Viral nervous necrosis （VNN） causes high mortality in marine fish, especially in the grouper, worldwide and in China. Since there is no effective vaccine or drug to deal with VNN, early detection and prevention is i...Viral nervous necrosis （VNN） causes high mortality in marine fish, especially in the grouper, worldwide and in China. Since there is no effective vaccine or drug to deal with VNN, early detection and prevention is important to block its outbreak. In this study, a reverse transcription-polymerase chain reaction （RT-PCR） was developed for the rapid, convenient, and sensitive detection of the VNN pathogen, nervous necro- sis virus （NNV）, in the grouper. The whole process was completed within 3.5 h from the RNA extraction to PCR product visualization. The detection limit of this method was 200 copies of NNV RNA standard, which corresponded to 200 copies of virus particles. This RT-PCR method was specific to the NNV detection with no cross-reactivity to other fish viral disease pathogens, such as infectious pancreatic necrosis virus （IPNV）, infectious hematopoietic necrosis virus （IHNV）, spring viraemia of carp virus （SVCV）, epizootic haematopoietic necrosis virus （EHNV）, and large yellow croaker iridovirus （LYC1V）. With this method, the orange-spotted grouper （Epinephelus coioides） fry from hatcheries with or without incidence of the VN- N epidemic in Fujian Province were detected. The results showed that all or 93% of the fry from the two hatcheries with incidence of the epidemic were diagnosed as positive, while 40% or 25% of fry from the t- wo hatcheries without the VNN epidemic were also detected as NNV positive, indicating that this RT-PCR method can be used for rapid, sensitive detection of NNV infection and applied in the VNN epidemic alert.展开更多
Aquaculture production efficiency may increase by using feed additives. This study investigated the effects of different dietary additives [w/w: 2% small peptides, 0.01% probiotics( Bacillus licheniformis) and 0.2% pr...Aquaculture production efficiency may increase by using feed additives. This study investigated the effects of different dietary additives [w/w: 2% small peptides, 0.01% probiotics( Bacillus licheniformis) and 0.2% prebiotics(inulin)] on growth performance, digestive enzyme activities, and oxidative stress in juvenile Epinephelus coioides reared in artificial seawater of two salt concentrations(13.5 vs. 28.5). Weight gain rate was significantly higher in fish fed the diet supplemented with small peptides, B. licheniformis, inulin, or synbiotics than that in fish fed the basal diet; the greatest weight gain rate was found in fish fed the small peptide treatment [56.0% higher than basal diet]. Higher feed efficiency was detected in fish fed the diet supplemented with small peptides than that of fish in the other dietary treatments. Total protease activity in the stomach and intestines was highest in fish fed the small peptide-treated diet, whereas lipase activity was highest in those fed synbiotics(combination of Bacillus licheniformis and inulin) than that in fish fed the other treatments. Antioxidant enzyme(total superoxide dismutase and catalase) activities and hepatic malondialdehyde content were higher in fish receiving the dietary supplements and maintained in artificial seawater containing 13.5 salinity compared with those in the control(28.5). Hepatic catalase activity in grouper fed the diets with small peptides or synbiotics decreased significantly compared with that in control fish. Overall, the three types of additives improved growth rate of juvenile grouper and digestive enzymes activities to varying degrees but did not effectively improve antioxidant capacity under low-salinity stress conditions.展开更多
Crossbreeding between Epinephelas coioides （ ♀ ） and Epinephelus lanceolatus （♂） was conducted by artificial insemination. Fertilized eggs were col- lected at 0, 30, 90 s, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,...Crossbreeding between Epinephelas coioides （ ♀ ） and Epinephelus lanceolatus （♂） was conducted by artificial insemination. Fertilized eggs were col- lected at 0, 30, 90 s, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 min post-insemination respectively, which were fixed by Smith＇s solution, embedded by paraffins and stained by H.E. According to the characteristics of Epinephelus coioides eggs, tissue section method was modified. The results showed that the sperms of Epinephelus lanceolatus rapidly entered the eggs of Epinephelus coioides at 30 s - 1 rain post-insemination. Observation results of tissue sections showed that mature eggs of Epinephelus coioides remained at metaphase of secondary maturation division. The eggs were activated after sperm penetration into the egg. With the develop- ment of secondary maturation division, at 2 rain post-insemination, eggs reached the metaphase of secondary maturation division ; at 3 - 6 rain post-insemination, sperm asters appeared; at 5 min post-insemination, eggs extruded secondary polar body; at 7 -15 rain post-insemination, male pronucleus and female pronucleus moved closer to each other and fused finally, forming a clear junction line; subsequently, zygote nucleus formed and karyotheca became faint; at 15 min pest-insem- ination, first karvokinetic division was develoued.展开更多
Using multi-molecular marker technologies and based on morphological criteria, the genetic relationship between Epinepheelus malabaricus and E, coioides was examined in the hope of resolving the long-standing issue of...Using multi-molecular marker technologies and based on morphological criteria, the genetic relationship between Epinepheelus malabaricus and E, coioides was examined in the hope of resolving the long-standing issue of identifying these two species. Results showed that： （ 1 ） E. coioides and E. malabaricus should be identified as two species, the consistency of mitochondrial DNA cytochrome b gene sequence between E. malabaricus and E. coioides is 94.4%, and the genetic similarity by AFLP was 0.753 9 ; （2） Hybridization exists between E. malabaricus and E. coioides, the specific RAPD and AFLP fragments are found to be useful in the identification of these two species, and the genetic properties （both with exterior and inheritance） of hybrid is significantly biased to the male parents ; and （3） AFLP was a potentially powerful tool in constructing the genetic linkage map for these two groupers.展开更多
基金The National Basic Research Program under contract No.2012CB114402the National High Technology Research and Development Program of China (863 Program) under contract No.2012AA092202Scientific Research Project of Marine Public Welfare Industry of China under contract No.200905020-07
文摘Viral nervous necrosis （VNN） causes high mortality in marine fish, especially in the grouper, worldwide and in China. Since there is no effective vaccine or drug to deal with VNN, early detection and prevention is important to block its outbreak. In this study, a reverse transcription-polymerase chain reaction （RT-PCR） was developed for the rapid, convenient, and sensitive detection of the VNN pathogen, nervous necro- sis virus （NNV）, in the grouper. The whole process was completed within 3.5 h from the RNA extraction to PCR product visualization. The detection limit of this method was 200 copies of NNV RNA standard, which corresponded to 200 copies of virus particles. This RT-PCR method was specific to the NNV detection with no cross-reactivity to other fish viral disease pathogens, such as infectious pancreatic necrosis virus （IPNV）, infectious hematopoietic necrosis virus （IHNV）, spring viraemia of carp virus （SVCV）, epizootic haematopoietic necrosis virus （EHNV）, and large yellow croaker iridovirus （LYC1V）. With this method, the orange-spotted grouper （Epinephelus coioides） fry from hatcheries with or without incidence of the VN- N epidemic in Fujian Province were detected. The results showed that all or 93% of the fry from the two hatcheries with incidence of the epidemic were diagnosed as positive, while 40% or 25% of fry from the t- wo hatcheries without the VNN epidemic were also detected as NNV positive, indicating that this RT-PCR method can be used for rapid, sensitive detection of NNV infection and applied in the VNN epidemic alert.
基金Supported by the Ministry of Science and Technology of China(No.2011BAD13B09)the Project of a Special Fund for Public Welfare Industrial(Agriculture)Research of China(No.200903001-5)
文摘Aquaculture production efficiency may increase by using feed additives. This study investigated the effects of different dietary additives [w/w: 2% small peptides, 0.01% probiotics( Bacillus licheniformis) and 0.2% prebiotics(inulin)] on growth performance, digestive enzyme activities, and oxidative stress in juvenile Epinephelus coioides reared in artificial seawater of two salt concentrations(13.5 vs. 28.5). Weight gain rate was significantly higher in fish fed the diet supplemented with small peptides, B. licheniformis, inulin, or synbiotics than that in fish fed the basal diet; the greatest weight gain rate was found in fish fed the small peptide treatment [56.0% higher than basal diet]. Higher feed efficiency was detected in fish fed the diet supplemented with small peptides than that of fish in the other dietary treatments. Total protease activity in the stomach and intestines was highest in fish fed the small peptide-treated diet, whereas lipase activity was highest in those fed synbiotics(combination of Bacillus licheniformis and inulin) than that in fish fed the other treatments. Antioxidant enzyme(total superoxide dismutase and catalase) activities and hepatic malondialdehyde content were higher in fish receiving the dietary supplements and maintained in artificial seawater containing 13.5 salinity compared with those in the control(28.5). Hepatic catalase activity in grouper fed the diets with small peptides or synbiotics decreased significantly compared with that in control fish. Overall, the three types of additives improved growth rate of juvenile grouper and digestive enzymes activities to varying degrees but did not effectively improve antioxidant capacity under low-salinity stress conditions.
文摘Crossbreeding between Epinephelas coioides （ ♀ ） and Epinephelus lanceolatus （♂） was conducted by artificial insemination. Fertilized eggs were col- lected at 0, 30, 90 s, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 min post-insemination respectively, which were fixed by Smith＇s solution, embedded by paraffins and stained by H.E. According to the characteristics of Epinephelus coioides eggs, tissue section method was modified. The results showed that the sperms of Epinephelus lanceolatus rapidly entered the eggs of Epinephelus coioides at 30 s - 1 rain post-insemination. Observation results of tissue sections showed that mature eggs of Epinephelus coioides remained at metaphase of secondary maturation division. The eggs were activated after sperm penetration into the egg. With the develop- ment of secondary maturation division, at 2 rain post-insemination, eggs reached the metaphase of secondary maturation division ; at 3 - 6 rain post-insemination, sperm asters appeared; at 5 min post-insemination, eggs extruded secondary polar body; at 7 -15 rain post-insemination, male pronucleus and female pronucleus moved closer to each other and fused finally, forming a clear junction line; subsequently, zygote nucleus formed and karyotheca became faint; at 15 min pest-insem- ination, first karvokinetic division was develoued.
基金This study was supported by the National Natural Science Foundation of China under contract Nos 40306023 and 40576064the Important Program of Science and Technology of Fujian Province in China under contract No.2004NZ03.
文摘Using multi-molecular marker technologies and based on morphological criteria, the genetic relationship between Epinepheelus malabaricus and E, coioides was examined in the hope of resolving the long-standing issue of identifying these two species. Results showed that： （ 1 ） E. coioides and E. malabaricus should be identified as two species, the consistency of mitochondrial DNA cytochrome b gene sequence between E. malabaricus and E. coioides is 94.4%, and the genetic similarity by AFLP was 0.753 9 ; （2） Hybridization exists between E. malabaricus and E. coioides, the specific RAPD and AFLP fragments are found to be useful in the identification of these two species, and the genetic properties （both with exterior and inheritance） of hybrid is significantly biased to the male parents ; and （3） AFLP was a potentially powerful tool in constructing the genetic linkage map for these two groupers.
