iTRAQ proteomic analysis of salinity acclimation proteins in the gill of tropical marbled eel (<Emphasis Type="Italic">Anguilla marmorata</Emphasis>)

Osmoregulation plays an important role in the migration process of catadromous fish. The osmoregulatory mechanisms of tropical marbled eel (Anguilla marmorata), a typical catadromous fish, did not gain sufficient attention, especially at the molecular level. In order to enrich the protein database of A. marmorata, a proteomic analysis has been carried out by iTRAQ technique. Among 1937 identified proteins in gill of marbled eel, the expression of 1560 proteins (80 %) was quantified. Compared with the protein expression level in the gill of marbled eel in freshwater (salinity of 0 ‰), 336 proteins were up-regulated and 67 proteins were down-regulated in seawater (salinity of 25 ‰); 33 proteins were up-regulated and 32 proteins were down-regulated in brackish water (salinity of 10 ‰). These up-regulated proteins including Na⁺/K⁺-ATPase, V-type proton ATPase, sodium–potassium–chloride co-transporter and heat shock protein 90 were enriched in many KEGG-annotated pathways, which are related to different functions of the gill. The up-regulated oxidative phosphorylation and seleno-compound metabolism pathways involve the synthesis and consumption of ATP, which represents extra energy consumption. Another identified pathway is the ribosome pathway in which a large number of up-regulated proteins are involved. It is also more notable that tight junction and cardiac muscle contraction pathways may have correlation with ion transport in gill cells. This is the first report describing the proteome of A. marmorata for acclimating to the change of salinity. These results provide a functional database for migratory fish and point out some possible new interactions on osmoregulation in A. marmorata.     

Effects of chronic high stocking density on liver proteome of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

The main aim of the present study was to assess the effects of chronic high stocking density on liver proteome of rainbow trout. Rainbow trout juveniles (42.6 ± 2.3 g average body weight) were randomly distributed into six tanks at two stocking densities (low stocking density (LD) = 20 kg m^?3 and high stocking density (HD) = 80 kg m^?3). Both treatments were performed in triplicate tanks for a period of 60 days. High stocking density caused a reduction in the growth performance compared with LD fish. Lysozyme activity increased with stocking density, while serum complement activity presented the opposite pattern. Serum cortisol and total protein levels did not show significant differences (P > 0.05) between experimental groups. The fish reared at high stocking density showed significantly lower osmolality and globulin values but higher albumin level. The HD group had significantly higher activities of catalase, glutathione peroxidase and superoxide dismutase, and malondialdehyde content in the liver when compared to the LD group. Comparative proteomics was used to determine the proteomic responses in livers of rainbow trout reared at high stocking density for 60 days. Out of nine protein spots showing altered abundance (>1.5-folds, P < 0.05), eight spots were successfully identified. Two proteins including apolipoprotein A-I-2 precursor and mitochondrial stress-70 protein were found to increase in HD group. The spots found to decrease in the HD group were identified as follows: 2-peptidylprolyl isomerase A, two isoforms of glyceraldehydes-3-phosphate dehydrogenase, an unnamed protein product similar to fructose-bisphosphate aldolase, 78 kDa glucose-regulated protein, and serum albumin 1 protein.     

Proteomic profiling of sea bass muscle by two-dimensional gel electrophoresis and tandem mass spectrometry

In this study, the proteome profile of European sea bass (Dicentrarchus labrax) muscle was analyzed using two-dimensional electrophoresis (2-DE) and tandem mass spectrometry with the aim of providing a more detailed characterization of its specific protein expression profile. A highly populated and well-resolved 2-DE map of the sea bass muscle tissue was generated, and the corresponding protein identity was provided for a total of 49 abundant protein spots. Upon Ingenuity Pathway Analysis, the proteins mapped in the sea bass muscle profile were mostly related to glycolysis and to the muscle myofibril structure, together with other biological activities crucial to fish muscle metabolism and contraction, and therefore to fish locomotor performance. The data presented in this work provide important and novel information on the sea bass muscle tissue-specific protein expression, which can be useful for future studies aimed to improve seafood traceability, food safety/risk management and authentication analysis. This work is also important for understanding the proteome map of the sea bass toward establishing the animal as a potential model for muscular studies.     

The effects of dietary vitamin C on mucosal immune responses and growth performance in Caspian roach (Rutilus rutilus caspicus) fry

This study was conducted to investigate the effects of different levels of dietary vitamin C on some skin mucus immune parameters, mucus antimicrobial activity and growth performance of Caspian roach (Rutilus rutilus caspicus) fry. Six hundred sixty Caspian roach (1.4 ± 0.02 g) fry were allocated to 12 tanks (55 fish per tank), and triplicate groups were fed diets containing 0, 1,000, 1,500 and 2,000 mg kg^?1 vitamin C for 60 days. At the end of the trial, the epidermal mucus protein level, alkaline phosphatase and antimicrobial activity against two gram-positive bacteria (Streptococcus faecium and Micrococcus luteus) and gram-negative bacteria (Escherichia coli and Serratia marcescens) as well as growth performance were measured. The results demonstrated that feeding on vitamin C significantly elevated skin mucus alkaline phosphatase and protein levels compared to the control group (P < 0.05). However, lysozyme activity was undetectable in both the vitamin C-fed roach fry and the control group. Skin mucus antimicrobial activity was increased following vitamin C administration, and the bacterial growth inhibition zones were significantly elevated in vitamin C-fed roach (P < 0.05). Similar results were obtained in case of the minimum inhibitory concentration of skin mucus. Also fish fed the control diet had a significantly lower weight gain, specific growth rate and condition factor compared to the other treatments (P < 0.05). These results revealed that dietary vitamin C beneficially affects the skin mucus immune parameters and growth performance of Caspian roach fry.     

A comparative study on innate immunity parameters in the epidermal mucus of Indian major carps

The innate immune system, particularly the external body surface, plays a frontier role in protecting fish from relevant infections. The present study is aimed at understanding and comparing the mucosal immunity of Indian major carp, that is, Labeo rohita, Catla catla and Cirrhinus mrigala, by evaluating different immune parameters such as protein content, lysozyme, myeloperoxidase, proteases and alkaline phosphatase activity in the skin mucus. The protein content of mucus sample of these species was compared, and the highest protein content was found in C. catla among the three Indian major carp species. The levels of proteases (40 ± 0.211 units/ml) and myeloperoxidase OD450 nm (1.525 ± 0.108) were found to be highest in the skin mucus of C. catla. However, lysozyme levels were highest in the skin mucus of L. rohita (10.95 ± 0.330 μg/ml), and C. mrigala had the highest alkaline phosphatase activity (30.74111 ± 0.680 U/l). Besides the enzyme activities, the epidermal mucus samples of three Indian major carp species were also tested and compared for the antibacterial activity against seven bacterial strains. Skin mucus of C. catla showed highest antibacterial activity among the three Indian major carps against all the seven bacterial strain, except that Micrococcus lysodeikticus and Vibrio cholerae, however, showed highest activity against mucus of C. mrigala. Also, the epidermal mucus from all the three species successfully agglutinated three freshwater pathogens, viz. Aeromonas hydrophila, Pseudomonas fluorescens and Edwardsiella tarda, with agglutination titres being the highest for Labeo rohita for all the pathogens. The epidermal mucus samples from the Indian major carp species showed haemagglutination activity and successfully lysed human, chicken and goat RBCs showing highest activity in C. catla. These results provide information for a better understanding of the role of epidermal mucus and its components in the innate immune system of Indian major carps.     

柱状黄杆菌强毒株和弱毒株胞外蛋白中差异蛋白的初步鉴定

柱状黄杆菌(Flavobacterium columnare)是一种世界范围的水产动物致病菌,是中国重要养殖鱼类草鱼(Ctenopharyngodon idellus)、鳜(Siniperca chuatsi)等烂鳃病的病原。本研究以1972年从患"烂鳃病"草鱼上分离的两株冻干柱状黄杆菌G4和G18菌株为研究对象,并将G4株再次分离纯化得纯化菌株,命名为G4R3。对草鱼鱼苗浸泡攻毒结果显示,G4R3的LD50至少比G18的高3个数量级,因此G4R3为"强毒株",G18为"弱毒株"。利用蛋白质组学方法分析柱状黄杆菌强毒株G4R3和弱毒株G18的胞外蛋白,经过双向电泳并结合图像分析,共发现了34个点是差异表达的蛋白。胶内酶解、肽质量指纹图谱和串联质谱分析后,鉴定出其中的7个蛋白点,代表滑动蛋白K、腺酐甲硫氨酸合成酶和一种可能的膜蛋白等3种蛋白,它们可能是柱状黄杆菌的毒力因子。     

Characterization of carboxylesterase in skin mucus of Cirrhinus mrigala and its assessment as biomarker of organophosphate exposure

Presence of carboxylesterase (CbE) activity in the skin mucus of Cirrhinus mrigala was investigated. CbE activity in skin mucus showed higher substrate preference for α-naphthyl acetate over p-nitrophenyl acetate. Four CbE isozymes—CbE-1, CbE-2, CbE-3, and CbE-4 were observed in skin mucus during zymography. The isozyme CbE-4 was characterized as typical serine esterase, whereas CbE-1, CbE-2, and CbE-3 were identified as sulphhydryl group-dependent serine esterases. In vitro treatment of skin mucus with the organophosphorus insecticide, Nuvan^® showed strong inhibition of CbE activity. In vivo exposure of the fish to sublethal test concentrations (5 and 15 mg/l) of the insecticide also revealed significant inhibition of CbE activity in mucus. After the cessation of exposure, CbE activity recovered to its control level during the recovery periods. Thus, CbE activity in skin mucus could be considered a biomarker of the organophosphorus insecticide exposure to fish and a useful tool in monitoring environmental toxicity.     

大弹涂鱼皮肤黏液的抑菌活性和蛋白质组学

皮肤黏液是鱼类免疫防御的第一道防线。大弹涂鱼皮肤黏液对其免疫防御、渗透压维持以及适应水陆生活等方面具有重要意义。为深入了解大弹涂鱼皮肤黏液的蛋白质分子组成,对其皮肤黏液开展了抑菌活性分析和蛋白质组学分析。通过电刺激法收集大弹涂鱼皮肤黏液,采用打孔法比较了皮肤黏液和血清的抑菌活性差异;进一步利用鳗弧菌对大弹涂鱼进行诱导,采用生长曲线抑制法分析和比较了诱导前后皮肤黏液的抑菌活性差异。利用Shotgun质谱技术,结合大弹涂鱼皮肤转录组数据库,对大弹涂鱼皮肤黏液开展了蛋白质组学分析;进一步利用String软件对所鉴定的蛋白质开展了蛋白质相互作用预测。大弹涂鱼皮肤黏液具有广谱抑菌活性,鳗弧菌诱导后的大弹涂鱼皮肤黏液与诱导前相比,对部分革兰氏阴性菌的抑菌活性明显上升,但对其他菌株的抑菌活性差异不明显。从大弹涂鱼皮肤黏液中共鉴定各类蛋白质分子97种,基本分子组成与其他硬骨鱼类皮肤黏液蛋白相似,但也有少数蛋白如泛素蛋白、胸腺素蛋白等未在其他鱼类皮肤黏液中报道。此外,其他鱼类中所鉴定到的部分蛋白如热休克蛋白、抗菌肽等在大弹涂鱼皮肤黏液中未能鉴定到。大弹涂鱼皮肤黏液中已鉴定的蛋白多数具有与免疫功能相关的结构域,且存在一个以肌动蛋白为核心的相互作用网络。大弹涂鱼皮肤黏液具有明显的广谱抑菌活性,其蛋白质组成与其他鱼类皮肤黏液具有一定的相似性。本研究为深入了解大弹涂鱼皮肤黏液的分子多样性及功能机制奠定了基础。     

Partial characterization of digestive proteases in tropical gar Atractosteus tropicus juveniles

Tropical gar (Atractosteus tropicus) is an economically and socially important freshwater species from Southeastern Mexico, with a high aquaculture potential. With this in mind, the purpose of this study was to characterize the digestive proteases of tropical gar juveniles through biochemical and electrophoretic analyses. Twenty specimens with an average weight of 73.6 ± 12.7 g were used to obtain stomach and intestinal tissue from which multienzymatic extracts were prepared. The general activities of the acid and alkaline proteases were evaluated, as well as the specific activities of trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A. The effect of the pH and temperature on the proteases was also analyzed, together with the composition of the multienzymatic extracts using protease inhibitors and electrophoretic tests. Results showed that A. tropicus have a functional stomach in which protein hydrolysis starts with pepsin and which contains endo- and exopeptidases (trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A) and proteases that are resistant to high temperatures (45 and 55 °C for alkaline and acid proteases, respectively) and pH values. Using zymogram technique, we found two acid protease isoforms (0.35 and 0.71 rf) and five alkaline protease isoforms (83.7, 43.7, 27.5, 24.0 and 19.4 kDa), which decrease or disappear with the different inhibitors. Thus, this species is considered to be a carnivore capable of adapting to its environment by consuming different types of proteins from preys and also could adapt rapidly to consume a compound diet with different animal protein sources.     

Proteome profile comparison of two differently fed groups of Atlantic cod (Gadus morhua) larvae

Proteome analysis was used to study the effects of feeding early Atlantic cod (Gadus morhua) larvae with a saithe (Pollachius virens) protein hydrolysate (SPH). Protein hydrolysates have previously been shown to beneficially affect fish larval development. Feeding was initiated on day 2 post hatch (ph) or as soon as the larvae opened their mouth and the protein expression was monitored 4 days later or in 6‐dph cod larvae. The results demonstrated changes in the abundance of 13 protein spots in the cod larvae fed SPH. Of these, seven protein spots were up‐regulated and six protein spots showed down‐regulation. Five of the up‐regulated proteins in cod larvae are known to be involved in energy metabolism. A few early larval specific proteins were down‐regulated in the SPH‐fed cod larvae possibly because of an enhanced development in this group relative to the control group. Two trypsin isoforms were detected within the cod larval proteome. The detection of the trypsin spots was made possible by co‐electrophoresis of known cod trypsins with the cod larval protein extract. Surprisingly, no difference in trypsin content was observed between the SPH‐fed and the control larval groups.     

Differential expression of proteins in the gills of Litopenaeus vannamei infected with white spot syndrome virus

Determination of differentially expressed protein profile is necessary to understand the host response to viral infection. Proteomics can be applied as a tool to examine white shrimp Litopenaeus vannamei molecular responses against white spot syndrome virus (WSSV) infection, thus enabling development of effective strategies to reduce their impact on farms. In the present study, specific pathogen-free shrimp was tested against WSSV infection under several time intervals. Shrimps were submitted to a viral load of with 5.5 × 10⁶ viral copies in 100 μL/shrimp. The monitoring of infection was performed in intervals of 6, 12, 24, 48 and 72 h after infection. The analysis was realized using 2-DE, and differentially expressed proteins were identified by MALDI-TOF mass spectrometry (MS) peptide mass fingerprint (PMF). Between the differentially expressed proteins found in the infected animals, the most important were identified as caspase-2, ubiquitin and F1-ATP synthase. They are interesting candidates for biomarkers because could be related to the beginning of apoptosis process. The differentially expressed protein profile creates a new paradigm in the analysis of L. vannamei shrimp molecular response to WSSV infection and in virus–host relationship. Furthermore, it proposes potential biomarkers that allow strategies both selecting less susceptible individuals and reducing the impact of viruses on farms.     

Proteomic Analysis of Mechanisms Responsible for the Waterless Preservation of Fenneropenaeus chinensis Based on Cold-Forced Hibernation

ABSTRACT

In this study, the comparative proteomic approach was used to identify the proteins that were changed significantly during the waterless preservation of Chinese white shrimp (Fenneropenaeus chinensis). Approximately 380–430 protein spots were observed in the two-dimensional protein electrophoresis (2-DE) gels. Among them, 14 altered proteins from hemolymph were excised and subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. Eleven protein spots were successfully identified—including hemocyanin, hemolymph clottable protein, myosin light chain, and sarcoplasmic calcium-binding protein. It could be speculated that the combined action of decreased hemocyanin, increased hemolymph clottable protein, and myosin light chain forced Chinese white shrimp into a temporary state of hibernation under cold temperature and could keep the hibernated shrimps alive during the waterless preservation. Moreover, increased expression of sarcoplasmic calcium-binding protein ensured that hibernated shrimps could be aroused at warm temperature. On the basis of these findings, it is believed that a protein-protein networking mechanism of hemocyanin, hemolymph clottable protein, myosin, and sarcoplasmic calcium-binding protein could interpret the cold-forced hibernation and warm-arousal of Chinese white shrimp.     

Physiological response,blood chemistry profile and mucus secretion of red sea bream (<Emphasis Type="Italic">Pagrus major</Emphasis>) fed diets supplemented with <Emphasis Type="Italic">Lactobacillus rhamnosus</Emphasis> under low salinity stress

Environmental stressors caused by inadequate aquaculture management strategies suppress the immune response of fish and make them more susceptible to diseases. Therefore, efforts have been made to relieve stress in fish by using various functional feed additives in the diet, including probiotics. The present work evaluates the effects of Lactobacillus rhamnosus (LR) on physiological stress response, blood chemistry and mucus secretion of red sea bream (Pagrus major) under low salinity stress. Fish were fed four diets supplemented with LR at [0 (LR0), 1 × 10² (LR1), 1 × 10⁴ (LR2) and 1 × 10⁶ (LR3) cells g^?1] for 56 days. Before stress, blood cortisol, urea nitrogen (BUN) and total bilirubin (T-BIL) showed no significant difference (P > 0.05), whereas plasma glucose and triglyceride (TG) of fish-fed LR2 and LR3 diets were significantly lower (P < 0.05) than those of the other groups. Plasma total cholesterol (T-CHO) of fish-fed LR3 diet was significantly (P < 0.05) lower than that of the other groups. Furthermore, total plasma protein, mucus myeloperoxidase activity and the amount of mucus secretion were significantly enhanced in LR-supplemented groups when compared with the control group (P < 0.05). After the application of the low salinity stress test, plasma cortisol, glucose, T-CHO and TG contents in all groups showed an increased trend significantly (P < 0.01) compared to the fish before the stress challenge. However, plasma total protein and the amount of secreted mucus showed a decreased trend in all groups. On the other hand, BUN, T-BIL and mucus myeloperoxidase activity showed no significant difference after exposure to the low salinity stress (P > 0.05). In addition, the fish that received LR-supplemented diets showed significantly higher tolerance against low salinity stress than the fish-fed LR-free diet (P < 0.05). The physiological status and the detected immune responses, including total plasma protein and mucus myeloperoxidase activity in red sea bream, will provide a more comprehensive outlook of the effects of probiotics to relieve stress in fish.     

温度对牙鲆皮肤黏液抗体产生的影响

在9℃、15℃、21℃和26℃4种不同水温下,用淋巴囊肿病毒(LCDV)灭活疫苗腹腔注射牙鲆,应用间接酶联免疫吸附试验(ELISA)研究了其皮肤黏液中特异性抗体水平的变化,以分析温度对牙鲆皮肤黏液抗体产生的影响.ELISA结果表明,9℃和15℃水温下牙鲆黏液OD值分别在注射LCDV后第9周和第7周达到峰值(9℃:OD=0.179; 15℃:OD=0.233); 21℃水温下OD值上升最快,5周达到峰值(0.316); 26℃水温下OD值较21℃无显著差异,也于5周达到峰值(0.295).采用硫酸铵分步盐析等技术粗提不同温度下OD值最高时的牙鲆皮肤黏液中的免疫球蛋白(Ig),SDS-PAGE检测发现,各温度组黏液蛋白中均含有72 kD和26 kD蛋白条带.Western blotting结果显示,抗牙鲆血清Ig重链的单克隆抗体只与黏液蛋白中72 kD条带发生反应,确定为牙鲆皮肤黏液Ig重链.综上结果表明,牙鲆在最适生活温度(21℃)下,抗体应答强度最大.牙鲆粗提黏液蛋白中Ig的初步确定,为探索牙鲆黏液免疫机制提供了材料.     

iTRAQ‐based identification of differentially expressed proteins related to growth in the swimming crab,Portunus trituberculatus

The swimming crab, Portunus trituberculatus, is an important farmed species in China, and it has been studied extensively, which requires more information on its genetic background. To date, information on the proteomics of P. trituberculatus is scarce. In this study, we used isobaric tags for relative and absolute quantitation (iTRAQ)‐based proteomics to investigate growth regulation in P. trituberculatus. Total proteins were isolated from five tissues (eyestalk, gill, heart, hepatopancreas and muscle). Equal quantities of protein from each tissue were pooled at the proteome level using the iTRAQ method. A total of 961 proteins were identified using liquid chromatography coupled with tandem mass spectrometry and de novo sequencing data. Using a 1.2‐fold change in expression as a physiologically significant benchmark, 30 differentially expressed proteins (DEPs) were found to undergo differential expression related to the growth of P. trituberculatus, and most of the growth‐related proteins, including those involved in metabolism, immune responses, DNA duplication and protein synthesis, were upregulated, indicating that conservation of energy is an important strategy to cope with growth. There was a high consistency between the expression levels determined using iTRAQ and mRNA, highlighting the high reproducibility of our proteomic approach and its great value in elucidating the molecular mechanisms of P. trituberculatus.     

Liver proteomic analysis of the large yellow croaker (Pseudosciaena crocea) following polyriboinosinic:polyribocytidylic acid induction

In the present study, we examined the liver protein profiles of the large yellow croaker (Pseudosciaena crocea) exposed to polyriboinosinic:polyribocytidylic acid [poly(I:C)], a viral mimic, using the differential proteomic approach. Sixteen altered protein spots were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry or matrix-assisted laser desorption ionization time of flight/time of flight mass spectrometry, including eight upregulated proteins and eight downregulated proteins. These altered host proteins were classified into six categories based on their biological function: cellular process, metabolic process, biological regulation, binding, and catabolic process, highlighting the fact that response to poly(I:C) induction in fish seems to be complex and diverse. Moreover, four corresponding genes of the differentially expressed proteins were validated by relative quantitative real-time PCR. Western blot analysis further demonstrated the changes in protein abundance of natural killer enhancing factor and peroxiredoxin 6. These results will be helpful in furthering our understanding of the changes of physiological processes in liver of fish during virus infection.     

Evaluation of antibacterial activity and innate immune components in skin mucus of Indian major carp,Cirrhinus mrigala

The present work has been undertaken to analyse the antibacterial activity and innate immune components in the skin mucus of Indian major carp, Cirrhinus mrigala. Skin mucus was extracted separately in triple‐distilled water (TDW), 3% acetic acid (3% AA) or 0.1% trifluoroacetic acid (1% TFA). All mucus extracts exhibited different spectrum of the antibacterial activity against different groups of pathogenic bacteria. Protein profiling by polyacrylamide gel electrophoresis revealed a series of protein bands in the TDW extract, four major protein bands in the AA extract and two protein bands in the TFA extract. Tandem mass spectrometry analysis of distinct protein bands identified potential innate immune factors – histone H2A, histone H3, histone H4, haemoglobin, cofilin and nucleoside diphosphate kinase in the TDW extract, and ubiquitin and histone H2B isoforms in acidic extracts of skin mucus of C. mrigala. The presence of these innate immune molecules suggests that skin mucus play an important role in the protection of the fish against microbial invasion.     

Proteomics analysis of mitochondrial extract from liver of female zebrafish undergoing starvation and refeeding

Many fish species can withstand long period of food deprivation and consequently compensate for any weight loss by undergoing rapid growth during resumption of feeding. There is an interest in taking advantage of compensatory growth to reduce feed cost. In this present study, we attempted to compare the changes in hepatic mitochondrial proteome of zebrafish undergoing starvation and refeeding. Two‐dimensional gel separation and image analysis revealed a total of 65 spots that showed changes in expression after 15 days of starvation followed by 7 days of refeeding. A total of 35 proteins were selected for mass spectrometry analysis, resulting in the positive identification of 18 proteins. Identified proteins indicated that starvation resulted in reduction in glycolysis and increase in gluconeogenesis, while refeeding caused these activities to return to normal levels. Expression pattern of several proteins related to fatty acid and amino acid metabolism also suggested the utilization of non‐carbohydrate resources for energy during starving conditions. Proteins with chaperoning and antioxidative roles such as glucose‐regulated protein, paraxonase and heat‐shock protein were also upregulated in starved conditions.     

Serum enolase: a non‐destructive biomarker of white skeletal myopathy during pancreas disease (PD) in Atlantic salmon Salmo salar L.

Diseases which cause skeletal muscle myopathy are some of the most economically damaging diseases in Atlantic salmon, Salmo salar L., aquaculture. Despite this, there are limited means of assessing fish health non‐destructively. Previous investigation of the serum proteome of Atlantic salmon, Salmo salar L., during pancreas disease (PD) has identified proteins in serum that have potential as biomarkers of the disease. Amongst these proteins, the enzyme enolase was selected as the most viable for use as a biomarker of muscle myopathy associated with PD. Western blot and immunoassay (ELISA) validated enolase as a biomarker for PD, whilst immunohistochemistry identified white muscle as the source of enolase. Enolase was shown to be a specific marker for white muscle myopathy in salmon, rising in serum concentration significantly correlating with pathological damage to the tissue.