Search Results (753)

The aim of this study was to design and validate an automated 5 L prototype Stirred-Tank Photobioreactor (ST-PBR) dedicated to the two-stage cultivation of the microalga Haematococcus pluvialis. The classic limitations of stirred-tank reactors (such as high shear stress and suboptimal light penetration) were overcome through precise phase-controlled illumination (60 and 300 μmol m⁻² s⁻¹) and the implementation of an advanced embedded control system integrated with Keysight VEE Pro 9.33 software. The design features an innovative mixing system utilizing a dual marine impeller driven by a brushless motor—operating at a mathematically defined tip speed of 0.48 m/s to preserve cellular integrity—alongside a precise gas dosing strategy (pH-stat) employing medical-grade components. Process verification demonstrated highly stable operation, maintaining a dry biomass concentration of 1.315 g/L with no recorded sedimentation, while achieving a highly competitive astaxanthin biosynthesis yield of 4.12% dry weight (DW). Furthermore, enzymatic extraction facilitated the recovery of a product with high biological activity, as confirmed by an increase in equine adipocyte viability up to 128.1 ± 3.1% in in vitro MTS assays, highlighting its potential for veterinary nutraceutical applications. The developed solution represents a scalable, cost-effective, and viable alternative to advanced tubular photobioreactors. Full article

The preweaning period is a critical phase for dairy calves, during which gastrointestinal disorders, particularly diarrhea, remain a major cause of morbidity and antimicrobial use. Astaxanthin, a xanthophyll carotenoid with antioxidant and anti-inflammatory properties, has shown potential to support intestinal health in several animal species, but information in preweaning dairy calves is limited. The objective of this study was to evaluate the effects of astaxanthin supplementation administered through milk replacer on growth performance, clinical health, metabolic profile, and fecal microbiota in preweaning Holstein calves. Twenty-four female Holstein calves (body weight, mean ± SD: 49.51 ± 12.14 kg) were randomly assigned to a control group (CTR; n = 12) or an astaxanthin-supplemented group (TRT; n = 12). Treated calves received 40 mg/d of astaxanthin from week 0 to 4 and 80 mg/d from week 4 to 8. Body weight, feed intake, rectal temperature, and fecal consistency score, fecal color score and clinical scores were recorded throughout the trial. Blood samples were collected in weeks 0 and 8 for metabolic profiling, and fecal samples were collected in weeks 0, 4, and 8 to assess fecal consistency and bacterial populations. Astaxanthin supplementation did not affect body weight, average daily gain, or overall feed intake. However, treated calves exhibited a lower frequency of abnormal fecal consistency scores, indicating reduced diarrhea incidence compared with control calves. Fecal microbiological analysis revealed lower coliform counts in astaxanthin-supplemented calves in weeks 4 and 8, whereas total bacterial counts were greater in week 8. Most blood metabolites were primarily influenced by age-related physiological changes; however, circulating calcium concentrations were greater in treated calves. These results suggest that astaxanthin may represent a promising nutritional strategy to support gastrointestinal health during early life, although larger studies are needed to confirm these findings. Full article

Astaxanthin (AST), despite its high bioactivity, exhibits poor stability and low bioavailability due to its strong lipophilicity and inherent degradation susceptibility. To overcome such a challenge, we developed a food-grade oleogel delivery system using a soy protein–arabinoxylan (SA) glycosylated complex modulated by different concentrations (0.5–3%) of sucrose ester (SE) or soy lecithin. We show that the emulsifier concentration has a non-linear effect on the oleogel microstructure: an optimal level of 1% had a significant impact on the interfacial compactness and network density, giving rise to improved thermal stability, rheological strength and AST encapsulation efficiency (81.27%). During in vitro digestion, the SA matrix in combination with emulsifiers allowed gastric protection and intestinal-targeted release of AST with a bioaccessibility of up to 88.84% (SAO-SE-AST). This controlled release profile directly translated into enhanced in vivo antioxidant efficacy in wild-type Bristol N2 Caenorhabditis elegans, as evidenced by reduced lipofuscin accumulation, elevated thermotolerance (survival rate: 64.44–73.33%), suppressed reactive oxygen species levels and activation of endogenous antioxidant enzymes (superoxide dismutase as well as glutathione peroxidase). Collectively, this research has uncovered that food-grade emulsifiers are not only stabilizers, but also key regulators of oleogel architecture and bioactive functionality. These results provide a structure–digestion–bioactivity correlation for protein–polysaccharide oleogels, representing a rational design strategy for high-performance delivery systems of lipid-soluble nutraceuticals. Full article

Background: To investigate the effects of probiotics and their postbiotics on mouse health, this study utilized healthy mice randomly assigned to a control group (CK, n = 6), a probiotic group (L, n = 6, oral gavage 200 μL Pediococcus lactis), and a postbiotic group (PL, n = 6, oral gavage 200 μL Pediococcus lactis postbiotic). Methods: Following 21 days of continuous intervention, changes in gut metabolic profiles, microbial community structure, tissue morphology, and tight junction protein expression were systematically analyzed using metabolomics, 16S rRNA sequencing, hematoxylin and eosin (HE) staining, and immunohistochemistry techniques. Results: The results revealed that screening for significantly altered endogenous metabolites identified core differences concentrated in metabolites related to intestinal barrier repair, anti-inflammation, and antioxidant activity (e.g., 3-indolepropionic acid, astaxanthin, hydroxybenzoic acid). 16S rRNA sequencing revealed that the overall community structure was relatively stable according to principal component analysis, although differences were detected in specific taxa. However, LEfSe analysis identified significantly enriched functional microbial groups at multiple taxonomic levels in the PL group: phylum: Actinomycetota; class: Coriobacteriia; order: Coriobacteriales, Erysipelotrichales; family: Erysipelotrichaceae, Eggerthellaceae; genus: norank_Erysipelotrichaceae, Intestinimonas. These results suggest that although the overall community structure remained relatively stable, specific taxa may have differed between groups. Hematoxylin and eosin staining revealed no pathological lesions in intestinal tissues from either group, with intact mucosal architecture. Immunohistochemistry demonstrated significantly elevated expression of intestinal tight junction proteins Claudin 1, MUC-2, Occludin, and ZO-1 in the PL group compared to the CK group (p < 0.001). Conclusions: In summary, this probiotic (Pediococcus lactis) and its postbiotic showed promising effects, which may be related to changes in specific microbiota taxa, intestinal metabolic profiles, and tight junction protein expression. Beyond maintaining gut microbiota and tissue homeostasis, it enhances intestinal barrier function, suppresses latent inflammation, and boosts antioxidant capacity. Postbiotics may exhibit superior efficacy compared to probiotics. This provides robust experimental evidence for its development and application in gut health products for healthy populations. However, these findings still require further validation in studies with longer intervention periods and in disease models. Full article

Psoriasis is a chronic immune-mediated inflammatory skin disorder characterized by excessive keratinocyte proliferation, oxidative stress, and dysregulated cytokine signaling. Although topical corticosteroids remain the first-line therapy, their long-term use is often limited by adverse effects, highlighting the need for safer non-steroidal therapeutic alternatives. This study investigated the therapeutic efficacy and underlying mechanisms of a topical astaxanthin (AST) formulation in an imiquimod (IMQ)-induced mouse model of psoriasiform dermatitis. Following IMQ induction, mice were randomly assigned to vehicle, clobetasol, or AST treatment groups (0.5–1.5%) for 14 days. Disease progression was evaluated through biochemical analysis of oxidative stress biomarkers, including NADPH oxidase (NOX), malondialdehyde (MDA), nitric oxide (NO), and superoxide dismutase (SOD), as well as ELISA-based quantification of inflammatory cytokines (TNF-α, IL-6, IL-17, and IL-23). Histopathological changes were assessed using hematoxylin and eosin staining, while molecular alterations were examined by RT-qPCR analysis of psoriasis-associated keratin genes (Krt16, Krt17, and Krt6a) and evaluation of JAK–STAT signaling activity. AST treatment significantly suppressed the IL-23/IL-17 inflammatory axis, reduced NOX activity and lipid peroxidation, restored endogenous antioxidant defenses, and inhibited JAK–STAT signaling. These biochemical and molecular effects were accompanied by marked downregulation of keratin gene expression and substantial histological improvement, including normalization of epidermal thickness, reduced parakeratosis, and decreased inflammatory infiltration. Notably, high-dose AST demonstrated therapeutic efficacy comparable to, and in some parameters exceeding, that of clobetasol. Collectively, these findings indicate that topical astaxanthin exerts coordinated antioxidant, anti-inflammatory, and anti-proliferative effects, supporting its potential as a promising multi-target non-steroidal therapeutic candidate for psoriasis management. Full article

Dimethomorph (DIM) is a commonly applied morpholine fungicide, yet its potential toxicity to non-target organisms raises significant environmental concerns. This study aims to elucidate the toxicological effects of DIM on zebrafish, with a particular focus on its cardiovascular impacts. Zebrafish embryos were exposed to a range of DIM concentrations for 48 h, and their cardiac and vascular performance was meticulously assessed to determine the extent of cardiovascular toxicity. The findings revealed notable cardiac hypertrophy, evidenced by a substantial enlargement in heart size, alongside a dose-dependent reduction in heart rate. These observations suggest direct impairment of cardiac function following DIM exposure. To further investigate the molecular underpinnings of these effects, gene expression analysis was conducted using quantitative real-time PCR (qRT-PCR). The results demonstrated significant alterations in the expression of key genes associated with cardiovascular development and function, providing mechanistic insights into DIM’s toxic effects. In addition to cardiac abnormalities, DIM exposure led to a significant increase in the metabolic rate of the zebrafish embryos, indicating a potential disruption in energy homeostasis. To explore possible protective measures, a rescue experiment was performed using Astaxanthin, a potent antioxidant. Notably, Astaxanthin treatment partially mitigated the observed cardiac and metabolic phenotypes, suggesting its potential as a therapeutic agent to counteract DIM-induced toxicity. In summary, this study provides compelling evidence of the cardiovascular toxicity of DIM in zebrafish, highlighting its potential to disrupt cardiac function and metabolic regulation. The observed effects underscore the importance of re-evaluating the environmental impact of DIM and emphasize the need for further research to fully understand its mechanisms of toxicity. The findings also suggest that Astaxanthin (AST) could serve as a protective agent against DIM-induced toxicity, opening avenues for future studies aimed at mitigating the adverse effects of this widely used fungicide. This research study contributes to the growing body of knowledge on the environmental and health risks associated with pesticide use, advocating for more stringent regulations and safer alternatives. Full article

In this study, a novel combination strategy of sodium trimetaphosphate (STMP) phosphorylation and dextran (DX) glycosylation was employed to modify soy protein isolate (SPI). The phosphorylated protein–dextran conjugate (TSPI-DX) was successfully prepared and then was used as an emulsifier to prepare the astaxanthin emulsion, with the aim to enhance the emulsion delivery performance. Structural analysis revealed that phosphorylation and glycosylation altered the microenvironment of the side chains, leading to changes in protein secondary structure, which consequently loosened the protein architecture and enhanced molecular flexibility. The functional properties of TSPI-DX, including its solubility, emulsifying activity (EAI) and emulsifying stability (ESI), were markedly enhanced. Furthermore, the concurrent modification through phosphorylation and the Maillard reaction yielded a synergistic effect, boosting the DPPH radical scavenging rate by 86.5% and increasing the ferric-ion reducing power nearly fourfold. The astaxanthin emulsion prepared by modified SPI also exhibited several advantages. The TSPI-DX emulsion exhibited a markedly smaller mean particle size and a larger absolute Zeta-potential value. Consequently, with the higher electrostatic repulsion and steric hindrance among the droplets, the astaxanthin emulsion prepared by TSPI-DX demonstrated superior encapsulation efficiency and stability across various conditions, including storage, oxidation, thermal, and pH challenges. Moreover, in vitro digestion experiments revealed that the modified SPI emulsion facilitated a higher extent of lipolysis and astaxanthin bioaccessibility. Therefore, this work proposes a novel strategy for constructing plant-protein emulsion systems with enhanced delivery and release capabilities. Full article

Background and Objectives: Pro-inflammatory diet and high-fat diet (HFD) often coexist in real-world, but their combined impact on the gut–liver axis and potential nutritional countermeasures remain insufficiently studied. This study aimed to evaluate a pro-inflammatory–high-fat composite dietary pattern on the intestine and liver in the population, and to further evaluate the protective potential of astaxanthin (ATX) in complementary experimental systems. Methods: Data from the NHANES 2005–2010 were used to construct four composite exposure groups based on the dietary inflammation index (DII) and energy from fat. Survey-weighted regression analyses were performed to examine associations with systemic inflammation and liver injury. Interaction and C-reactive protein (CRP)-mediated effect analyses were conducted. Fifty SD rats were randomly divided into control group, model group induced by HFD combined with inflammatory factors, and low-, medium-, and high-dose Haematococcus pluvialis (HP) intervention groups. Serum lipids, liver enzymes, liver and colon pathology, and inflammatory and oxidative markers were measured in rats. In an in vitro organ-on-chip barrier model, the effect of ATX was observed when colonic barrier damage was induced using palmitic acid and lipopolysaccharides. Results: The high DII combined with HFD showed the largest increases in CRP, liver enzymes, and fatty liver index. A synergistic interaction was observed between DII and HFD, with CRP mediating approximately 20% of the effect. In rat model, HP-derived ATX improved the lipid profile, attenuated hepatic steatosis and oxidative damage, and reduced colonic pro-inflammatory cytokines, while restoration of tight junction proteins was limited. In colon organoid model, ATX showed limited efficacy in improving inflammation and barrier function. Conclusions: The pro-inflammatory–high-fat dietary pattern synergistically exacerbates gut–liver dysfunction. HP-derived ATX alleviates metabolic and inflammation-induced enterohepatic comorbidity, but its effect on repairing barrier structure is limited. Full article

Autophagy is a crucial process for cellular self-regulation and renewal. Upon exposure to stress, membrane structures—primarily derived from the endoplasmic reticulum and mitochondria, with contributions from the plasma membrane—drive autophagosome biogenesis. This process begins with the formation of a cup-shaped phagophore, which elongates to sequester cytoplasmic cargo, closes to form an autophagosome, and ultimately fuses with lysosomes to create an autolysosome where degradation and recycling occur. This regulated process plays a vital role in maintaining cellular homeostasis, the pathogenesis of various diseases, and modulation of inflammation. Astaxanthin (AST), a carotenoid produced by microalgae, various microorganisms and marine organisms, possesses a unique chemical structure that endows it with significant biological activities, including potent antioxidant and anti-inflammatory properties. Emerging evidence, primarily from preclinical studies, suggests that AST modulates autophagy by regulating signaling pathways such as Reactive Oxygen Species (ROS)/Mitogen-activated Protein Kinase (MAPK) and interacting with nuclear factor erythroid 2-related factor 2(Nrf2)-mediated antioxidant responses, thereby influencing inflammatory balance. This review systematically elucidates how AST acts as a key “molecular modulator” in animal or cellular models, dynamically regulating autophagy to restore cellular homeostasis and thereby influencing the course and outcome of inflammation. Furthermore, we explore the autophagy-mediated anti-inflammatory effects of AST across different organ systems and discuss its preliminary clinical translational potential and future challenges, aiming to provide a concise and forward-looking roadmap for this promising research field. Full article

Carotenoproteins from marine sponges represent an underexplored class of pigment–protein complexes with distinctive structural and functional properties. Here, we report the isolation and biophysical characterization of a blue carotenoprotein from the sponge Tedania ignis, termed Ti-CP. The protein was purified and shown to consist of two closely related isoforms with molecular masses of approximately 27–29 kDa. Reverse-phase chromatography enabled separation of the apoprotein (ApoTi-CP) and its associated carotenoids, which were identified as oxygenated carotenoids consistent with astaxanthin and mytiloxanthin. Circular dichroism analysis revealed that both Ti-CP and ApoTi-CP are dominated by β-sheet secondary structure and display highly similar conformational profiles. In contrast, dynamic light scattering demonstrated that carotenoid binding is critical for protein stability, as the native form exhibited a compact and monodisperse organization, whereas ApoTi-CP showed pronounced aggregation. Isothermal titration calorimetry revealed that Ti-CP, but not ApoTi-CP, interacts with tetracycline, oxacillin, and streptomycin, indicating that pigment-mediated stabilization modulates ligand binding. Both Ti-CP and ApoTi-CP reduced bacterial viability and biofilm formation in a strain-dependent manner and enhanced antibiotic activity, including synergistic effects against resistant bacteria. Together, these results provide a comprehensive description of a previously uncharacterized sponge carotenoprotein and highlight the dual role of carotenoids in structural stabilization and antimicrobial modulation, reinforcing the biotechnological relevance of marine pigment–protein complexes. Full article

This study investigated the effects of Lycium barbarum polysaccharides (LBP) supplementation on various indicators in coral trout (Plectropomus leopardus), including growth performance, digestive enzyme activity, muscle and skin morphology, inflammatory immune gene expression, as well as immune and antioxidant responses. In the experiment, fish were fed diets supplemented with different concentrations of LBP (0%, 0.05%, 0.1%, 0.2%, 0.5%, and 1%) over a designated experimental period. The results showed that moderate supplementation of LBP significantly improved growth performance, with the optimal concentration being around 0.243%, achieving the highest specific growth rate. LBP supplementation also enhanced intestinal digestive enzyme activity, such as trypsin in the 0.1% and 1% groups, and α-amylase in the 0.5% group. Additionally, LBP improved the nutritional composition of muscle, with the 1% group showing higher crude protein content and the 0.2–1% groups having lower crude fat content. Moderate LBP supplementation improved skin color and pigmentation, increasing the brightness, redness, and yellowness of the dorsal skin, as well as boosting carotenoid and astaxanthin concentrations. It also enhanced the immune and antioxidant functions of the skin (e.g., SOD, CAT, GSH-Px, AKP, and LZ) and improved the immune functions of the mucus (e.g., C3, C4, IgM, IgT, AKP, and LZ). Furthermore, the expression of key pro-inflammatory genes, such as TNF-α and IL-1β, was reduced. These findings suggest that LBP can serve as a natural feed additive to enhance the overall quality and health of coral trout, contributing to sustainable aquaculture practices. Full article

Fresh bluefin tuna is highly susceptible to quality deterioration during refrigerated storage due to lipid oxidation and microbial activity, creating a need for effective clean-label preservation strategies. This study evaluated the efficacy of natural astaxanthin as an antioxidant treatment to improve the refrigerated stability of fresh bluefin tuna (Thunnus thynnus) fillets stored under vacuum packaging (VP) or modified atmosphere packaging (MAP; 70% N₂/30% CO₂). Tuna fillets were treated by short immersion in astaxanthin solutions (10–20 mg/L), applied alone or in combination with other natural antioxidants, including ascorbic acid, and compared with a rosemary–ascorbic acid reference system. Selected treatments incorporated microencapsulated astaxanthin to enhance antioxidant stability. Quality changes were monitored during refrigerated storage (4 °C) through sensory evaluation (appearance, colour, and odour), total volatile basic nitrogen (TVBN), histamine determination, and microbiological analyses. Astaxanthin-treated samples exhibited improved colour stability, delayed sensory deterioration, and significantly lower TVBN accumulation compared with the rosemary–ascorbic acid reference treatment. Under MAP conditions, astaxanthin reduced TVBN values by approximately 20% after 12 days of storage, while microencapsulated astaxanthin combined with ascorbic acid achieved reductions of up to 30% under vacuum packaging. All selected treatments complied with regulatory microbiological and histamine limits throughout storage. These results indicate that natural astaxanthin, particularly in microencapsulated formulations, can enhance quality stability of fresh bluefin tuna when applied in combination with oxygen-limiting packaging systems under controlled refrigerated conditions. The findings provide a scientific basis for further investigation of astaxanthin-based preservation strategies in high-value seafood products. Full article

Carotenoids play a central role in photosynthesis and cellular protection, and microalgae represent a sustainable platform for their commercial production. Here, we optimized the accumulation of the high-value carotenoids astaxanthin and lutein in continuous photoautotrophic cultures of Chromochloris zofingiensis by modulating nitrogen supply and light intensity. Reducing nitrate availability strongly promoted astaxanthin accumulation, whereas lutein levels remained largely unaffected. For 4% N in the dry biomass, accumulation of astaxanthin was highest and that of lutein lowest, while the opposite was recorded for 9% N. Average irradiance positively affected lutein accumulation independently of nitrate, whereas that of astaxanthin only increased under nitrogen-limiting conditions. Integrated transcriptomics and carotenoid profiling analysis revealed nitrogen availability as the dominant regulatory factor, with a synergistic interaction with light that enhances their individual effects. Nitrate limitation redirected metabolic flux from lycopene toward β-carotene and its subsequent conversion to astaxanthin via BKT1 overexpression, while high irradiance induced CYP97A1 and CYP97C expression, favoring lutein biosynthesis. Together, these findings demonstrate that targeted control of nitrogen and light enables the continuous and programmable production of C. zofingiensis biomass with a specific astaxanthin-to-lutein ratio, highlighting its potential for industrial carotenoid bioprocesses. Full article

Sterol regulatory element-binding proteins (SREBPs) regulate lipid homeostasis and coordinate sterol metabolism and carotenogenesis in the astaxanthin-producing yeast Phaffia rhodozyma. While Sre1, the SREBP ortholog, and the site-2 protease Stp1 have been identified as essential components of this pathway in P. rhodozyma, additional factors involved in Sre1 processing or regulation remain unknown. In Aspergillus species, a signal peptide peptidase contributes to the activation of the SREBP ortholog, raising the possibility of a similar role in this yeast. In this work, we identified and characterized the P. rhodozyma signal peptide peptidase (SppA) homolog. Sequence analysis, domain prediction, and phylogenetic analyses supported its classification within the SPP family of intramembrane aspartyl proteases. To evaluate its functional role, ΔsppA mutants were constructed in genetic backgrounds with constitutive Sre1 activity, including the cyp61⁻ mutant and a strain expressing the active form of Sre1 (Sre1N). Deletion of SPPA did not alter sensitivity to clotrimazole or cobalt chloride, nor affect pigmentation, indicating that SppA is not required for Sre1 activation in P. rhodozyma. Transcriptomic analyses further showed that expression of SRE1 and of its known target genes remained unchanged upon SPPA deletion. Interestingly, the loss of SppA in the Sre1N background caused marked downregulation of genes associated with protein refolding and unfolded protein binding. In agreement with these transcriptional changes, the Sre1NΔsppA strain displayed increased sensitivity to dithiothreitol. These findings suggest that, although SppA is not involved in Sre1 activation in P. rhodozyma, it may play a role in protein stress-related processes. Future studies will be required to define the molecular mechanisms underlying this role and its integration with protein homeostasis networks. Full article

Seafood processing generates large volumes of by-products that are often underutilized despite their potential as sources of high-value bioactive lipids. In this study, a hybrid process integrating microwave (MW) pretreatment with Soxhlet (SOX) extraction was developed and optimized to intensify the recovery of astaxanthin (ASX)- and ω-3 PUFA-rich oil from green tiger shrimp (Penaeus semisulcatus) residues. Response surface methodology (RSM) comprising 22 experimental runs was applied to optimize key MW process variables, including power (100–400 W) and irradiation time (30–90 s). Both factors significantly influenced oil yield, with optimal operating conditions identified at 400 W and 75 s. MW pretreatment promoted structural disruption of shrimp shells, as confirmed by scanning electron microscopy, thereby enhancing solvent penetration and mass transfer. Solvent selection further affected extraction performance: hexane:isopropanol (1:1, v/v) achieved the highest oil yield (3.86 g/100 g dry weight), while hexane:acetone produced extracts with the highest ASX concentration (1032.24 µg/g oil), ω-3 PUFA content (29.85%), and antioxidant activity (93.30% DPPH scavenging). Colorimetric analysis supported these results, with increased redness (a* = 18.12) correlating with ASX enrichment. Overall, this integrated MW-SOX process represents an effective process-intensification strategy for sustainable shrimp waste valorization and production of bioactive lipid fractions. Full article