Search

This study selected Trachinotus ovatus and Nibea albiflora as the focal subjects to investigate the impacts of probabilistic frequency of temperature increment through laboratory simulations that mimicked the seasonal water elevated temperature adjacent to two coastal nuclear power plants. This research was underpinned by the probabilistic analysis of temperature increase frequencies, aiming to evaluate the thermal tolerance of these species across different seasonal contexts. Results demonstrated that the T. ovatus did not exhibit mortality in the spring, autumn, and winter. Mortality in T. ovatus occurred only during the summer in temperature-duration probability experimental groups subjected to 8.5°C above ambient temperature with exposure probabilities of 50%, 75%, and 100%. The average survival rates were (93.3±3.3) %, (93.3±5.1) %, and (86.7±2.9) % respectively. The N. albiflora experienced mortality in spring, summer, autumn, and winter, with the highest mortality rate in summer. Compared to N. albiflora, T. ovatus exhibited significantly higher thermal tolerance across all seasons. As the experimental temperature increased and the duration probability rose, the mortality rates of both fish species showed an upward trend. There was an interaction between elevated temperature and duration probability, with the duration of different elevated temperature amplitudes significantly impacting the fish's survival rates. [ABSTRACT FROM AUTHOR]

According to numerous scientific publications and commercial offers, two species of pompano, Trachinotus blochii and T. falcatus, are currently cultivated in the mariculture in Taiwan and Southeast Asia, particularly, in Vietnam. It is also believed that T. blochii and T.ovatus are grown in aquatic farms of mainland China. Taxonomic identification by morphological characters of pompano species from a farm in the southern part of Central Vietnam and the results of the DNA barcoding showed that one of these species is indeed T. blochii, while the second one is not T. falcatus, but T. anak. Analysis of the literature data did not reveal any confirmed evidence of either introduction or presence of T. falcatus and T. ovatus in Asian waters. Moreover, the comparison of the generated nucleotide sequences with the sequences from genetic databases (GenBank and BOLD), allowed us to conclude that these species are unlikely to be present in mariculture, and all the mentions of them in numerous scientific publications from this region are the result of misidentification of T. anak. [ABSTRACT FROM AUTHOR]

This study examined the impact of varying doses of mannan oligosaccharide (MOS) supplementation on antioxidant defense, non-specific immunity, resistance to typhoon stress, and resistance to disease in Trachinotus ovatus. Fish groups C, M1, M2, and M3 were fed 1%, 0.3%, 0.6%, and 1% MOS-supplemented feed, respectively. On the 28th and 56th day of the feeding trial, samples from all groups were taken to measure the antioxidant and non-specific immunity parameters and challenged with Vibrio harvey. On the 32nd day, a typhoon hit the experimental site, and the survival rates of all groups were calculated. Results showed that on the 28th day, groups M2 and M3 showed considerably higher levels of antioxidant abilities (T-AOC), and groups M1 and M2 showed significantly enhanced non-specific immunity (AKP, LZM, and TP) levels than those of group C (p < 0.05). All MOS groups had significantly lower cumulative mortality following the challenge test and typhoon stress than the control group (p < 0.05). On the 56th day, groups M2 and M3 showed significantly enhanced antioxidant ability (CAT) compared to the control group. Only one non-specific immunity parameter increased significantly in groups M2 and M3 (p < 0.05). After the challenge test, only group M3 exhibited a significantly declined cumulative mortality rate compared to the control groups (p < 0.05). In summary, supplementation of MOS at dose 0.6% (M2) for 28 days showed the best overall improving effects on the antioxidant capacity, non-specific immunity, disease resistance, and typhoon stress resistance in T. ovatus juveniles. [ABSTRACT FROM AUTHOR]

The research aimed to create a shelf life prediction model for Trachinotus ovatus in different freezing temperatures by using back propagation (BP) neural network model. The pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), water retention (water holding capacity [WHC]; cooking loss), and sensory evaluation were measured under 266 K, 255 K, 243 K, 233 K, and 218 K temperatures. The results of TVB-N and water retention during 266 K, 255 K, 233 K, and 218 K conditions were selected to build a BP neural network model and verify the model at 243 K. Results indicated that low temperatures retarded the rise of pH, TVB-N, and TBA values, improving water retention capacity of Trachinotus ovatus. The BP neural network model had high regression coefficients (r2: 0.8642-0.9904), low mean square error (MES: 0.1658-1.7882), and relative error within 10% and could accurately predict the quality change of Trachinotus ovatus under the freezing temperatures of 266 K-218 K. Therefore, (BP) neural network model has great potential in predicting the shelf life of Trachinotus ovatus in frozen storage. [ABSTRACT FROM AUTHOR]

A 12-week growth trial was conducted to evaluate the complete coreplacement of fish meal (FM) and fish oil (FO) in juvenile Florida pompano (Trachinotus carolinus) diets. Five open-formula experimental diets were formulated as iso-nitrogenous (approximately 46% crude protein) and isolipidic (approximately 15% crude lipid). It is assumed that Florida pompano lack the mechanisms for synthesizing sufficient LC-PUFA. In the FM/FO-free diets, to meet the necessary dietary intake of LC-PUFA, a commercially available Schizochytrium algal oil was used. Four diets were prepared from a basal mix, with spirulina and poultry by-product meal as the principal protein sources. They differed only in their oil source, containing fish oil (FO), algal oil (AO), soy oil (SO), or a 50/50 blend of algal oil and soy oil (A/S). The fifth experimental diet (control) was a standard open-formula FM diet. In addition to the experimental diets, two commercial closed-formula diets served as references. The seven diets, each with four replicates, were stocked with 20 Florida pompano (approximately 4 g) in each. The experimental open-formula diets were tested against the control using Dunnett's t-test, and different oil sources were tested against each other using orthogonal contrasts. The four experimental diets were each tested against the two reference diets with equivalency tests. Feed intake and survival were not different between the experimental diets and control. However, all production metrics were lower in the SO diet than the control. No other differences were observed between the FO, AO, and A/S diets and the control, or between the three diets. The feed conversion ratio (FCR) was higher in fish fed the SO diet than in fish fed the control diet, and no other differences were found. The protein efficiency ratio (PER) was higher in fish fed the control diet than in fish fed the experimental diets. Protein productive values (PPV) were similar to PER, except that the PPV in fish fed the AO diet was not different from the control. The contrasts revealed that the FO, AO, and A/S diets resulted in a lower FCR than the SO diet. The PER was higher in fish fed the AO diet, and lower in fish fed the SO diet. The PPV was higher in fish fed the AO diet than in fish fed the A/S and SO diets, but similar to that of fish fed the FO diet. There were striking differences in performance between the two commercial reference feeds, underscoring the importance of using well-defined open-formula diets as a reference or control. To our knowledge this is the first study to demonstrate that co-replacement of FM and FO can be achieved in Florida pompano by supplying an FM- and FO-free diet. The development of successful open-formula diets without FO will help spur innovation and sustainability in aquaculture production. [ABSTRACT FROM AUTHOR]

Golden pompano (Trachinotus ovatus) is a marine fish of great commercial value. It was selected for a study on allometric growth using fermented soybean meal (SBM) as the primary protein source during an 8-week culture period. By comparing the gene expression levels of different individuals in the fermented soybean meal group, we discovered that 1026 genes exhibited significant changes in slow and fast-growth individuals. Among these genes, 358 showed high expression levels, while 668 showed low ones. Subsequently, we conducted go function annotation and KEGG pathway enrichment analysis on all the significantly differentially expressed genes. This analysis revealed that many of these genes were associated with oxidative phosphorylation, steroid biosynthesis, glyceride metabolism, alanine, aspartic acid, and glutamate metabolism. Identifying these differentially expressed genes is a foundation for unraveling the molecular mechanisms behind growth and development. Additionally, it provides valuable gene data for future studies on the cloning and expression of growth-related genes and offers insights for subsequent biological research. [ABSTRACT FROM AUTHOR]

In mariculture, often the locations of fish hatcheries and farming are distantly situated, and hence, there is a need to transport the seeds/seedlings to a longer distance with maximum survival rate. In the present study, length and weight of fingerlings, duration of starvation, packing density, water volume, water temperature and oxygen level in the packing bags were standardized to ensure maximum survival during transportation. The cobia fingerlings with mean length and weight of 48±12 mm and 3.0±1.0 g, respectively were transported for a duration 48 h at 25 °C with 100 % survival at a packing density of 2.5 fingerlings per litre (L) (7.5±2.5 g/L). Similarly, silver pompano fingerlings with mean length and weight of 24±0.48 mm and 0.6±0.08 g, respectively were transported for a duration of 48 h at 25 °C with 100 % survival at a packing density of 18.75 fingerlings/L (11.25±1.9 g/L). Experiments on bulk transportation of pompano fingerlings in 1000 litres capacity HDPE tanks containing 600 litres of seawater with continuous aeration using oxygen cylinders fitted in a transportation vessel revealed that the silver pompano fingerlings can be transported for a duration of 48 h at 25 °C and 5 - 6 ppm dissolved oxygen concentration with 100 % survival at a packing density of 8.3 fingerlings/L (4.98±0.8 g/L). [ABSTRACT FROM AUTHOR]

The structures of the microbial community in the intestine, aquaculture water, and sediment of Litopenaeus vannamei, both in monoculture and mixed culture with Trachinotus ovatus, were analyzed by sequencing 16S rRNA amplicons. 1,120,500 valid reads were obtained from 21 samples, and 3,767 operational taxonomic units (OTUs) were classified. In the two culture modes, the abundance and diversity of bacterial in the sediment were significantly higher than in the L. vannamei intestine under the monoculture mode, in the water and intestines of L. vannamei and T. ovatus under the mix-culture mode (P < 0.05). There was no significant difference between the intestinal flora structures of L. vannamei and T. ovatus in the monoculture mode (P > 0.05). The dominant phyla in the sediment under two culture modes were Proteobacteria, Bacteroidetes, and Chloroflexi. The microbial community structure in the water and L. vannamei intestine were similar in both culture modes. The dominant phyla included Cyanobacteria, Proteobacteria, and Actinobacteria, with their abundances ranging from 80.88% to 97.10%. Proteobacteria was the dominant phylum in each group of samples, and the dominant genus in both culture modes was GpIIa. There was little difference in microbial community structures under the two culture modes; while the culture mode did not affect the core phyla/genera, there were differences in relative abundance. The experimental results provide a reference for the exploration of efficient and specific probiotic screening and microbial formulation techniques. [ABSTRACT FROM AUTHOR]

Water and texture properties are important indicators for evaluating surimi and surimi seafood quality. The present study assessed the impact of surimi processing on the water and texture properties and analyzed their correlations. The results showed that the moisture content exhibited significant positive correlations with T22 and A22 (P < 0.05). However, water‐holding capacity (WHC) revealed significant negative correlation with T21 and A22 (P < 0.05). Moreover, correlations between water and texture properties were observed. Moisture content and A22 displayed significant negative correlation with hardness (P < 0.05). WHC exhibited significant positive correlations with cohesiveness, springiness, and chewiness (P < 0.05), whereas T21 exhibited significant negative correlation with those properties (P < 0.05). Springiness is an important indicator for texture properties of surimi gel. T21 and WHC exhibited significant correlations with springiness (P < 0.05). We used two equations to assess the relationship between springiness and T21 (y = 9.64 × x2 − 33.79 × x + 29.62, R2 = 0.995, P < 0.05) and between springiness and WHC (y = 0.57 + 9.05/{1+e[−29.29 × (x −83.90)]}0.01, R2 = 0.999, P < 0.05), respectively. Verification experiments proved that these two regression equations could be used to predict the change law among feature indicators during the processing of surimi seafood. The present study finds an easy‐to‐control method to monitor the quality of surimi production and processing for all the stages, and provides ideas for quality design of surimi products. Practical Application: The quality of surimi seafood is affected by the process used for surimi production. Early detection of the material quality can efficiently prevent resource wastage. The feature indicators and their correlations help in easy‐to‐control of all surimi processing stages. Low‐field nuclear magnetic resonance (LF‐NMR) is a fast, nondestructive method for monitoring food real‐time, but the instrument is expensive; whereas water‐holding capacity and texture profile analysis (TPA) are traditional methods but time‐consuming and material‐consuming. Surimi enterprises or researchers choose the right methods based on their needs. [ABSTRACT FROM AUTHOR]

Heat shock protein 90 family, a class highly conserved protein and important molecular chaperone and its plays a role in enhancing animal adaptability to environmental stress and improving immunity. In this study, a full-length HSP90β cDNA (ToHSP90β) sequence was identified from Trachinotus ovatus. The cDNA of ToHSP90β was 2648 base-pairs (bp) long and contained a 5'-terminal untranslated region of 130 bp, a 3'-terminal untranslated region of 334 bp, and the open reading frame length 2184 bp, which can encode 728 amino acids. The ToHSP90β has a heat shock protein 90 family signature. The ToHSP90β amino acid sequence has high homology with other fish HSP90β amino acids (92.5-99.17%) and contains five conserved signal regions and a structural feature of the cytoplasmic HSP90 family. Phylogenetic tree analysis indicated that ToHSP90β was most closely related to Seriola dumerili HSP90β. Tissues expression analysis showed that the ToHSP90β was expressed in all nine tissues of T. ovatus, and its expression was the highest in the intestine. The stocking density significantly affected the expression of ToHSP90β in the kidney and brain tissues, and its expression levels increased significantly with increasing stocking densities, indicating that it plays an important regulatory role in the process of T. ovatus' chronic stress response. After Cryptocaryon irritans infection, the mRNA expression of ToHSP90β was significantly increased in liver and kidney tissues, indicating that ToHSP90β would be involved in the immune regulatory response. This study was the first to analyze the expression pattern of HSP90β mRNA in T. ovatus tissues and their expression responses to stocking density stress and C. irritans infection. To provide a theoretical basis for further study of the function of fish HSP90 and its physiological mechanism in environmental stress and parasite infection [ABSTRACT FROM AUTHOR]

Golden pompano (Trachinotus ovatus) is a commercially important marine fish and is widely cultured in the coastal area of South China. We explored the distribution difference of intestinal microflora with the same growth condition and the difference of gut microflora with different growth rates fed with fermented soybean meal (FSM) and fish meal (FM) primary protein source. After 8 weeks of the breeding experiment, select significant growth fish (Zcd, 156.04 ± 1.04 g) average growth fish (Zc, 120.01 ± 1.05 g) stagnant growth fish (Zcx, 98.03 ± 1.08 g) in FSM and select average growth fish (Dc, 158.03 ± 1.02 g) in FM. Sequencing results show that a total of 86303 sequences had been obtained in the intestine of Trachinotus ovatus. The number of OTUs that can be annotated to the database was 2315 (98.97%). At the phylum level, Proteobacteria, Tenericutes, Spirochaetes and Firmicutes were the predominant phyla. Alpha diversity and beta diversity analyses show that gut microbes' richness and diversity in the Dc group were the highest. The diversity of gut microbiota in the FSM: Zc > Zcd >Zcx. At the genus classification level, the differences between FM and FSM were mainly in Gueglia, Grimontia, Klebsiella, Alistipes, Staphylococcus, and Parasutterella (p <0.05). Alistipes and Staphylococcus were the different genera between Dc and Zcd (p <0.05). We found significant differences in the relative abundance of Ruegeria between the Zc and Zcd groups. Also, significant differences were found in the distribution of Brevinema, Ruegeria, Unidentified-Lachnospiraceae, Blautia, and Bacteroides between Zc and Zcx groups. The results showed that fermented soybean meal had an essential effect on gut microflora of T. ovatus with the unsynchronized growth. [ABSTRACT FROM AUTHOR]

Defatted soybean meal (SBM), which is produced by defatting soybean with solvents, has been considered as the most cost-effective substitute for fish meal (FM) in fish diets. However, SBM contains alcohol-soluble components which may interfere with growth performance and digestive physiology of fish. This study examined the effects of alcohol extract (Ext) containing alcoholsoluble components extracted from SBM on bile acid level, digestive enzyme activity and nutrient digestibility of pompano Trachinotus blochii. SBM was processed and separated into Ext and ethanol-extracted SBM (ESBM), thus, ESBM was SBM without alcohol-soluble components. Four experimental diets were formulated, denoted as FMD (FM-based diet), SBMD (SBM-based diet), ESBMD (ESBM-based diet), and ESBM+ExtD (ESBM-based diet plus Ext). Each diet was fed to two groups of fish (20 fish/group, 25 g/fish) for 4 weeks. Results showed that plasma lipid components, anterior intestinal bile acid level, anterior intestinal trypsin and lipase activities, and protein and lipid apparent digestibility coefficients (ADCs) of SBMD -fed fish were similar to those of ESBM+ExtD-fed fish. These parameters were significantly lower in SBMD-fed and ESBM+ExtD-fed fish than in ESBMD-fed and FMD-fed fish (P < 0.05). There were no significant differences in plasma total cholesterol level, trypsin activity, and protein ADC between ESBMD and FMD groups, however, total bile acid level, lipase activity, and lipid ADC were significantly lower in ESBMD -fed fish than fish fed FMD (P < 0.05). These results indicated that alcohol extract containing alcohol-soluble components extracted from SBM inhibited the secretions of bile acids and pancreatic digestive enzymes in pompano fish, and these abnormalities might impair nutrient digestion and absorption. The findings of the present study suggested that removing alcohol extract and supplementation of taurine could be effective for improving nutritional quality of SBM and enhancing feed utilization and growth performance of pompano which were fed SBM-based diets. [ABSTRACT FROM AUTHOR]

Golden pompano (Trachinotus ovatus) is a commercially important marine fish and is widely cultured in the coastal area of South China. The aims of this study are to investigate the effect of feeding frequency on growth performance, biochemical indices, muscle composition of Trachinotus ovatus, 6 groups of feeding frequency were designed (1, 2, 3, 4, 5 and 6TD) for 10 weeks to analyze the survival rate of T. ovatus. The results showed that final body weight, weight gain rate, specific growth rate, viscerosomatic index and hepatosomatic index of the 4TD group were significantly higher than of the other groups (P < 0.05). However, there was no difference in survival rate and feed conversion ratio in the group (P > 0.05). The crude fat and crude protein content were higher in the 4TD group, but there was no difference in moisture and ash among the groups (P > 0.05). Total protein, total cholesterol, low-density lipoprotein and high-density lipoprotein content was lowest in the 4TD group. Superoxide dismutase, catalase and total antioxidant capacity were significantly higher in the 3 and 4TD groups than that of the other groups (P < 0.05), while no significant difference was found among the other groups (P > 0.05). Malondialdehyde was significantly higher in the 4TD group than that of the 1, 2 and 5TD groups (P < 0.05), but there was no significant difference among the other groups (P>0.05). Lysozyme was significantly lower in the 1 and 6TD groups than other groups (P < 0.05), while there was no significant difference among the other groups (P > 0.05). Feeding frequency of 4TD for the T. ovatus seems suitable since the fish of this treatment group showed a fast and a healthy growth while muscle quality was maintained. [ABSTRACT FROM AUTHOR]

Pharmacokinetics and residues of oxolinic acid (OXO) in serum, muscle, liver, and kidney were measured in orange-spotted grouper Epinephelus coioides, snubnose pompano Trachinotus blochii and giant seaperch Lates calcarifer. Fish were treated with OXO after a single-dose trial (60 mg/kg) by oral gavages and repeat-doses of 60 mg/kg of body weight once daily in feed for five consecutive days. Analysis of OXO kinetic profiles, when determined by HPLC provided elimination half-life in muscle were 131, 26, and 85 h for 26-27 °C orange-spotted grouper, snubnose pompano, and giant seaperch, respectively. Depletion studies were conducted the time for OXO concentrations to fall below 0.1 µg/g (the current tolerance set by the European Medicines Agency (EMA) among fish species establishing an adequate depletion period). The mean tissue OXO concentration in the edible portion was below maximum residue level (MRL) of snubnose pompano at 6 d postdosing, for orange-spotted grouper and giant seaperch, at 10 d postdosing, respectively. When possible, depletion data were fitted to a one-compartment pharmacokinetic model. For all test species, the longest withdrawal period of 9 days in snubnose pompano and 15 days in orange-spotted grouper and giant seaperch were calculated because of a safety span (corresponds to 50% of the time point when at which residues fall below the MRL added to the depletion time). These results suggest withdrawal times with reference to human consumption of treated fish, to establish policy guidelines and basic principles regarding the use of OXO for fish-farming, and to fish-farmers for the proper handling to ensure safe fish that the consumer will not be at risk. [ABSTRACT FROM AUTHOR]

In this study, we first isolate phospholipid (PL) from Golden pompano head (GPH), and elucidate its structure. Gas chromatography (GC) was used to assess the GPH-PL fatty acid composition, Fourier transform infrared spectroscopy (FTIR) and ultraviolet absorption spectrometry (UV) were used for the qualitative analysis of GPH-PL, and LC-MS analysis was used to determine the major PL species. The results show that the contents of the various molecular species of GPH-PL were generally in the order phosphatidylcholine (PC) > sphingomyelin (SM) > lysophosphatidylcholine (LPC) > phosphatidylethanolamine (PE). The main molecular PC species are 16:0/18:2, 13:0/23:2, 27:2/9:0, 16:0/18:1, 12:0/22:2, 18:0/18:1, 18:0/24:1, and 18:1/24:0. The major SM species are 16:1/16:0, 16:0/18:1, 16:0/18:2, 16:0/26:2, and 18:1/24:1. The major LPC species are 18:1 and 16:0. The major PE species are 18:0/18:1 and 16:0/22:6. The total eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents in the GPH-PLs were 18.39%, and the content of DHA in the PL fraction was 16.47%. These results suggest that PLs from GPH is rich in polyunsaturated fatty acids (PUFA), which have good activity in anti-inflammation, anti-tumor, antiosteoporosis and other aspects, and have important development prospects in the future. [ABSTRACT FROM AUTHOR]

A new coelozoic myxozoan species, Ceratomyxa batam n. sp., was identified in cultured carangid fish, Trachinotus ovatus (Perciformes: Carangidae), in waters off Batam Island of Indonesia. The bi- and trivalved spores were observed in the gallbladder of T. ovatus. Mature bivalved spores of C. batam n. sp. were transversely elongated and narrowly crescent in shape, 3.8 ± 0.36 (2.7–4.6) μm long and 19.2 ± 1.75 (16.2–22.0) μm thick. Two sub-spherical polar capsules were 2.3 ± 0.18 (2.0–2.8) μm long and 2.6 ± 0.16 (2.3–2.9) μm wide. Prevalence was 72.2% in 72 examined T. ovatus according to evaluations dating from November 2016. The maximum likelihood phylogenetic tree based on small subunit rDNA sequence showed similarity with Ceratomyxa robertsthomsoni and Ceratomyxa thalassomae found in Australia. This is the first report of Ceratomyxa species identified in a seawater fish at Batam Island, Indonesia. [ABSTRACT FROM AUTHOR]

Abstract CC chemokines are a large subfamily of chemokines that play an important role in the innate immune system. To date, several CC chemokines have been identified in fish species; however, the activities and functions of these putative chemokines remain ambiguous in teleosts, especially in the golden pompano, Trachinotus ovatus. Here, we characterized CC chemokine ligand 4 from T. ovatus (TroCCL4) and studied its functions. TroCCL4 contains a 294 bp open reading frame that encodes a putative peptide comprising 97 amino acids. TroCCL4 shares a high amino acid sequence similarity of 31.11%–78.35% with other CC chemokines sequences in humans and teleosts and has four cysteine residues that are conserved among other CC chemokines. TroCCL4 is also related to the macrophage inflammatory protein (MIP) group of CC chemokines. TroCCL4 expression was most abundant in immune organs and significantly upregulated in a time-dependent manner following Edwardsiella tarda infection. Recombinant TroCCL4 (rTroCCL4) induced the migration of peripheral blood leukocytes and the cellular proliferation of head kidney lymphocytes. In addition, rTroCCL4 inhibited the growth of Escherichia coli and E. tarda , indicating an antimicrobial function. Furthermore, the results of in vivo analysis showed that TroCCL4 overexpression in T. ovatus significantly enhanced macrophage activation; upregulated the gene expression of interleukin 1-β (IL-1β), interleukin 15 (IL15), interferon-induced Mx protein (Mx), tumor necrosis factor α (TNFα), complement C3, and major histocompatibility complex (MHC) class Iα and class IIα; and protected against bacterial infection in fish tissues. In contrast, knockdown of TroCCL4 expression resulted in increased bacterial dissemination and colonization in fish tissues. Taken together, our results provide evidence indicating that TroCCL4 has the ability to stimulate leukocytes and macrophages and enhance host immunity to defend against bacterial infection. Highlights • A CC chemokine ligand 4 in Trachinotus ovatus (TroCCL4) was identified and characterized. • TroCCL4 could induce PBL migration and lymphocyte proliferation, inhibit bacteria growth, and induce macrophage activation. • The in vivo and in vitro studies demonstrated that TroCCL4 was involved in antibacterial immunity. [ABSTRACT FROM AUTHOR]

Trachinotus blochii (golden pompano) is an economically important cultured marine fish that is rich in polyunsaturated fat. The fatty acid profiles of triacylglycerols and phospholipids of T. blochii tissues were analyzed. Lipid contents in tissues followed the order of viscera (28.27%) > skin (17.25%) ≈ bone (16.18%) ≈ head (15.12%) > muscle (7.38%). In triacylglycerols (TAG), saturated fatty acids (palmitic acid predominated) were preferentially esterified in the sn‐2 position, and monounsaturated fatty acids (oleic acid predominated) were mainly distributed in the sn‐1, 3 positions. The numbers of n‐3 polyunsaturated fatty acids (PUFA) in the sn‐2 position were significantly greater than those in positions 1 and 3, while the n‐6 PUFA were mainly found in the sn‐1, 3 positions. Muscle TAG had a higher content of EPA+DHA (3.90%) than did the other tissues. In phosphatidylethanolamines, EPA+DHA in muscle (6.76%) predominated over that in other tissues. In phosphatidylcholines, EPA+DHA in bone (6.50%) predominated. This study is a guide for the biochemical and nutritional values of the T. blochii species and can be useful for further investigation of industrial applications. Practical Application: The high proportion of sn‐2‐palmitic acid (greater than 50%) is close to that of breast milk and the n‐3 PUFA, especially EPA and DHA have the preferential distribution in the sn‐2 position of triacylglycerol. Hence, golden pompano is an excellent dietary component for human nutrition and health. [ABSTRACT FROM AUTHOR]

Abstract The major histocompatibility complex (MHC) plays an important role in the vertebrate immune system by binding and presenting foreign peptides to T cell receptors. MHC genes encode cellular proteins that regulate the acquired immune response of vertebrates and affect the development of disease in animals. In the present study, we obtained 36 different full-length open reading frame sequences of Trov-MHC IIα from 20 adult golden pompano individuals. High levels of polymorphisms were detected among the 36 sequences. An excess of non-synonymous substitutions (d N) relative to synonymous substitutions (d S) was presented in the peptide-binding regions (PBRs), which suggested that the positive balancing selection driven by pathogens may maintain and promote the high diversity of the PBR domain. Bayesian inference revealed evidence for positive selection of specific codons in Trov-MHC IIα, and most of the positive selection sites were identified in the α1 domain. Furthermore, 26 exon 2 sequences of Trov-MHC IIα were identified from 70 individuals and exhibited high levels of diversity. Six alleles were selected to explore the correlations between the alleles and resistance/susceptibility to viral nervous necrosis virus (VNNV) in golden pompano. The frequency distribution showed that the Trov-DAA*6304 allele in golden pompano was associated with resistance to VNNV, while the Trov-DAA*7701 allele was associated with susceptibility to VNNV. These results confirmed the association between alleles of MHC class IIα and resistance to viral infection in golden pompano and they may provide valuable strategies to enhance the species' resistance to disease caused by viral infections and to help in marker-assisted selection breeding programmes for golden pompano. Highlights • We found high polymorphism in the ORF and exon 2 of MHC class IIα from golden pompano. • Positive balancing selection maintains and promotes the polymorphism of MHC class IIα. • Trov-DAA*6304 allele was showed associated with the resistance to VNNV in golden pompano. • Trov-DAA*7701 allele was showed associated with the susceptibility to VNNV in golden pompano. [ABSTRACT FROM AUTHOR]

Abstract Insulin-responsive glucose transporter 4 (GLUT4), a member of the glucose transporter family, plays a vital role in mediating glucose movement across cell membranes in insulin-sensitive tissues. In this study, we aimed to compare the molecular characterization and expression analysis of GLUT4 from three fish species of different feeding habits: golden pompano (Trachinotus ovatus), cobia (Rachycentron canadum) and tilapia (Oreochromis niloticus) after being fed three different dietary carbohydrate-to-lipid (CHO:L) ratios for 8 weeks. The results showed that the full length of golden pompano GLUT4 (ToGLUT4) and cobia GLUT4 (RcGLUT4) gene cDNA are 1973 and 2241 bp, containing an open reading frame (ORF) encoding 506 and 507 amino acids, respectively. Sequence alignment and phylogenetic analysis of GLUT4 revealed a high degree of conservation among most fish and higher vertebrates, and high homology were found in GLUT4 of golden pompano, cobia and tilapia, which share several identical motifs but contain small substitutions in GLUT4 protein. In addition, the highest GLUT4 gene expression was observed in white muscle followed by heart in these three fish species. Furthermore, in all these three species, the expression of GLUT4 was regulated in heart and white muscle by dietary CHO:L ratios. Expression of GLUT4 in heart decreased when golden pompano and tilapia were fed medium or high CHO:L ratio diets. However, in cobia, GLUT4 was induced when fed medium CHO:L ratio diet but depressed when fed high CHO:L ratio diet. With respect to white muscle, high expression of GLUT4 was found in these three fish species when fed medium CHO:L ratio diet, and high CHO:L ratio diet intake depressed its abundance in white muscle. The results indicate that GLUT4 of golden pompano, cobia and tilapia share several functionally important structural characteristics but contain small substitutions in GLUT4 protein that may lead to differences in the traffic behavior and affect the efficiency of glucose transport. In accordance with mammalian expression pattern, GLUT4 of golden pompano, cobia and tilapia are all expressed primarily in heart and white muscle, which could be regulated by dietary CHO:L ratios but appear to be species-specific and tissue-specific. However, none of the parameters examined clarifies the differences in carbohydrate utilization between carnivorous (golden pompano, cobia) and omnivorous (tilapia) fish. Decreased GLUT4 mRNA in heart and white muscle caused by feeding a relatively high carbohydrate with low lipid diet might partially explain the poor utilization of carbohydrate in these three fish species. Highlights • Sequence alignment and phylogenetic analysis of GLUT4 revealed a high degree of conservation among most fish and higher vertebrates. • Heart and white muscle GLUT4 of golden pompano, cobia and tilapia are regulated by dietary carbohydrate-to-lipid ratios. • Decreased GLUT4 mRNA in heart and white muscle after a carbohydrate rich diet could be a partial explanation for the poor utilization of carbohydrate in these three fish species. [ABSTRACT FROM AUTHOR]

Phosphoenolpyruvate carboxykinase (PEPCK) is known to exist as mitochondrial (PEPCK‐M) and cytosolic isoforms (PEPCK‐C). They are involved in glucose production and play vital roles in regulating glucose homeostasis. This study aimed to (1) clone and characterize PEPCK‐C cDNA from golden pompano fish (Trachinotus ovatus), which are known to have poor utilization of dietary carbohydrates, and (2) analyze the regulation of its expression by varying dietary carbohydrate‐to‐lipid ratios and nutritional status. A full length golden pompano PEPCK‐C cDNA fragment of 2,652 bp was cloned, which contains an open reading frame of 1,875 bp encoding 624 amino acids and shows a high homology to cobia (Rachycentron canadum) PEPCK‐C sequence (92% similarity). The analysis of tissue distributions of PEPCK‐C mRNA showed that a high abundance of PEPCK‐C was expressed in golden pompano liver, followed by kidney; while lower expression levels were found in the heart and intestine. In liver, PEPCK is under the regulation of dietary composition and nutritional status at the enzymatic and molecular levels. Our results indicate that PEPCK‐C plays a modulating role in the adaptation of hepatic gluconeogenesis to different nutrient conditions. Thus, the absence of molecular inhibition of gluconeogenic PEPCK gene expression in rainbow trout (Oncorhynchus mykiss) and gilthead sea bream (Sparus aurata), which can at least partially account for their poor utilization of dietary carbohydrate, is specific to these species and is not observed in golden pompano. Further studies that examine, at the enzymatic and molecular levels, other key enzymes involved in hepatic glucose metabolism are necessary to understand the poor utilization of carbohydrates in golden pompano. [ABSTRACT FROM AUTHOR]

This study explored the effects of dietary pantothenic acid (PA) supplement on juvenile golden pompano (Trachinotus ovatus). Six isonitrogenous and isolipidic diets containing six graded levels of pantothenic acid (0, 16.4, 20.0, 26.0, 33.4 and 37.0 mg/kg) were formulated. Juvenile golden pompano (8.80±0.10g) were randomly assigned into six groups with three replicates in each group and 20 fish in each replicate. The fish were fed twice a day for 8 weeks. The results indicated that PA deficiency caused clubbed gills with interlamellar proliferative lesions. Survival rate increased significantly (P<0.05) when PA levels were increased. Dietary PA significantly increased the activities of hepatic acid phosphatase (ACP), alkaline phosphatase (ALP), peroxidase (POD) and glutathione reductase (GR) (P<0.05) and their activities reached the maximum in the Diet-P4 group. A diet supplemented with 20.0 and 26.0 mg/kg PA significantly decreased (P<0.05) the activity of hepatic MDA. Dietary PA also increased the diversity and abundance of intestinal microflora and inhibited the growth of harmful bacteria. In conclusion, PA deficiency caused lesions of gills and optimal PA supplement in diet increased hepatic antioxidative abilities and improved intestinal microflora of juvenile golden pompano. [ABSTRACT FROM AUTHOR]

Golden pompano (Trachinotus ovatus) is a commercially important marine fish which is widely cultured in the coastal area of South China. Salinity is one of the most important environmental factors influencing the intestinal microbiota. The aim of this study was to investigate the intestinal microbiota of juvenile golden pompano reared at different salinities. In this 56 day experiment, juveniles were reared at 5, 15, 25 and 35? salinities. Based on ACE, Chao1 and Shannon, Simpson diversity indices, salinity did not influence the bacterial richness and diversity in golden pompano intestine. The data indicated that the dominant phyla in golden pompano intestine reared at each salinity group were Proteobacteria. The principal coordinates analysis (PCoA) indicated that the bacterial communities were not clustered, and the bacterial communities were very different in the salinity groups. The findings showed that golden pompano have specific intestinal microbiota in different salinity environments. However, the intestinal microbiota in golden pompano were strongly influenced by salinity and were also affected by the phylogeny of golden pompano. Further studies are needed to explore the relationship between the intestinal microbiota and growth of golden pompano under different salinities. [ABSTRACT FROM AUTHOR]

Golden pompano, Trachinotus ovatus, belongs to the family Carangidae. Within one decade, this species has rapidly become one of the most important cultured marine fish species in South China. However, the lack of a comprehensive genetic diversity assessment hinders the conservation of natural resources and management of cultured populations. Thus, we sampled one wild population and six cultured populations of golden pompano, which represented the whole cultured population, to assess the genetic diversity and population structure. The level of genetic diversity was low compared with those of other cultured fish, as the values of allelic richness, number of effective alleles and expected heterozygosity in the combined whole sample were 3.709, 2.592, and 0.591, respectively. These populations were little differentiated (Fst = 0.02091, p value = 0.00), and the whole sample did not show an explicit population structure at the individual level. The effective population size in each cultured population was small and in the whole sample was acceptable for a closed selection system. The pedigree reconstruction showed no evidence of artificial disturbance in mating. This general survey of cultured golden pompano populations showed the common characteristics of domestication with wild inputs. However, the low level of and potential decrease in genetic diversity should receive close attention in future breeding programs. In addition, we recommend wide surveys of natural resources and the establishment of closed breeding systems to increase genetic gain. [ABSTRACT FROM AUTHOR]

To explore the molecular response of fish larvae to nutritional manipulation, the partial sequences of bone morphogenetic protein (BMP1, BMP2, BMP4, BMP5, and BMP10) genes were obtained, and their expressions were quantified on golden pompano Trachinotus ovatus at 28 days post hatching. Artemia nauplii were separately enriched with Nannochloropsis and Algamac 3080, and non-enriched Artemia nauplii were used as a control feed. The lowest jaw deformity rate occurred in fish fed Algamac 3080 enriched Artemia nauplii. The expression level of BMP4 of fish fed Algamac 3080 enriched Artemia nauplii was significantly lower than those fed Nannochloropsis enriched and non-enriched Artemia nauplii. The lowest expression level of BMP10 was found in fish fed non-enriched Artemia nauplii, and the highest expression of BMP10 was observed in fish fed Algamac 3080 enriched Artemia nauplii. Correlation analysis indicates that nutritional manipulations can significantly affect the expression level of BMP4 and BMP10 genes. The concentration of dietary docosahexaenoic acid (DHA) can significantly affect the expression level of BMP10. This study indicates that the use of Algamac 3080 enriched Artemia nauplii results in fast fish growth and low jaw deformity, and BMP4 and BMP10 gene expressions were closely related to jaw deformity in golden pompano larvae. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the effect of different feed types on the fatty acid profiles of golden pompano (Trachinotus ovatus). Three feed types (pelleted feed, frozen squid and frozen fish) were assigned to triplicate groups of fish (146.22 ± 3.26 g) in a total of 9 floating cages (50 fish per cage). Analysis of the fatty acid profiles of the three feed types revealed that frozen squid had the highest levels of long-chain polyunsaturated fatty acids (LC-PUFA), while the pelleted feed and frozen fish had lower levels of LC-PUFA, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). After three months of being fed a specific feed type, the fatty acid profiles of golden pompano muscle tissues were analysed. The highest levels of LC-PUFA were detected in fish fed with frozen squid. Golden pompano fed with frozen fish had intermediate levels of LC-PUFA content. The results suggest that the fatty acid composition of prey items can significantly affect the muscle fatty acid composition of the consumer. Muscle fatty acid composition could also be used as an indicator of diet type for golden pompano in the aquaculture industry. [ABSTRACT FROM AUTHOR]

Seeking alternatives to the depleting fish oil are crucial for marine fish aquaculture, which is currently dependent on fish oil as the primary source of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs). Five isonitrogenous (46% crude protein) and isolipidic (16% crude lipid) feed diets (FO, ISO2.9, ISO4.8, ISO6.7, ISO8.6) were formulated by partially replacing fish oil with microalgae Isochrysis galbana. These diets were fed to triplicate tanks of Trachinotus ovatus (mean initial weight 1.92 g) for 80 days. This work demonstrates that a moderate inclusion (around 4.5-5.0 wt%, equivalent to the replacement of 24-26 wt% fish oil) of I. galbana biomass in fish diet improves fish growth performance, lipid deposition and enhances total n-3 fatty acids, DHA, and EPA contents in neutral and polar lipids (PLs) of fish muscle and liver of T. ovatus. The results disclosed in this study suggest that I. galbana microalgae represents a potential high-quality substitute for fish-based ingredients in aquaculture feeds, which can be a promising sustainable solution to resolve the depleting fish oil resource in a cost-effective manner. [ABSTRACT FROM AUTHOR]

The present study describes the first trial on broodstock development, induced breeding and larval rearing of Indian pompano, Trachinotus mookalee . Indian pompano fingerlings were collected from wild and raised to adults having an average size of 2.84 ± 0.10 kg weight and 47.6 ± 1.43 cm length. These adult fishes were stocked in 125 t capacity circular tank having re-circulatory facility for broodstock development. The fishes were fed with squid along with clam meat and matured in four months. Mature females with >500 μm ova and oozing males were selected in the ratio of 1:2 (female:male) and were induced with single dose of hCG at the rate of 350 IU /kg body weight. Three trials with same sex ratio and hormonal doses were tried. The fish spawned after 36–38 h of induction at a temperature 29 ± 1 °C. Eggs were collected and treated with iodophore and stocked in 1 t FRP tank for hatching. The eggs hatched out after 18–20 h of incubation at a temperature of 29 ± 1 °C. The overall fertilization and hatching rate was found to be 69 ± 1.55% and 87.67 ± 0.81%, respectively. Larval rearing was carried out in 2 t capacity fibre reinforced plastic (FRP) tanks using green water system. The newly hatched larvae was 2.12 ± 0.02 mm in total length, with an oval shaped yolk sac of 0.55 mm 2 and an oil droplet of 0.06 mm 2 in area. The mouth opening was formed 40–46 h post hatch with mouth gape measuring 228.10 ± 1.31 μm. A systematic and overlapping regime of live feed beginning from copepod nauplii, rotifer, Artemia nauplii and artificial pellet were utilized during larval rearing. Weaning of larvae to inert diet was started from 15 th day post hatching (DPH) onwards. Larvae started metamorphosis by 17 th DPH onwards and was completed by 21 st DPH, when the larvae reached 27.33 ± 0.10 mm. The larval rearing protocol resulted in an average survival rate of 21.53 ± 1.45% till complete metamorphosis. The present study showed T. mookalee to mature in captive conditions. The potential for induced spawning in captivity and larval rearing with a survival rate of 21.53% makes Indian pompano an excellent candidate for mariculture. This forms the first report of broodstock development, induced breeding and larval rearing of this species in captivity. The results of this study would facilitate mass scale seed production of Indian pompano in captivity, which is essential for its aquaculture. [ABSTRACT FROM AUTHOR]

The nuclear peroxisome proliferator-activated receptors (PPARs) regulate the transcription of elongases of very long-chain fatty acids (Elovl), which are involved in polyunsaturated fatty acid (PUFA) biosynthesis in mammals. In the present study, we first characterized the function of Elovl5 elongase in Trachinotus ovatus. The functional study showed that ToElovl5 displayed high elongation activity toward C18 and C20 PUFA. To investigate whether PPARαb was a regulator of Elovl5 , we also reported the sequence of T. ovatus PPARαb (ToPPARαb). The open reading frame (ORF) sequence encoded 469 amino acids possessing four typical characteristic domains, including an N-terminal hypervariable region, a DNA-binding domain (DBD), a flexible hinge domain and a ligand-binding domain (LBD). Thirdly, promoter activity experiments showed that the region from PGL3-basic-Elovl5-5 (-146 bp to +459 bp) was defined as the core promoter by progressive deletion mutation of Elovl5. Moreover, PPARαb overexpression led to a clear time-dependent enhancement of ToElovl5 promoter expression in HEK 293T cells. Fourth, the agonist of PPARαb prominently increased PPARαb and Elovl5 expression, while PPARαb depletion by RNAi or an inhibitor was correlated with a significant reduction of Elovl5 transcription in T. ovatus caudal fin cells (TOCF). In conclusion, the present study provides the first evidence of the positive regulation of Elovl5 transcription by PPARαb and contributes to a better understanding of the transcriptional mechanism of PPARαb in fish. [ABSTRACT FROM AUTHOR]

The major histocompatibility complex (MHC) plays an important role in the vertebrate immune response to antigenic peptides, and it is essential for recognizing foreign pathogens in organisms. In this study, MHC class IIα (Trov-MHC IIα) from the golden pompano ( Trachinotus ovatus ) was first cloned and identified. The gene structure of Trov-MHC IIα was contained four exons and three introns. High levels of polymorphism were found in the exon 2 of Trov-MHC IIα. A total of 29 different MHC class IIα alleles with high polymorphism were identified from 80 individuals. The ratio of non-synonymous substitutions (dN) to synonymous substitutions (dS) was 3.157 (>1) in the peptide binding regions (PBRs) of Trov-MHC IIα, suggesting positive balancing selection. Six alleles were selected to analyze the association between alleles and resistance/susceptibility to Vibrio harveyi in golden pompano. The results showed that Trov-DAA*6401 and Trov-DAA*6702 alleles were associated with the resistance to V. harveyi in golden pompano, while alleles Trov-DAA*6304 and Trov-DAA*7301 were associated with the susceptibility to V. harveyi in golden pompano. This study confirmed the association between alleles of MHC class IIα and disease resistance, and also detected some alleles which might be correlated with high V. harveyi -resistance. These disease resistance-related MHC alleles could be used as potential genetic markers for molecular marker-assisted selective breeding in the golden pompano. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) play an essential role in the immune response. Here two Toll-like receptors from golden pompano ( Trachinotus ovatus ), ToTLR1 and ToTLR2, were characterized, the full-length cDNAs were 3126 bp and 7430 bp, and the deduced proteins consisted of 801 and 825 amino acids, respectively. ToTLR1 and ToTLR2 both contained the typical TLR domain architecture including signal peptide, leucine rich repeat (LRR), C-terminal LRR domain at the extracellular region and Toll/interleukin (IL)-1 receptor (TIR) domain in the cytoplasmic region. ToTLR1 only had one intron and two exons, but ToTLR2 consisted of twelve introns and thirteen exons. The promoters of ToTLR1 and ToTLR2 contained several putative transcription factor binding sites. Phylogenetic analysis showed that ToTLR1 and ToTLR2 were clustered into the clade of TLR1 and TLR2, respectively. Tissues distribution analysis indicated that both genes were ubiquitously expressed in all examined tissues, with higher expression levels observed in blood, head-kidney and spleen. After injection with poly inosinic:cytidylic [poly(I:C)], flagellin and lipopolysaccharides (LPS), ToTLR1 and ToTLR2 mRNAs were significantly up-regulated in the immune related tissues, indicating the possible the role of ToTLR1 and ToTLR2 in defense against pathogenic microbes. Further research should be carried out to identify ligands of fish TLR1 and TLR2 in order to understand the function of these receptors. [ABSTRACT FROM AUTHOR]

Trachinotus ovatus is widely cultured in the ponds and gulf on the southeast coast of China. The dramatic salinity decrease caused by heavy rainfall could cause mass mortality of T. ovatus in aquaculture. It is very important to understand the osmoregulatory mechanism of T. ovatus . Na + /K + /2Cl − cotransporter 1a (NKCC1a) is involved in the osmoregulation of fish and plays a crucial role in cell volume homeostasis and maintenance of the electrolyte content. In this study, we characterized nkcc1a (designed as Tonkcc1a ) from T. ovatus and investigated its expression responses to acute salinity changes. Tonkcc1a is approximately 70 kb in length and contains 26 exons and 25 introns. The phylogenetic analysis confirmed that ToNKCC1a belonged to the NKCC1a subclade. Quantitative real-time (qRT-PCR) analysis indicated that Tonkcc1a was ubiquitously expressed in all examined tissues, with the highest mRNA levels observed in gills, and the lowest level in liver. When T. ovatus were transferred from seawater (30‰) into fresh water, the expression levels of Tonkcc1a mRNA were significantly downregulated in gills and kidney, whereas its expression level was markedly upregulated in intestine. When transferred from seawater (30‰) to 10‰ sea water, the expression levels of Tonkcc1a mRNA were clearly increased in gills and kidney. When transferred from seawater (30‰) to 20‰ sea water, the expression of Tonkcc1a mRNA increased to some extent in gills, kidney, and intestine. When transferred from seawater (30‰) to 40‰ sea water, the expression levels of Tonkcc1a mRNA were dramatically upregulated in gills and intestine compared to that in the control. These results suggested that Tonkcc1a was involved in the response to acute salinity changes. [ABSTRACT FROM AUTHOR]

Abstract: Bromelain was used to tenderize golden pomfrets (Trachinotus blochii). The enzyme kinetic model was x = 2.447 × ln [ 1 + ( 1332.21 × E 0 S 0 − 1.74 ) t ] , which indicated that the degree of hydrolysis (DH, x) was dependent on hydrolysis time (t), the initial concentration of myofibril (S0) and bromelain (E0). The relationship between the overall hydrolysis rate (v), S0, E0, and t is demonstrated as: v = ( 16.50 ( E 0 S 0 ) − 1.33 ) S 0 exp { − 2.447 ln [ 1 + ( 1332.21 E 0 S 0 − 1.74 ) t 2 ] }. Sample of 0.40% E0/S0 was further used to study the effects of hydrolysis time on the changes of proteins, peptides, free amino acids (FAA), and protein nanostructure. SDS‐PAGE result showed that myosin heavy chain was degraded dramatically from 22.88% before treatment to 12.03% after 2 min bromelain treatment. Meanwhile, bromelain did not exhibit activity towards actin, trypomyosin, myosin light chain, and troponin C. A general increase of amino acids indicated the increased DH and the preferential cleavage sites of bromelain in the descending order of lysine, glutamic acid, glycine, ornithine, methionine sulfoxide, and alanine. Atomic force microscope images showed that the strip‐like structure of myofibril was considerably degraded by bromelain, and the granulation of protein after 20 min indicated possible self‐assembling of protein hydrolysate. Confocal laser scanning microscopy further confirmed the degradation of myofibril proteins and formation of protein aggregates. Practical Application: Meat of golden pomfrets is tough, thus not idea for fish balls or fish cakes. Tenderization is essential to achieve desired texture and consumer acceptance, especially for this fish meat with intrinsic hard texture. Bromelain can be extracted from pineapple processing waste. Enzymatic kinetics was studied to instruct industry to control the tenderness of the processed fish meat. The microstructural and mechanism study elucidate the process, thus could be applied to improve the quality of the seafood products correspondingly. [ABSTRACT FROM AUTHOR]

The interferon-g-inducible lysosomal thiol reductase ( GILT ) plays a significant character in the processing and presentation of MHC class II restricted antigen (Ag) by catalyzing disulfide bond reduction in mammals. To explore the function of GILT in the immune system of fish, we cloned a GILT gene homologue from Trachinotus ovatus , the full-length cDNA of GILT , which consisted of 2, 747 bp with a 771 bp open reading frame, encoding a protein of 256 amino acids. Moreover, similar to other species GILT gene, 7 exons and 6 introns were identified in T. ovatus , the deduced protein also possessed a representative characteristic of known GILT proteins. The result of real-time quantitative PCR showed that GILT mRNA was dramatically expressed in immune-associated tissues, such as spleen ( p  < 0.01) and kidney ( p  < 0.05). Bacterial challenge revealed that GILT mRNA level remarkably up-regulation in liver, spleen, kidney and intestine after induction with Photobacterium damsela . Furthermore, based on cloned sequences and genome BLAST, only one SNP site (ToGILT-S1-g.148C>G) was identified, and the allele C was significantly associated with high-susceptibility (HS) group, nevertheless, the allele G was dramatically associated with high-resistance (HR) group, indicating potential application for disease resistant breeding selection in T. ovatus . [ABSTRACT FROM AUTHOR]

An epizootic outbroke in offshore cage-cultured Trachinotus ovatus , in Hainan provinces of China, causing massive mortality. Necropsy, histopathology and bacteriology experiments were carried out to identify the cause of this disease. The most prominent lesions happened in the brain, spleen and kidney, and a gram-positive bacterium was isolated from diseased fish. Through analysis of 16s rRNA and biochemical profiles, we identified this isolate as a strain of Streptococcus iniae , and named it HN strain. Artificial infection experiments were carried out, the HN strain can cause similar symptom with an LD50 value of 8.9 × 10 3 colony-forming units (CFU), which confirmed the isolated HN strain was virulent for T. ovatus . The HN strain is sensitive to all of the antimicrobial drugs tested, some of them, such as florfenicol and norfloxacin may be used to control the disease. [ABSTRACT FROM AUTHOR]

The article presents information on a study which identified the nervous necrosis virus isolated from cultured golden pompano (Trachinotus ovatus) in Guangxi, China. In this study, researchers collected the suspected NNV-infected golden pompano with body lengths of 10 cm from the farm in Guangxi Province. It is reported that cell lines isolated from fish are useful tools for viruses isolation and pathogenesis research.

A new cell line derived from the caudal fin of golden pompano Trachinotus ovatus (TOCF) was successfully established and characterized. TOCF cells grew well at 28° C in L‐15 medium supplemented with 10% foetal bovine serum (FBS). The cell line has been subcultured in more than 100 passages. Molecular characterization of 18S ribosomal (r)RNA and cytochrome oxidase subunit 1 (COI) confirmed that the TOCF cells were derived indeed from T. ovatus. TOCF cells have a modal chromosome number of 54. It was further showed that TOCF cells were transfected successfully with pEGFP‐N3 and pDsRED‐N1 plasmid, suggesting that TOCF cells could be used to research gene functions in vitro. Viral susceptibility tests showed that TOCF cells were susceptible to Singapore grouper iridovirus (SGIV), observed by the occurrence of the cytopathic effect (CPE) with the formation of inclusion bodies. In addition, the expression of major capsid protein (MCP) gene of SGIV changed during virus infection in TOCF cells. Thus, our present results described the characteristic of a TOCF cell line that could be a valuable tool for genetic manipulation, as well as isolation and propagation of iridovirus studies. [ABSTRACT FROM AUTHOR]

Intestinal morphology, antioxidant status, immune function and tight junction proteins mRNA expression were examined in golden pompano ( Trachinotus ovatus ) that fed respectively six diets containing dandelion extracts (DE) at 0, 0.5, 1, 2, 4 and 10 g kg −1 after 8 weeks feeding. The study indicated that dietary DE significantly improved intestinal antioxidant abilities by increasing SOD, CAT, T-AOC activities and up-regulating intestinal cat , gpx mRNA levels, but by decreasing MDA content and down-regulating intestinal keap1 mRNA levels in golden pompano. Meanwhile, dietary DE improved intestinal morphology, suggesting that enhances intestinal digestion and absorption, by increasing muscle thickness, villus length, villus width and villus number in the foregut and hindgut; as well as villus number, villus width and muscle thickness in the midgut ( P  < .05). Dietary DE enhanced intestinal barrier function by increasing intestinal zo-1 and occludin mRNA levels, but by decreasing the mRNA levels of claudin-12 and claudin-15 . Furthermore, dietary DE improved intestinal immunity via increasing goblet cells numbers and regulating expression of immune-related genes. In conclusion, dietary DE supplementation promoted intestine health by improving intestine morphology, immunity, antioxidant abilities and intestinal barrier in golden pompano. [ABSTRACT FROM AUTHOR]

Trachinotus ovatus is an important economic species in China, with an annual output of over 100,000 tons (FAO). The major histocompatibility complex (MHC) genes, which are a highly polymorphic gene superfamily, play a vital role in the adaptive immune system. In our study, due to the threat caused by Photobacterium damselae , the associations between polymorphisms of exon 2 of MHC IIß and disease resistance/susceptibility were analysed in Trachinotus ovatus . The gene structure of MHC IIß was composed of six exons and five introns in T . ovatus , similar to Hippocampus erectus MHC IIß . Among the forty-three alleles, high levels of polymorphism were found (24.8% of nucleotide positions were variable). In the peptide-binding region (PBR) and non-PBR sites, the value of d N was 6.60 and 12.22 (> 1) times higher than the value of d S , respectively. Six alleles were chosen to calculate their distributions in the high-resistance (HR) and high-susceptibility (HS) groups. The analysis of the associations between alleles and resistance/susceptibility to P . damselae indicated that the TO-DAB-01 allele was associated with immunity to P . damselae and the TO-DAB-04, TO-DAB-05 and TO-DAB-10 alleles were associated with its sensitivity to P . damselae . The results suggest that the diversity of exon 2 of MHC IIß alleles could be used to explore the association between disease susceptibility/resistance and the multiformity of MHC IIß and to achieve the molecular-assisted selection of T . ovatus with enhanced disease resistance. [ABSTRACT FROM AUTHOR]

It is well known that the enzyme glucokinase (GK) plays an important role in the control of glucose homeostasis. In the present study, a glucokinase (To-GK) was cloned from golden pompano, Trachinotus ovatus . The To-GK cDNA is composed of 2151 bp with a 33 bp of 5′-UTR, 1437 bp open reading frame (ORF) and 681 bp 3′-UTR, encoding a polypeptide of 478 amino acids (GenBank accession no: ALX36181.1 ). Phylogenetic analysis revealed that To-GK showed highest similarity to Cynoglossus semilaevis GK. Tissue distribution analysis showed that the highest expression of the To-GK was detected in liver. Then, 8-week feeding trial was conducted to investigate the effects of dietary carbohydrate levels (57.5, 120.4, and 277.7 g kg − 1 ) on the activity and mRNA expression of To-GK in T. ovatus . Higher GK activity was found in fish fed 277.7 g kg − 1 carbohydrate diet. To-GK expression was higher in fish fed the 277.7 g kg − 1 carbohydrate diet. Overall, our data suggest that the hepatic GK activity and mRNA expression of T. ovatus were up-regulated significantly as dietary carbohydrate levels increased. These results indicated that To-GK plays a crucial role in the adaptation of hepatic glycolysis to dietary high carbohydrates in T. ovatus . [ABSTRACT FROM AUTHOR]

Abstract: An 8‐week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio (CHO: L) on growth, feed utilization, body composition and digestive enzyme activities of golden pompano, Trachinotus ovatus. Five iso‐nitrogenous (450 g/kg protein) and iso‐energetic (19 MJ/kg gross energy) diets with varying CHO: L ratios of 0.68, 1.02, 1.62, 2.61 and 4.35, respectively, were fed to triplicate groups of 30 fish (average 13.8 ± 0.1 g). Results showed that dietary CHO: L ratios did not show any significant influence on survival of golden pompano (p > .05) but significantly affected its growth performance and feed utilization (p < .05). Fish fed diets with CHO: L ratios at 1.62 and 2.61 exhibited the highest final body weight, weight gain ratio, specific growth rate, feed efficiency ratio and protein efficiency ratio. Fish body lipid and liver glycogen contents were also significantly influenced by CHO: L ratio (p < .05). Hepatic amylase activity increased firstly and then decreased as the dietary CHO: L ratio increased, while lipases activity decreased with increasing dietary CHO:L level. The regression model analysis showed that the most suitable dietary CHO: L ratio (protein 450 g/kg) to reach the highest weight gain ratio is 2.38. [ABSTRACT FROM AUTHOR]

Abstract: This experiment was designed to investigate the effects of dietary valine on the growth performance, feed utilization, digestive enzymes, serum antioxidant and immune indices of juvenile Trachinotus ovatus and determine its valine requirement. Six diets with different concentrations of L‐valine (15.0, 16.6, 18.6, 20.7, 23.5 and 25.4 g/kg dry diet, defined as diet Val‐1 to Val‐6.), were formulated to contain 430 g/kg crude protein with fish meal, soybean meal, peanut meal and precoated crystalline amino acids. Each diet was randomly assigned to triplicate treatments of 20 fish (the initial body weight was 5.34 ± 0.03 g) for 8 weeks. The results indicated that the final body weight and percent weight gain (PWG) increased with increasing valine concentration up to 18.6 g/kg (diet Val‐3), whereas the diets containing higher valine concentration reduced the growth performance significantly (p < .05). Moreover, the protein efficiency ratio, body protein deposition (BPD), muscle protein content, intestinal amylase and pepsin activities, serum T‐AOC, LZM activities, IgM, complement 3 and complement 4 concentration had a similar trend with PWG, and the trend of feed conversion ratio, serum AST, ALT activities, urea and MDA content was opposite. Meanwhile, the lipid contents of whole fish and muscle in diet Val‐6 were particularly lower than other diets (p < .05). The survival rate of diet Val‐1 was lowest in this study and was significantly lower than diet Val‐2 (p < .05). The results of polynomial regression based on PWG and BPD indicated that the optimal dietary valine requirement for Trachinotus ovatus reared in seawater‐floating net cages was 19.87–20.17 g/kg valine of dry diet, correspondingly 46.22–46.91 g/kg of dietary protein. [ABSTRACT FROM AUTHOR]

Golden pompano (Trachinotus ovatus) quality forecasting method utilising Vis/NIR spectroscopy combined with electronic nose (EN) was investigated in this article. Responses of Vis/NIR spectroscopy and EN to pompanos stored at 4°C were measured for 6 days. Physical/chemical indexes including texture, total volatile basic nitrogen, pH, total viable counts, and human sensory evaluation were synchronously examined as quality references. Chemometric methods including principal component analysis (PCA) and stochastic resonance (SR) were employed for spectroscopic and EN data analysis. Physicochemical examination demonstrated that fish quality decreased rapidly during storage. PCA qualitatively classified freshness degree of pompano samples, while SR signal-to-noise ratio (SNR) spectrum using SNR maximum quantitatively characterised quality for all samples. Golden pompano quality predictive models were developed based on spectroscopy, EN, and spectroscopy combined with EN, respectively. Results demonstrated that the model developed based on spectroscopy combined with EN presented a forecasting accuracy of 93.3%. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the effects of dietary hawthorn extract (HTE) supplementation on growth performance, immune responses, hepatic antioxidant abilities, growth- and immune-related and heat shock protein genes expression and resistance to the pathogen Vibrio harveyi in Trachinotus ovatus . A basal diet supplemented with HTE at 0 (Diet 1), 0.50 (Diet 2), 1.00 (Diet 3), 2.00 (Diet 4), 4.00 (Diet 5) and 10.00 (Diet 6) g kg −1 were fed to golden pompano for 8 weeks. The highest final body weight, weight gain rate, specific growth rate, feed efficiency ratio and protein efficiency rate were observed in fish fed Diet 2 ( P < 0.05). Dietary HTE significantly increased plasma complement 3, complement 4 and immunoglobulin M content ( P < 0.05). Hepatic antioxidant enzymes (SOD, T-AOC, CAT, GPx, GR) significantly increased ( P < 0.05), whereas MDA content decreased first and then increased in fish fed HTE supplement. After challenge with Vibrio harveyi , significant higher post-challenge survival was observed in fish fed Diet 2 and Diet 3 than the control group ( P < 0.05). Transcription levels of growth-related genes (IGF-I and IGF-II) were significantly up-regulated in fish fed HTE supplement ( P < 0.05), whereas HSP70 and HSP90 mRNA levels were significantly down-regulated ( P < 0.05). With respect to immune-related genes, such as tumour necrosis factor-alpha (TNF-α), interleukin-8 (IL-8) and inhibitor protein κBα (IκB-α), upregulation was observed in the liver of fish fed with the diet supplemented with HTE. In contrast, the expression of antioxidant enzyme genes (CAT, GPx, MnSOD and Keap1) and cytokines (IL-10, TGF-β1 and TOR) was downregulated. These results indicated that golden pompano fed a diet supplemented with 0.50 g kg −1 HTE could significantly promote growth performance and growth-related genes expression, strengthen immunity, and improve hepatic antioxidative abilities and resistance to Vibrio harveyi infection. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the effects of dietary dandelion extracts (DE) supplementation on growth performance, feed utilization, body composition, plasma biochemical indices, immune responses, hepatic antioxidant abilities, and resistance to the pathogen Vibrio harveyi in Trachinotus ovatus . A basal diet supplemented with DE at 0, 0.50, 1.00, 2.00, 4.00 and 10.00 g kg −1 were fed to golden pompano for 8 weeks. The study indicated that dietary supplementation with DE could significantly improve final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), feed efficiency ratio (FER), feed intake (FI), protein efficiency ratio (PER) and protein deposit rate (PDR) ( P < 0.05). The highest FBW, WGR, SGR, FI and PDR were observed in fish fed 1.00 g kg −1 dietary DE ( P < 0.05). The highest FER and PER were recorded at 0.50 g kg −1 dietary DE ( P < 0.05). Condition factor, viscerosomatic index, hepatosomatic index and survival were not significantly different among all groups. Fish fed 1.00 g kg −1 dietary DE showed significant increase in plasma total protein, complement 4 content and alkaline phosphatase, lysozyme, glutathione reductase (GSR) activity, but significant decrease in triglyceride, low density lipoprotein cholesterol, malondialdehyde (MDA) content and aspartate aminotransferase activities compared to the control group ( P < 0.05). Hepatic antioxidant enzymes (SOD, T-AOC, CAT, GSH-Px, GSR) significantly increased whereas MDA content significantly decreased in fish fed 1.00 g kg −1 DE supplement ( P < 0.05). After challenge with Vibrio harveyi , significant higher post-challenge survival was observed in fish fed DE supplement ( P < 0.05). These results indicated that golden pompano fed a diet supplemented with DE (especially at 1.00 g kg −1 of fed supplement) could significantly promote its growth performance, feed utilization, body protein deposit, immune ability, hepatic and plasma antioxidative enzyme activities and improve its resistance to infection by Vibrio harveyi . [ABSTRACT FROM AUTHOR]

In the present study, members of the interleukin (IL)-10 family of cytokines, including IL-10 (TOIL-10) and IL-22 (TOIL-22) of golden pompano ( Trachinotus ovatus ), were cloned for the first time, and their expression patterns and 3D structures analyzed. The full-length cDNA sequences of TOIL-10 and TOIL-22 contained open reading frames of 564 and 567 bp, respectively. TOIL-10 and TOIL-22 shared higher homology (78%–89%) with the corresponding genes from various fish relative to other species (25%–34%) and contained the IL-10 family signature and four cysteine residues that are well conserved in other vertebrate IL-10 members. Phylogenetic tree analysis of our sequences alongside other IL-10 family proteins revealed that TOIL-10 and TOIL-22 cluster together with other teleost IL-10 and IL-22 molecules. Expression of TOIL-10 and TOIL-22 genes was ubiquitous in all tissues examined. The TOIL-10 gene was also highly expressed in skin, heart, gill, spleen, kidney, brain and liver, and lower levels were detected in intestine and muscle. High expression of the TOIL-22 gene was observed in gill, intestine, kidney, spleen, with the lowest levels in liver. TOIL-10 and TOIL-22 were rapidly activated after SAΔ phoB immunization and significantly increased to peak levels at 12 h and 4 d in golden pompano kidney and spleen respectively following challenge. Expression in the brain reached peak levels at 4 d and 3 d respectively after post-immunization. Our results collectively indicate that TOIL-10 and TOIL-22 participate in the host immune response to bacterial infection. Moreover, TOIL-22 plays a potentially important role in mucosal immunity. [ABSTRACT FROM AUTHOR]

Streptococcus agalactiae is a Gram-positive pathogen that can survive inside professional phagocytes and nonphagocytic cells to cause septicemia and meningoencephalitis in freshwater and marine fish. However, vaccines based on extracellular products (ECP) and formalin-killed whole S. agalactiae cells, as well as subunit vaccine are unable to protect fish from infection by variant serotypes S. agalactiae . The search for live attenuated vaccine with highly conserved and virulent-related genes is essential for producing a vaccine to help understand and control streptococcosis In this study, the phoB gene was cloned from pathogenic S. agalactiae TOS01 strain and the mutant strain SAΔ phoB was constructed via allelic exchange mutagenesis. The results showed that the deduced amino acid of S. agalactiae TOS01 shares high similarities with other Streptococcus spp. and has high conserved response regulator receiver domain (REC) and DNA-binding effector domain of two-component system response regulators (Trans_reg_C). Cell adherence and invasion assays, challenge experiments and histopathological changes post-vaccination were performed and observed, the results showed that the mutant strain SAΔ phoB has a lower adherence and invasion rate and less virulent than the wild type strain in golden pompano, and it doesn't induce clinical symptoms and obvious pathological changes in golden pompano, thereby indicating that the deletion of phoB affects the virulence and infectious capacity of S. agalactiae . Golden pompano vaccinated via intraperitoneal injection SAΔ phoB had the relative percent survival value of 93.1% after challenge with TOS01, demonstrating its high potential as an effective attenuated live vaccine candidate. Real-time PCR assays showed that the SAΔ phoB was able to enhance the expression of immune-related genes, including MHC-I, MyD88, IL-22 and IL-10 after vaccination, indicating that the SAΔ phoB is able to induce humoral and cell-mediated immune response in golden pompano over a long period of time. [ABSTRACT FROM AUTHOR]

Sox5, Sox8, and Sox9 genes in golden pompano larvae were cloned and analyzed in this study. In the first trial, the expression of Sox genes during ontogeny of fish larvae in the first 18 days was examined, after which the expression of Sox genes in tissues was evaluated on 18 days post hatching (DPH). Subsequently, the response of Sox genes to water temperature (23, 26, and 29°C) on day 12 DPH and 18 DPH were compared. The expression levels of Sox8, Sox9a, and Sox9b peaked around 2 DPH before first feeding during fish ontogeny, and remained at low levels from 3-18 DPH. The expressions of Sox5 and Sox9a were affected by water temperature on 12 DPH and 18 DPH, while the expression of Sox8 was not affected by water temperature on 12 DPH and 18 DPH. The expression of Sox9b was affected by water temperature on 12 DPH. This study detected gene expression of Sox5, Sox8, and Sox9 at the early stage of development of golden pompano larvae. The time dependent expression of Sox genes in fish larvae is important for the understanding of bone ontogeny of fish larvae in early life. [ABSTRACT FROM AUTHOR]