Asian seabass(Lates calcarifer)is becoming an important species for aquaculture.However,the Asian seabass aquaculture industry faces a significant challenge of disease outbreaks that can jeopardize fish health and pro...Asian seabass(Lates calcarifer)is becoming an important species for aquaculture.However,the Asian seabass aquaculture industry faces a significant challenge of disease outbreaks that can jeopardize fish health and production.This review delves into the major diseases affecting Asian seabass aquaculture and explores their causes,symptoms,and management approaches.We focused on the key pathogens responsible for these outbreaks,the environmental factors contributing to disease susceptibility,and the latest advancements in disease prevention and management.By addressing these critical aspects,this review addresses the needs of aquaculturists,researchers,and policymakers with the knowledge required to promote resilient and sustainable Asian seabass farming.We aim to shed light on the challenges posed by disease while highlighting innovative strategies that offer promise for the future of this thriving industry.This comprehensive examination serves as a valuable resource for those invested in ensuring the health and vitality of Asian seabass,securing a consistent supply to meet the demands of global seafood markets.展开更多
A 56-day feeding trial was conducted to examine the dietary leucine requirement of juvenile Japanese seabass in sea- water floating net cages （1.5 m × 1.5 m × 2.0 m）. Six isonitrogenous （crude protein 40%...A 56-day feeding trial was conducted to examine the dietary leucine requirement of juvenile Japanese seabass in sea- water floating net cages （1.5 m × 1.5 m × 2.0 m）. Six isonitrogenous （crude protein 40%） and isoenergetic （gross energy 20 kJ g-1） diets were formulated to contain different concentrations of leucine （0.9%, 1.49%, 2.07%, 2.70%, 3.30% and 3.88% of dry matter）. Crys- talline L-amino acids were supplemented to simulate the whole body amino acid pattern of Japanese seabass except for leucine. Three groups （30 fish individuals each, 8.0g±0.20g in initial weight） were fed to apparent satiation at 5：00 and 17：30 every day. During the experimental period, the water temperature ranged from 26 to 32℃ and salinity from 26 to 30, and the dissolved oxygen was maintained at 7mgL-l. The results showed that weight gain （WG）, nitrogen retention （NR）, feed efficiency （FE） and protein efficiency ratio （PER） were significantly increased when dietary leucine was increased from 0.90% to 2.70% of dry matter, and then declined. WG was the highest when fish were fed D4 containing 2.70% of leucine. No significant differences were observed in body composition among dietary treatments （P 〉 0.05）. Considering the change of WG, the optimum dietary leucine requirement of juve- nile Japanese seabass was either 2.39% of dry matter or 5.68% of dietary protein.展开更多
Total of 1072 Asian seabass or barramundi (Lates calcarifer) were harvested at two different locations in Queensland, Australia. Each fish was digitally photographed and weighed. A subsample of 200 images (100 from ea...Total of 1072 Asian seabass or barramundi (Lates calcarifer) were harvested at two different locations in Queensland, Australia. Each fish was digitally photographed and weighed. A subsample of 200 images (100 from each location) were manually segmented to extract the fish-body area (S in cm2), excluding all fins. After scaling the segmented images to 1mm per pixel, the fish mass values (M in grams) were fitted by a single-factor model (M=aS1.5, a=0.1695 )achieving the coefficient of determination (R2) and the Mean Absolute Relative Error (MARE) of R2=0.9819 and MARE=5.1%, respectively. A segmentation Convolutional Neural Network (CNN) was trained on the 200 hand-segmented images, and then applied to the rest of the available images. The CNN predicted fish-body areas were used to fit the mass-area estimation models: the single-factor model, M=aS1.5, a=0.170, R2=0.9819, MARE=5.1%;and the two-factor model, M= aSb, a=0.124, b=0.155, R2=0.9834, MARE=4.5%.展开更多
This study investigates the relationship between polymorphisms in the cathepsin B(ctsb)gene and body weight in Asian seabass(Lates calcarifer).Despite the economic significance of this species,the genetic factors that...This study investigates the relationship between polymorphisms in the cathepsin B(ctsb)gene and body weight in Asian seabass(Lates calcarifer).Despite the economic significance of this species,the genetic factors that influence growth performance in fish remain poorly understood.CTSB,a lysosomal cysteine protease involved in protein degradation and tissue remodelling,is a crucial regulator of growth.We analysed the full-length cDNA of ctsb and mapped it to the major quantitative trait locus(QTL)for growth on linkage group 2 in L.calcarifer.Single nucleotide polymorphisms(SNPs)within ctsb were identified and their associations with body weight were analysed in 298 individuals.Results revealed that SNP1(C>T)in intron 2 of ctsb was significantly correlated with body weight.Quantitative real-time PCR(qRT-PCR)showed that ctsb was expressed in all tissues,with the highest expression in the gills and kidney of developing seabass.Knockdown/overexpression of ctsb in cell lines respectively promoted/inhibited cell proliferation without altering cell size.These findings suggest that ctsb plays a significant role in growth regulation in Asian seabass.This study provides a potential molecular marker for selecting fast-growing Asian seabass.Future research should focus on identifying causal variants in ctsb associated with accelerated growth,conducting in vivo studies,and exploring related signalling pathways.展开更多
To establish a new breeding program,genetic diversity of five domesticated populations and two commercial stocks of Asian seabass(Lates calcarifer)were examined.Moderate levels of genetic diversity based on microsatel...To establish a new breeding program,genetic diversity of five domesticated populations and two commercial stocks of Asian seabass(Lates calcarifer)were examined.Moderate levels of genetic diversity based on microsatellite polymorphism were found.The number of alleles per locus(NA)was 3.429–11.571.Observed(Ho)and expected(He)heterozygosities were 0.416–0.772 and 0.423–0.805.FST and genetic heterogeneity analysis revealed significant genetic differences of most pairwise comparisons(P<0.001).Genetic distance between populations was 0.000–0.703.Phylogenetic analysis divided examined populations to two genetic stocks;A:DOF-Chachoengsao 2,DOF-Songkhla,and DOF-Trang and B:Commercial Farm 1(Phuket)and Commercial Farm 2(Chachengsao),DOF-Chachoengsao 1 and DOF-Krabi.The base population(G0,51 families)was established from crosses between these founder populations.Heritability and estimated breeding values(EBVs)for growth in G0 families were evaluated at 519 day post hatch(dph,mean body weight=616.64±266.80 g,N=1655).The heritability(h2)for growth of L.calcarifer in this study was 0.386±0.020.The additive genetic coefficient of variation was 28%indicating high potential of genetic improvement for growth in this population.The distribution of EBVs showed high variation both between and within families.Fish exhibiting high EBVs(SATREPS-DOF-G0-hEBVs)clustered with a phylogenetic clade A while the SATREPS-DOF-G0-lEBVs group was phylogenetically allocated to clade B.Genetic selection with+1SD criteria is expected to achieve genetic gain of 28.5%per generation.The information on genetic diversity and EBVs estimates allows efficient implementation of our ongoing breeding program of L.calcarifer.展开更多
Viral nervous necrosis(VNN)caused by a betanodavirus(NNV)is one of the major diseases in Asian seabass(Lates calcarifer)hatcheries.Our previous studies showed that the tbx21 gene was in a QTL for NNV resistance in lin...Viral nervous necrosis(VNN)caused by a betanodavirus(NNV)is one of the major diseases in Asian seabass(Lates calcarifer)hatcheries.Our previous studies showed that the tbx21 gene was in a QTL for NNV resistance in linkage group 23 in Asian seabass.The expression of this gene was changed in tissues of Asian seabass challenged with NNV.However,the role of tbx21 in NNV resistance remains largely unknown.In this study,tbx21 of Asian seabass was characterized.This gene consists of an ORF of 1866 bp,a 5′UTR of 357 bp,and a 3′UTR of 4674 bp.The TBX21 protein showed substantial amino acid similarity(70-96%)with other fish but exhibited lower identity(47-52%)with mammals.One SNP identified in the first intron was significantly associated with NNV resistance.In healthy fish,tbx21 was expressed in all tissues examined,and was highly expressed in the kidney and liver.The expression of tbx21 increased in the eye,gills,heart,kidney and gut,but decreased in the brain and spleen at five days after NNV challenge.Overexpression of tbx21 reduced the replication of NNV,whereas knockdown increased viral expression and virus titers.These results suggest that tbx21 plays a key role in NNV resistance.The SNP in this gene could be used as a marker to facilitate marker-assisted selection for NNV resistance.Further investigation of polymorphisms in the 5’and 3’UTRs of tbx21 may provide additional insights into the gene's role in NNV resistance.展开更多
Adapted European seabass(Dicentrarchus labrax L.)larvae at 25 days post-hatching(dph)with a primary weight and length of 23 mg and 9.92 mm,start the weaning up to 46 dph using the weaning micro-diet(54%crude protein f...Adapted European seabass(Dicentrarchus labrax L.)larvae at 25 days post-hatching(dph)with a primary weight and length of 23 mg and 9.92 mm,start the weaning up to 46 dph using the weaning micro-diet(54%crude protein from fish meal,powder milk,and poultry egg)concurrently with Artemia enriched with fortification emulsions(0.6 g/L)of DHA selco®as a control group(DHAS)or Fish oil+20%Vitamin C(FOVC),or Fish oil+20%Vitamin E(FOVE),or Fish oil+10%Vit.C+10%Vit.E(FOCE),or Fish oil only(FO).At 46 dph,groups of larvae fed enriched Artemia with DHAS and FOVE exhibited the highest final body weight,weight gain,average daily gain,specific growth rate,feed intake,protein efficiency ratio,and survival%as well as the lowest feed conversion ratio.Meanwhile,larvae in FOVC displayed the lowest final body weight,total length,weight gain,average daily gain,specific growth rate,feed intake,protein efficiency ratio,and survival%as well as the highest feed conversion ratio.Gastrointestinal histological assessment exhibited no pathological alteration as well as an improvement in the structure with DHAS,FOVE,FOVC,and FOCE co-additives compared to FO.Glutathione peroxidase enzyme(GPx)recorded the highest rates(P<0.05)in groups fed Artemia supplemented with DHAS and FOVE followed by FOCE and FOVC.While the lowest record for GPx activity was noted in the FO group.In conclusion,Using augmented Artemia nauplii with fish oil+vitamin E in single or in companion with vitamin C as cheap antioxidants support D.labrax larval growth,survival,and antioxidant efficacy during the critical weaning period.展开更多
Growth is an economically important trait in aquaculture.To improve growth trait of the Asian seabass(Lates calcarifer)we have been carrying out,since 2004,a selective breeding program.This study focuses on growth tra...Growth is an economically important trait in aquaculture.To improve growth trait of the Asian seabass(Lates calcarifer)we have been carrying out,since 2004,a selective breeding program.This study focuses on growth traits in the F2 fish generation,comprised of offspring from 23 mass crosses from 383 F_(1) brooders.Using genotyping analysis for 10 microsatellites from both brood stock and progeny we have reconstructed the pedigree of each mass-cross.For F_(2) generation at 90 days post hatch(dph),we have recorded body weight(BW)for 12,117 individuals and total length(TL),standard length(SL)and condition factor(K_(tl) and K_(sl))for 3530 individuals;and all five traits for 2136 individuals at 270 dph.At 90 dph the average BW was 46.88±20.95 g.Combining pedigree information,recorded growth traits and Restricted Maximum Likelihood method,we have estimated that the narrow sense heritability(h^(2))in F_(1) fish for BW,TL,SL,K_(tl) and K_(sl) was at,90 dph,0.12±0.03,0.11±0.03,0.10±0.03,0.20±0.04 and 0.11±0.03,respectively and,at 270 dph,0.34±0.07,0.32±0.07,0.30±0.06,0.13±0.04 and 0.11±0.04,respectively.At 90 dph the realised heritability for BW was 0.13.Comparing with F_(1) generation,the growth performance of F_(2) fish was increased by 14.4%.Heritability of growth traits will be useful for future genetic improvement programmes of the Asian seabass.展开更多
基金financially supported by internal funding from the Temasek Life Sciences Laboratory,Singapore.
文摘Asian seabass(Lates calcarifer)is becoming an important species for aquaculture.However,the Asian seabass aquaculture industry faces a significant challenge of disease outbreaks that can jeopardize fish health and production.This review delves into the major diseases affecting Asian seabass aquaculture and explores their causes,symptoms,and management approaches.We focused on the key pathogens responsible for these outbreaks,the environmental factors contributing to disease susceptibility,and the latest advancements in disease prevention and management.By addressing these critical aspects,this review addresses the needs of aquaculturists,researchers,and policymakers with the knowledge required to promote resilient and sustainable Asian seabass farming.We aim to shed light on the challenges posed by disease while highlighting innovative strategies that offer promise for the future of this thriving industry.This comprehensive examination serves as a valuable resource for those invested in ensuring the health and vitality of Asian seabass,securing a consistent supply to meet the demands of global seafood markets.
基金supported by the National Key Technologies R&D Program for the 15th Five-year Plan of China (Grant no. 2004BA526B-06)Program for New Century Excellent Talents in University (NCET-07-0776)
文摘A 56-day feeding trial was conducted to examine the dietary leucine requirement of juvenile Japanese seabass in sea- water floating net cages （1.5 m × 1.5 m × 2.0 m）. Six isonitrogenous （crude protein 40%） and isoenergetic （gross energy 20 kJ g-1） diets were formulated to contain different concentrations of leucine （0.9%, 1.49%, 2.07%, 2.70%, 3.30% and 3.88% of dry matter）. Crys- talline L-amino acids were supplemented to simulate the whole body amino acid pattern of Japanese seabass except for leucine. Three groups （30 fish individuals each, 8.0g±0.20g in initial weight） were fed to apparent satiation at 5：00 and 17：30 every day. During the experimental period, the water temperature ranged from 26 to 32℃ and salinity from 26 to 30, and the dissolved oxygen was maintained at 7mgL-l. The results showed that weight gain （WG）, nitrogen retention （NR）, feed efficiency （FE） and protein efficiency ratio （PER） were significantly increased when dietary leucine was increased from 0.90% to 2.70% of dry matter, and then declined. WG was the highest when fish were fed D4 containing 2.70% of leucine. No significant differences were observed in body composition among dietary treatments （P 〉 0.05）. Considering the change of WG, the optimum dietary leucine requirement of juve- nile Japanese seabass was either 2.39% of dry matter or 5.68% of dietary protein.
文摘Total of 1072 Asian seabass or barramundi (Lates calcarifer) were harvested at two different locations in Queensland, Australia. Each fish was digitally photographed and weighed. A subsample of 200 images (100 from each location) were manually segmented to extract the fish-body area (S in cm2), excluding all fins. After scaling the segmented images to 1mm per pixel, the fish mass values (M in grams) were fitted by a single-factor model (M=aS1.5, a=0.1695 )achieving the coefficient of determination (R2) and the Mean Absolute Relative Error (MARE) of R2=0.9819 and MARE=5.1%, respectively. A segmentation Convolutional Neural Network (CNN) was trained on the 200 hand-segmented images, and then applied to the rest of the available images. The CNN predicted fish-body areas were used to fit the mass-area estimation models: the single-factor model, M=aS1.5, a=0.170, R2=0.9819, MARE=5.1%;and the two-factor model, M= aSb, a=0.124, b=0.155, R2=0.9834, MARE=4.5%.
基金supported by the Internal Funds of the Temasek Life Sciences Laboratory(5020),Singapore.
文摘This study investigates the relationship between polymorphisms in the cathepsin B(ctsb)gene and body weight in Asian seabass(Lates calcarifer).Despite the economic significance of this species,the genetic factors that influence growth performance in fish remain poorly understood.CTSB,a lysosomal cysteine protease involved in protein degradation and tissue remodelling,is a crucial regulator of growth.We analysed the full-length cDNA of ctsb and mapped it to the major quantitative trait locus(QTL)for growth on linkage group 2 in L.calcarifer.Single nucleotide polymorphisms(SNPs)within ctsb were identified and their associations with body weight were analysed in 298 individuals.Results revealed that SNP1(C>T)in intron 2 of ctsb was significantly correlated with body weight.Quantitative real-time PCR(qRT-PCR)showed that ctsb was expressed in all tissues,with the highest expression in the gills and kidney of developing seabass.Knockdown/overexpression of ctsb in cell lines respectively promoted/inhibited cell proliferation without altering cell size.These findings suggest that ctsb plays a significant role in growth regulation in Asian seabass.This study provides a potential molecular marker for selecting fast-growing Asian seabass.Future research should focus on identifying causal variants in ctsb associated with accelerated growth,conducting in vivo studies,and exploring related signalling pathways.
基金supported by Science and Technology Research Partnership for Sustainable Development(SATREPS),Japan Science and Technology Agency(JST)/Japan International Cooperation Agency(JICA)grant no.JPMJSA1806.
文摘To establish a new breeding program,genetic diversity of five domesticated populations and two commercial stocks of Asian seabass(Lates calcarifer)were examined.Moderate levels of genetic diversity based on microsatellite polymorphism were found.The number of alleles per locus(NA)was 3.429–11.571.Observed(Ho)and expected(He)heterozygosities were 0.416–0.772 and 0.423–0.805.FST and genetic heterogeneity analysis revealed significant genetic differences of most pairwise comparisons(P<0.001).Genetic distance between populations was 0.000–0.703.Phylogenetic analysis divided examined populations to two genetic stocks;A:DOF-Chachoengsao 2,DOF-Songkhla,and DOF-Trang and B:Commercial Farm 1(Phuket)and Commercial Farm 2(Chachengsao),DOF-Chachoengsao 1 and DOF-Krabi.The base population(G0,51 families)was established from crosses between these founder populations.Heritability and estimated breeding values(EBVs)for growth in G0 families were evaluated at 519 day post hatch(dph,mean body weight=616.64±266.80 g,N=1655).The heritability(h2)for growth of L.calcarifer in this study was 0.386±0.020.The additive genetic coefficient of variation was 28%indicating high potential of genetic improvement for growth in this population.The distribution of EBVs showed high variation both between and within families.Fish exhibiting high EBVs(SATREPS-DOF-G0-hEBVs)clustered with a phylogenetic clade A while the SATREPS-DOF-G0-lEBVs group was phylogenetically allocated to clade B.Genetic selection with+1SD criteria is expected to achieve genetic gain of 28.5%per generation.The information on genetic diversity and EBVs estimates allows efficient implementation of our ongoing breeding program of L.calcarifer.
文摘Viral nervous necrosis(VNN)caused by a betanodavirus(NNV)is one of the major diseases in Asian seabass(Lates calcarifer)hatcheries.Our previous studies showed that the tbx21 gene was in a QTL for NNV resistance in linkage group 23 in Asian seabass.The expression of this gene was changed in tissues of Asian seabass challenged with NNV.However,the role of tbx21 in NNV resistance remains largely unknown.In this study,tbx21 of Asian seabass was characterized.This gene consists of an ORF of 1866 bp,a 5′UTR of 357 bp,and a 3′UTR of 4674 bp.The TBX21 protein showed substantial amino acid similarity(70-96%)with other fish but exhibited lower identity(47-52%)with mammals.One SNP identified in the first intron was significantly associated with NNV resistance.In healthy fish,tbx21 was expressed in all tissues examined,and was highly expressed in the kidney and liver.The expression of tbx21 increased in the eye,gills,heart,kidney and gut,but decreased in the brain and spleen at five days after NNV challenge.Overexpression of tbx21 reduced the replication of NNV,whereas knockdown increased viral expression and virus titers.These results suggest that tbx21 plays a key role in NNV resistance.The SNP in this gene could be used as a marker to facilitate marker-assisted selection for NNV resistance.Further investigation of polymorphisms in the 5’and 3’UTRs of tbx21 may provide additional insights into the gene's role in NNV resistance.
文摘Adapted European seabass(Dicentrarchus labrax L.)larvae at 25 days post-hatching(dph)with a primary weight and length of 23 mg and 9.92 mm,start the weaning up to 46 dph using the weaning micro-diet(54%crude protein from fish meal,powder milk,and poultry egg)concurrently with Artemia enriched with fortification emulsions(0.6 g/L)of DHA selco®as a control group(DHAS)or Fish oil+20%Vitamin C(FOVC),or Fish oil+20%Vitamin E(FOVE),or Fish oil+10%Vit.C+10%Vit.E(FOCE),or Fish oil only(FO).At 46 dph,groups of larvae fed enriched Artemia with DHAS and FOVE exhibited the highest final body weight,weight gain,average daily gain,specific growth rate,feed intake,protein efficiency ratio,and survival%as well as the lowest feed conversion ratio.Meanwhile,larvae in FOVC displayed the lowest final body weight,total length,weight gain,average daily gain,specific growth rate,feed intake,protein efficiency ratio,and survival%as well as the highest feed conversion ratio.Gastrointestinal histological assessment exhibited no pathological alteration as well as an improvement in the structure with DHAS,FOVE,FOVC,and FOCE co-additives compared to FO.Glutathione peroxidase enzyme(GPx)recorded the highest rates(P<0.05)in groups fed Artemia supplemented with DHAS and FOVE followed by FOCE and FOVC.While the lowest record for GPx activity was noted in the FO group.In conclusion,Using augmented Artemia nauplii with fish oil+vitamin E in single or in companion with vitamin C as cheap antioxidants support D.labrax larval growth,survival,and antioxidant efficacy during the critical weaning period.
基金This study was supported by the project“Selective Breeding of Marine Food Fish”funded by AVA,Singapore and by the Singapore National Research Foundation under CRP Award No.NRF-CRP7-2010-01.
文摘Growth is an economically important trait in aquaculture.To improve growth trait of the Asian seabass(Lates calcarifer)we have been carrying out,since 2004,a selective breeding program.This study focuses on growth traits in the F2 fish generation,comprised of offspring from 23 mass crosses from 383 F_(1) brooders.Using genotyping analysis for 10 microsatellites from both brood stock and progeny we have reconstructed the pedigree of each mass-cross.For F_(2) generation at 90 days post hatch(dph),we have recorded body weight(BW)for 12,117 individuals and total length(TL),standard length(SL)and condition factor(K_(tl) and K_(sl))for 3530 individuals;and all five traits for 2136 individuals at 270 dph.At 90 dph the average BW was 46.88±20.95 g.Combining pedigree information,recorded growth traits and Restricted Maximum Likelihood method,we have estimated that the narrow sense heritability(h^(2))in F_(1) fish for BW,TL,SL,K_(tl) and K_(sl) was at,90 dph,0.12±0.03,0.11±0.03,0.10±0.03,0.20±0.04 and 0.11±0.03,respectively and,at 270 dph,0.34±0.07,0.32±0.07,0.30±0.06,0.13±0.04 and 0.11±0.04,respectively.At 90 dph the realised heritability for BW was 0.13.Comparing with F_(1) generation,the growth performance of F_(2) fish was increased by 14.4%.Heritability of growth traits will be useful for future genetic improvement programmes of the Asian seabass.
