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The genome of Candidatus Xenohaliotis californiensis was assembled from shotgun metagenomic sequencing of experimentally infected white abalone. Ninety-one percent genome completeness was achieved with low contamination. Sequencing this genome provides the opportunity to track pathogen evolution over time, conduct gene expression experiments, and study dynamics between this pathogen and its phage.

This study addresses the problem that the traditional method is not effective in improving the adsorption performance of vacuum suckers. From the perspective of bionics, the adsorption performance of bionic suckers based on the excellent adsorption of the abalone abdominal foot was studied. A bionic sucker was designed by extracting the sealing ring structure of the abdominal foot tentacle. The bionic sucker was subjected to tensile experiments using an orthogonal experimental design, and the adsorption of the bionic sucker was simulated and analyzed to explore its adsorption mechanism. The results show that the primary and secondary factors affecting the adsorption of the sucker are the number of sealing rings, the width of sealing rings and the spacing of sealing rings. At 60% vacuum, the bionic sucker with two sealing rings, a 1.5 mm sealing ring width and 3 mm sealing ring spacing has the largest adsorption force, and its maximum adsorption force is 15.8% higher than that of the standard sucker. This study shows that the bionic sucker design can effectively improve the adsorption performance of the sucker. The bionic sucker had a different stress distribution on the sucker bottom, which resulted in greater Mises stress in the sealing ring and the surrounding area, while the Mises stress in the central area of the sucker was smaller. [ABSTRACT FROM AUTHOR]

Abalone is a rich source of nutrition, the viscera of which are discarded as by-product during processing. This study explored the biological activities of peptides derived from abalone viscera (AV). Trypsin-hydrolysate of AV (TAV) was purified into three fractions using a Sephadex G-10 column. Nine bioactive peptides (VAR, NYER, LGPY, VTPGLQY, QFPVGR, LGEW, QLQFPVGR, LDW, and NLGEW) derived from TAV-F2 were sequenced. LGPY, VTPGLQY, LGEW, LDW, and NLGEW exhibited antioxidant properties, with IC50 values of 0.213, 0.297, 0.289, 0.363, and 0.303 mg/mL, respectively. In vitro analysis determined that the peptides VAR, NYER, VTPGLQY, QFPVGR, LGEW, QLQFPVGR, and NLGEW inhibited ACE, with IC50 values of 0.104, 0.107, 0.023, 0.023, 0.165, 0.004, and 0.146 mg/mL, respectively. The binding interactions of ACE-bioactive peptide complexes were investigated using docking analysis with the ZDCOK server. VTPGLQT interacted with HIS513 and TYR523, and QLQFPVGR interacted with HIS353, ALA354, GLU384, HIS513, and TYR523, contributing to the inhibition of ACE activity. They also interacted with amino acids that contribute to stability by binding to zinc ions. QFPVGR may form complexes with ACE surface sites, suggesting indirect inhibition. These results indicate that AV is a potential source of bioactive peptides with dual antioxidant and anti-hypertensive dual effects. [ABSTRACT FROM AUTHOR]

Abalone, a marine edible gastropod with nutritional value, is a popular seafood delicacy worldwide, especially in Asia; however, viscera by-products are generally discarded during processing. Therefore, we investigated the skin health benefits of abalone viscera ultrasonic extract (AVU) in human dermal fibroblasts (HDFs) and human keratinocyte (HaCaT) cells. AVU showed valuable protein contents, indicating that it is a worthy and safe material for industrial application. AVU increased collagen synthesis production and messenger RNA (mRNA) expression of Collagen Type I Alpha 1, 2, and 3 chains through the transforming growth factor beta/suppressor of mother against the decapentaplegic pathway in HDF cells. AVU also increased hyaluronic acid production, upregulated Hyaluronan Synthases 1, 2, and 3, filaggrin and aquaporin3 mRNA levels, and downregulated hyaluronidase mRNA levels in HaCaT cells. Furthermore, mechanistic studies showed that AVU increased the phosphorylation of extracellular signal-regulated kinase, p38, and cyclic AMP response-binding protein activation. AVU activated the transcription factors, phosphoinositide 3-kinase, protein kinase B, and nuclear factor kappa B cell p65 and downregulated the degranulation of inhibitory kappa B in HaCaT cells. Studies of hyaluronic acid production in AVU by inhibiting EKR, p38 and NF-κB have shown that p38 MAPK and NF-κB signaling are pivotal mechanisms, particularly in the AVU. These results demonstrated that AVU produced from by-products may improve skin health and may thus be used as a functional food and cosmetics ingredient. [ABSTRACT FROM AUTHOR]

Prostaglandin E2 (PGE2) has been reported to be involved in reproduction as one of the most abundant and widely distributed prostaglandins in invertebrates. Regulating gonad development and gamete production in mollusks can greatly assist artificial breeding, which is believed to promote the commercial benefits of various mollusk species. In the present study, the contents of PGE2 in the gonads of abalone at different developmental stages (maturing stage, ripe stage, and spawning stage) and reproduction states (before and after spawning) were measured. A higher PGE2 level was found in the gonads of abalones at the ripe stage than other stages, and the highest PGE2 level was detected in the ovaries of female H. diversicolor in the UV-stimulated group. Then the effects of PGE2 injection on the spawning efficiency were explored, and the gamete emission rates of female and male abalone were significantly increased after PGE2 injection. Through qRT-PCR and in situ hybridization assay, higher expression levels and wide distribution of phospholipase A2 (PLA2), cyclooxygenase 2 (COX2), prostaglandin E synthases (PGES2), and prostaglandin E2 receptor 4 (EP4) in the gonads of H. diversicolor were observed after spawning. It is speculated that PGE2 may promote the reproductive cycle in both male and female H. diversicolor, although the regulation mechanism of PGE2 in female and male abalone might be different. The results will be useful for the application of PGE2 in the abalone aquaculture practices to increase the reproduction efficiency in future. [ABSTRACT FROM AUTHOR]

Prostaglandin E2 (PGE2) has been reported to be involved in reproduction as one of the most abundant and widely distributed prostaglandins in invertebrates. Regulating gonad development and gamete production in mollusks can greatly assist artificial breeding, which is believed to promote the commercial benefits of various mollusk species. In the present study, the contents of PGE2 in the gonads of abalone at different developmental stages (maturing stage, ripe stage, and spawning stage) and reproduction states (before and after spawning) were measured. A higher PGE2 level was found in the gonads of abalones at the ripe stage than other stages, and the highest PGE2 level was detected in the ovaries of female H. diversicolor in the UV-stimulated group. Then the effects of PGE2 injection on the spawning efficiency were explored, and the gamete emission rates of female and male abalone were significantly increased after PGE2 injection. Through qRT-PCR and in situ hybridization assay, higher expression levels and wide distribution of phospholipase A2 (PLA2), cyclooxygenase 2 (COX2), prostaglandin E synthases (PGES2), and prostaglandin E2 receptor 4 (EP4) in the gonads of H. diversicolor were observed after spawning. It is speculated that PGE2 may promote the reproductive cycle in both male and female H. diversicolor, although the regulation mechanism of PGE2 in female and male abalone might be different. The results will be useful for the application of PGE2 in the abalone aquaculture practices to increase the reproduction efficiency in future.

Abalone farming produces nutrient-rich sludge, and the frequent cleaning and removal of sludge from abalone tanks is labour and capital-intensive. This study aimed to assess the effect of culture methods and tank cleaning frequency on abalone growth, water quality, and sludge characteristics. The study was conducted for 16 weeks. Four treatments were used, namely, abalone cocultured with sea cucumber cleaned once (AS1) and twice weekly (AS2); abalone monoculture cleaned once (A1) and cleaned twice weekly (A2). Abalone (initial avg weight = 40.9 g) were maintained under commercial stocking conditions in flow through systems at a salinity of 35 ppt and fed a commercial formulated diet (Abfeed™) and fresh seaweed (Ulva lacinulata and Gracillaria gracilis). The stocking densities were 200 abalone m−2 and 50 sea cucumbers m−2. The sea cucumbers (initial average weight = 12.5 g) fed on the abalone faeces and leftover feed, which settled at the abalone tank's bottom (sludge). There was a significant interaction between the type of culture and the frequency of cleaning on abalone weight (F (1,476) = 12.41, p < 0.001). Abalone in the A2 treatment group showed higher growth (p = 0.006) than those of the A1 treatment group, while abalone in AS1 had significantly higher growth (p < 0.001) than those in the AS2 treatment group. Also, abalone in AS1 showed higher growth (p = 0.026) than abalone in the A1 treatment. However, abalone in AS1 had growth similar (p = 0.53) to those in A2. The survival rate of the sea cucumbers was high, however, the sea cucumbers experienced a reduction in weight regardless of the treatment. This study showed that growth optimisation in abalone farming can be achieved by cleaning tanks twice instead of once weekly. However, when abalone are cocultured with sea cucumber, tanks need only be cleaned once a week without compromising abalone growth or water quality. The coculture of abalone and sea cucumber results in an additional aquacultured product, a significant reduction in labour and other associated costs of cleaning, without an additional cost of production. [ABSTRACT FROM AUTHOR]

Objective: To improve the quality of abalone polysaccharide, the purification process by macroporous resins was optimized, and the immunomodulatory activities of polysaccharides before and after purification were evaluated. Methods: The purification effects of six kinds of macroporous resins on abalone polysaccharide were investigated with the comprehensive score of polysaccharide recovery rate, deproteinization rate and decolorization rate as the index. Single-factor experiment and response surface analysis were employed to optimize the purification process parameters. The immunomodulatory activities of abalone polysaccharide before and after purification were studied by cell experiment in vitro. Results: HPD100 had the best purification effect on abalone polysaccharide with the highest comprehensive score. The optimal purification process parameters were as follows: Polysaccharide to resin mass ratio 1:42, adsorption time 3.10 h, adsorption temperature 35 ℃. Under these conditions, the polysaccharide recovery rate, deproteinization rate and decolorization rate were 97.58%±1.58%, 30.20%±0.66% and 45.78%±1.01%, respectively, and the resulting average comprehensive score was 61.83%. Furthermore, the in vitro cell experiment results showed that the immunomodulatory activity of abalone polysaccharide was markedly enhanced after purification by HPD100, with stronger viability of RAW264.7 macrophages and higher secretion of cytokines including NO, TNF-α and IL-6. Conclusions: An optimal purification process of abalone polysaccharide by macroporous resins was obtained, and the purified polysaccharide exhibited significantly improved biological activity. This research would provide a theoretical basis for preparation of highly bioactive abalone polysaccharide.

Abalone is a popular mollusk in the marine aquaculture industry of China. However, existing challenges, like slow growth, individual miniaturization, and the absence of abundant abalone, have emerged as significant obstacles impeding its long-term progress in aquaculture. Studies have demonstrated that insulin-related peptide (IRP) is a crucial factor in the growth of marine organisms. However, limited studies have been conducted on IRP in abalone. This study indicated that the hdh-MIRP1 open reading frame (ORF) was composed of 456 base pairs, which encoded 151 amino acids. Based on the gene expression and immunofluorescence analyses, the cerebral ganglion of Haliotis discus hannai (H. discus hannai) was the primary site of hdh-MIRP1 mRNA expression. Moreover, hdh-MIRP1 expression was observed to be higher in the larger group than in the smaller group abalones. Only single nucleotide polymorphism (SNP) was related to their growth characteristics. However, approximately 82 proteins that may interact with hdh-MIRP1 were identified. The functional enrichment analysis of the 82 genes indicated that hdh-MIRP1 may be involved in the regulation of glucose metabolism and the process of growth. This study established a benchwork for further investigating the role of IRP in the growth of abalone. [ABSTRACT FROM AUTHOR]

Objective: To improve the quality of abalone polysaccharide, the purification process by macroporous resins was optimized, and the immunomodulatory activities of polysaccharides before and after purification were evaluated. Methods: The purification effects of six kinds of macroporous resins on abalone polysaccharide were investigated with the comprehensive score of polysaccharide recovery rate, deproteinization rate and decolorization rate as the index. Single- factor experiment and response surface analysis were employed to optimize the purification process parameters. The immunomodulatory activities of abalone polysaccharide before and after purification were studied by cell experiment in vitro. Results: HPD100 had the best purification effect on abalone polysaccharide with the highest comprehensive score. The optimal purification process parameters were as follows: Polysaccharide to resin mass ratio 1:42, adsorption time 3.10 h, adsorption temperature 35 °C. Under these conditions, the polysaccharide recovery rate, deproteinization rate and decolorization rate were 97.58%±1.58%, 30.20%±0.66% and 45.78%±1.01%, respectively, and the resulting average comprehensive score was 61.83%. Furthermore, the in vitro cell experiment results showed that the immunomodulatory activity of abalone polysaccharide was markedly enhanced after purification by HPD100, with stronger viability of RAW264.7 macrophages and higher secretion of cytokines including NO, TNF-α and IL-6. Conclusions: An optimal purification process of abalone polysaccharide by macroporous resins was obtained, and the purified polysaccharide exhibited significantly improved biological activity. This research would provide a theoretical basis for preparation of highly bioactive abalone polysaccharide. [ABSTRACT FROM AUTHOR]

Haliotis arabiensis Owen, Regter & Van Laethem, 2016 was found near Muscat city of Oman in the Sea of Oman in September 2021. A total of 85 abalone specimens were collected under small boulders from a depth of 2–5 m during the scuba diving survey from seven stations located from Sidab to Bandar Khairan. The shell length (SL) of the abalone ranged between 10.0 and 30.0 mm, on average 19.9 ± 0.22 mm SL. The sex was determined in 15 females and 21 males. The study presents photos and a comparative table with morphological descriptions of four abalone species (H. arabiensis, H. mariae, H. rugosa multiperforata and H. unilateralis) which are important for differentiating the small abalone species from juveniles of H. mariae during monitoring surveys of this important commercial species in Oman.

To investigate the effects of different drying methods on the rehydration and quality characteristic of low salt pickled abalone, this study used vacuum freeze drying, cold air drying and hot air drying to dry them. The mass volume and rehydration rate of the rehydration process were studied. Low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were used to study the water distribution during the rehydration process and investigated the changes in the samples of color, texture, tissue morphology and free amino acids after rehydration. The results showed that the rehydration rate of vacuum freeze-dried abalone was 278.73% at 72 hours, which was significantly higher than that of cold-air dried abalone and hot-air dried abalone (P

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Generally, one of the most significant bottlenecks of land-based abalone aquaculture is the high cost of the feed, which is associated with the use of wild fish stocks to produce fish meal. Fish meal is a key ingredient used in aquaculture feeds due to its nutritional profile and palatability. Alternative ingredients, such as insect meal and grape marc, are potential candidates to be included in aquafeeds due to their suitable nutritional profile and more sustainable production. This study aimed to evaluate the effect of insect meal and grape marc on growth and nutritional profile using abalone as an animal model in a feeding trial for 165 days. Proximate analyses were used to identify nutritional variations in abalone tissue and faecal matter, and liquid chromatography-mass spectrometry and gas chromatography mass-spectrometry analyses were utilised to characterise amino acid and fatty acid composition. Results showed a 95% survival for all treatments. The inclusion of insect meal and grape marc did not affect the protein proportions of abalone tissues, but differences were found in the carbohydrate and lipid proportions. The inclusion of insect meal and grape marc significantly affected levels of amino acids L-histidine, L-methionine, and L-phenylalanine, and fatty acids oleic acid, linoleaidic acid, palmitic acid, palmitoleic acid, and α-linolenic suggesting a correlation between the feed source and fatty acid tissue composition. This work provides promising results for future optimisation of abalone diets including more affordable and sustainable alternative ingredients. [ABSTRACT FROM AUTHOR]

To date, research on abalone adhesion has primarily analyzed the organism's adhesion to smooth surfaces, with few studies on adhesion to non-smooth surfaces. The present study examined the surface morphology of the abalone's abdominal foot, followed by measuring the adhesive force of the abalone on a smooth force measuring plate and five force measuring plates with different surface morphologies. Next, the adhesion mechanism of the abdominal foot was analyzed. The findings indicated that the abdominal foot of the abalone features numerous stripe-shaped folds on its surface. The adhesion of the abalone to a fine frosted glass plate, a coarse frosted glass plate, and a quadrangular conical glass plate was not significantly different from that on a smooth glass plate. However, the organism's adhesion to a small lattice pit glass plate and block pattern glass plate was significantly different. The abalone could effectively adhere to the surface of the block pattern glass plate using the elasticity of its abdominal foot during adhesion but experienced difficulty in completely adhering to the surface of the quadrangular conical glass plate. The abdominal foot used its elasticity to form an independent sucker system with each small lattice pit, significantly improving adhesion to the small lattice pit glass plate. The elasticity of the abalone's abdominal foot created difficulty in handling slight morphological size changes in roughness, resulting in no significant differences in its adhesion to the smooth glass plate. [ABSTRACT FROM AUTHOR]

Ocean warming and extreme heatwaves threaten marine species supporting commercial fisheries and aquaculture. Predicting the responses of these industries to chronic and acute warming depends on understanding which life stages are most vulnerable, the potential for stocks to adapt to changing thermal environments, and the availability of thermally adapted genotypes to help enhance stock resilience through strategic interventions. Here, we shed light on some of these knowledge gaps by quantifying the critical thermal maximum (CTmax) of ~ 10–210 g hybrid abalone (Haliotis rubra × H. laevigata) from two farms representing contrasting thermal environments from south-eastern Australia. CTmax was not dependent on body size or provenance (farm) when heating rates were rapid (1 °C per h), but a significant relationship between CTmax and body size was observed when heating rates were slower and more ecologically realistic (1 °C per 12 h). Histological analyses revealed a negative relationship between CTmax and the stage of gonadal development when abalone were exposed to chronic thermal stress conditions. These results suggest that marine heatwaves and ongoing ocean warming might favour smaller, less fecund animals in natural and farm settings. This could potentially impact future harvestable biomass, recruitment and population dynamics in wild-capture fisheries, and production of larger, high-value animals in farm settings. This study adds to a growing body of literature pointing to complex and often negative effects of climate change on commercial fisheries, and the potential need for interventions aimed at bolstering fisheries resilience against the effects of ocean warming. [ABSTRACT FROM AUTHOR]

An analytical method using GC–MS/MS combined with quick, easy, cheap, effective, rugged, and safe extraction was developed to determine 57 pesticides in fishery products. The limits of detection and quantification (LOD and LOQ, respectively) of the analytical method ranged between 0.91 and 2.12 ng/g wet mass and 3 and 7 ng/g wet mass, respectively. Moreover, the linearity of the calibration curves was acceptable (R2 > 0.99). The relative pesticide recoveries ranged between 53.87 and 127.2%, and reproducibility ranged between 0.25 and 10.87%. The pesticide residues in brown seaweed, eel, flatfish, shrimp, and abalone samples were analyzed using the developed analytical method, and the results indicate that most samples were not contaminated by the 57 target pesticides, except low levels (< 10 ng/g) of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene, alachlor, ametryn, isoprothiolane, and prometryn in several samples. [ABSTRACT FROM AUTHOR]

The effects of different dietary EPA/DHA ratios (2.19, 1.59, 0.98, 0.55 and 0.38, respectively) on the growth performance, intestinal microbiota, immunity and resistance to heat stress in abalone Haliotis discus hannai Ino was evaluated after a 93-day feeding trial. Five isonitrogenous and isolipic (about 33% crude protein and 3% crude lipid) practical diets were formulated to fed abalones (initial body weight: 25.82 ± 0.51 g; initial mean shell length: 59.57 ± 0.40 mm). Results showed that 0.98–2.19 dietary EPA/DHA ratio significantly increased abalone’s weight gain rate (WGR) and daily increment in shell length (DISL). As for the intestine enzyme activity, trypsin activity was significantly higher when 0.55 EPA/DHA ratio was applied to the diet. The lipase activity in the groups with 0.98 and 0.55 dietary EPA/DHA ratio was significantly higher than those in other groups. And 1.59 dietary EPA/DHA ratio significantly increased α-amylase activity. In regard to the intestinal microbiota, the 0.98 dietary EPA/DHA ratio significantly increased the diversity indices and number of OTUs in the intestine, followed by the 2.19 dietary EPA/DHA ratio. At the phyla level, Firmicutes, Proteobacteria, Bacterioidota and Actinobacteria were dominant in all groups. The Mycoplasma was the most prevalent genus among all the groups. The highest abundance of Clostridium_sensu_stricto_11, Mycobacterium and Bacteroides belonged to the group with the 0.38 dietary EPA/DHA ratio. The abundance of Bacilli, Terasakiellacease and Ahrensia in 0.38 group were higher than that in the group with 0.98 and 2.19 dietary EPA/DHA ratio. Moreover, 1.59 dietary EPA/DHA ratio significantly reduced the falling rate of abalone after heat stress. And the hsp70 and hsp90 mRNA expression levels in the digestive gland were up-regulated significantly in the group with the 2.19 dietary EPA/DHA ratio. The 0.98 dietary EPA/DHA ratio could increase the content of malondialdehyde in cell-free hemolymph and the expressions of tnfa and nrf2 in digestive gland. In conclusion, the optimal dietary EPA/DHA ratio for abalone was estimated to be 1.63 using a second-order quadratic regression based on WGR. The 1.59–2.19 dietary EPA/DHA ratio could increase the immunity and resistance of abalone against heat stress.

The potential role of peroxisome proliferator-activated receptor (PPAR) in regulating the biosynthesis of long-chain polyunsaturated fatty acids (LCPUFA) has not been explored in marine gastropod. In this study, we identified and characterized a PPAR gene from the abalone species Haliotis discus hannai Ino. This gene encodes a peptide consisting of 469 amino acids and comprises typical four domains: A/B domain, DNA-binding domain, D domain, and ligand-binding domain. Highest homology with that of the Patella depressa (51.08 %) from multiple alignments and phylogenetic tree analyses revealed it is a direct orthologue of the vertebrate PPAR. Tissue distribution analysis demonstrated that PPAR was highly expressed in muscle and gill, with lower expression observed in the kidney, female gonad, and hepatopancreas. Dual-luciferase reporter assays indicated that abalone PPAR significantly up-regulated the promoter activity of Δ5 fatty acyl desaturase (Δ5fad), a crucial enzyme in LCPUFA biosynthesis. Furthermore, C18PUFA significantly increased the expressions of Δ5fad and PPAR in the hepatopancreas of abalone compared to the control group fed with an LCPUFA-rich diet. These findings suggest that PPAR acts as a positive transcription factor for the fad gene, contributing to the transcriptional regulation of LCPUFA biosynthesis in abalone.

Our understanding of the specificities of innate immune protection against viral pathogens in non-model invertebrate species is limited, and comparative immunological approaches may offer opportunities to protect aquaculturally significant species such as abalone, against viral threats. Haliotid herpesvirus (HaHV-1) is a re-emerging viral pathogen of abalone, and has a high mortality rate in the dominant wild and farmed species in Australia, the Australian greenlip abalone (Haliotis laevigata), the blacklip (Haliotis rubra) and a hybrid of the two. To gain a better understanding of the anti-viral immune system counterparts of Australian abalone, gene mining strategies and domain analysis of the recently released H. laevigata draft genome was performed, with comparisons made to the better studied mollusc, the oyster (Crassostrea gigas). Significant divergence in members of the TLR, cytosolic RNA/DNA and RNA interference signalling pathways was observed between the two molluscs, with the oyster more closely reflecting that of the mammalian immune response. Interestingly, a homolog for the anti-viral RNA sensing adaptor protein Mitochondrial anti-viral-signalling protein was absent in H. laevigata, as well as the 4 other abalone protein databases currently available, despite the presence of a RIG-I homolog. Additionally, STING, a member of the dsDNA sensing pathway was absent in H. laevigata, as well as 2 other abalone species, however is present in the oyster genome, and two additional abalone species (Haliotis rufescens, Haliotis discus hannai).This work provides a better understanding of the key features of the abalone anti-viral innate immune signalling system and may provide much needed information towards the development of anti-viral strategies in these animals.

During oven drying of abalone muscle, microwave treatment was conducted at regular time intervals (0, 30, 60, 90 and 120 days). Abalone muscle digestion products (AMDP) were prepared by subjecting dried abalone to in vitro simulated digestion. Our aim was to investigate the effect of microwave treatment during the drying of abalone muscle on the in vitro and in vivo antioxidant activities of AMDP. The results showed that the half maximal inhibitory concentration (IC50) values of AMDP from fresh abalone muscle for scavenging capacity against hydroxyl (·OH) radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) and 1,1-diphenyl-2-phenylhydrazine (DPPH) radical were 3.04, 15.18 and 21.12 mg/mL, respectively. The IC50 values for the scavenging of these three radical species decreased gradually with increasing the drying time of abalone muscle. After being fed AMDP from abalone muscle dried for 120 days, the body length of Caenorhabditis elegans increased from 768.90 to 1 034.62 μm, the head swing frequency increased from 206 to 281 times/min, and the life span was extended by 36.16% under normal conditions and by 59.41% and 38.48% under heat stress and oxidative stress conditions, respectively compared with the control group. Meanwhile, with prolonging the drying time of abalone muscle, the antioxidant enzyme activities, reduced glutathione (GSH) content and total antioxidant capacity of C. elegans fed AMDP increased, and the reactive oxygen species (ROS) content decreased. In summary, prolonging the drying time and using microwave treatment during the drying process could improve the antioxidant capacity of AMDP.

Abalone is a rich source of nutrition, the viscera of which are discarded as by-product during processing. This study explored the biological activities of peptides derived from abalone viscera (AV). Trypsin-hydrolysate of AV (TAV) was purified into three fractions using a Sephadex G-10 column. Nine bioactive peptides (VAR, NYER, LGPY, VTPGLQY, QFPVGR, LGEW, QLQFPVGR, LDW, and NLGEW) derived from TAV-F2 were sequenced. LGPY, VTPGLQY, LGEW, LDW, and NLGEW exhibited antioxidant properties, with IC50 values of 0.213, 0.297, 0.289, 0.363, and 0.303 mg/mL, respectively. In vitro analysis determined that the peptides VAR, NYER, VTPGLQY, QFPVGR, LGEW, QLQFPVGR, and NLGEW inhibited ACE, with IC50 values of 0.104, 0.107, 0.023, 0.023, 0.165, 0.004, and 0.146 mg/mL, respectively. The binding interactions of ACE-bioactive peptide complexes were investigated using docking analysis with the ZDCOK server. VTPGLQT interacted with HIS513 and TYR523, and QLQFPVGR interacted with HIS353, ALA354, GLU384, HIS513, and TYR523, contributing to the inhibition of ACE activity. They also interacted with amino acids that contribute to stability by binding to zinc ions. QFPVGR may form complexes with ACE surface sites, suggesting indirect inhibition. These results indicate that AV is a potential source of bioactive peptides with dual antioxidant and anti-hypertensive dual effects.

This study addresses the problem that the traditional method is not effective in improving the adsorption performance of vacuum suckers. From the perspective of bionics, the adsorption performance of bionic suckers based on the excellent adsorption of the abalone abdominal foot was studied. A bionic sucker was designed by extracting the sealing ring structure of the abdominal foot tentacle. The bionic sucker was subjected to tensile experiments using an orthogonal experimental design, and the adsorption of the bionic sucker was simulated and analyzed to explore its adsorption mechanism. The results show that the primary and secondary factors affecting the adsorption of the sucker are the number of sealing rings, the width of sealing rings and the spacing of sealing rings. At 60% vacuum, the bionic sucker with two sealing rings, a 1.5 mm sealing ring width and 3 mm sealing ring spacing has the largest adsorption force, and its maximum adsorption force is 15.8% higher than that of the standard sucker. This study shows that the bionic sucker design can effectively improve the adsorption performance of the sucker. The bionic sucker had a different stress distribution on the sucker bottom, which resulted in greater Mises stress in the sealing ring and the surrounding area, while the Mises stress in the central area of the sucker was smaller.

Abalone, a marine edible gastropod with nutritional value, is a popular seafood delicacy worldwide, especially in Asia; however, viscera by-products are generally discarded during processing. Therefore, we investigated the skin health benefits of abalone viscera ultrasonic extract (AVU) in human dermal fibroblasts (HDFs) and human keratinocyte (HaCaT) cells. AVU showed valuable protein contents, indicating that it is a worthy and safe material for industrial application. AVU increased collagen synthesis production and messenger RNA (mRNA) expression of Collagen Type I Alpha 1, 2, and 3 chains through the transforming growth factor beta/suppressor of mother against the decapentaplegic pathway in HDF cells. AVU also increased hyaluronic acid production, upregulated Hyaluronan Synthases 1, 2, and 3, filaggrin and aquaporin3 mRNA levels, and downregulated hyaluronidase mRNA levels in HaCaT cells. Furthermore, mechanistic studies showed that AVU increased the phosphorylation of extracellular signal-regulated kinase, p38, and cyclic AMP response-binding protein activation. AVU activated the transcription factors, phosphoinositide 3-kinase, protein kinase B, and nuclear factor kappa B cell p65 and downregulated the degranulation of inhibitory kappa B in HaCaT cells. Studies of hyaluronic acid production in AVU by inhibiting EKR, p38 and NF-κB have shown that p38 MAPK and NF-κB signaling are pivotal mechanisms, particularly in the AVU. These results demonstrated that AVU produced from by-products may improve skin health and may thus be used as a functional food and cosmetics ingredient.

Understanding the mechanisms by which individual organisms respond and populations adapt to global climate change is a critical challenge. The role of plasticity and acclimation, within and across generations, may be essential given the pace of change. We investigated plasticity across generations and life stages in response to ocean acidification (OA), which poses a growing threat to both wild populations and the sustainable aquaculture of shellfish. Most studies of OA on shellfish focus on acute effects, and less is known regarding the longer term carryover effects that may manifest within or across generations. We assessed these longer term effects in red abalone (Haliotis rufescens) using a multi‐generational split‐brood experiment. We spawned adults raised in ambient conditions to create offspring that we then exposed to high pCO2 (1180 μatm; simulating OA) or low pCO2 (450 μatm; control or ambient conditions) during the first 3 months of life. We then allowed these animals to reach maturity in ambient common garden conditions for 4 years before returning the adults into high or low pCO2 treatments for 11 months and measuring growth and reproductive potential. Early‐life exposure to OA in the F1 generation decreased adult growth rate even after 5 years especially when abalone were re‐exposed to OA as adults. Adult but not early‐life exposure to OA negatively impacted fecundity. We then exposed the F2 offspring to high or low pCO2 treatments for the first 3 months of life in a fully factorial, split‐brood design. We found negative transgenerational effects of parental OA exposure on survival and growth of F2 offspring, in addition to significant direct effects of OA on F2 survival. These results show that the negative impacts of OA can last within and across generations, but that buffering against OA conditions at critical life‐history windows can mitigate these effects. [ABSTRACT FROM AUTHOR]

Donkey's ear abalone (Haliotis asinina Linnaeus, 1758) is rich in essential nutrients and harbors bioactive compounds with antibacterial properties, potentially aiding in cholesterol reduction. This study focused on assessing antibacterial activity against Staphylococcus aureus (ATCC25923) and Escherichia coli (ATCC25922), determining the amino acid composition, screening for bioactive phytochemical compounds, and evaluating the effect of abalone meat extract on blood cholesterol in male house mice (Mus musculus Linnaeus, 1758) using an in vivo method. Results indicated significant antibacterial activity of H. asinina methanol extract (20% concentration) against S. aureus, while ethyl acetate extract (10% and 20% concentrations) showed inhibition zones against both S. aureus and E. coli. The n-hexane extract demonstrated antibacterial activity at a 10% concentration on both organisms, and at a 20% concentration against S. aureus. Phytochemical screening revealed the presence of saponins and alkaloids in the methanol extract. Amino acid analysis identified arginine (7,827.15 mg·kg-1) as the highest essential amino acid and glutamic acid (14,803.9 mg·kg-1) as the highest non-essential amino acid. Moreover, the methanol extract significantly reduced cholesterol levels in male house mice across various doses (100, 200, and 300 mg·kg-1). [ABSTRACT FROM AUTHOR]

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Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Growing demand for high-value seafood is fuelling provenance fraud, which threatens the sustainability of wild fisheries while posing biosecurity and human health risks. Here, we investigated carbon (δ 13C) and oxygen (δ 18O) isotopes in abalone shells (Haliotis sp.) to determine the production method and geographical provenance. Using X-ray diffraction and isotope ratio mass spectrometry, we found that shell mineralogy did not influence isotope values. Isotope values between wild and farmed sectors were statistically different, with 64% of individuals correctly classified as farmed or wild. Subsequently, we successfully distinguished the provenance of abalone collected from farms (with 83% of individuals correctly classified), as well as wild-caught abalone collected from four state jurisdictions (with 88% correctly classified). Carbon isotopes were strongly correlated to longitude, with both isotopes correlated to latitude. Overall, this study demonstrates the potential of isotopic fingerprints in gastropod shells to track the provenance of commercially valuable species.

Homoyessotoxin (homo-YTX) and nitrite (NO2-N), released during harmful dinoflagellate cell lysis adversely affect abalones. However, their toxicity mechanisms in shellfish remain unclear. This study investigated the economic abalone species Haliotis discus hannai exposed to varying concentrations of homo-YTX (0, 2, 5, and 10 µg L−1) and NO2-N (0, 3, and 6 mg L−1) on the basis of their 12 h LC50 values (5.05 µg L−1 and 4.25 mg L−1, respectively) and the environmentally relevant dissolved concentrations during severe dinoflagellate blooms, including mixtures. The test abalones were exposed to homo-YTX and NO2-N for 12 h. The mortality rate (D), reactive oxygen species (ROS) levels, antioxidant defense capabilities, and expression levels of antioxidant-related, Hsp-related, and apoptosis-related genes in abalone gills were assessed. Results showed that the combined exposure to homo-YTX and NO2-N increased the D and ROS levels and upregulated B-cell lymphoma-2 (BCL2)-associated X (BAX) and caspase3 (CASP3) expression levels while reducing glutathione peroxidase (GPx) activity and GPx, CuZnSOD, and BCL2 expression levels. High concentrations of homo-YTX (10 µg L−1) and NO2-N (6 mg L−1) solutions and the combinations of these toxicants inhibited the activities of superoxide dismutase (SOD) and catalase (CAT) and downregulated the expression levels of MnSOD, CAT, Hsp70, and Hsp90. The ROS levels were negatively correlated with the activities of SOD, CAT, and GPx and the expression levels of MnSOD, CuZnSOD, CAT, GPx, Hsp70, Hsp90, and BCL2. These results suggest that homo-YTX, in conjunction with NO2-N, induces oxidative stress, disrupts antioxidant defense systems, and triggers caspase-dependent apoptosis in the gills of abalone. ROS-mediated antioxidative and heat-shock responses and apoptosis emerge as potential toxicity mechanisms affecting the survival of H. discus hannai due to homo-YTX and NO2-N exposure.

In this work, whiteness, water-holding capacity, gel strength, textural profile analysis were performed to examine the quality of fish balls with abalone (FBA). In addition, a correlation between quality and sensory properties was established. The addition of abalone significantly increased the water holding capacity, gel strength and textural properties of FBA, and decreased their whiteness, the best overall quality was achieved at 9 % w/w abalone addition. The E-nose and E-tongue results revealed that the addition of abalone changed the flavour of FBA. HS-SPME-GC–MS identified 65 volatile organic compounds (VOCs) and proved to be effective in reducing fishy flavour. E-nose can distinguish between the VOCs in FBA. Moreover, Umami and 1-octen-3-ol can serve as important indicators to observe changes in the quality of FBA, as they were positively connected with WHC, gumminess, chewiness, resilience, a*, hexanal, etc. The results provided a theoretical basis for the development of abalone and surimi products.

Abalone, which belongs to marine shellfish, is a kind of single-shelled mollusk. Abalone has high nutritional value, and they are considered a good source of protein, trace elements, minerals, lipids, and carbohydrates required by human beings. Bioactive substance from abalone has the pharmacological effects of anticancer, antioxidant, anti-inflammation, anti-coagulant, and regulating glucose and lipid metabolism. However, the research on the active substances contained in abalone is only at the theoretical stage, and their applications in medicinal and health food products are still not fully developed. As fresh abalone is not easy to store and transport, further processing, including drying and freezing, has become the main means to develop abalone-processed products and extend their shelf life. Different processing methods have different effects on the nutritional and active ingredients and muscle structure of abalone, which in turn affect the innovation and breakthrough of abalone processing technology. This article summarizes the nutritional value, functional activity, and mechanism of action of abalone, as well as the current processing status, with a view to providing a theoretical basis for in-depth research applications of abalone, and a comprehensive outlook on the innovative applications of abalone in the food industry.

The patterns of changes in the physicochemical properties and volatile flavors of abalone muscle during drying at 50 ℃ and 65% relative humidity were investigated in this study. With an increase in drying time, the browning intensity and fluorescence intensity of both surface and internal muscles of abalone increased gradually, which started to decrease after reaching a peak on the 90th day. The contents of reducing sugar and lysine in the surface muscle were 3.11 mg/g and 2.60% after pretreatment, and decreased to 1.95 mg/g and 1.61% after 120 days of drying, respectively. High molecular mass polymers were observed in the electrophoretic pattern of abalone muscle after 30 days of drying. Fourier transform infrared spectra showed that the intensity of the characteristic absorption peaks (1 403 and 1 026 cm-1) of glycoproteins gradually enhanced with increasing drying time. The response values of the electronic nose sensors W1W (sulfides) and W2S (alcohols, aldehydes and ketones) increased, and the content of 1-octen-3-ol decreased while the contents of linalool and (E,E)-2,4-decadienal increased after 30 days of drying, as determined by gas chromatography-mass spectrometry (GC-MS). At the same drying time, the intensity of Maillard reaction in the surface muscle was weaker than that in the internal muscle.

Abalone pearl farming is an aquaculture activity with great potential for future growth and diversification of the global pearl sector, which has been dominated for decades by pearls of marine pearl oysters of the genus Pinctada. Despite this potential, there is a significant lack of knowledge regarding methods for nucleus (bead) seeding and the process of pearl formation in abalone, compared to the well-studied pearl oyster model. To address this problem, this review first compares the main anatomical differences and similarities between both groups of mollusks, particularly those associated with the structure and role of mantle tissue on the synthesis of CaCO3 compounds that integrate the inner nacreous layer. The iridescence (orient) and color properties of nacre in a cultured pearl is particularly related to the microstructure of aragonite crystals during biomineralization in each mollusk group. We then analyze the advantages and disadvantages of the adoption in abalone of methods originally developed for pearl oysters to produce bead-seeded pearls and half-pearls (or mabé pearls). For the red abalone Haliotis rufescens in particular, updated information on commercial production of both bead-seeded and mabé pearls is provided as a case of success for Latin America (Chile). Finally, the current status and future prospects for abalone pearl farming are discussed, assessing technology gaps and challenges to be addressed for the pearl sector to achieve its full potential, particularly for Latin America.

Lipid profiles of the lipids from female gonads (LFG) and male gonads (LMG) of abalones (Haliotis discus hannai) were evaluated based on the analysis of phospholipid (PL) molecular species, PL class composition, fatty acid (FA) composition, and lipid class composition. These results suggested that lipids from abalone gonads were abundant in omega‐3 polyunsaturated FA (n − 3 PUFA, 14.42%–18.27% of total FAs) and PLs including phosphatidylcholine (PC, 21.26–47.85 mg g−1) and phosphatidylethanolamine (PE, 9.29–24.10 mg g−1). Furthermore, more than 60 molecular species of PC and PE were determined. Particularly, the molecular species containing n − 3 PUFA including eicosapentaenoic acid (EPA) constituted majority of PC and PE in LFG and LMG. By contrast, LFG contained more PC and PE species containing EPA. Considering the lipid profiles, abalone gonads are a potential source of PL‐form n − 3 PUFA. [ABSTRACT FROM AUTHOR]

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Molluscs are among the most valuable resources of the Philippines, an archipelagic country of 7,107 islands bounded by 36,000 km of coastline and 26.6 million ha of coastal waters. In 2020, production from mussels and oysters alone valued at PhP1.552 billion. As primary sources of food and livelihood for marginalized fisherfolk, they are considered important in food security, nutrition, and poverty alleviation. Nevertheless, for almost a century, mollusc culture remained small-scale, with most fish farmers investing in non-fed species, like mussels and oysters. Moreover, mollusc culture in the country is still dependent on wild sources of seed stocks, making production unsustainable and unreliable. This dependence on the wild seed stocks will continue until the issue of the lack of commercial-scale hatcheries or the limited capacity of existing hatcheries to produce seeds, both for top and emerging mollusc aquaculture species, is resolved. Although technologies from broodstock management to post-harvest are available in some species, the lack of capital and the limited government support limit these artisanal fishers from doing large commercial-scale culture. This paper summarizes what has been done and published on the leading mollusc species cultured in the Philippines. Future research activities may be designed based on the research gaps to refine available technologies and develop new ones to improve culture production. The lack of or limited relevant information on the viable economics of the different culture techniques at different culture phases, the limited availability of post-harvest technologies, and the sparse or lack of genetic information for these leading mollusc species are among the gaps that need to be addressed. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of polyphenol reduction in a feed formulated with Eisenia arborea and its effect on the feeding preference of the abalone Haliotis fulgens through multiple selection tests. Two feeds were formulated: one without polyphenol reduction (EA01) and one with polyphenol reduction (EA02). Rehydrated E. arborea (ER03) was used as the control feed. The polyphenol content was quantified in EA01 and EA02, and the stability and hardness of all three feeds were measured at 24 h after immersion. Feed preference was evaluated through attraction and consumption tests on day 1, 6, and 12. The polyphenol concentration was reduced by 41% in EA02 (13.9 mg GAE g−1) compared to that of EA01 (33.3 mg GAE g−1). Both formulated feeds showed 88% stability and hardness values > 680 g cm−2, which were greater than those of the control (ER03, 66% and 285 g cm−2, respectively). Abalone were more attracted to EA02 and ER03 on day 1, 6, and 12 than to EA01 on the same days. A similar trend was observed with consumption. EA02 and ER03 were the most consumed feeds (> 6 g day−1) throughout the experiment, and no significant differences in consumption were observed between these feeds. On the other hand, juvenile H. fulgens showed a greater attraction to and consumption of EA02 (reduced polyphenol content) than EA01 (no reduction in polyphenol content). This allows us to conclude that EA02 can replace rehydrated algae as a suitable feed source for juvenile H. fulgens. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The hemocytes of molluscs take various roles including immunity and wound healing. Oyster gill was found to undergo hematopoiesis and produce adult somatic progenitor cells. In gastropod molluscs, however, such special gill structure has not been reported. In the present study, we used Pacific abalone, a gastropod mollusc, and explored unique gill structures undergoing active proliferation. By immunofluorescence staining, two proliferation markers, proliferating cell nuclear antigen (PCNA) and phospho-histone H3 (H3P), were detected in marginal regions of the gill filaments, which were characterized by thick epithelium with cilia. In situ hybridization for Sox genes, the stem cell markers, also showed signals in the corresponding regions. BrdU, a DNA replication-detecting reagent, and nuclear-localized β-catenin, a putative epithelial–mesenchymal transition (EMT) marker, were also detected in the same regions. These results suggest that the marginal regions of gill filaments are highly proliferative, possess stemness, and likely undergoing EMT. Further immunofluorescence staining for hemocytes with PCNA, H3P, and β-catenin revealed that these cells also exhibited these markers, implying a possible link between the hemocytes and the gill cells. These results showed a structure containing actively proliferating cells in abalone gills, and points to the importance of classification of cell population in this tissue. [ABSTRACT FROM AUTHOR]

Abalone species are economically important shellfish in China's aquaculture industry. In 2020, China's abalone aquaculture production was 203,500 tonnes, accounting for nearly 90% of total global production. However, many problems have accompanied the rapid development of this industry, including a reduction in near‐shore space suitable for culture and the risk of exposure of farms to natural disasters such as typhoons and red tides. In addition, high temperatures and low oxygen levels resulting from global climate change are causing increased abalone mortality in summer. In this review, the culture patterns and characteristics used in different countries are compared with respect to larvae nurseries, intermediate juvenile culture and the grow‐out phase. Next, the transitions and challenges in China's abalone culture industry over the past 60 years are summarized. Finally, a coordinated land‐sea program for reducing solid waste emissions into the water and increasing carbon sinks is suggested based on the 'Carbon Neutrality' theory. Under the framework of the program, new facilities, technologies and models should be created to achieve increased mechanization and a greater understanding of the abalone aquaculture industry as soon as possible. This review provides references and data to support the scientific planning and mapping of China's abalone culture industry as well as the transition of China's perceived identity from a major fishery country to a strong fishery power with an awareness of environmental protection and resource use. [ABSTRACT FROM AUTHOR]

To date, research on abalone adhesion has primarily analyzed the organism’s adhesion to smooth surfaces, with few studies on adhesion to non-smooth surfaces. The present study examined the surface morphology of the abalone’s abdominal foot, followed by measuring the adhesive force of the abalone on a smooth force measuring plate and five force measuring plates with different surface morphologies. Next, the adhesion mechanism of the abdominal foot was analyzed. The findings indicated that the abdominal foot of the abalone features numerous stripe-shaped folds on its surface. The adhesion of the abalone to a fine frosted glass plate, a coarse frosted glass plate, and a quadrangular conical glass plate was not significantly different from that on a smooth glass plate. However, the organism’s adhesion to a small lattice pit glass plate and block pattern glass plate was significantly different. The abalone could effectively adhere to the surface of the block pattern glass plate using the elasticity of its abdominal foot during adhesion but experienced difficulty in completely adhering to the surface of the quadrangular conical glass plate. The abdominal foot used its elasticity to form an independent sucker system with each small lattice pit, significantly improving adhesion to the small lattice pit glass plate. The elasticity of the abalone’s abdominal foot created difficulty in handling slight morphological size changes in roughness, resulting in no significant differences in its adhesion to the smooth glass plate.

Abalone is a high-value resource that is an important export market fishery of Mexico that is managed through territorial use rights for fisheries allocated to a coastal community. A specific age-structured spatial bioeconomic model was applied to this fishery to undertake stock recovery to target levels. The model incorporates uncertainty in the parameter k of a von Bertalanffy growth function with environmental variability. The risk of falling below and exceeding the target and bioeconomic limit reference points of the population with alternative fisheries management strategies was studied using a Monte Carlo analysis. The management strategy evaluation showed that Emin (minimum effort) and EmaxNPV (resource rent maximization effort) generated higher biomass levels and higher present value of resource rent than Emsy (effort in maximum sustainable yield) at the end of the simulation period, regardless of the bioeconomic reference points and assuming a reduction in fishing effort. Emin and EmaxNPV increased and maximized the present value of resource rent generated by the species while avoiding its overexploitation. The social consequences of the management strategies were considered with the participation of fishers of this co-managed fishery.

This paper compares the effect of feeding the abalone Haliotis asinina with seaweed (SW), formulated (FD), and mixed (SW+FD) diets. The feeding experiment, in six replicates, was conducted in a tank facility and lasted for 10 months. At the end of the experiment, abalone fed mixed diets had significantly the highest mean shell length and body weight (45.90±0.19 mm, 22.82±0.31 g), followed by those fed seaweeds (43.47±0.17 mm, 18.25±0.26 g), and lastly, by those fed formulated diets (41.78±0.18 mm, 15.76±0.22 g). Mean growth rates were significantly higher in abalone fed mixed diets at 1.48±0.03 mm and 1.69±0.04 g mo−1 than those fed seaweeds (1.26±0.03 mm, 1.27±0.06 g mo−1) or formulated diet (1.06±0.09 mm, 1.00±0.11 g mo−1). Survival was consistent 1 month from the start of culture until harvest—highest in abalone fed mixed diets (78.81±2.48%), followed by those fed seaweeds (70.12±4.07%), and lastly formulated diet (64.53±4.61%). Moreover, feed conversion ratios (FCR) were significantly lower in abalone fed mixed diets (15.48±0.69) and formulated diet (18.07±3.50) compared with those fed seaweeds (41.31±2.36). The body weight to shell length ratios (BW:SL), which were the same in all treatments at the start of the experiment (0.19 g mm−1), increased to 0.51, 0.44, and 0.38 in abalone fed mixed diets, seaweeds, and formulated diet, respectively. Based on the results of this experiment, giving abalone a mix of formulated and natural diets is the best feeding regime. The importance of a balanced and more nutritional diet on the well-being of the abalone was observed in this study. [ABSTRACT FROM AUTHOR]

Abalones reveal unique taste after processing, mainly because of their abundant free amino acids (FAAs) and nucleotides. FAAs are nutrition components that can contribute to the unique taste. However, which factor(s) is responsible for the accumulation of FAAs still need further studies. To analyze the production of FAAs, we studied the variation of FAAs during 7 days of storage at 4°C. The content of taste-active amino acids, including Asp, Glu, Ser, and Gly increased by 1.7-fold, 2.0-fold, 3.0-fold, and 8.4-fold, respectively. The relative activity of cathepsin L and aminopeptidase (AP) increased significantly during the cold storage period. To identify AP in abalone and its function in mediating the production of FAAs, an aminopeptidase with wide substrate specificity was then extracted and purified from abalone muscle to homogeneity. Purified AP with a molecular mass of 100 kDa exhibited its maximum activity at 30°C, pH 7.5, and was further confirmed by LC-MS. Bestatin specifically inhibited the activity of AP, and metalloproteinase inhibitors EDTA, EGTA and 1, 10-phenanthroline also suppressed its activity to different degrees. Based on its highest activity to substrate Leu-MCA and its peptide sequences, the purified enzyme was identified as leucine aminopeptidase (LAP). Our present study indicated the essential role of AP for FAAs accumulation during cold storage of abalone. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this research work, an approach using You Only Look Once version three (YOLOv3)-TensorFlow for abalone detection and Deep Simple Online Real-time Tracking (DeepSORT) for abalone tracking in conveyor belt systems is proposed. The conveyor belt system works in coordination with the cameras used to detect abalones. Considering the computational effectiveness and improved detection algorithms, this proposal is promising compared to the previously proposed methods. Some of these methods have low effectiveness and accuracy, and they provide an incorrect counting rate because some of the abalones tend to entangle, resulting in counting two or more abalones as one. Conducting detection and tracking research is crucial to achieve modern solutions for small- and large-scale fishing industries that enable them to accomplish higher automation, non-invasiveness, and low cost. This study is based on the development and improvement of counting analysis tools for automation in the fishing industry. This enhances agility and generates more income without the cost created by inaccuracy. [ABSTRACT FROM AUTHOR]