Loach(Misgurnus anguillicaudatus) is a commercially important fish in China and an ideal aquaculture species. However, culturists experience high larval and juvenile mortality during mass production. To provide insigh...Loach(Misgurnus anguillicaudatus) is a commercially important fish in China and an ideal aquaculture species. However, culturists experience high larval and juvenile mortality during mass production. To provide insight into ways to improve larviculture techniques, we describe the morphological characteristics and behavior of loach during the larval and early juvenile stages. Yolksac larvae ranged from 2.8 to 4.0 mm body length(BL) between days 0 to 4; preflexion larvae ranged from 3.6 to 5.5 mm BL between days 4 to 6; flexion larvae ranged from 4.8 to 8.1 mm BL between days 5 and 14; and postflexion larvae ranged from 7.1 to 15.7 mm BL between days 11 to 27; the minimum length and age of juveniles was 14.1 mm BL and 23 d, respectively. Loach are demersal from hatch through to the early juvenile stages. A suite of morphological characteristics(e.g., external gill filament and ventral mouth opening) and behavioral traits have developed to adapt to demersal living. We observed positive allometric growth in eye diameter, head length, head height, and pectoral fin length during the early larval stages, reflecting the priorities in the development of the organs essential for survival. Our results provide a basis for developing techniques to improve the survival of larval and juvenile loach during mass production.展开更多
Maggot meal was used to replace 0, 20% , 40% , 60% , 80% , 100% of the fish meal in the hasal feed, getting 6 kinds of feed with the same nitrogen content and equal energy （marked as group H0, H20, H40, H60, H80, H10...Maggot meal was used to replace 0, 20% , 40% , 60% , 80% , 100% of the fish meal in the hasal feed, getting 6 kinds of feed with the same nitrogen content and equal energy （marked as group H0, H20, H40, H60, H80, H100）, which were used to feed the Misgurnus anguillicaudatus （loach） for60 d. The effects of the fish meal replacement by maggot meal on the growth performance of M. anguiUicaudatus were studied by comparing the growth performances and body indica- tors of M. anguillicaudatus fed with different feed groups. The results showed that the final weight, weight gain rate, specific growth rate of the M. anguillicaudatus in group H40 showed no significant difference with the control P 〉0.05 ）, but was significantly higher than that of other groups P 〈0.05 ）. Moreover, except group H40, the feed coefficients of all other groups were significantly higher than that in control group （P 〈0.05 ）. The M. anguillicaudatus in group 1-140 had the highest condition factor and COR and the lowest viscera index, all of which showed significant differences with the other replacement groups （P 〈0.05） but the difference with the control group was not significant （P 〉 0.05）. Thus, a proportion of 40% of the fish meal replaced with maggot meal in the mixed feed for the M. anguilli- caudatus could improve the growth performance and physique indexes of M. anguillicaudatus.展开更多
Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and w...Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。展开更多
Male Chinese loaches were exposed to 17β-estradiol (E2) and nonylphenol (NP) both singly and in combination for 42 days using semi-static waterborne exposure system. Plasma vitellogenin (Vtg) was chosen as determinin...Male Chinese loaches were exposed to 17β-estradiol (E2) and nonylphenol (NP) both singly and in combination for 42 days using semi-static waterborne exposure system. Plasma vitellogenin (Vtg) was chosen as determining endpoint. The results demonstrated that 0.5 μg/L E2 could induce the enhancement of Vtg contents in male Chinese loaches after exposure for 21 days, which showed a time-related increasing manner; NP was also estrogenic to male Chinese loach, and the vitellogenic responses showed in a time-and dose-related manner, which was less potent than that of E2. The bi- nary mixtures of E2 and NP can significantly elicit the production of Vtg in male Chinese loaches, which was more potent than that of individual compounds, and Vtg induced in the binary mixture groups was higher than the summation of Vtg induced in the corresponding single-compound groups at the same concentration.展开更多
The effects of heavy metals Cd^(2+),Pb^(2+)and Zn^(2+)at 0.05,0.5 and 5.0 mg/L level and their interactions at 0.5 mg/L level on DNA damage in hepatopancreas of loach Misgurnus anguillicaudatus for 1-35 days exposure ...The effects of heavy metals Cd^(2+),Pb^(2+)and Zn^(2+)at 0.05,0.5 and 5.0 mg/L level and their interactions at 0.5 mg/L level on DNA damage in hepatopancreas of loach Misgurnus anguillicaudatus for 1-35 days exposure were examined by single cell gel electrophoresis(SCGE).For each test group,20 loaches with similar body size(5.17-7.99 g;11.79-13.21 cm)were selected and kept in aquaria with dechlori-nated water at(22±1)℃and fed a commercial diet every 48 h.According to the percentage of damaged DNA with tail and its TL/D(tail length to diameter of nucleus)value,the relationship between DNA damage degree and heavy metal dose and exposure time was determined.Results showed that the percentage of damaged DNA and the TL/D value were increased with the prolonged exposure time.The highest percentage(84.85%)of damaged DNA was shown in 5.0 mg/L Zn^(2+)group after 28 days exposure and the biggest TL/D value(2.50)in all treated groups after 35 days exposure.During the first treated week,the damnification of DNA was mainly recognized as the first level,after that time,the third damaged level was mostly observed and the percentage of damaged DNA was beyond 80%.The joint toxic effects among Cd^(2+),Pb^(2+)or Zn^(2+)revealed much complexity,but it generally displayed that the presence of Cd^(2+)could enhance the genotoxicity of Pb^(2+)or Zn^(2+).In conclusion,the results suggestedthattherewasasignificanttime-anddose-depended relationship between the heavy metal and DNA damage in hepatopancreas of loach,and SCGE could represent a useful means to evaluate the genotoxicity of environmental contamination on aquatic organisms.展开更多
基金Supported by the Key Technology Research and Development Program of Huai’an(Nos.SN12100 and SN12101)the Construction of Innovation Carrier and Platform Project of Huai’an for the Key Laboratory of Sustainable Fisheries and Environmental Protection for Lakes of Northern Jiangsu(No.HAP201204)the Special Research Fund for Public Interest of MWR of China(No.201201028-02)
文摘Loach(Misgurnus anguillicaudatus) is a commercially important fish in China and an ideal aquaculture species. However, culturists experience high larval and juvenile mortality during mass production. To provide insight into ways to improve larviculture techniques, we describe the morphological characteristics and behavior of loach during the larval and early juvenile stages. Yolksac larvae ranged from 2.8 to 4.0 mm body length(BL) between days 0 to 4; preflexion larvae ranged from 3.6 to 5.5 mm BL between days 4 to 6; flexion larvae ranged from 4.8 to 8.1 mm BL between days 5 and 14; and postflexion larvae ranged from 7.1 to 15.7 mm BL between days 11 to 27; the minimum length and age of juveniles was 14.1 mm BL and 23 d, respectively. Loach are demersal from hatch through to the early juvenile stages. A suite of morphological characteristics(e.g., external gill filament and ventral mouth opening) and behavioral traits have developed to adapt to demersal living. We observed positive allometric growth in eye diameter, head length, head height, and pectoral fin length during the early larval stages, reflecting the priorities in the development of the organs essential for survival. Our results provide a basis for developing techniques to improve the survival of larval and juvenile loach during mass production.
基金Supported by the College Project of Xuzhou Vocational College of Bioengineering(2014B07)
文摘Maggot meal was used to replace 0, 20% , 40% , 60% , 80% , 100% of the fish meal in the hasal feed, getting 6 kinds of feed with the same nitrogen content and equal energy （marked as group H0, H20, H40, H60, H80, H100）, which were used to feed the Misgurnus anguillicaudatus （loach） for60 d. The effects of the fish meal replacement by maggot meal on the growth performance of M. anguiUicaudatus were studied by comparing the growth performances and body indica- tors of M. anguillicaudatus fed with different feed groups. The results showed that the final weight, weight gain rate, specific growth rate of the M. anguillicaudatus in group H40 showed no significant difference with the control P 〉0.05 ）, but was significantly higher than that of other groups P 〈0.05 ）. Moreover, except group H40, the feed coefficients of all other groups were significantly higher than that in control group （P 〈0.05 ）. The M. anguillicaudatus in group 1-140 had the highest condition factor and COR and the lowest viscera index, all of which showed significant differences with the other replacement groups （P 〈0.05） but the difference with the control group was not significant （P 〉 0.05）. Thus, a proportion of 40% of the fish meal replaced with maggot meal in the mixed feed for the M. anguilli- caudatus could improve the growth performance and physique indexes of M. anguillicaudatus.
基金This study was financially supported by the Natural Science Foundation of the Science and Technology Commission of Shanghai Municipality(Grant No.13ZR1427300)Spark Program of the state ministry of science and technology of China(2015GA680005).
文摘Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。
基金Supported by the State High Tech Development Plan (Grant No. 2006AA06Z424)National Basic Research Program of China (Grant No. 2003CB415001)+1 种基金 National Natural Science Foundation of China (Grant No. 40503014)Chinese Academy of Sciences (Grant No. KZCX3-SW-431)
文摘Male Chinese loaches were exposed to 17β-estradiol (E2) and nonylphenol (NP) both singly and in combination for 42 days using semi-static waterborne exposure system. Plasma vitellogenin (Vtg) was chosen as determining endpoint. The results demonstrated that 0.5 μg/L E2 could induce the enhancement of Vtg contents in male Chinese loaches after exposure for 21 days, which showed a time-related increasing manner; NP was also estrogenic to male Chinese loach, and the vitellogenic responses showed in a time-and dose-related manner, which was less potent than that of E2. The bi- nary mixtures of E2 and NP can significantly elicit the production of Vtg in male Chinese loaches, which was more potent than that of individual compounds, and Vtg induced in the binary mixture groups was higher than the summation of Vtg induced in the corresponding single-compound groups at the same concentration.
基金This work was supported by the Key Project of Chinese Ministry of Education(02080)the Open Fund of State Key Laboratory of Freshwater Ecology and Biotechnology,Institute of Hydrobiology,The Chinese Academy of Science(2002FB08).
文摘The effects of heavy metals Cd^(2+),Pb^(2+)and Zn^(2+)at 0.05,0.5 and 5.0 mg/L level and their interactions at 0.5 mg/L level on DNA damage in hepatopancreas of loach Misgurnus anguillicaudatus for 1-35 days exposure were examined by single cell gel electrophoresis(SCGE).For each test group,20 loaches with similar body size(5.17-7.99 g;11.79-13.21 cm)were selected and kept in aquaria with dechlori-nated water at(22±1)℃and fed a commercial diet every 48 h.According to the percentage of damaged DNA with tail and its TL/D(tail length to diameter of nucleus)value,the relationship between DNA damage degree and heavy metal dose and exposure time was determined.Results showed that the percentage of damaged DNA and the TL/D value were increased with the prolonged exposure time.The highest percentage(84.85%)of damaged DNA was shown in 5.0 mg/L Zn^(2+)group after 28 days exposure and the biggest TL/D value(2.50)in all treated groups after 35 days exposure.During the first treated week,the damnification of DNA was mainly recognized as the first level,after that time,the third damaged level was mostly observed and the percentage of damaged DNA was beyond 80%.The joint toxic effects among Cd^(2+),Pb^(2+)or Zn^(2+)revealed much complexity,but it generally displayed that the presence of Cd^(2+)could enhance the genotoxicity of Pb^(2+)or Zn^(2+).In conclusion,the results suggestedthattherewasasignificanttime-anddose-depended relationship between the heavy metal and DNA damage in hepatopancreas of loach,and SCGE could represent a useful means to evaluate the genotoxicity of environmental contamination on aquatic organisms.
