Scallop Adductor Research Articles

Effect of different drying methods on free amino acid and flavor nucleotides of scallop (patinopecten yessoensis) adductor muscle

The effects of hot air drying (HAD), vacuum hot air drying (VHAD), microwave drying (MWD), and vacuum freeze drying (VFD) on free amino acids (FAAs) and flavor nucleotides in scallop adductor muscle (SAM) were studied. The liquid chromatography and multidimensional infrared spectroscopy (MM-IR) were used. Compared with fresh SAM, the main FAAs were glycine, alanine, arginine, and glutamic acid in dried SAM. The total FAAs content in VFD group was 1.40–1.90 times of the other group. The umami taste nucleotides (IMP and AMP) content in the VFD and MWD groups was significantly higher than that in HAD and VHAD groups. Equivalent umami concentrations were found: VFD > MWD > VHAD > HAD. MM-IR analysis was an efficient method for identifying taste components. The results revealed FAAs and flavor nucleotides and the mutual adjustment of compounds were related to drying method, and VFD was preferred for taste substance retention in scallops.

Effects of Boiling Processing on Texture of Scallop Adductor Muscle and Its Mechanism.

The objective of this study was to reveal the effects of boiling processing on the texture of scallop adductor muscle (SAM) and its mechanism. Compared to the fresh sample, all the texture indicators, including the hardness, chewiness, springiness, resilience, cohesiveness, and shear force of 30-s- and 3-min-boiled SAMs increased time-dependently (p < 0.05). As the boiling time increased further to 15 min, the shear force and cohesiveness still increased significantly (p < 0.05), and the resilience and hardness were maintained (p > 0.05), but the springiness and chewiness decreased significantly (p < 0.05). The overall increase in the texture indicators of the boiled SAMs was due to the boiling-induced protein denaturation, aggregation, and increased hydrophobicity, resulting in the longitudinal contraction and lateral expansion of myofibrils, the longitudinal contraction and lateral cross-linked aggregation of muscle fibers, and the loss of free water. However, the decreasing springiness and chewiness of the 15-min-boiled SAMs was due to the significant degradation of proteins (especially collagen), resulting in the destruction of the connective tissue between the muscle fiber clusters. Both from a subjective sensory point of view and from the objective point of view of protein denaturation and degradation, 3-min-boiled SAMs are recommended. The quality improvement of thermally processed products by controlled, moderate cooking is of practical value from the perspective of food consumption.

Effect of different sous-vide cooking conditions on textural properties, protein physiochemical properties and microstructure of scallop (Argopecten irradians) adductor muscle

Among 26 sous-vide cooking conditions of scallop adductor muscle (SAM), 65 °C-5.5 h, 70 °C-1.5 h and 100 °C-5 min were selected by the differential scanning calorimetry analysis. After sous-vide cooking, the shear force, hardness, springiness, cohesiveness, chewiness and recoverability of SAM increased significantly compared to fresh sample. The cooking also changed the secondary structures of the proteins in SAM with the rising β-sheet and descending α-helix, and the chemical interactions with the rising hydrophobic interactions and disulfide bonds but the descending ionic bonds and hydrogen bonds. These caused the longitudinal shrinkage and transverse aggregation of muscle fibers, and the aggregation and cross-linking between myofibrils which led to the squeeze of immobile water from myofibril network structure. This indicated that the denaturation, oxidation, aggregation and cross-linking of proteins caused by heat treatment changed the microstructure and water distribution, which contributed to the increased textural indicators of sous-vide cooked SAM.

Different tea polyphenol treatments on lipid oxidation of scallop ( Argopecten irradians ) adductor muscle during hot air drying

This study investigated the effects of different tea polyphenol (TP) treatments (control, unmarinated, and marinated) on scallop adductor muscle lipid oxidation during hot air drying. Results showed that the marinated sample had the lowest peroxide value, thiobarbituric acid reactive substances, polyunsaturated fatty acids loss, free radical level, and lipoxygenase activity during drying, indicating that the marination process maximized the antioxidant effects of TP. These results were achieved by the distributing of TP on lipid oxidation site, effectively intercepting free radical chain reaction and inhibiting lipoxygenase activity. The significant loss of total phenolic content in the marinated sample confirmed this result. The control, unmarinated, and marinated sample lost 26.52%, 9.99%, and 6.46% of eicosapentaenoic acid and docosahexaenoic acid during drying, respectively, indicating that the marination more efficiently maintained its high nutritive value in terms of lipid. This study provided a more effective way of using TP to control lipid oxidation in seafood during drying. Novelty impact statement Marinated with TP improved its antioxidant effect during scallop drying. More than 26% of EPA + DHA lost in scallop adductor muscle, while less than 7% of EPA + DHA lost in marinated scallop adductor muscle during drying. Marinated with TP maintained the higher nutritive value of scallop during drying.

Effect of immersion time of dried scallop on amino acids, antioxidant and ACE inhibitory activities in Japanese traditional Dashi

The dried adductor muscle of scallop (Mizuhopecten yessoensis) has been used as a material for “dashi.” To prepare dashi, the dried scallop must be soaked in water before boiling. Although dashi recipes using dried scallops have been passed down for many generations as a local food, the optimum immersion time prior to cooking has not been elucidated. Thus, the objective of the present study was to determine the optimum immersion time of dried scallops for the preparation of dashi from the viewpoint of components and biological activities.Immersion of dried scallops changed the L * (lightness), a* (redness), and b* (yellowness) of dashi, and subsequent heat treatment led to evident changes in these values. Glycine (Gly), taurine (Tau), and arginine (Arg) are the major components of dashi, accounting for approximately 62%, 15%, and 11% of the total free amino acids, respectively. When the immersion time was 8 h and more, these major amino acids were significantly increased in dashi with or without heating compared to that after 1 h of immersion without heating.Heat treatment significantly decreased maltose in dashi prepared after 8 h of immersion. Dashi prepared following 4 h or more of immersion had significantly enhanced peroxyl radical scavenging and angiotensin converting enzyme (ACE) inhibitory activities compared to those prepared following 1 h of immersion.A minimum of 8 h of immersion appears to be necessary for preparing dashi rich in umami, sweetness, and antioxidant and ACE inhibitory activities. An extended immersion time (12 h) caused evident progress in the Maillard reaction. The soluble and aromatic compounds of the reaction products may affect the taste and functionality of dashi.

Effects of Ultrasound-Assisted Vacuum Impregnation Antifreeze Protein on the Water-Holding Capacity and Texture Properties of the Yesso Scallop Adductor Muscle during Freeze–Thaw Cycles

The effect of antifreeze protein (AFP) on the water-holding capacity (WHC) and texture properties of the Patinopecten yessoensis adductor muscles during freeze–thaw cycles (FTCs) were evaluated based on three impregnation methods: general impregnation (GI), vacuum impregnation (VI), and ultrasound-assisted VI (US-VI). The WHC, texture properties, and tissue microstructure were all evaluated. Results showed that the WHC and texture properties of adductor muscle were significantly improved in the VI and US-VI groups during FTCs (p < 0.05). The WHC of the adductor muscle in the US-VI group was maximally enhanced in terms of yield (6.63%), centrifugal loss, cooking loss, and T22. The US-VI group of the adductor muscle had the optimal chewiness and springiness compared to others, and the shear force and hardness were most effectively enhanced by VI. The growth and recrystallization of ice crystals in the frozen adductor muscle were significantly inhibited by VI and US-VI. The average cross-sectional area and roundness of ice crystals in the US-VI group were decreased by 61.89% and increased by 22.22% compared with those of the control, respectively. The partial least squares regression (PLSR) model further confirmed that the WHC and texture properties of the adductor muscle were correlated appreciably with the degree of modification of ice crystal morphology through the AFP.

Independent and combined effects of ultrasound and transglutaminase on the gel properties and in vitro digestion characteristics of bay scallop (Argopecten irradians) adductormuscle

The effects of transglutaminase (TGase) addition (0.4–1.2 g/100g), ultrasound (120–720 W, 20 min), and their combination on the gel properties and in vitro digestion characteristics of bay scallop adductor muscle were studied. The gel strength of the gel sample with TGase content of 0.8 g/100g (TG-0.8) was 58.2% higher than that of the control sample (CON). The gel sample treated with ultrasound at 480 W (UT-480) had the highest gel strength. The strength of the gel prepared by combination of 0.8 g/100g TGase and 360 W ultrasound (UT-TG) was 82.3% higher than that of CON. The whiteness and water holding capacity of the gel increased regardless of the addition of TGase or ultrasound treatment. SDS-PAGE patterns showed that the myosin heavy chain of the treated samples became thinner, and the changes of actin and tropomyosin were not significant. The scanning electron microscopy results of gel samples prepared by ultrasound combined with TGase showed a denser structure, which was related to the lowest total sulfhydryl content and TCA-soluble peptide content. The results of dynamic rheology show that the UT-TG sample had the highest G′ value, followed by TG-0.8. The in vitro digestion characteristics of the selected gel samples were also discussed. The degree of protein hydrolysis and the content of free amino acids in TG-0.8 samples were the lowest, which improved after ultrasound treatment. Overall, the combination of appropriate ultrasound treatment and TGase addition provides an effective means for improving gel properties and digestibility of scallop surimi product.

Identification and Quantitation of Taste-Active Compounds in Dried Scallops by Combined Application of the Sensomics and a Quantitative NMR Approach.

Application of the sensomics concept on dried scallops, a Japanese specialty produced from the adductor muscle of scallops, revealed after activity-guided fractionation with subsequent (comparative) taste dilution analyses besides nucleotides, amino acids, organic acids, and inorganic ions, the presence of taste-modulating quaternary ammonium compounds and opines in highly taste-active fractions. In order to recreate the taste of dried scallops, two independent quantitation approaches were applied and compared. The first approach used multiple targeted UHPLC-MS/MS and high-performance ion chromatography methods. Besides already established quantitation methods for basic taste compounds, a new HILIC-UHPLC-MS/MSMRM method for the quantitation of chromatographically challenging opines, using synthesized stable isotope-labeled standards, was developed. Furthermore, a qHNMR approach was applied, enabling a direct identification and quantitation of organic taste compounds in a food extract without prior fractionation using a reference 1H NMR database. Both methods yielded similar quantitative results of taste-active compounds in dried scallop extracts and subsequent taste recombination experiments based on these data were able to recreate the taste of dried scallops.

Mitochondrial activity as an indicator of scallop (Mizuhopecten yessoensis) adductor muscle in early cold storage.

The purpose of this study was to reveal the role of mitochondria in indicating a change in the freshness of the adductor muscle of Mizuhopecten yessoensis during cold storage and hardening. The adductor muscle hardens after 96h of cold storage and reaches the maximum degree of hardening in 6h. In this study, after hardening (102 h), the muscle fiber structure obviously broke and curled, and the sarcomere structure disappeared at 150 h. After hardening (102 h), the morphology of the mitochondria changed, including swelling, cristea breaking and membrane structure disappearance. The arginine phosphate content decreased gradually from the initial 4.618 to 1.306µmol/g at 48 h, and there was no further obvious change. The ATP content decreased from 6.02 to 1.07µmol/g in 120 h. The mitochondrial membrane potential (Δφ) was measured by a fluorescence method (JC-1). The changes in freshness could be divided into three classes according to the Δφ difference between the mitochondria in the adductor muscle after adding ADP and CCCP. Mitochondrial function was complete from 0 to 6 h; mitochondrial function began to decline at 6 to 48 h; and mitochondrial function completely disappeared after 48 h. The results showed that the mitochondrial membrane potential compared with other indicators could more sensitively reflect the changes in freshness during the cold storage hardening process of the adductor muscle. PRACTICAL APPLICATION: It is very important to interprete the post-mortem energy metabolism for controlling the muscle quality of Yesso scallop. The K value which was developed based on ATP-related compounds is widely used in evaluating the freshness of seafood. Mitochondria is the main sites of cellular energy metabolism and the changes of its structure and activity can sensitively reflect the quality changes in muscle cell. It is expected to develop a more sensitive freshness evaluation index.

Effect of high pressure processing on the physicochemical and sensorial properties of scallop (Mizuhopecten yessoensis) during iced storage

SummaryScallops are the third largest aquaculture mollusks product, while they are highly perishable during storage. The main purpose of the present study was to evaluate the effect of high pressure processing (HPP) on physicochemical and sensorial properties of scallop (Mizuhopecten yessoensis) during refrigeration storage. The scallop adductor muscle was treated with different pressures (200, 300, 400 and 500 MPa, 5 min) and iced storage for 28 days. Results showed that HPP delayed microbial growth as pressure increased. HPP (≥400 MPa) resulted in myosin and actin denaturation, increased hardness, whiteness, pH and promoted water migration. However, preliminary sensory analysis showed no significant difference between pressure‐treated and control adductor muscles in appearance, odour, texture and overall acceptability after cooking. In addition, pressure‐treated adductor muscles (≥300 MPa) remained edible after 28 days of storage. Overall, these results can provide basic knowledge for the storage of pressure‐treated scallop meat.

Combined effects of ultrasound and antioxidants on the quality maintenance of bay scallop (Argopecten irradians) adductor muscles during cold storage

The combined effects of ultrasound and the antioxidants of bamboo leaves (AOB) on the quality maintenance of the adductor muscle of scallops (AMSs) during cold storage was investigated. Ultrasound power at 350 W coupled with AOB solution (2% w/v) (UAOB-350) was applied to treat the AMSs according to Taylor diagram analysis. The microstructure, oxidative changes (lipid and protein oxidation), total numbers of colonies, total volatile basic nitrogen, and texture of the AMSs during 6 days of cold storage were analysed. The results indicated that UAOB-350 treatment could effectively retard protein and lipid oxidation and bacterial growth and maintain better microstructure and texture characteristics than AOB solution treatment alone, prolonging the shelf life of the AMSs by 2 days during storage at 4 °C. These results indicate that the UAOB-350 combination method has promising potential to maintain the quality and extend the shelf life of AMSs during cold storage.

Gastrointestinal digestion and absorption characterization in vitro of zinc-chelating hydrolysate from scallop adductor (Patinopecten yessoensis).

Zinc (Zn) is an essential catalytic element in the human health system but its absorption in the intestinal system can be strongly affected by gastrointestinal (GI) digestion. In this study, the food-derived potential Zn carrier, scallop adductor hydrolysates (SAHs), was produced and characterized. During temporary storage at 4 °C, SAH decreased in Zn-chelating capacity in the aqueous phase, whereas the SAH-Zn complex exhibited high stability. Moreover, the secondary structure of SAH had no significant alteration. Zn morphologically altered the surface structures of SAH, which was involving in carboxyl group of SAH. Results of in vitro GI digestion suggested that the SAH-Zn maintained good stability in GI system and only proportion of high molecular weight cleaved. In addition, SAH could successfully carry and transport Zn while the fluorescence staining revealed free Zn accumulation inside the tissue. Finally, three representative absorbed peptides (around 600 Da) were identified and synthesized. Three synthetic peptides exhibit higher Zn-chelating capacity than SAH and could also successfully transported through the intestine. This study provided a theoretical basis for the investigation of digestion and absorption of marine animal-derived peptides as Zn carriers. © 2021 Society of Chemical Industry.

Seasonal variations in free amino acid, 5′-nucleotide, and lipid profiles of scallop (Patinopecten yessoensis) revealed by targeted and untargeted metabolomic approaches

Scallop is popular for its delicious taste and rich nutrition value. This study investigated the metabolomic changes in free amino acid (FAA), 5′-nucleotide, and lipid composition of scallops collected in different seasons. Results showed that the content of the FAA and 5′-nucleotide in summer was significantly higher than in other seasons. Adenosine 5′-monophosphate, glycine, and alanine were dominant from June to August. A total of 176 lipids, including 50 triacylglycerols (TAG), 60 phosphatidylcholines (PC), and 30 phosphatidylethanolamines (PE), were identified in the scallop adductor muscle. PC and PE were dominant from February to June, and TAG was dominant in November. The unsaturation degree of TAG was increased from July to November, and the highest proportion of polyunsaturated phospholipids appeared in August and September. Overall, scallops have high nutritional value in summer. This study is helpful for the development of scallop products with high nutrition and high value.

Differentiation between fresh and frozen-thawed scallop adductor muscle as raw materials for sashimi during cold storage.

The changes of sensory and biochemical characteristics on the fresh and frozen-thawed scallop adductor muscle during storage at 4°C were discussed in this study. The Quality Index Method (QIM) scheme for evaluating scallop adductor muscle as raw materials for sashimi was proposed for the first time. The results of sensory evaluation showed that frozen-thawed scallop adductor muscle within zero to one day of refrigeration can be happily accepted by consumers, indicating the superiority of freezing for long-distance transportation, although the triangle test confirmed that there are still sensorial differences between fresh and frozen-thawed scallop adductor muscle. The microscopic observation of myofibrils extracted from scallop adductor muscle suggested that the myofibrillar protein which constitutes myofibrils has suffered some extent change due to freezing and thawing, even though the head region of myosin remained stable judging by the fact that there was no significant difference in Ca2+ -ATPase activity (p > 0.05). The changes of adenosine triphosphate (ATP) and its related compounds, and pH value during storage can be regarded as indicators to differentiate fresh and frozen-thawed scallop adductor muscle. The changes of Mg2+ -ATPase activity indicated that the interaction between myosin and actin was weakened by the freezing and thawing process. Practical Application: The QIM scheme can be used to evaluate the scallop adductor muscle as raw materials for sashimi. The mechanism of quality changes in the frozen-thawed scallop adductor muscle was discussed in combination with the destruction of myofibrils, ATP degradation and the decrease of pH value. This study has positive significance for improving the quality of frozen-thawed scallop adductor muscle by combining the changes of sensory and biochemical characteristics.

Cell type diversity in scallop adductor muscles revealed by single-cell RNA-Seq

Studies on cell atlas in marine invertebrates provide a better understanding of cell types, stem cell maintenance, and lineages of cell differentiation. To investigate the molecular features of various cell types in molluscan muscles, we performed single-cell RNA sequencing (scRNA-seq) to map cell types in scallop adductor muscles. We uncovered the cell type-specific features of 20 cell clusters defined by the expression of multiple specific molecular markers. These cell clusters are mainly classified into four broad classes, including mesenchymal stem cells, muscle cells, neurons, and haemolymph cells. In particular, we identified a diverse repertoire of neurons in the striated adductor muscle, but not in the smooth muscle. We further reconstructed the cell differentiation events using all the cell clusters by single-cell pseudotemporal trajectories. By integrating dual BrdU-PCNA immunodetection, neuron-specific staining and electron microscopy observation, we showed the spatial distribution of mesenchymal stem cells and neurons in striated adductor muscle of scallops. The present findings will not only be useful to address the cell type-specific gene expression profiles in scallop muscles, but also provide valuable resources for cross-species comparison of marine organisms.

Tissue distribution and seasonal accumulation of carotenoids in Yesso scallop (Mizuhopecten yessoensis) with orange adductor muscle

Carotenoids are colored compounds with important physiological functions. The Haida golden scallop, which has an orange adductor muscle, is a carotenoid-enriched variety of scallop Mizuhopecten yessoensis, an important aquaculture shellfish. In this study, we investigated the tissue distribution of the carotenoids, pectenolone and pectenoxanthin, in both Haida golden scallop and normal Yesso scallop. Both carotenoids were detected in all the sampled tissues of the two scallops, except in the adductor muscle of normal scallop. There were significantly more carotenoids in Haida golden scallop than in normal scallop, in the tissues of the mantle, female gonad, kidney, and adductor muscle. Increased carotenoid concentrations were detected in Haida golden scallop adductor muscle during the spring spawning season, indicating the effects of reproduction on muscle carotenoids accumulation. This study was the first systematic investigation of carotenoid distribution in Yesso scallop tissues and will benefit future research on carotenoid accumulation and function in scallops.

Synergistic gelation in the hybrid gel of scallop (Patinopecten yessoensis) male gonad hydrolysates and xanthan gum

This study evaluated the gel and microstructure properties of scallop (Patinopecten yessoensis) male gonads hydrolysates (SMGHs) combined with xanthan gum (XG). SMGHs/XG hydrogel matrix properties and structures were elucidated via different analysis tools such as rheometry, LF-NMR, FTIR, AFM, and Cryo-SEM. The addition of XG significantly improved the rheological properties of SMGHs, as indicated by 3.1-fold G' and 1.3-fold melting temperature with increasing the XG dose to 5.6mg/ml. The corresponding decrease in the T23 relaxation time from 450.3 to 365.6ms also signified the strong binding between SMGHs and XG. SMGHs/XG also had a higher proton density (T1 and T2 weighted images) due to the higher bound and free water content of the hybrid gel systems, respectively. Additionally, the blueshift in the amide I and II bands in SMGHs/XG further indicated stronger electrostatic interactions between SMGHs and XG. Such scenarios resulted in a well-distributed and compact network with a rougher surface of SMGHs/XG in comparison to pure SMGHs and XG, as assessed by AFM and SEM. These results suggest that SMGHs/XG gel could be a potential hybrid gel applied in the food industry. PRACTICAL APPLICATION: Scallop (Patinopecten yessoensis) male gonads are edible, but are usually discarded during processing of scallop adductor. Because of its rich nutrition and gelation properties, scallop male gonads have a potential role in developing marine source-protein as a functional food base. The SMGHs/XG binary gel would be potentially applied in delivery system in food and biological fields. Further study is undergoing to apply SMGHs/XG binary gel to embed bioactive compounds, such as curcumin and β-carotene.

Determination of Tributyltin and Triphenyltin in Fish and Shellfish Using Accelerated Solvent Extraction and Liquid Chromatography with Tandem Mass Spectrometry

A determination method for tributyltin (TBT) and triphenyltin (TPT) in fish and shellfish using an accelerated solvent extractor (ASE) and LC-MS/MS was developed. The chromatographic separation was conducted on a Poroshell 120 EC-C18 column using an isocratic mobile phase of 0.1% formic acid in 70% methanol. Sample preparation was performed using ASE at 125℃ with n-hexane and a cleanup using a Florisil cartridge. Internal calibration curves using deuterium-labeled TBT and TPT were employed for quantification. For both TBT and TPT, the calibration curves were linear in the range of 0.2-250 ng/mL, and the method quantification limits were 0.8 ng/g for both TBT and TPT. A National Institute for Environmental Studies certified reference material, No. 15 (adductor muscle of scallop), was analyzed to assess the performance of the developed method. The trueness, relative standard deviations of repeatability, and within laboratory reproducibility of this method, evaluated using a recovery test with four spiked fish species and one shellfish, ranged from 89.3 to 105.3%, 1.0 to 4.5%, and 1.3 to 7.6%, respectively.

Combining effect of soybean protein isolate and transglutaminase on the gel properties of Zhikong scallop (Chlamys Farreri) adductor muscle

The effects of soy protein isolate (SPI) in combination with transglutaminase (TGase) on the gel properties of Zhikong scallop (Chlamys farreri) adductor muscle were investigated. When 4 g/100 g SPI combined with 0.4 g/100 g TGase were added, the gel strength and water holding capacity (WHC) of heat induced Zhikong scallop adductor muscle gel was significantly improved. The textural profiles, such as hardness, cohesiveness, springiness and chewiness, reached their peaks as well. Although the whiteness continued to decrease with the increase of SPI content, TGase did not influence the whiteness of Zhikong scallop adductor muscle gel regardless of SPI levels. According to the results of LF-NMR, the free water was transformed into bound and immobilized water in gels containing SPI and/or TGase. SDS-PAGE showed that TGase would promote the cross-linking of SPI and Zhikong scallop adductor muscle protein, and offset the negative effects of excessive SPI. Further optical microscopy and SEM observed that the formation of the most compact network structure, which was caused by more inter- and intra-molecular cross-linking of proteins. The results suggested that the addition of 4 g/100 g SPI combined with 0.4 g/100 g TGase could effectively improve the gel properties of Zhikong scallop adductor muscle.

The presence of Apicomplexan parasites in king scallops (Pecten maximus) in Scottish waters

The king scallop (Pecten maximus) is a commercially important species found around the United Kingdom coast. The association of an Apicomplexan-like parasite with mass mortality of Icelandic scallop (Chlamys islandica) in Iceland and the presence of identical parasites in king scallop (Pecten maximus) and queen scallop (Aequipecten opercularis) in Scotland raised serious concerns regarding the health of Scottish king scallops. Marine Scotland Science (MSS) conducted a survey in 2016 to assess the prevalence and the intensity of parasite infection in king scallops. King scallops were collected and sampled during the annual scallop dredge surveys in the Shetland Isles and the east and west coast of Scotland. The king scallop adductor muscle was macroscopically examined and tissue imprints taken to grade the intensity of infection. The parasite was present in the majority of the king scallops sampled in all surveyed areas: Shetland Isles 87.1%, east coast 76.0% and west coast of Scotland 64.1%. However, the parasitic infestations were light in intensity with the majority of the king scallops graded as 1 (≤20 zoites per microscopic field). No macroscopic changes in the adductor muscle were observed and histopathology examination revealed minor localized fiber degeneration of adjacent fibers to parasite clusters. The results suggested the parasite to be widespread around the Scottish coast and it appears to be able to live within the king scallop at low intensity of infection without causing significant downgrade of the adductor muscle (in terms of colour or texture) or mortality. The partial genome sequence of the parasite in king scallops from Scottish waters was identical to the one reported by Kristmundsson and Freeman (2018) in the Icelandic scallop in Icelandic waters.