Analysis of quality-related proteins in golden pompano(Trachinotus ovatus)fillets with modified atmosphere packaging under superchilling storage

Here,we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage.Tandem mass tags(TMT)-labeled quantitative proteomic strategy was applied to investigate the relationships between protein changes and quality characteristics of modified atmosphere packaging(MAP)fillets during superchilling(-3°C)storage.Scanning electron microscopy was used to show that the muscle histology microstructure of fillets was damaged to varying degrees,and low-field nuclear magnetic resonance was used to find that the immobilized water and free water in the muscle of fillets changed significantly.Total sulfhydryl content,TCA-soluble peptides and Ca2+-ATPase activity also showed that the fillet protein had a deterioration by oxidation and denaturation.The Fresh(FS),MAP,and air packaging(AP)groups were set.Total of 150 proteins were identified as differential abundant proteins(DAPs)in MAP/FS,while 209 DAPs were in AP/FS group.The KEGG pathway analysis indicated that most DAPs were involved in binding proteins and protein turnover.Correlation analysis found that 52 DAPs were correlated with quality traits.Among them,8 highly correlated DAPs are expected to be used as potential quality markers for protein oxidation and water-holding capacity.These results provide a further understanding of the muscle deterioration mechanism of packaging golden pompano fillets during superchilling.

Effect of Cu toxicity at different salinity on selective group of juvenile pompano Trachinotus ovatus

Effects of copper toxicity and salinity shock on selective group of juvenile pompano Trachinotus ovatus were investigated.The fish were exposed to different Cu2+ concentrations of 0(blank),0.02(C1),0.05(C2),0.10(C3),and 0.15 mg·L–1(C4)at a salinity of 10‰ or 40‰ for 96 h,with the salinity of 29‰ as the control.The results showed that the effects of the acute salinity stimulation to survival rates of pompano between control(29‰)and lower or higher salinity for 96 h were not significant(p>0.05).However,the survival rates in each treatment were decreased with the increase of Cu2+ concentration.The dominant factor influencing body moisture of the fish was salinity,and there was no sign that body moisture was correlated with exposure to Cu2+.The gill lamellas in high level of Cu2+ concentration(C4 treatments)were abnormal under the salinity of 40‰ and extremely curly under the salinity of 10‰.Hemorrhage in gill was observed in the two C4 treatments.Under transmission electron microscope,pillar cells in gill lamellas appeared deformed and ruptured in some areas of the epithelia in the higher concentration of Cu2+,resulting in the death of the fish due to the destruction of gill tissue,elevation of the arithmetic mean distance from water to blood,the decrease of oxygen diffusion capacity,and other physiological functions.These findings indicate that the pompano might suffer much more pressure when encountered with Cu2+ pollution and low salinity.

Study of the Compensatory Growth Following Starvation of Juvenile Golden Pompano Trachinotus ovatus

A starvation trial was conducted to determine compensatory growth of the juvenile golden pompano Trachinotus ovatus which were deprived of food for 1, 2, 5 and 7 days respectively. The results of tests in outdoor cement pools and net pens showed that, in the first 15 days and 30 days, the growth of 1 day and 2 days-deprived groups was probably the same with that of control group, which accorded with fully compensatory description. However, the weight of 5 days and 7 days-deprived fingerlings were lower than that of the control group, which accorded with the description of the partial compensatory growth. As the starvation prolonged, feed conversion efficiency of the starved groups increased and was higher than the control group. Meanwhile, feeding rate also increased, but the fish of 1 day and 2 days-deprived groups was lower than that of the control group, and feeding quantity reduced and was lower than that of the control group. It suggested that the mechanism of compensatory growth was mainly due to improving feed conversion efficiency. Fish biochemical composition was analyzed： the water content and ash of fish sample increased due to starvation, while the lipid and protein decreased. The loss of lipid was greater than that of the protein, and the biochemical composition of fish in each group was restored to the control level by the end of the experiment. It suggested that Trachinotus ovatus may mainly consume lipid during the period of starvation.

Predicting the shelf life of Trachinotus ovatus during frozen storage using a back propagation(BP)neural network model

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.

Novel potential XOD inhibitory peptides derived from Trachinotus ovatus:Isolation,identification and structure-function analysis

This study aimed to isolate and identify the novel potential Xanthine oxidase(XOD)inhibitory peptides derived from Trachinotus ovatus hydrolysate(TOH)(hydrolysis by neutral protease),and investigate their structure-function relationship.Initially,TOH was separated to four fractions(F1–F4)by gel filtration chromatography and F4 was chosen with higher XOD inhibitory rate(85.16%±0.566,25 mg/mL)and lower molecular weight(95.73%,<1000 Da).F4 was further characterized by reversed-phase high performance liquid chromatography(RP-HPLC)coupled with Nano-HPLC-MS/MS and four peptides(FPAW,LLPW,WLLP and FHLP)were identified with IC50 value of 3.81±0.18 mM,4.17±0.12 mM,43.06±0.73 mM,and over 50.00 mM respectively.It can be concluded that Trp-containing peptides especially located in C-terminal could inhibit XOD effectively.Moreover,the XOD-inhibiting actions of these peptides involvedπ-πstacking(Phe914 and Phe1009 in XOD),hydrogen bonding via molecular docking.Lineweaver-Burk equation showed the inhibition type of FPAW was a mixed inhibition.Circular dichroism(CD)spectra indicated FPAW could combine and change the secondary structure of XOD.Therefore,two peptides of FPAW and LLPW might have potential to be used to alleviate hyperuricemia in the future.

Gonadal transcriptomic analysis and differentially expressed genes between the testes and ovaries in Trachinotus ovatus

The Trachinotus ovatus is a popular aquaculture species in China.There are no obvious morphological differences between male and female fish,even during maturity,prompting research studies on sex-related features of this fish.To examine sex determination-and gonadal development-related genes,we conducted transcriptome analysis of the ovaries and testes of T.ovatus.A total of 345,972,132 high-quality clean reads were obtained from 12 libraries.In addition,28,137 gonad-expressed unigenes were obtained by mapping the clean reads to the T.ovatus reference genome.A total of 8,237 differentially expressed genes(DEGs)were identified between stage I ovaries and testes,including 3,235 testicular upregulated and 5,002 ovarian upregulated genes.Furthermore,13,448 DEGs were obtained between stage III ovarian and testicular libraries,including 7,576 testicular upregulated and 5,872 ovarian upregulated genes.The DEGs included some sex-determining genes such as sry,dmrt1,and amh.DEGs between ovarian and testicular libraries were significantly enriched with KEGG pathways that are involved in gonadal development,sex determination,and gonadal function.Then,10 DEGs(seven testicular upregulated and three ovarian upregulated unigenes)were selected for quantitative real-time PCR analysis.Four genes(zinc-binding protein A33-like,pro-opiomelanocortin-like,leucine-rich repeat and transmembrane domain-containing protein 2-like,and forkhead boxC1)showed a specific testicular expression pattern.The gonadally expressed as well as testicular and ovarian DEGs provide useful information for further research on the reproductive biology of T.ovatus.

不同热加工方式对卵形鲳鲹肌肉蛋白及品质的影响

为研究热加工方式对鱼肉蛋白的影响,对新鲜、蒸制、油炸、微波、烤制下卵形鲳鲹肌肉的水分含量、失重率、蛋白质组成、肌原纤维蛋白的总巯基含量、SDS-聚丙烯酰胺凝胶电泳、氨基酸组成等多方面的指标进行测定和分析。结果表明,4种热加工方式对卵形鲳鲹的肌肉蛋白和品质的影响存在显著差异性,单位质量样品中总蛋白含量为烤制>油炸>微波>蒸制,与肌肉中水分的含量呈负相关。蒸制鱼肉盐溶性蛋白和水溶性蛋白在蛋白质组分中所占的比例更高,鱼肉外观和结构保存最完整。微波处理组对肌原纤维蛋白质的破坏作用最强,经微波处理的鱼肉更利于人体消化吸收。经烤制和油炸后,卵形鲳鲹肌肉的非蛋白氮含量和呈味氨基酸含量均是最高,风味要优于另外2组。

金鲳网箱养殖现状及病害防治对策

金鲳(Trachinotus ovatus)为名贵的海水养殖品种之一,因为其鲜嫩的肉质以及较高的营养价值受到人们的广泛欢迎。文章对网箱养殖金鲳的优缺点进行了介绍,并对金鲳养殖过程中常见的肠炎病和疖疮病的流行情况和防治对策进行了详细说明,可供广大金鲳养殖者参考。