Yellowfin Seabream Acanthopagrus Latus Research Articles

Development of SNP parentage assignment techniques in the yellowfin seabream Acanthopagrus latus

Development of SNP parentage assignment techniques in the yellowfin seabream Acanthopagrus latus

Molecular and cellular regulation on sexual fate and gonadal development in hermaphrodite yellowfin seabream Acanthopagrus latus

Yellowfin seabream (Acanthopagrus latus) is a hermaphroditic fish with male prematurity, which is also an economically important mariculture species in coastal areas of China. Although the production yield has been increasing in recent years, artificial breeding of this species remains imperfect due to the lack understanding of its sex differentiation mechanism. In this study, we conducted transcriptomic sequencing to screen for sex-related genes in different stage of the testis, ovotestis, ovary, hypothalamus, and pituitary tissues of yellowfin seabream. During gonad development (from intersex to mature stage), Gnrh3, Kiss2, and Dbh were expressed in the hypothalamus and Lhb and Fshb were expressed in the pituitary. Sex-related genes such as Hsd11b1, Foxl2l, Amh, and Gsdf were among the top 10 downregulated genes in the intersex testis compared with the mature testis. The expression of Hsd11b, Wnt, and Sox families genes differed significantly in the sex change process among functional mature gonads. In addition, treatment with estradiol resulted in feminizing of the ovotestis. Inhibition of androgens or estrogens promoted ovarian or testicular steps of ovotestis development. In summary, we systematically evaluated gene expression profiles during yellowfin seabream gonad development from intersex to functional male or female. Our results confirmed that regulation by the hypothalamus-pituitary-gonad (HPG) axis and the promotion of sex steroid hormones acted on this process, and they provide a reference for further studies of the involvement of the HPG axis in sex change and of sex induction methods in yellowfin seabream.

Evaluation of the effects of diets containing different lipid levels for juvenile yellowfin seabream Acanthopagrus latus

This study evaluated the effect of dietary lipid levels on growth, body composition, amino acid and fatty acid profile, and nutrient utilization of juvenile yellowfin seabream (Acanthopagrus latus). Six diets with different crude lipid levels at 7% (CL7), 9% (CL9), 11% (CL11), 13% (CL13), 15% (CL15), and 17% (CL17) were designed, and each diet was fed to 4 cages (50 fish per cage; 19.00 ± 0.01 g per fish) for sixteen weeks. Results indicated that weight gain (WG) and specific growth rate (SGR) were highest at 13% dietary lipid level, while feed conversion ratio (FCR) was lowest (P < 0.05). Intraperitoneal fat ratio (IPF) increased with increasing dietary lipid level from 7% to 17%. The lipid efficiency ratio (LER), lipid retention (LR), and nitrogen excretion (NE) decreased significantly with increasing dietary lipid level (P < 0.05). Crude protein and lipid of the whole body decreased or increased with increasing dietary lipid level, respectively (P < 0.05). The dorsal muscle and liver lipid content significantly increased with increasing dietary lipid (P < 0.05). With the dietary lipid increasing, total fatty acid content was significantly increased (P < 0.05). Results about the fatty acid profile of the whole body indicated that the proportions of C14:0, C16:1, C20:4, C20:5, and C20:6 were significantly decreased with increased dietary lipid level (P < 0.05). In contrast, the proportions of C18:0, C18:1, and C22:1 were increased with increased dietary lipid level (P < 0.05). The retention of fatty acids was decreased with increasing dietary lipid (P < 0.05). Form a nutritional, environmental, and economic point of view, 13% dietary crude lipid was recommended. Excess dietary lipid levels in diets negatively affect the structure of the liver, leading to lipid accumulation and inflammation development.

Improvement of water quality with probiotics inclusion during simulated transport of Yellowfin Seabream Acanthopagrus latus larvae.

The expansion of marine aquaculture requires the shipment of early life stages from hatcheries to breeding centers. Thus, maintaining water quality parameters during transportation is crucial. This experiment investigated the effects of a commercial probiotic mixture (PM) (consisting of Bacillus licheniformis, Bacillus subtilis, Pediococcus acidilactici, and Lactobacillus acidophilus with a total count of 107  CFU/g) on water quality, bacterial population, and the survival of larvae of Yellowfin Seabream Acanthopagrus latus during a 24-h simulated transportation experiment. To simulate transportation, purified seawater was used as a control and purified seawater supplemented with 3 g of PM was used as the PM48 treatment. For the PM48 treatment, 3 g of PM was added to 1 L of purified seawater and mixed with 200 L of purified seawater 48 h prior to the main experiment. The use of probiotics resulted in an increase in larval survival up to 93.3% compared with 89.85% in the control group. Initial sampling showed a statistically significant difference in levels between the control and PM48 treatments. After transportation, the pH of the control treatment showed a significant decrease. The total number of bacteria and the total number of Vibrio spp. in water and fish larvae showed that within 48 h, the probiotics became the dominant population in the PM48 treatment. After 24 h, water samples and larvae from the control treatment showed a significant increase in bacterial load. The results showed that probiotics can play a significant role in maintaining biotic and abiotic water quality parameters, leading to a better survival rate of larvae during transportation. These findings represent an important step in improving long-distance transport protocols.

Functional Characterization of the Almstn2 Gene and Its Association with Growth Traits in the Yellowfin Seabream Acanthopagrus latus (Hottuyn, 1782).

Myostatin (mstn), also known as GDF8, is a growth and differentiation factor of the transforming growth factor-β (TGF-β) superfamily and plays a key inhibitory effect in the regulation of skeletal muscle development and growth in vertebrates. In the present study, to comprehend the role of the mstn2 gene of the yellowfin seabream Acanthopagrus latus (Almstn2b), the genomic sequence of Almstn2b is 2359 bp, which encodes 360 amino acids and is composed of three exons and two introns, was obtained. Two typical regions, a TGF-β propeptide and TGF-β domain, constitute Almstn2b. The topology indicated that Almstn2 was grouped together with other Perciformes, such as the gilthead seabream Sparus aurata. Moreover, Almstn2b was mainly expressed in the brain, fins, and spleen. Furthermore, five SNPs, one in the exons and four in the introns, were identified in the Almstn2b gene. The allele and genotype frequencies of SNP-Almstn2b +1885 A/G were significantly related to the total weight, interorbital distance, stem length, tail length, caudal length, caudal height, body length, and total length (p < 0.05). The allele and genotype frequencies of SNP-Almstn2b +1888 A/G were significantly related to the weight, interorbital distance, long head behind the eyes, body height, tail length, caudal length, and body length. Additionally, the relationship between the SNP-Almstn2b +1915 A/G locus and weight and long head behind the eyes was significant (p < 0.05). Furthermore, the other two SNPs were not significantly associated with any traits. Thus, the SNPs identified in this study could be utilized as candidate SNPs for breeding and marker-assisted selection in A. latus.

Development and characterization of a spleen cell line from yellowfin seabream Acanthopagrus latus and its susceptibility to Mandarinfish ranavirus.

Yellowfin seabream (Acanthopagrus latus) is one of the most commercially important marine fish in China. In this study, a new continuous cell line, named ALS cells, was developed from the spleen tissue of A. latus. The cell line was maintained in Dulbecco's modified Eagle medium/Nutrient Mixture F-12 Ham (DMEM/F-12) supplemented with 10% fetal bovine serum (FBS) and successfully cultured up to 50 passages. The cell line was authenticated by amplifying and sequencing mitochondrial cytochrome C oxidase subunit-I (coi-I) gene. The ALS cell line had the maximum growth rate in DMEM/F-12 medium containing 20% FBS at 27°C. Chromosome number analysis showed that the ALS cells have a modal diploid chromosome number of 34. The ALS cell line was transfected with the pEGFP-N1 plasmid, and green fluorescence was observed. The ALS cell line was used for testing Mandarinfish ranavirus (MRV) susceptibility, and the cytopathic effects in the cell line were observed at 4 days post-infection (dpi). Furthermore, the susceptibility of the ALS cell line to MRV and the levels of MRV mRNA and viral loads were found to be significantly increased at 1-7 dpi. This study revealed that the ALS cell line could be useful for molecular, virological, and biotechnological studies on yellowfin seabream.

A mandarinfish Siniperca chuatsi infection and vaccination model for SDDV and efficacy evaluation of the formalin-killed cell vaccine in yellowfin seabream Acanthopagrus latus

Scale drop disease virus (SDDV) is a distinct member in genus Megalocytivirus. Knowledge underlying pathogenesis of SDDV is still very limited. Here, a mandarinfish Siniperca chuatsi infection and vaccination model for SDDV was established. Artificial infection either by intraperitoneal or by intramuscular injection caused over 80% lethality to various sizes of mandarinfish juveniles. Cohabitation infection also resulted in over 70% lethality in the same infectious recycling water system. All data demonstrated that mandarinfish is a very highly susceptible fish species for SDDV. Real-time quantitative PCR showed that SDDV loads in infected-mandarinfish was the highest in spleen, followed by heart, gill, kidney, liver, muscle, intestines and brain, which was further confirmed by histopathology, immunofluorescence and immunochemistry. Histological analysis showed that although SDDV caused very high mortality to mandarinfish, its histopathology was not so typical as by ISKNV-infected mandarinfish. Formalin-killed cell (FKC) vaccines with 107.2 TCID50/0.1 mL, 106.9 TCID50/0.1 mL and 106.5 TCID50/0.1 mL SDDV antigens were prepared to immunize mandarinfish. As a result, the survivals of immunized fish were 100% (40/40), 97.5% (39/40) and 62.5% (25/40), respectively. By contrast, all un-immunized fish died upon SDDV challenge. Effectiveness of SDDV FKC vaccine was evaluated by immunizing 11,520 and 1038 yellowfin seabream and >90% protective effects were observed in both individual tests at 30 days post vaccination. Collectively, mandarinfish was confirmed as an ideal fish model for studying the infection and vaccination of SDDV, and MFF-1-based FKC vaccine renders highly effective protection against SDDV infection both in mandarinfish and yellowfin seabream.

Full-length transcriptome sequence and SSR marker development for genetic diversity research in yellowfin seabream Acanthopagrus latus

Full-length transcriptome sequence and SSR marker development for genetic diversity research in yellowfin seabream Acanthopagrus latus

A chromosome-level genome assembly of the yellowfin seabream (Acanthopagrus latus; Hottuyn, 1782) provides insights into its osmoregulation and sex reversal

The yellowfin seabream Acanthopagrus latus is the economically most important Sparidae fish in the northern South China Sea. As euryhaline fish, they are perfect model for investigating osmoregulatory mechanisms in teleosts. Moreover, the reproductive biology of hermaphrodites has long been intriguing; however, little information is known about the molecular pathways underlying their sex change. Here, we report a chromosome level reference genome of A. latus generated by employing the PacBio single molecule sequencing technique (SMRT) and high-throughput chromosome conformation capture (Hi-C) technologies. The draft genome of yellowfin seabream was 806 Mb, with 732 Mb scaffolds anchored on 24 chromosomes. The contig N50 and scaffold N50 were 2.6 Mb and 30.17 Mb, respectively. The assembly is of high integrity and includes 92.23% universal single-copy orthologues based on benchmarking universal single-copy orthologs (BUSCO) analysis. A total of 19,631 protein-coding genes were functionally annotated in the reference genome. Moreover, ARRDC3 and GSTA gene families which related to osmoregulation underwent an extensive expansion in two euryhaline sparids fish genomes compared to other teleost genomes. Moreover, integrating sex-specific transcriptome analyses, several genes related to the transforming growth factor beta (TGF-β) signalling pathway involved in sex differentiation and development. This genomic resource will not only be valuable for studying the osmoregulatory mechanisms in estuarine fish and sex determination in hermaphrodite vertebrate species, but also provide useful genomic tools for facilitating breeding of the yellowfin seabream.

A new myxosporean species, Henneguya lata n. sp. (Myxozoa: Myxobolidae), from the gills of yellowfin seabream Acanthopagrus latus (Perciformes: Sparidae) in the Gulf of Tonkin, Vietnam.

During a survey of myxosporean parasites of marine fish in the coastal region of Vietnam, a species of the genus Henneguya (Myxosporea: Bivalvulida) was found in the gill of yellowfin seabream Acanthopagrus latus (Perciformes: Sparidae). White and oval cysts, measuring 145-220 μm in diameter, were detected in the gill lamellae of 4 of 15 fish examined (26.7%). Mature myxospores were elongate, with smooth valves, two similar polar capsules, and having the following dimensions: spore body length 9.9 ± 0.5 (8.9-12.5) μm, body width 6.7 ± 0.3 (6.1-7.6) μm, thickness 5.1 ± 0.2 (4.8-5.4) μm, caudal appendage length 10.0 ± 1 (8.3-11.6) μm, and total myxospore length 19.3 ± 1.4 (16.5-21.5) μm. The polar capsules were ovoid, measuring 3.2 ± 0.2 (2.8-3.9) μm long and 1.9 ± 0.2 (1.5-2.3) μm wide. Each polar capsule has a polar filament with 4-5 coils. Histological analysis revealed plasmodia in the connective tissues of the gill lamellae, but inflammation and deformation of the gills were not observed. In the phylogenetic tree reconstructed from the small subunit ribosomal DNA (SSU rDNA), sequences of the Henneguya specimens found in this study form a distinct branch. Morphological characteristics and molecular data identified a new species, namely Henneguya lata n. sp.

Landing, consumption, and DNA barcoding of commercial seabream (Perciformes: Sparidae) in Kuwait

Abstract To our knowledge, this is the first inclusive assessment of the status of Sparidae fisheries in the territorial waters of Kuwait, integrating information on catch trends, consumer preferences, recreational fishing behaviour, and molecular based identification of fish species by DNA barcoding Fisheries landing data were obtained from the official fisheries bulletin released by the Kuwait Central Statistical Bureau. Surveys were conducted to assess consumer preferences on seabream species, landed seabream species, and the behaviour of recreational anglers towards seabream species. DNA barcodes were generated to authenticate commercial seabream using the mitochondrial cytochrome c oxidase subunit I (COXI) gene and then compared with GenBank sequence entries; these sequences were then used to construct a neighbour‐joining (NJ) phylogenetic tree. Yellowfin seabream Acanthopagrus latus was the prime and most favoured commercial seabream species (45%), followed by Sparidentex hasta, which was the top‐rated secondary, unassessed seabream species. Approximately 54% of households conduct recreational fishing more than twice a month, and most (77%) primarily target S. hasta and Ac. latus. Consumer demand for secondary seabreams, which were not assessed and are listed in the bulletin under the category ‘others’, was evident. The NJ phylogenetic tree revealed that Arabian Gulf seabreams, including those of Kuwait, are genetically different from their counterparts inhabiting neighbouring waters. The data presented here highlight the urgency to modify the existing fisheries list using accurate identification tools, such as DNA barcoding, for the sustainable and conservation‐oriented management of local fisheries, which are in decline.

Reproductive characteristics of the hermaphroditic yellowfin seabream Acanthopagrus latus in the waters off western Taiwan

The reproductive characteristics of a commercially important sparid fish used in aquaculture systems, the yellowfin seabream Acanthopagrus latus, were described based on 938 specimens caught by various fisheries in the waters off western Taiwan from January 2016 to September 2017. Based on macroscopic appearances, gonadosomatic indices and histological examinations of the gonad tissues, the spawning season of this species was identified to be from September to December. This species is an asynchronous spawner, with an estimated mean fecundity of 2,444,787 ± 1,205,991. The sex ratio was significantly different from 0.5, and females predominated in most size classes and months. The sizes at 50% maturity were estimated to be 29.7 and 21.0 cm FL for females and males respectively. Although A. latus is believed to be a protandrous hermaphrodite in many geographical locations, the possibility of being a rudimentary hermaphrodite could not be excluded in this study. The positive correlations found between the fecundity and length, weight and age of the individuals and implications of these results with respect to their inshore migration pattern and the stock enhancement success were addressed.

Responses of immune organs after single-dose exposure to phenanthrene in yellowfin seabream (Acanthopagrus latus): CYP1A induction and oxidative stress

The effect of phenanthrene (Phe) on induction of ethoxyresorufinO-deethylase (EROD) activity and oxidative stress was examined in immune organs of yellowfin seabream Acanthopagrus latus. Fish were treated with a single intraperitoneal injection at 2, 20, or 40 mg kg−1. The Phe concentration in spleen, EROD activity, superoxide dismutase (SOD) and catalase (CAT) activity, ascorbic acid (AsA), total glutathione (GSH), lipid peroxidation (LPO), and protein carbonylation (PC) levels in spleen and head kidney were assessed at one, four, seven, and 14 days post-injection. Dose response relationship was explored for data on day four. Phe concentration reached the highest observed level on day four, showed decline on day seven, and was undetectable at the end of trial. EROD activity in both organs followed the pattern of Phe level in all treated groups. Catalase and SOD activity at low Phe concentrations was significantly higher than controls, while LPO and PC level showed no differences from controls. In contrast, at 20 and 40 mg kg−1, CAT and SOD activity, an indicator of oxidative stress, was significantly lower than in untreated controls, while AsA, GSH, LPO, and PC levels were higher on days 4 and 7. No parameter of any treatment group in either organ tissue showed difference from control values at the end of the experiment. The SOD and CAT activity in both organs exhibited a biphasic (initial stimulatory effect) effect, whereas other parameters showed a monophasic effect in terms of dose-response. Results suggest that Phe induced CYP1A and antioxidant responses in immune organs.

Comparison of genetic characteristics and pathogenicity of Lactococcus garvieae isolated from aquatic animals in Taiwan

Seventy-six Taiwanese bacterial isolates including 74 from diseased, cultured, aquatic animals (54 grey mullet Mugil cephalus, 3 basket mullet Chelon alatus, 2 tilapia Oreochromis niloticus, 1 grouper Epinephelus coioides, 2 yellowfin seabream Acanthopagrus latus, 1 Borneo mullet Chelon macrolepis, 1 bullfrog Rana catesbeiana, 1 Japanese eel Anguilla japonica, and 9 giant freshwater prawns Macrobrachium rosenbergii), 1 wild-caught seafood species (squid muscle collected from a restaurant) and 1 human isolate (from a patient with a history of consuming raw squid in the previously mentioned restaurant), all collected between 1999 and 2006, were confirmed by PCR assay to be Lactococcus garvieae. The phenotypic characterization was determined by rabbit anti-KG+ and KG- serums, and 74 of the 76 Taiwanese strains displayed a KG- phenotype. The genetic characterization was investigated by pulsed-field gel electrophoresis (PFGE). Genomic DNA was digested with restriction endonucleases ApaI and SmaI and separated by PFGE. Ten different L. garvieae pulsotypes were identified. Predominant pulsotypes A1a/S1a were obtained from >96% of strains (52 of 54) from grey mullet, demonstrating a clonal dissemination of L. garvieae in grey mullet in Taiwan. In experimental challenges with grey mullet and tilapia, L. garvieae pulsotypes A1/S1 and A11/S11 showed higher virulence compared with other pulsotypes.

Philometroides acanthopagri sp. nov., a new philometrid (Nematoda, Philometridae) from the musculature of Acanthopagrus latus (Sparidae) from marine waters of Iraq

A new nematode species, Philometroides acanthopagri sp. nov. (Philometridae), is described from gravid and subgravid specimens found in the musculature near pectoral fins and in nasal cavity of the yellowfin seabream Acanthopagrus latus (Houttuyn) (Sparidae, Perciformes) from marine waters off the coast of southern Iraq. Based on light and scanning electron microscopical examination, the new species differs from its congeners in a combination of morphological and biometrical features. It is the first species of Philometroides reported from a sparid fish and the first representative of this genus recorded from fishes in the Arabian Gulf. A key to Philometroides species parasitizing marine and brackish-water fishes is provided.

The Osmoregulatory Status of the Juveniles of Yellow Fin Seabream Acanthopagrus latus (Houttyn,1782) in Natural Habitats (Shatt Al-Arab and Basrah Channel)

The Osmoregulatory Status of the Juveniles of Yellow Fin Seabream Acanthopagrus latus (Houttyn,1782) in Natural Habitats (Shatt Al-Arab and Basrah Channel)

Significant population genetic structure of yellowfin seabream Acanthopagrus latus in China

The yellowfin seabream Acanthopagrus latus is widely distributed throughout the Indo‐West Pacific. The genetic analyses of mtDNA control region sequence variation in samples from Chinese waters revealed a pattern of genetic structure between southern and northern samples (P &lt; 0·05) and high levels of genetic diversity in this species. Significant isolation by distance between southern and northern locations (Mantel test r = 0·35, P = 0·04) and among northern populations (r = 0·55, P = 0·01) indicated that ocean straits and other barriers substantially limit gene flow. Phylogeographical analysis also revealed two major divergent mtDNA lineages across Chinese waters. For conservation, A. latus populations in Chinese waters should be divided into at least two management units for protection.

Complete mitochondrial DNA sequence of the yellowfin seabreamAcanthopagrus latusand a genomic comparison among closely related sparid species

The complete mitochondrial genome of the yellowfin seabream Acanthopagrus latus was determined in the present study. The genome was 16,609 bp in length and contained 37 genes (2 ribosomal RNA, 22 transfer RNA and 13 protein-coding genes) and the control region (CR), with the content and order of genes being similar to those in typical teleosts. Comparisons of the 37 genes and CR among species indicate the CR was the highest divergent (0.3341), but tRNAGly possesses the lowest genetic variation (0.0542). Much greater p-genetic distances [mean = 0.1559, standard deviation (SD) = 0.0235; n = 1653] for the interspecies level with high frequency (99.4%) than those of the intraspecies level (mean = 0.0098, SD = 0.0090; n = 20) were inferred from 212 Cyt b sequence data, suggesting the Cyt b gene is conserved within Sparidae species and supporting the barcoding validity of Cyt b sequence data for Sparidae species identification. Phylogenetic analysis using amino acid sequences of 13 protein-coding genes supporte...

Characterization of 11 polymorphic microsatellite loci in the yellowfin seabream Acanthopagrus latus

AbstractThe development and characterization of polymorphic microsatellite loci in the yellowfin seabream Acanthopagrus latus are presented. Allelic diversity was estimated in 50 samples collected from southeastern China. Eleven loci displayed polymorphism that ranged from 10 to 25 alleles per locus and the observed heterozygosity ranged from 0.48 to 0.91. These markers could be very useful for the study of population genetics of the yellowfin seabream.

Temperature and salinity tolerances of yellowfin sea bream,Acanthopagrus latus,at different salinity and temperature levels

Abstract Yellowfin sea bream Acanthopagrus latus (Houttuyn) (0.98 ± 0.27 g) were examined for temperature and salinity tolerances at nine different environmental regimes (0.3, 15 and 33 ppt combined with 10, 25 and 32 °C), in which the fish were subjected to gradual and sudden changes in temperature and salinity respectively. The 50% CTMax (critical thermal maximum) and the UILT (upper incipient lethal temperature) were in the range of 34.8–38.2 °C and 32.8–36.4 °C respectively. The 50% CTMin (critical thermal minimum) and the LILT (lower incipient lethal temperature) were in the ranges of 4.9–9.4 °C and 7.1–17.6 °C respectively. The 50% CSMax (critical salinity maximum) and the UILS (upper incipient lethal salinity) were in the ranges of 54–69‰ and 9–44‰, respectively. The fish at lower temperature (10 °C) and salinity of 33‰ tolerated temperature as low as 6 °C when the temperature was decreased gradually. The fish at 33 and 15‰ and lower temperature (10 °C) tolerated salinity as high as 66–67‰, whereas those at freshwater salinity level (0.3‰) and 32 °C tolerated salinity to 50‰ when salinity was increased gradually. The relationships among UILT, LILT, 50% CTMax, 50% CTMin, UILS, 50% CSMax, salinity and temperature are given.