The National Fishery Technical Extension Center

Beijing, China

The National Fishery Technical Extension Center

Beijing, China
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Luan S.,Chinese Academy of Fishery Sciences | Yang G.,Zhejiang Institute of Freshwater Fisheries | Yang G.,Zhejiang South Tailake Freshwater Fish Breeding Co. | Wang J.,Zhejiang Institute of Freshwater Fisheries | And 8 more authors.
Aquaculture | Year: 2012

Genetic parameters and response to selection were estimated for harvest body weight of the giant freshwater prawn Macrobrachium rosenbergii using a fully pedigreed synthetic population from three introduced strains. The data included 65,917 progeny that were from 331 sires and 544 dams in five generations with a nested mating structure. Harvest body weight was transformed by square root for analysis. Variance components and genetic parameters were estimated using an animal model and the restricted maximum likelihood method. The estimated breeding values of all animals over five generations were calculated using best linear unbiased prediction. Within generations, the heritability estimates for harvest body weight in each generation ranged from low to moderate (0.055±0.012 to 0.223±0.045) and were significantly different from zero (P<0.05). Only the common environmental effect of the three generations from G 1 to G 3 could be estimated, which was found to vary from 0.024±0.012 to 0.032±0.014. Across generations, the heritability and common environmental effect estimates were low (0.056±0.014 and 0.039±0.005, respectively) and significantly different from zero (P<0.05). Heritability of harvest body weight in females was significantly higher than that in males across populations. However, the genetic correlation of harvest body weight between sexes across population was close to unity (0.942±0.070), indicating that body weight in male and female shrimp is most likely controlled by the same genes. The response to selection in harvest body weight was estimated by two methods (the realised and predicted responses). The realised response was estimated from the difference in the least squares means of body weight for the selection and control populations, while the predicted response was obtained from the difference in the mean breeding values between generations. The back-transformed realised response was 26.22%, while the predicted responses estimated using two set of genetic parameters obtained from within- and across-generations datasets were 18.06% and 12.38% in actual units, respectively, after performing four selections. The results are discussed in relation to selection work with other farmed shrimps, and solutions for increasing and disseminating genetic gain are outlined. © 2012 Elsevier B.V.


Sui J.,Chinese Academy of Fishery Sciences | Luan S.,Chinese Academy of Fishery Sciences | Yang G.,Zhejiang Institute of Freshwater Fisheries | Chen X.,Zhejiang Institute of Freshwater Fisheries | And 5 more authors.
Aquaculture | Year: 2016

Data from a Macrobrachium rosenbergii selection program were analyzed to investigate how different pedigree depths and the volume of data can affect the estimation of variance components on harvest body weight and the breeding values of candidate parents. Seven years of data and reliable pedigree information back to the founding parents were available. The harvest body weights of 81,418 prawns from 724 families were recorded. The variance components were estimated using an animal model and the restricted maximum likelihood method. The estimated breeding values of the candidate parents were calculated using best linear unbiased prediction. Additive genetic variances, common environmental variances, their standard errors and the estimated breeding values of candidate parents obtained from different pedigree depths and historical data were compared. The volume of data had a much larger impact than pedigree depth on variance component estimation and estimated breeding values of candidate parents. The additive genetic variances showed significant differences among the data sets and no obvious trend was found as more years of data were included in the analysis. The common environmental variances showed a downward trend as more years of data were included. The standard errors for additive genetic variance and common environmental variance decreased substantially when two years of data were included, and errors decreased only slightly as more data were included. The accuracy of estimated breeding values improved as more pedigree information and historical data were included in the analysis for all candidate parents. The effect of different pedigree depths and historical data were more striking for family selection than within-family selection on harvest body weight. The results are discussed in a practical context of genetic evaluation for aquatic animals. Statement of relevance: This paper investigated how different pedigree depths and the volume of data can affect the estimation of variance components on harvest body weight and the breeding values of candidate parents using data from a Macrobrachium rosenbergii selection program. The results provide a useful reference for genetic evaluation in M. rosenbergii and other aquatic animal breeding programs. © 2016 Published by Elsevier B.V.


Luan S.,Chinese Academy of Fishery Sciences | Wang J.,Zhejiang Institute of Freshwater Fisheries | Wang J.,Zhejiang South Tailake Freshwater Fish Breeding Co Ltd. | Yang G.,Zhejiang Institute of Freshwater Fisheries | And 8 more authors.
Aquaculture Research | Year: 2015

Genetic parameters were estimated for survival of Macrobrachium rosenbergii using a fully pedigreed synthetic population formed by three introduced strains. The data included 107 398 progeny from 394 sires and 654 dams in six generations with a nested mating structure. The variance components and genetic parameters were estimated using a generalized linear mixed model with the probit link function. Available heritabilities in survival from the generation G3 to G5 ranged from 0.007 ± 0.020 to 0.066 ± 0.044 (P > 0.05) using a model that included the common environmental effect (c). Across generations, low heritability (0.016 ± 0.012, P > 0.05) was estimated using the model with inclusion of the c effect. There were statistically significant differences in the heritability estimates between different ponds for most generations. Moreover, the genetic correlation of survival between ponds over six generations varied from low to high (-0.0007 ± 0.17 to 0.80 ± 0.069) and was significantly different from unity. There were low correlation coefficients (-0.039 ± 0.096 to 0.342 ± 0.081) between body weight estimated breeding value (EBV) and survival EBV of families in different generations. The low heritabilities for survival are most likely caused by low genetic variation in the founder populations and reduced genetic variation because of consecutive selection. © 2013 John Wiley & Sons Ltd.


Luan S.,Chinese Academy of Fishery Sciences | Yang G.,Zhejiang Institute of Freshwater Fisheries | Yang G.,Zhejiang South Tailake Freshwater Fish Breeding Co. | Wang J.,Zhejiang Institute of Freshwater Fisheries | And 8 more authors.
Aquaculture International | Year: 2014

A selective breeding program was established to improve the growth and survival of the cultured giant freshwater prawn Macrobrachium rosenbergii. The response to selection was estimated for the survival of M. rosenbergii using a fully pedigreed synthetic population formed by three introduced strains. The data included 122,761 progeny from 437 sires and 723 dams in seven generations with a nested mating structure. The genetic parameters and estimated breeding values (EBVs) were estimated using a generalized linear mixed model with the probit link function. The realized response was estimated from the difference in the marginal means of survival for the selection and control populations, while the predicted response was obtained from the difference in the mean retransformed survival rate based on the survival EBVs between generations. The realized genetic gain in survival from the G1 to G6 generation ranged from -1.24 to 2.72 %. The accumulated realized genetic gain (5.02 %) expressed as a percentage was 8.46 %. Across the generations, high heritability (0.401 ± 0.020, Set 1) was obtained when using the model without the c effect and was significantly different from zero (P < 0.05). However, the low heritability and common environment (0.013 ± 0.011 and 0.088 ± 0.007, Set 2) were estimated using the model that included the c effect. The accumulated predicted gains (6.29 and 0.61 %, respectively) from the Set 1 and Set 2 parameters over the five generations of selection expressed as proportions were 9.08 and 0.87 %, respectively. The low genetic gain for survival is most likely caused by a low relative weight in the selection index and reduced genetic variation because of consecutive between-family selection. © 2013 Springer Science+Business Media Dordrecht.


Zhuang P.,CAS East China Sea Fisheries Research Institute | Luo G.,CAS East China Sea Fisheries Research Institute | Luo G.,The National Fishery Technical Extension Center | Zhang T.,CAS East China Sea Fisheries Research Institute | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2010

Chinese sturgeon, Acipenser sinensis, is an endangered anadromous species that is currently only found in the Yangtze River and the coastal China Seas. It spawns in the upper Yangtze River in autumn every year. Juvenile fish make a downstream migration and reach the Yangtze Estuary during May and June of next year. All of juveniles leave the estuary for ocean during August to September. Yangtze Estuary is not only a passage route for both juveniles and adults migrating between freshwater and the ocean, but also an important feeding ground for juveniles. Because of overfishing and habitat alteration, the population of Chinese sturgeon has been rapidly declining during last decades. This species has been listed as the highest level of national protected wild animals by Chinese Government since 1980s. Understanding feeding habits and food competition of juvenile Chinese sturgeon with other fish species that inhabit in the Yangtze Estuary is very important for the conservation of this species. In this study, we compared feeding habitat and food competition between juvenile Chinese sturgeon and other 6 important fish species that widely inhabit in the Yangtze Estuary. Fish samples were obtained using tidal nets. During June and August of 2004 and 2005, tidal nets were set in the tidal flat of the Yangtze Estuary. Sample locations were 31°25.26'N, 121°54. 38'E - 31°32. 57'N, 122°05.45'E, where are major habitats for juvenile Chinese sturgeon. Seven hundred and seven individuals of 7 fish species were collected, including Acipenser sinensis, Lateolabrax maculates, Liza haematochiela, Mygil cephalus, Coilia ectenes, Coilia mystus, and Cynoglissus gracilis. The alimentary canals of sample fish were taken out and preserved by quick-freezing. We weighed inclusions of the alimentary canals and indentified food items in laboratory. The study results indicated that the major food items of juvenile Acipenser sinensis are small fishes, amphipoda, polychaeta and crabs. Juvenile Acipenser sinensis and Cynoglissus gracilis feed on benthic organisms. Lateolabrax maculates mainly feeds on swimming animals, including fishes, shrimps, isopoda and crabs. Coilia ectenes and Coilia mystus feed on zooplanktons. Liza haematochiela and Mygil cephalus mainly feed on organic scraps and benthic algae. The decreasing order of the index of relative importance (IRI) of juvenile Acipenser sinensis is fishes > amphipoda > polychaetes > crabs, that of Cynoglissus gracilis is shrimps > lamellibranchiata > fishes, that of Lateolabrax maculatesb is fishes > shrimps > isopoda > crabs, that of Coilia ectenes is shrimp bran > shrimps > copepod > fishes, that of Coilia mystus is shrimp bran > copepod > shrmps > fishes, and that of Mygil cephalus and Liza haematochiela is organic detritus > benthic algae > lamellibranchiata > copepod. The food overlap coefficient (0jk) of juvenile Acipenser sinensis and other 6 species were analyzed and the results showed that 0jkbetween juvenile Acipenser sinensis and Cynoglissus gracilis is 0. 4, and Ojk between juvenile Acipenser sinensis and the rest of other 5 species are less than 0. 12, respectively. Therefore, it may be inferred that the food competition between juvenile Acipenser sinensis and Cynoglissus gracilis is high, and the food competition between juvenile Acipenser sinensis and the rest of other 5 fish species is low. In conclusion, the feeding habits between juvenile Acipenser sinensis and the most of other 6 fish species those are dominant species in the Yangtze Estuary are mainly different, thus, food competition between them are generally low. Moreover, abundant food may be provided for juvenile Acipenser sinensis in the Yangtze Estuarine area. Yangtze Estuary is a very important and suitable feeding ground for juvenile Acipenser sinensis.

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