Search Results (40)

This study multidimensionally investigates the comprehensive effects of Lactobacillus plantarum (LP)-fermented feed on growth performance, intestinal health, and metabolic regulation in Pacific abalone (Haliotis discus hannai). The results demonstrate that LP fermentation significantly alters feed’s physical properties and nutritional profile, softening texture, increasing viscosity, and emitting an acidic aroma. Notably, it enhanced contents of cis-9-palmitoleic acid, α-linolenic acid (ALA), and functional amino acids (GABA, L-histidine, and L-asparagine), indicating that fermentation optimized ω-3 fatty acid accumulation and amino acid profiles through the modulation of fatty acid metabolic pathways, thereby improving feed biofunctionality and stress-resistant potential. Further analyses revealed that fermented feed markedly improved intestinal morphology in abalone, promoting villus integrity and upregulating tight junction proteins (ZO-1, Claudin) to reinforce intestinal barrier function. Concurrently, it downregulated inflammatory cytokines (TNF-α, NF-κB, IL-16) while upregulating anti-inflammatory factors (TLR4) and antioxidant-related genes (NRF2/KEAP1 pathway), synergistically mitigating intestinal inflammation and enhancing antioxidant capacity. Sequencing and untargeted metabolomics unveiled that fermented feed substantially remodeled gut microbiota structure, increasing Firmicutes abundance while reducing Bacteroidetes, with the notable enrichment of beneficial genera such as Mycoplasma. Metabolite profiling highlighted the significant activation of lipid metabolism, tryptophan pathway, and coenzyme A biosynthesis. A Spearman correlation analysis identified microbiota–metabolite interactions (such as Halomonas’ association with isethionic acid) potentially driving growth performance via metabolic microenvironment regulation. In conclusion, LP-fermented feed enhances abalone growth, immune response, and aquaculture efficiency through multi-dimensional synergistic mechanisms (nutritional optimization, intestinal homeostasis regulation, microbiota–metabolome crosstalk), providing critical theoretical foundations for aquafeed development and probiotic applications in aquaculture. Full article

Background/Objectives: Abalone viscera is a discarded seafood by-product that contains a wealth of protein and is a good source of collagen peptides which have proven to have great potential in ameliorating host inflammation. The present study was conducted to evaluate the anti-inflammatory capacity of collagen peptide extracted from abalone viscera. Methods: Low, medium, and high dosages (300, 600, and 900 mg/kg/d) of abalone viscera collagen peptide (AVCP) were orally administered to DSS-induced acute colitis mice. The inflammatory mediators and oxidative stress factors were assessed using the ELISA method, and gut microbiota was widely studied by 16S rRNA sequencing technology. Results: The results showed that oral administration of AVCP led to a significant alleviation of weight loss, colon length shortening, and DAI escalation in colitis mice. AVCP could also alleviate the pathological damage of colon tissue; inhibit splenic edema and thymic atrophy; reduce the serum level of inflammatory mediators (IL-1β, IL-6, TNF-α, IL-17A, and myeloperoxidase (MPO)); and improved antioxidant capacity (the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) increased and malondialdehyde (MDA) level decreased). Moreover, AVCP restored the balance of the gut microbiota, such as Escherichia-Shigella, Bacteroides, norank_f_Muribaculaceae, Rikenellaceae_RC9_gut_group, and Parasutterella. Conclusions: Collectively, our observations elucidated the potential use of AVCP as a prebiotic for ulcerative colitis alleviation. Full article

This study analyzed the basic nutritional components and amino acid, fatty acid, and mineral composition of hybrid abalone Haliotis discus hannai ♀ × H. fulgens ♂ adductor (AM), transition (TM), and skirt (SM) muscles. The taste characteristics of the muscles were measured via electronic tongue, and the volatile compounds were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis. Compared to SM, AM and TM exhibited relatively similar basic nutritional compositions. Although SM exhibited the highest moisture content (84.67%), its protein content (only 11.83%) and total carbohydrate content (only 0.19%) were significantly lower than those of AM (20.42% and 4.14%) and TM (19.10% and 4.48%). The ash and fat contents were similar across the three muscle parts. The amino acid composition was consistent across three parts, and AM showed the highest total amino acid content, ratio of essential amino acids, and essential amino acid index. All three muscle parts were rich in polyunsaturated fatty acids, but the content was higher in AM and TM than in SM. The mineral elements were rich in variety, with high K, P, Mg, and Zn contents. Bitterness intensities were lower and umami and richness intensities were higher in AM and TM than in SM. The contents of volatile compounds related to fishy odor were higher in TM and SM than in AM. The results provided a scientific basis for the intensive processing and comprehensive utilization of Haliotis discus hannai ♀ × H. fulgens ♂. Full article

Reproduction and breeding are crucial to maintaining abalone aquaculture. Understanding the molecular underpinnings of sexual maturation is essential for advancing knowledge in reproductive biology. However, the molecular mechanisms of gonadal development in abalones remain poorly understood, particularly in microRNA (miRNA)-mediated regulation. Thus, this study conducted a comprehensive transcriptomic analysis of abalone Haliotis discus hannai (H. discus hannai) to identify genes and miRNAs associated with ovarian and testicular discovery. This study identified 685 differentially expressed (DE) genes between the H. discus hannai ovary (DD_ovary) and testis (DD_testis) groups, comprising 479 upregulated and 206 downregulated genes in the DD_ovary. Moreover, 137 miRNAs, including 83 novel and 54 known miRNAs, were detected, with 30 upregulated and 27 downregulated in the DD_ovary compared to the DD_testis. Bioinformatics analysis revealed that these miRNAs regulate key processes such as carbohydrate metabolic processes, kinase and hydrolase activity, and starch and sucrose metabolism, all potentially associated with reproductive traits. Further, key mRNA candidates, including Vitelline envelope sperm lysin receptor (Verl) and Testis-specific serine/threonine-protein kinase (Tssk) 1, and miRNAs such as novel_90 and novel_120, were identified as components of a functional miRNA-mRNA network associated with sexual maturity and sex determination. These key genes were verified using qRT-PCR and fluorescence in situ hybridization (FISH). These transcriptomic and miRNA datasets provide valuable resources for understanding abalone reproductive biology and may support molecular breeding strategies. Full article

Bioactive components of abalone and other marine organisms have attracted significant attention owing to their functional performance. The development of peptides with bioactivity like angiotensin-converting enzyme inhibitory (ACEi) and antioxidant properties is of great significance for chronic disease management and drug discovery. In this study, according to the issues of low utilization rate and bioactive content from the hydrolysate of abalone, single-factor and orthogonal experiments were designed to improve the utilization rate of abalone protein, and step hydrolysis with specific proteases was used to improve the overall biological activity of the hydrolysate. A total of 1937 peptide sequences were obtained from the highly bioactive components after separation and peptidomic analysis. Through virtual screening and molecular docking, 14 peptides exhibiting ACEi activity were identified and synthesized for experimental verification, with IC₅₀ values ranging from 0.05 to 0.54 mg/mL. Notably, nine of these peptides were powerful antioxidants. The developed step enzymatic hydrolysis and in silico screening-assisted preparation also provided a feasible and efficient method for exploring more bioactive peptides from diverse biomasses. Full article

This study conducted a systematic comparison of four drying methods (vacuum freeze-drying, spray drying, spray freeze-drying, and hot air drying) on abalone bioactive peptides, investigating their effects on physicochemical properties and nutritional composition. Scanning electron microscopy revealed distinct morphological characteristics: hot-air-dried samples showed compact structures with large particles, and vacuum-freeze-dried samples exhibited flaky morphology, while spray-freeze-dried and spray-dried samples demonstrated advantageous smaller particle sizes. Spray freeze-drying achieved superior emulsification capacity and fat absorption, significantly higher than hot air drying. The enhanced performance was attributed to increased exposure of hydrophobic amino acid residues and improved surface activity. Regarding nutritional composition, vacuum freeze-drying demonstrated optimal protein and total amino acid preservation, while spray freeze-drying showed the highest retention of Ca and Fe. Interestingly, hot air drying exhibited superior vitamin A retention, attributed to its fat-soluble nature and stability below 100 °C. The particle size reduction in spray-freeze-dried samples enhanced solvent–solute contact area, contributing to improved solubility and consequently superior foaming properties. These findings provide valuable insights into the relationship between drying methods and product characteristics, offering guidance for optimizing processing conditions in marine protein production. Full article

Background/Objectives: Vasa and PL10 belong to the DEAD-box protein family, which plays crucial roles in various cellular functions, such as DNA replication, DNA repair, and RNA processing. Additionally, DEAD-box family genes have also been identified as being related to gonadal development in many species. However, the function of vasa and PL10 in abalone is poorly understood on a molecular level. Methods: In the present study, we individually isolated and characterized the vasa and PL10 orthologs in Haliotis discus hannai (Hdh-vasa and Hdh-PL10). We also characterized the mRNA distributions of vasa and PL10 in various tissues from adult organisms and different embryonic developmental stages using real-time PCR (RT-qPCR) techniques. Furthermore, spatial and temporal expression of Hdh-vasa and Hdh-PL10 throughout embryonic and larval development was examined by whole-mount in situ hybridization (WMISH). Results: The two predicted amino acid sequences contained all of the conserved motifs characterized by the DEAD-box family. Homology and phylogenetic analyses indicate that they belong to the vasa and PL10 subfamilies. We found that vasa and PL10 mRNA were not solely restricted to gonads but were widely expressed in various tissues. WMISH showed that Hdh-vasa and Hdh-PL10 largely overlapped, with both being maternally expressed and specifically localized to the micromere lineage cells during early cleavage stages. By the gastrulation stage, Hdh-vasa were expressed strongly in two bilaterally symmetrical paraxial clusters, but Hdh-PL10 was dispersed in entire endodermal region. Our results suggest that Hdh-vasa-expressing cells are located as a subpopulation of undifferentiated multipotent cells that express Hdh-PL10. As such, we infer that primordial germ cells are specified from these vasa-expressing cells at some point during development, and inductive signals (epigenesis) play an important role in specifying primordial germ cells (PGCs) in H. discus hannai. Conclusions: This study provides valuable insights into the molecular characteristics and expression patterns of Hdh-vasa and Hdh-PL10, contributing to a better understanding of their roles in germ cell specification and early embryonic development in H. discus hannai. Full article

Few studies are concerned with the effect of the conjugat protein on the bioactivities of the abalone gonad polysaccharide (AGP). In this study, a series of treatments, including raw material (female and male) defatting, extraction temperature (25–121 °C), proteolysis, ultrafiltration, and ethanol precipitation, was conducted to investigate the role of the conjugate protein on AGP anticoagulant activity. All AGP extracts significantly prolonged activated partial thromboplastin time (APTT) and thrombin time (TT). The strongest was observed in the female AGPs prepared at 50 and 121 °C. The most active is located at 30–300 kDa by ultrafiltration. After being exposed to neutral protease, quick shortening of APTT and TT was found in all AGPs. Further ethanol precipitating of found the longest APTT in the sediment, which contains most polysaccharides and proteins. Defatting lowered the activity of female AGP but increased that of males. Proteolysis also significantly weakened the clotting factor inhibition effect of the 50 °C female AGP, but heating seemed not affect the effect. Five fractions were obtained after the 50 °C female AGP was subjected to ion exchange column. Fraction V, with the highest protein and medium polysaccharide content, showed the strongest anticoagulant effect and was also much higher than AGSP, which was obtained by multi-step proteolysis. The findings supported positive effect of the conjugate protein in AGP anticoagulant activity. Full article

The Nrf2/ARE pathway is considered the most important endogenous antioxidant signaling pathway in mammals, playing a crucial role in defending against external damage. This study investigated the functional characteristics of Nrf2 in the abalone, Haliotis discus hannai. The full-length cDNA sequence of the HdhNrf2 gene was cloned using rapid amplification of cDNA ends (RACE) technology and consists of 4568 base pairs encoding a protein of 694 amino acids. The predicted theoretical molecular weight was 77 kDa, with an isoelectric point of 4.72. Multiple sequence alignment analysis revealed the relative conservation of the HdhNrf2 amino acid sequence in H. discus hannai. The tissue expression pattern of the HdhNrf2 gene was analyzed using real-time fluorescence quantitative PCR, which showed the highest expression in the gills, followed by hemocytes, with the lowest levels in the foot and mantle. The inducible expression of HdhNrf2 and antioxidant genes in abalone under H₂O₂ stress was investigated at various time points. Furthermore, an expression vector, pET-28a(+)-rHdhNrf2, was constructed, and the recombinant protein rHdhNrf2 was obtained through induced expression and purification. These findings indicated that HdhNrf2 plays a crucial role in the defense of abalones against oxidative stress. Full article

Perlucin is a shell matrix protein that plays a significant role in regulating shell biomineralization. This study aimed to isolate and characterize the perlucin gene and analyze its expression to explore its role in shell formation, regeneration, and responses to thermal stress and starvation in Pacific abalone. The isolated full-length cDNA sequence of Hdh-Perlucin is 1002 bp long, encoding a 163-amino-acid polypeptide with a signal peptide. The mature peptide of Hdh-Perlucin contains a C-type lectin domain with signature motif and six conserved cysteine residues. Gene Ontology analysis suggests that Hdh-Perlucin exhibits carbohydrate-binding activity. Significantly higher expression of Hdh-Perlucin was observed during the juvenile, veliger, and trochophore stages, compared with cell division stage during early development. Upregulated expression was recorded from slow to rapid growth phases and during shell biomineralization, while downregulated expression was noted during starvation. Under thermal stress, expression peaked at 30 °C and 25 °C for 6 and 12 h, respectively, while consistently higher levels were observed at 15 °C throughout the experiment. This study provides the first comprehensive structural and expression analysis of Hdh-Perlucin, highlighting its roles in metamorphosis, shell formation and regeneration, and responses to heat stress and starvation in abalone. Full article

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. Full article

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. Full article

Marine molluscs are of enormous scientific interest due to their astonishing diversity in terms of their size, shape, habitat, behaviour, and ecological roles. The phylum Mollusca is the second most common animal phylum, with 100,000 to 200,000 species, and marine molluscs are among the most notable class of marine organisms. This work aimed to show the importance of marine molluscs as a potential source of nutraceuticals as well as natural medicinal drugs. In this review, the main classes of marine molluscs, their chemical ecology, and the different techniques used for the extraction of bioactive compounds have been presented. We pointed out their nutraceutical importance such as their proteins, peptides, polysaccharides, lipids, polyphenolic compounds pigments, marine enzymes, minerals, and vitamins. Their pharmacological activities include antimicrobial, anticancer, antioxidant, anti-inflammatory, and analgesic activities. Moreover, certain molluscs like abalones and mussels contain unique compounds with potential medicinal applications, ranging from wound healing to anti-cancer effects. Understanding the nutritional and therapeutic value of marine molluscs highlights their significance in both pharmaceutical and dietary realms, paving the way for further research and utilization in human health. Full article

Seafood, especially from the ocean, is now seen as a greener and more sustainable source of protein, causing an increase in its demand. This has also led to people making choices towards seafood as a replacement for carbon-intensive protein sources. As a result, the demand for seafood is growing, and as the aquaculture industry looks to increase production, keeping products safe and sustainable is imperative. There are many challenges faced by the aquaculture industry in meeting these increased demands. One such challenge is the presence of harmful algal blooms (HABs) in the ocean, which can have a major impact on aquatic life. In this paper, we look at the impact of this challenge on aquaculture and monitoring strategies whilst illustrating the potential for technological interventions to help mitigate the impact of an HAB. We will focus on Abagold Limited, a land-based marine aquaculture business that specialises in the large-scale production of abalone (Haliotis midae) based in Hermanus, South Africa. HABs are considered a threat to commercial-scale abalone farming along the South African coastline and require continuous monitoring. The most recent HAB was in February–April 2019, when the area experienced a severe red-tide event with blooms of predominantly Lingulodinium polyedrum. We present some of the monitoring strategies employing digital technologies to future-proof the industry. This article presents the development of a novel hybrid water quality forecasting model based on a TriLux multi-parameter sensor to monitor key water quality parameters. The actual experimental real water quality data from Abagold Limited show a good correlation as a basis for a forecasting model which would be a useful tool for the management of HABs in the aquaculture industry. Full article

The development of a shell is a complex calcium metabolic process involving shell matrix proteins (SMPs). In this study, we describe the isolation, characterization, and expression of SMP5 and investigate its potential regulatory role in the shell biomineralization of Pacific abalone Haliotis discus hannai. The full-length Hdh-SMP5 cDNA contains 685 bp and encodes a polypeptide of 134 amino acids. Structurally, the Hdh-SMP5 protein belongs to the EF-hand-binding superfamily, which possesses three EF-hand Ca²⁺-binding regions and is rich in aspartic acid. The distinct clustering patterns in the phylogenetic tree indicate that the amino acid composition and structure of this protein may vary among different SMPs. During early development, significantly higher expression was observed in the trochophore and veliger stages. Hdh-SMP5 was also upregulated during shell biomineralization in Pacific abalone. Long periods of starvation cause Hdh-SMP5 expression to decrease. Furthermore, Hdh-SMP5 expression was observed to be significantly higher under thermal stress at temperatures of 15, 30, and 25 °C for durations of 6 h, 12 h, and 48 h, respectively. Our study is the first to characterize Hdh-SMP5 comprehensively and analyze its expression to elucidate its dynamic roles in ontogenetic development, shell biomineralization, and the response to starvation and thermal stress. Full article