,and average gonad somatic index（GSI） of 1.32±0.31.The ages of the males ranged from 3 to 5 a（average：4.38） with an average TL of（518±51） mm,average BW of（234±76） g,average condition factor of 1.62±0.18,and average GSI of 0.21±0.11.All biological parameters of females were significantly larger than those of the male specimens（P0.05）.According to the average Sr/Ca ratio（7.99±1.05） ×10-3 of the elver mark of sagitta,17 individuals（62.96%） were river eels and 10 individuals（37.04%） were estuarine eels.Of 16 females,13 individuals（81.25%） were river eels and 3 were estuarine eels,while of 11 males,36.36% were river eels and 63.64% were estuarine eels.The analysis on Sr/Ca ratios for every growth layer group（GLG） indicated there were no significant differences between second-age males and females.However,significant differences were observed between the third-age,fourth-age,and migration-age male and female specimens.This was likely related to the fact that second-age eels of both sexes stay in the same inhabitation waters;however,as they grow older,they move to different areas.
基金Supported by the Ocean and Fishery Bureau of Fujian Province(No.201212140006)the Scientific Research Foundation of Jimei University,China(No.ZQ2008013)+1 种基金the National Natural Science Foundation of China(No.31272685)the Program of the Education Department of Fujian Province(No.JA11150)
文摘As a potent pleiotropic cytokine, tumor necrosis factor-alpha （TNF-ct） plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene （AjTNF-c0 in the Japanese eel （Anguilla japonica） were identified and characterized. The full-length AjTNF-α cDNA was 1 546 bp, including a 5＇-untranslated region （UTR） of 13 bp, a 3＇-UTR of 879 bp and an open reading frame of 654 bp encoding a protein of 218 amino acids. The full-length genomic sequence of AjTNF-ct was 2 392 bp and included four exons and three introns. The putative AjTNF-α protein contained TNF family signature motifs, including a protease cleavage site, a transmembrane domain and two conserved cysteine residues. Quantitative real-time reverse transcription PCR analysis revealed AjTNF-α expression in a wide range of tissues, with predominant expression in blood and liver. Lower levels of expression were seen in spleen, gills, kidney, intestine, heart, and skin, with very low levels in muscle. The modulation of AjTNF-ct expression after injection of eels with lipopolysaccharide （LPS）, the viral mimic, poly I：C, or Aeromonas hydrophila was assessed in blood, liver, and kidney. In blood, TNF-α mRNA levels increased rapidly and then rapidly decreased after stimulation with LPS, poly I：C or A. hydrophila. However, the response to LPS and A. hydrophila peaked at 6 h while for poly I：C the peak was at 12 h. In liver, after injection with A. hydrophila, an up- and down-regulation of AjTNF-ct expression occurred twice, peaking at 6 h and 24 h, respectively. No remarkable increase of AjTNF-α expression appeared in liver until 72 h after LPS or poly I：C treatment. In kidney, ApiNF-α expression increased significantly only at 72 h post-stimulation with LPS orA. hydrophila. Our results suggest that AjTNF-α plays an important role in fish in the defense against viral and bacterial infection.
基金supported by the National Key R&D Program of China (No.2019YFD0900102)the Science and Technology Commission of Shanghai Municipality (Nos.17050502100 and 18391901500)+1 种基金the National Natural Resources Platform of ChinaKnowledge Service Platform of Shanghai Ocean University。
文摘Methylene blue(MB) is commonly used in aquaculture as a fungicide and antidotes. This study was designed to explore the pharmacokinetics of MB in Japanese eel(Anguilla Japonica) immersed in 10 mg L^-1 and 20 mg L^-1 MB for 0.5 h. The concentrations of MB and its derivatives in the blood, liver, kidney, skin and muscle were determined by HPLC after immersion. The results showed that the changes of drug concentrations in Japanese eel were basically the same in different dose groups, showing a general trend of increasing at first and then decreasing, but the peak time was slightly different. The peak concentration of the drug was positively correlated with the dose level. The peak concentrations of MB in MB(20 mg L^-1) group, MB, azure A and azure B in the tissues of Japanese eel were significantly higher than those in MB(10 mg L^-1) group. Moreover, MB, azure A and azure B remained for a long time and could still be detected at 64 days, and azure C was not detected in tissues.
基金Supported by the National Natural Science Foundation of China(NSFC)(No.41676137)the Creative Team Project of the Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology(No.LMEES-CTSP-2018-1)。
文摘The Japanese eel(Anguilla japonica)is a commercially important fi sh species in East Asia and its recruitment has been rapidly declining since 1990s.Clarifying the genetic population structure of A.japonica is the basis of multinational cooperation on its management and protection,due to its large distribution range.Gene-associated markers have been proved powerful in delineating fi ne-scale population genetic structure and spatially varying selection.In the present study,we developed 24 polymorphic gene-associated microsatellite markers including 18 loci associated with the genes under selection in the two North Atlantic eel species(Anguilla anguilla and Anguilla rostrata)and 6 loci based on transcript sequences.A total of 13 geographic populations were sampled across its distribution range,including 11 samples from China(9 from China’s mainland and 2 from Taiwan region),and 2 samples from Japan.A total of 416 individuals(mostly glass eels)were collected and genotyped at the 24 microsatellites.All measures of diff erentiation were accordant with a panmictic scenario(F ST=-0.001)in A.japonica.No footprints of spatially varying selection were found,indicating that the selection pattern in A.japonica might be diff erent from that in the two North Atlantic eel species.We suggest that A.japonica should be managed as a single unit and management and conservation eff orts must be coordinated at the international level,as overexploitation in any region will decrease its recruitment across the whole distributional range.
基金Supported by Xiamen Marine Research and Development Institute [K10102(1)]~~
文摘[Objective] The aim was to find a suitable weaning regime, including weaning period and weaning feed, for Angui//a mormorata glass eels. [Method] A weaning processing experiment was conducted indoor in fiberglass tanks, two kinds of artificial feeds （eel grower powder feed and eel grower piece feed） were selected as weaning diets against a control group fed on natural food （minced octopus flesh）, two weaning periods, 5 and 15 d, were introduced in weaning experiment. [Result] The growth rate and survival rate of the groups with 15-day＇s weaning period were higher than that of the groups with 5-day＇s weaning period, revealing that a 20% increase every 3 d from 0% to 100% in the proportion of grower paste in the minced octopus flesh during weaning is suitable for A. mormorata glass eels. [Conclusion] A. mormorata glass eels can be weaned from natural food to the commer- cially available eel grower feeds over a certain weaning period, and of the artificial feeds with same ingredients and nutrient, A. mormorata glass eels accepted powder feed more readily over 28 d than piece feed.
基金supported by Xiamen Marine Research and Development Institute
文摘[ Objective] To find a suital;）le food for initial feeding of Anguilla mormorata glass eels. [ Method] A pre -weaning feeding experiment was conducted indoor in fiberglass tanks, three different diets, Tubifex, minced octopus flesh and 1：1 mixture （ by weight ） of Tubffex and minced octo- pus flesh were introduced, r Result] All three kinds of diets were acceptable to A. morrnorata glass eels, and of three diets, the minced octopus flesh could serve as the best food for initial feeding of A. mormorata glass eels, which contributed 93% survival at the termination of the 21 - day＇s exped- ment and provided with relatively fast growth and homogeneous size variation. [ Conclusion] The minced octopus flesh can serve as a suitable food to replace Tubifex for the initial feeding of anguilla glass eels.
基金LI Shang-da Jimei University Subject construction Fund(ZC2010001)
文摘[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 normal Japanese eels （Weight from 126.4 to 140.2 g per eel） and 20 growth retarded eels （Weight from 3.5 to 8.6 g per eel） were selected, then, the protease, amylase, lipase activities in hepatopancreas, intestine and stomach under the reaction temperature 5, 10, 15, 25, 30, 35, 40, 45 and 55℃ were measured. [ Result] The protease activities in hepatopancreas, intestine and stomach all reached the highest value for both normal eels and growth retarded eels, and the order of protease activities was intestine 〉 stomach 〉 hepatopancreas except the protease activities of growth retarded eels at the temperature of 5, 15, 55℃ The protease activities in hepatopancreas, intestine and stomach of growth retarded eels were 29.5%, 15.7% and 25.2% of those of normal eels（ P 〈0. 05）. The amylase activities of both normal and growth retarded eels reached the highest value at the temperature of 30 ~C. The amylase activity or- der of normal eels was hepatopancreas 〉 intestine 〉 stomach expect the amylase activity at the temperature of 5 ~C, while the amylase activity order of growth retarded eels is intestine 〉 hepatopancreas 〉 stomach. The amylase activities in hepatopancreas, intestine and stomach of growth retarded eels were 42.4%, 73.7% and 43.8% of those of normal eels （ P 〈 0.05）. The lipase activities of both normal and growth retarded eels reached the highest value at the temperature of 35 ~C. The lipase activity order of normal eels was hepatopancreas 〉 stomach 〉 intestine, while the lipase activity order of growth retarded eels was hepatopancreas 〉 intestine 〉 stomach expect the lipase activity at the temperature of 35 ~C. The lipase activities in hepatopancreas, intestine and stomach of growth retarded eels were 41.5%, 45.6% and 23.2% of those of normal eels（ P 〈0.05）. [ Conclusion] The protease, amylase, lipase activities in hepatopancreas, intestine and stomach of growth retarded Japanese eels were significantly lower than those of normal Japanese eels, therefore, its growth was affected directly.
