This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using convention...This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using conventional methods,and then were isolated. The further tests and analysis of the isolated strain were developed,including the regression experiment to P. clarkia,the morphology,physiological and biochemical characteristics,sequence analysis of their 16 S rRNA and gyr B genes,and the susceptibility test to antibiotics. Large colonies with similar morphology and color were obtained. Strain X120523 was identified as Citrobacter freundii,proved to have strong pathogenicity,and was susceptible to quinolones and aminoglycosides.展开更多
Three different treatment methods, including topical application method, injection method and immersion method were employed to treat 17or - hydroxyprogesterone, so as to investigating its effect on ovarian developmen...Three different treatment methods, including topical application method, injection method and immersion method were employed to treat 17or - hydroxyprogesterone, so as to investigating its effect on ovarian development red swamp crayfish （Procambarus clarkii）. The results showed that all the three differ- ent methods could facilitate the synchronous ovarian development of red swamp crayfish at different degree, with the degree of maturity of 10% high compared with the control group. The highest maturity degree was 50% that was observed in immersion treatment group. The effect was determined as in order immersion method 〉 injection method 〉 topical apphcation method 〉 control group. The immersion method and the injection method could facilitate synchronization spawning of red swamp crayfish, with the order of immersion method 32.5%, injection method 20%, topical application 17.5% and the control group 17.5 %. Taking the synchro- nization spawning rate, final spawning rate and mortality into account, the order was the immersion method 〉 injection method 〉 topical application method 〉 control group.展开更多
[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experime...[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experiment in a relatively small polyculture system. The agonistic behavior of P. clarkii and E. sinensis in the first 30 min of the initial encounter and the fighting results were observed and recorded; the approach-avoidance behavior of P. clarkii to bigger E. sinensis in a relatively large space （the ＂Y＂ maze） was observed and recorded. [Result] The re- sults showed that the times of first aggressions and approaches and the total times of active aggressions and approaches of P. clarkii in the initial period of polyculture experiment were all significantly more than E. sinensis （/：＇〈0.05）; after 30 d of poly- culture, P. clarkfi died in 30% of the groups while E. sinensis died in only 10% of the groups, and they coexisted in 60% of the groups. In the experiment of ap- proach-avoidance behavior of P. clarkii to bigger E. sinensis, with the increase of experiment times, the tendency of approach and avoidance of P. clarkii to the con- trol and E. sinensis became control-prefer （P〈0.05） from insignificantly different （P〉 0.05）, which indicated that the recognition ability of P. clarkii for E. sinensis was sig- nificantly improved, and the selection behavior of E. sinensis was obviously inhibited. [Conclusion] Presumably, polyculture of crayfishes and crabs can achieve better effi- ciency when under appropriate habitat conditions.展开更多
Genetic breeding is an important approach to improve the economic traits of aquaculture animals.Unfortunately,the genetic basis for important economic traits of red swamp crayfish,including growth-related traits,has n...Genetic breeding is an important approach to improve the economic traits of aquaculture animals.Unfortunately,the genetic basis for important economic traits of red swamp crayfish,including growth-related traits,has not yet been reported.In the present study,two full-sib families and two natural populations were employed to identify quantitative trait loci(QTLs)for growth-related traits of red swamp crayfish.In total,28 QTLs for five growth-related traits,including body weight,body length,carapace length,carapace width,and abdomen length,were repeatedly identified in more than two families/populations,by means of association analysis;nine of these displayed a heterosis effect.The phenotypic variations of the five investigated traits explained by the 28 QTLs ranged from 4.2%to 19.0%.Eight additive and three heterosis QTLs were further successfully validated using comparative analysis of favoured alleles between the small and big size crayfish groups in the natural population.In conclusion,this study investigated the genetic basis of growth-related traits in red swamp crayfish,which is of great significance for their application in the future molecular breeding of the species.展开更多
基金Supported by the Science and Technology Innovative Research Team of Anhui Academy of Agricultural Sciences(14C0504)the Youth Innovation Foundation of President of Anhui Academy of Agricultural Sciences(14B0529)Anhui Aquaculture Industry Technology System for Shrimp and Crab
文摘This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using conventional methods,and then were isolated. The further tests and analysis of the isolated strain were developed,including the regression experiment to P. clarkia,the morphology,physiological and biochemical characteristics,sequence analysis of their 16 S rRNA and gyr B genes,and the susceptibility test to antibiotics. Large colonies with similar morphology and color were obtained. Strain X120523 was identified as Citrobacter freundii,proved to have strong pathogenicity,and was susceptible to quinolones and aminoglycosides.
文摘Three different treatment methods, including topical application method, injection method and immersion method were employed to treat 17or - hydroxyprogesterone, so as to investigating its effect on ovarian development red swamp crayfish （Procambarus clarkii）. The results showed that all the three differ- ent methods could facilitate the synchronous ovarian development of red swamp crayfish at different degree, with the degree of maturity of 10% high compared with the control group. The highest maturity degree was 50% that was observed in immersion treatment group. The effect was determined as in order immersion method 〉 injection method 〉 topical apphcation method 〉 control group. The immersion method and the injection method could facilitate synchronization spawning of red swamp crayfish, with the order of immersion method 32.5%, injection method 20%, topical application 17.5% and the control group 17.5 %. Taking the synchro- nization spawning rate, final spawning rate and mortality into account, the order was the immersion method 〉 injection method 〉 topical application method 〉 control group.
基金Supported by National R&D Special Fund for Public Welfare Industry of China(201003070)National Natural Science Foundation of China (NSFC J0730641)~~
文摘[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experiment in a relatively small polyculture system. The agonistic behavior of P. clarkii and E. sinensis in the first 30 min of the initial encounter and the fighting results were observed and recorded; the approach-avoidance behavior of P. clarkii to bigger E. sinensis in a relatively large space （the ＂Y＂ maze） was observed and recorded. [Result] The re- sults showed that the times of first aggressions and approaches and the total times of active aggressions and approaches of P. clarkii in the initial period of polyculture experiment were all significantly more than E. sinensis （/：＇〈0.05）; after 30 d of poly- culture, P. clarkfi died in 30% of the groups while E. sinensis died in only 10% of the groups, and they coexisted in 60% of the groups. In the experiment of ap- proach-avoidance behavior of P. clarkii to bigger E. sinensis, with the increase of experiment times, the tendency of approach and avoidance of P. clarkii to the con- trol and E. sinensis became control-prefer （P〈0.05） from insignificantly different （P〉 0.05）, which indicated that the recognition ability of P. clarkii for E. sinensis was sig- nificantly improved, and the selection behavior of E. sinensis was obviously inhibited. [Conclusion] Presumably, polyculture of crayfishes and crabs can achieve better effi- ciency when under appropriate habitat conditions.
基金the key research and development program of Hubei province(2021BBA232)the earmarked fund for CARS-48,and the research start-up fund of high level talent introduction of Huazhong Agricultural University.
文摘Genetic breeding is an important approach to improve the economic traits of aquaculture animals.Unfortunately,the genetic basis for important economic traits of red swamp crayfish,including growth-related traits,has not yet been reported.In the present study,two full-sib families and two natural populations were employed to identify quantitative trait loci(QTLs)for growth-related traits of red swamp crayfish.In total,28 QTLs for five growth-related traits,including body weight,body length,carapace length,carapace width,and abdomen length,were repeatedly identified in more than two families/populations,by means of association analysis;nine of these displayed a heterosis effect.The phenotypic variations of the five investigated traits explained by the 28 QTLs ranged from 4.2%to 19.0%.Eight additive and three heterosis QTLs were further successfully validated using comparative analysis of favoured alleles between the small and big size crayfish groups in the natural population.In conclusion,this study investigated the genetic basis of growth-related traits in red swamp crayfish,which is of great significance for their application in the future molecular breeding of the species.
