The gut microbiota promotes distal tissue regeneration via RORγ+ regulatory T cell emissaries.

Specific microbial signals induce the differentiation of a distinct pool of RORγ+ regulatory T (Treg) cells crucial for intestinal homeostasis. We discovered highly analogous populations of microbiota-dependent Treg cells that promoted tissue regeneration at extra-gut sites, notably acutely injured skeletal muscle and fatty liver. Inflammatory meditators elicited by tissue damage combined with MHC-class-II-dependent T cell activation to drive the accumulation of gut-derived RORγ+ Treg cells in injured muscle, wherein they regulated the dynamics and tenor of early inflammation and helped balance the proliferation vs. differentiation of local stem cells. Reining in IL-17A-producing T cells was a major mechanism underlying the rheostatic functions of RORγ+ Treg cells in compromised tissues. Our findings highlight the importance of gut-trained Treg cell emissaries in controlling the response to sterile injury of non-mucosal tissues.

Mesenchymal condensation in tooth development and regeneration: a focus on translational aspects of organogenesis.

The teeth are vertebrate-specific, highly specialized organs performing fundamental functions of mastication and speech, the maintenance of which is crucial for orofacial homeostasis and is further linked to systemic health and human psychosocial well-being. However, with limited ability for self-repair, the teeth can often be impaired by traumatic, inflammatory, and progressive insults, leading to high prevalence of tooth loss and defects worldwide. Regenerative medicine holds the promise to achieve physiological restoration of lost or damaged organs, and in particular an evolving framework of developmental engineering has pioneered functional tooth regeneration by harnessing the odontogenic program. As a key event of tooth morphogenesis, mesenchymal condensation dictates dental tissue formation and patterning through cellular self-organization and signaling interaction with the epithelium, which provides a representative to decipher organogenetic mechanisms and can be leveraged for regenerative purposes. In this review, we summarize how mesenchymal condensation spatiotemporally assembles from dental stem cells (DSCs) and sequentially mediates tooth development. We highlight condensation-mimetic engineering efforts and mechanisms based on ex vivo aggregation of DSCs, which have achieved functionally robust and physiologically relevant tooth regeneration after implantation in animals and in humans. The discussion of this aspect will add to the knowledge of development-inspired tissue engineering strategies and will offer benefits to propel clinical organ regeneration.

Membrane-dependent actin polymerization mediated by the Legionella pneumophila effector protein MavH.

L. pneumophila propagates in eukaryotic cells within a specialized niche, the Legionella-containing vacuole (LCV). The infection process is controlled by over 330 effector proteins delivered through the type IV secretion system. In this study, we report that the Legionella MavH effector localizes to endosomes and remodels host actin cytoskeleton in a phosphatidylinositol 3-phosphate (PI(3)P) dependent manner when ectopically expressed. We show that MavH recruits host actin capping protein (CP) and actin to the endosome via its CP-interacting (CPI) motif and WH2-like actin-binding domain, respectively. In vitro assays revealed that MavH stimulates actin assembly on PI(3)P-containing liposomes causing their tubulation. In addition, the recruitment of CP by MavH negatively regulates F-actin density at the membrane. We further show that, in L. pneumophila-infected cells, MavH appears around the LCV at the very early stage of infection and facilitates bacterium entry into the host. Together, our results reveal a novel mechanism of membrane tubulation induced by membrane-dependent actin polymerization catalyzed by MavH that contributes to the early stage of L. pneumophila infection by regulating host actin dynamics.

Vitamin D promotes the folate transport and metabolism in zebrafish (Danio rerio).

Vitamin D (VD) is a fat-soluble sterol that possesses a wide range of physiological functions. The present study aimed to evaluate the effects of VD on folate metabolism in zebrafish and further investigated the underlying mechanism. Wild-type (WT) zebrafish were fed with a diet containing 0 IU/kg VD3 or 800 IU/kg VD3 for 3 wk. Meanwhile, cyp2r1 mutant zebrafish with impaired VD metabolism was used as another model of VD deficiency. Our results showed that VD deficiency in zebrafish suppressed the gene expression of folate transporters, including reduced folate carrier (RFC) and proton-coupled folate transporter (PCFT) in the intestine. Moreover, VD influenced the gene expression of several enzymes related to cellular folate metabolism in the intestine and liver of zebrafish. Importantly, VD-deficient zebrafish contained a remarkably lower level of folate content in the liver. Notably, VD was incapable of altering folate metabolism in zebrafish when gut microbiota was depleted by antibiotic treatment. Further studies proved that gut commensals from VD-deficient fish displayed a lower capacity to produce folate than those from WT fish. Our study revealed the potential correlation between VD and folate metabolism in zebrafish, and gut microbiota played a key role in VD-regulated folate metabolism in zebrafish.NEW & NOTEWORTHY Our study has identified that VD influences intestinal uptake and transport of folate in zebrafish while also altering hepatic folate metabolism and storage. Interestingly, the regulatory effects of VD on folate transport and metabolism diminished after the gut flora was interrupted by antibiotic treatment, suggesting that the regulatory effects of VD on folate metabolism in zebrafish are most likely dependent on the intestinal flora.

Assessment of optimal combinations of therapeutic probiotics for depression, anxiety, and stress.

BACKGROUND: Accumulating data show that probiotics may be beneficial for reducing depressive, anxiety, and stress symptoms. However, the best combinations and species of probiotics have not been identified. The objective of our study was to assess the most effective combinations and components of different probiotics through network meta-analysis. METHOD: A systematic search of four databases, PubMed, Web of Science, Cochrane, and Embase, was conducted from inception to 11 January 2024. The GRADE framework was used to assess the quality of evidence contributing to each network estimate. RESULTS: We deemed 45 trials eligible, these included 4053 participants and 10 types of interventions. The quality of evidence was rated as high or moderate. The NMA revealed that Bifidobacterium exhibited a greater probability of being the optimal probiotic species for improving anxiety symptoms (SMD = -0.80; 95% CI -1.49 to -0.11), followed by Lactobacillus (SMD = -0.49; 95% CI -0.85 to -0.12). In addition, for multiple strains, compared with the other interventions, Lactobacillus + Bifidobacterium (SMD = -0.41; 95% CI -0.73 to -0.10) had a positive effect on depression. CONCLUSION: The NMA revealed that Lactobacillus and Bifidobacterium had prominent efficacy in the treatment of individuals with anxiety, depression, and combination of Lactobacillus + Bifidobacterium had a similar effect. With few direct comparisons available between probiotic species, this NMA may be instrumental in shaping the guidelines for probiotic treatment of psychological disorders.

A Rab10-ACAP1-Arf6 GTPases cascade modulates M4 muscarinic acetylcholine receptor trafficking and signaling.

Membrane trafficking processes regulate the G protein-coupled receptor activity. The muscarinic acetylcholine receptors (mAChRs) are highly pursued drug targets for neurological diseases, but the cellular machineries that control the trafficking of these receptors remain largely elusive. Here, we revealed the role of the small GTPase Rab10 as a negative regulator for the post-activation trafficking of M4 mAChR and the underlying mechanism. We show that constitutively active Rab10 arrests the receptor within Rab5-positive early endosomes and significantly hinders the resensitization of M4-mediated Ca2+ signaling. Mechanistically, M4 binds to Rab10-GTP, which requires the motif 386RKKRQMAA393 (R386-A393) within the third intracellular loop. Moreover, Rab10-GTP inactivates Arf6 by recruiting the Arf6 GTPase-activating protein, ACAP1. Strikingly, deletion of the motif R386-A393 causes M4 to bypass the control by Rab10 and switch to the Rab4-facilitated fast recycling pathway, thus reusing the receptor. Therefore, Rab10 couples the cargo sorting and membrane trafficking regulation through cycle between GTP-bound and GDP-bound state. Our findings suggest a model that Rab10 binds to the M4 like a molecular brake and controls the receptor's transport through endosomes, thus modulating the signaling, and this regulation is specific among the mAChR subtypes.

Electron-transferring flavoprotein and its dehydrogenase contributed to growth development and virulence in Beauveria bassiana.

Electron-transferring flavoprotein (Etf) and its dehydrogenase (Etfdh) are integral components of the electron transport chain in mitochondria. In this study, we characterize two putative etf genes (Bbetfa and Bbetfb) and their dehydrogenase gene Bbetfdh in the entomopathogenic fungus Beauveria bassiana. Individual deletion of these genes caused a significant reduction in vegetative growth, conidiation, and delayed conidial germination. Lack of these genes also led to abnormal metabolism of fatty acid and increasing lipid body accumulation. Furthermore, the virulence of Bbetfs and Bbetfdh deletion mutants was severely impaired due to decreasing infection structure formation. Additionally, all deletion strains showed reduced ATP synthesis compared to the wild-type strain. Taken together, Bbetfa and Bbetfb, along with Bbetfdh, play principal roles in fungal vegetative growth, conidiation, conidial germination, and pathogenicity of B. bassiana due to their essential functions in fatty acid metabolism.

Ultrasound is helpful to diagnose and identify aggressive angiomyxoma: A case report.

Aggressive angiomyxoma (AAM) is a rare kind of neoplasm derived from mesenchyma, which is easily confused with other superficial masses. Here, we present a 21-year-old young female with a 2-year history of a mass in the right vulva. The patient's laboratory analysis yielded unremarkable results. Ultrasound examination revealed the presence of a heterogeneous solid mass in the right vulva with blood flow. Enhanced computed tomography imagines showed a capsular neoplasm in the posterior the perineal region without obvious enhancement. The patient received surgery. Biopsy after surgery revealed that the tumor was AAM. The patient was followed up regularly. In this article, we will describe sonographic and computed tomography imagines, histologic features of AAM, and review the related literature.

Advancing Metallic Lithium Anodes: A Review of Interface Design, Electrolyte Innovation, and Performance Enhancement Strategies.

Lithium (Li) metal is one of the most promising anode materials for next-generation, high-energy, Li-based batteries due to its exceptionally high specific capacity and low reduction potential. Nonetheless, intrinsic challenges such as detrimental interfacial reactions, significant volume expansion, and dendritic growth present considerable obstacles to its practical application. This review comprehensively summarizes various recent strategies for the modification and protection of metallic lithium anodes, offering insight into the latest advancements in electrode enhancement, electrolyte innovation, and interfacial design, as well as theoretical simulations related to the above. One notable trend is the optimization of electrolytes to suppress dendrite formation and enhance the stability of the electrode-electrolyte interface. This has been achieved through the development of new electrolytes with higher ionic conductivity and better compatibility with Li metal. Furthermore, significant progress has been made in the design and synthesis of novel Li metal composite anodes. These composite anodes, incorporating various additives such as polymers, ceramic particles, and carbon nanotubes, exhibit improved cycling stability and safety compared to pure Li metal. Research has used simulation computing, machine learning, and other methods to achieve electrochemical mechanics modeling and multi-field simulation in order to analyze and predict non-uniform lithium deposition processes and control factors. In-depth investigations into the electrochemical reactions, interfacial chemistry, and physical properties of these electrodes have provided valuable insights into their design and optimization. It systematically encapsulates the state-of-the-art developments in anode protection and delineates prospective trajectories for the technology's industrial evolution. This review aims to provide a detailed overview of the latest strategies for enhancing metallic lithium anodes in lithium-ion batteries, addressing the primary challenges and suggesting future directions for industrial advancement.

[Research Status of Nanomaterial Medical Device and Discussion on Biological Evaluation].

In recent years, China has made great progress in basic nanomedicine, nanotoxicology and nanobiology research. Nanotechnology has been continuously applied in biomaterial and medical device, more and more medical devices applying nanomaterials are developed and manufactured. In order to gain more comprehension and accurate understanding of the research and industrial development in nanobiomaterial medical devices, this study reviewed the common nanomaterial in medical devices and the regulatory situation of nanomaterial medical devices at home and abroad, and discussed the current challenges in biological evaluation of nanomaterial medical devices, with a view to providing ideas for the safety evaluation and research of related products.

A systematic review of cost­effectiveness analyses of sequential treatment for osteoporosis.

Sequential treatment of osteoporosis has been increasingly mentioned in recent years. However, the corresponding systematic review has not been reported. This study aims to systematically review and assess all full-text pharmacoeconomic studies of sequential treatment for osteoporosis. A comprehensive literature search was performed using PubMed, EMBASE (Ovid), CNKI, and Wanfang Database to identify original articles, published before June 17, 2022. The quality of included articles was evaluated by the updated Consolidated Health Economic Evaluation Reporting Standards (CHEERS 2022) and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases International Osteoporosis Foundation (ESCEO-IOF). In general, ten articles were included in this review. For the comparison between sequential treatment and bisphosphonate monotherapy, more than 75% of studies demonstrated the sequential treatment was cost-effective or dominant, with the exception of sequential treatment involving teriparatide. When the comparisons occurred between the two sequential treatment groups, the sequential treatments associated with either abaloparatide or romosozumab were cost-effective or dominant compared to the sequential treatment involving teriparatide. Several major key drivers of cost-effectiveness included drug cost, medication persistence and adherence, drug effect on fracture risk, offset effect, time horizon, and baseline fracture risk. The most of studies were identified as high quality in CHEERS (2022) and ESCEO-IOF. The cost-effectiveness of sequential treatment for osteoporosis is influenced by multiple factors. Generally, the sequential treatments involving abaloparatide, romosozumab, denosumab, and bisphosphonates may be considered as the preferred option for osteoporosis with high fracture risk, while the sequential treatment with teriparatide was not a cost-effectiveness strategy. The ESCEO-IOF and CHEER (2022) increase the transparency, comparability, extrapolation, and quality of research, engage patients and the general public in research on health services and policies, and help improve the quality of health technology assessment.

Vitamin D regulates insulin pathway and glucose metabolism in zebrafish (Danio rerio).

1,25-dihydroxyvitamin D3 [1,25(OH)2 D3 ], the most active vitamin D (VD) metabolite, is a steroid hormone playing an important role in many physiological functions in addition to maintaining mineral homeostasis. In this study, we explored the mechanism that the VD regulated insulin pathway and glucose metabolism in zebrafish in vitro and in vivo. Our results show that 1,25(OH)2 D3  significantly enhances the expression of insulin receptor a (insra), insulin receptor substrate 1 (irs1) and glucose transporter 2 (glut2), and promotes glycolysis and glycogenesis, while suppressing gluconeogenesis in zebrafish liver cell line (ZFL) under the condition of high glucose (20 mM), instead of the normal glucose (10 mM). Moreover, consistent results were obtained from the zebrafish fed with VD3 -deficient diet, as well as the cyp2r1-/- zebrafish, in which endogenous VD metabolism is blocked. Furthermore, results from dual-luciferase reporting system exhibited that 1,25(OH)2 D3 directly activated the transcription of insra, rather than insrb in zebrafish by binding to vitamin D response element (VDRE) located at -181 to -167 bp in the promoter region of insra. Importantly, the 1,25(OH)2 D3 treatment significantly alleviated the symptoms of hyperglycemia in diabetic zebrafish. In conclusion, our study demonstrated that VD activates VDRE located in the promoter area of insra in zebrafish to promote insulin/insra signaling pathway, thereby contributing to the maintenance of glucose homeostasis.

Precise Design of Molecular Ferroelectrics with High TC and Tunable Band Gap by Molecular Modification.

Molecular ferroelectric materials are widely applied in piezoelectric converters, non-volatile memorizers, and photovoltaic devices due to their advantages of adjustable structure, lightweight, easy processing, and environmental friendliness. However, designing multifunctional molecular ferroelectrics with excellent properties has always been a great challenge. Herein, a multiaxial molecular ferroelectric is successfully designed by modifying the quasi-spherical cation dabco with CuBr2 to obtain halogenated [Bretdabco]CuBr4 (Bretdabco = N-bromoethyl-N'-diazabicyclo [2.2.2]octane), which crystallizes in polar point groups (C6). Typical ferroelectric behaviors featured by the P-E hysteresis loop and switched ferroelectric domain are exhibited. Notably, the molecular ferroelectric shows a high TC of 460 K, which is rare in the field and could greatly expand the application range of this material. In addition, the band gap is adjustable through the regulation of halogen. Both the UV absorption spectra and theoretical calculations indicate that the molecular ferroelectrics belong to a direct band gap (2.14 eV) semiconductor. This tunable and narrow band gap semiconductor molecular ferroelectric material with high TC can be utilized more effectively in the study of optoelectronics and sensors, including piezoelectric energy harvesters. This research may provide a promising approach for the development of multiaxial molecular ferroelectrics with a tiny band gap and high TC.

Butyrate induces STAT3/HIF-1α/IL-22 signaling via GPCR and HDAC3 inhibition to activate autophagy in head kidney macrophages from turbot (Scophthalmus maximus L.).

As one of short-chain fatty acids, butyrate is an important metabolite of dietary fiber by the fermentation of gut commensals. Our recent study uncovered that butyrate promoted IL-22 production in fish macrophages to augment the host defense. In the current study, we further explored the underlying signaling pathways in butyrate-induced IL-22 production in fish macrophages. Our results showed that butyrate augmented the IL-22 expression in head kidney macrophages (HKMs) of turbot through binding to G-protein receptor 41 (GPR41) and GPR43. Moreover, histone deacetylase 3 (HDAC3) inhibition apparently up-regulated the butyrate-enhanced IL-22 generation, indicating HDACs were engaged in butyrate-regulated IL-22 secretion. In addition, butyrate triggered the STAT3/HIF-1α signaling to elevate the IL-22 expression in HKMs. Importantly, the evidence in vitro and in vivo was provided that butyrate activated autophagy in fish macrophages via IL-22 signaling, which contributing to the elimination of invading bacteria. In conclusion, we clarified in the current study that butyrate induced STAT3/HIF-1α/IL-22 signaling pathway via GPCR binding and HDAC3 inhibition in fish macrophages to activate autophagy that was involved in pathogen clearance in fish macrophages.

Butyrate-induced IL-22 expression in fish macrophages contributes to bacterial clearance.

IL-22 has been characterized as a critical cytokine in maintaining barrier integrity and host immunity. So far, it has been known that IL-22 is mainly produced by lymphoid lineage cells. In the present study, we have thoroughly investigated butyrate-induced production and function of IL-22 in fish macrophages. Our results demonstrated that short-chain fatty acids (SCFAs), major microbiota-derived metabolites, promoted the expression of IL-22 in head kidney macrophages (HKMs) of turbot (Scophthalmus maximus L.). Interestingly, butyrate-mediated intracellular bacterial killing in HKMs diminished when IL-22 expression was interfered. Furthermore, the turbot fed the diet containing sodium butyrate (NaB) exhibited significantly lower mortality after bacterial infection, compared to the fish fed a basal diet. At the meantime, a higher level of IL-22 expression and bactericidal activity was detected in HKMs from the turbot fed NaB-supplemented diet. In addition, NaB treatment promoted the expression of antimicrobial peptides (AMPs) ß-defensins in zebrafish (Danio rerio). However, butyrate-induced expression of AMPs was reduced in IL-22 mutant zebrafish compared to wild-type (WT) fish. Meanwhile, NaB treatment was incapable to protect IL-22 mutant fish from bacterial infection as it did in WT zebrafish. Importantly, our results demonstrated that IL-22 expression was remarkably suppressed in macrophage-depleted zebrafish, indicating that macrophage might be a cell source of IL-22 production in vivo. In conclusion, all these findings collectively revealed that SCFAs regulated the production and function of IL-22 in fish macrophages, which facilitated host resistance to bacterial invasion.

Vitamin D3 enhances the antibacterial ability in head-kidney macrophages of turbot (Scophthalmus maximus L.) through C-type lectin receptors.

It has been known that vitamin D3 (VD3) not only plays an important role in regulating calcium and phosphorus metabolism in animals, but also has extensive effects on immune functions. In this study, the mechanism how VD3 influences bactericidal ability in turbot was explored. The transcriptomic analysis identified that dietary VD3 significantly upregulated the gene expression of C-type lectin receptors (CLRs), including mannose receptors (mrc1, mrc2, pla2r1) and collectins (collectin 11 and collectin 12) in turbot intestine. Further results obtained from in vitro experiments confirmed that the gene expression of mannose receptors and collectins in head-kidney macrophages (HKMs) of turbot was induced after the cells were incubated with different concentrations of VD3 (0, 1, 10 nM) or 1,25(OH)2D3 (0, 10, 100 pM). Meanwhile, both phagocytosis and bactericidal functions of HKMs were significantly improved in VD3 or 1,25(OH)2D3-incubated HKMs. Furthermore, phagocytosis and bacterial killing of HKMs decreased after collectin 11 was knocked down. Moreover, VD3-enhanced antibacterial activities diminished in collectin 11-interfered cells. Interestingly, the evidence was provided in the present study that inactive VD3 could be metabolized into active 1,25(OH)2D3 via hydroxylases encoded by cyp27a1 and cyp27b1 in fish macrophages. In conclusion, VD3 could be metabolized to 1,25(OH)2D3 in HKMs, which promoted the expression of CLRs in macrophages, leading to enhanced bacterial clearance.

A caprylate esterase-activated fluorescent probe for sensitive and selective detection of Salmonella enteritidis.

Salmonella enteritidis is one of the most common foodborne pathogens. Many methods have been developed to detect Salmonella, but most of them are expensive, time-consuming, and complex in experimental procedures. Developing a rapid, specific, cost-effective, and sensitive detection method is still demanded. In this work, a practical detection method is presented using salicylaldazine caprylate as the fluorescent probe, which could be hydrolyzed by caprylate esterase liberated from Salmonella lysed by phage, to form strong fluorescent salicylaldazine. The Salmonella could be detected accurately with a low limit of detection of 6 CFU/mL and a broad concentration range of 10-106 CFU/mL. Moreover, this method was successfully used for the rapid detection of Salmonella in milk within 2 h through pre-enrichment by ampicillin-conjugated magnetic beads. The novel combination of fluorescent turn-on probe salicylaldazine caprylate and phage ensures this method has excellent sensitivity and selectivity.

Atmospheric Turbulence Aberration Correction Based on Deep Learning Wavefront Sensing.

In this paper, research was conducted on Deep Learning Wavefront Sensing (DLWS) neural networks using simulated atmospheric turbulence datasets, and a novel DLWS was proposed based on attention mechanisms and Convolutional Neural Networks (CNNs). The study encompassed both indoor experiments and kilometer-range laser transmission experiments employing DLWS. In terms of indoor experiments, data were collected and training was performed on the platform built by us. Subsequent comparative experiments with the Shack-Hartmann Wavefront Sensing (SHWS) method revealed that our DLWS model achieved accuracy on par with SHWS. For the kilometer-scale experiments, we directly applied the DLWS model obtained from the indoor platform, eliminating the need for new data collection or additional training. The DLWS predicts the wavefront from the beacon light PSF in real time and then uses it for aberration correction of the emitted laser. The results demonstrate a substantial improvement in the average peak intensity of the light spot at the target position after closed-loop correction, with a remarkable increase of 5.35 times compared to the open-loop configuration.

Effects of Tributyrin Supplementation on Growth Performance, Intestinal Digestive Enzyme Activity, Antioxidant Capacity, and Inflammation-Related Gene Expression of Large Yellow Croaker (Larimichthys crocea) Fed with a High Level of Clostridium autoethanogenum Protein.

An 8-week growth experiment was conducted to investigate effects of tributyrin (TB) supplementation on growth performance, intestinal digestive enzyme activity, antioxidant capacity, and inflammation-related gene expression of juvenile large yellow croaker (Larimichthys crocea) (initial weight of 12.90 ± 0.02 g) fed diets with high level of Clostridium autoethanogenum protein (CAP). In the negative control diet, 40% fish meal was used as the major source of protein (named as FM), while 45% fish meal protein of FM was substituted with CAP (named as FC) to form a positive control diet. Based on the FC diet, grade levels of 0.05%, 0.1%, 0.2%, 0.4%, and 0.8% tributyrin were added to formulate other five experimental diets. Results showed that fish fed diets with high levels of CAP significantly decreased the weight gain rate (WGR) and specific growth rate (SGR) compared with fish fed the FM diet (P < 0.05). WGR and SGR were significantly higher than in fish fed diets with 0.05% and 0.1% tributyrin that fed the FC diet (P < 0.05). Supplementation of 0.1% tributyrin significantly elevated fish intestinal lipase and protease activities compared to FM and FC diets (P < 0.05). Meanwhile, compared to fish fed the FC diet, fish fed diets with 0.05% and 0.1% tributyrin showed remarkably higher intestinal total antioxidant capacity (T-AOC). Malondialdehyde (MDA) content in the intestine of fish fed diets with 0.05%-0.4% tributyrin was remarkably lower than those in the fish fed the FC diet (P < 0.05). The mRNA expressions of tumor necrosis factor α (tnfα), interleukin-1ß (il-1ß), interleukin-6 (il-6), and interferon γ (ifnγ) were significantly downregulated in fish fed diets with 0.05%-0.2% tributyrin, and the mRNA expression of il-10 was significantly upregulated in fish fed the 0.2% tributyrin diet (P < 0.05). In regard to antioxidant genes, as the supplementation of tributyrin increased from 0.05% to 0.8%, the mRNA expression of nuclear factor erythroid 2-related factor 2 (nrf2) demonstrated a trend of first rising and then decreasing. However, the mRNA expression of Kelch-like ECH-associated protein 1 (keap1) was remarkably lower in fish fed the FC diet than that fed diets with tributyrin supplementation (P < 0.05). Overall, fish fed tributyrin supplementation diets can ameliorate the negative effects induced by high proportion of CAP in diets, with an appropriate supplementation of 0.1%.

Vitamin D impacts on the intestinal health, immune status and metabolism in turbot (Scophthalmus maximus L.).

Vitamin D (VD) plays a vital role in various physiological processes in addition to its classic functions on maintaining the balance of Ca and P metabolism. However, there still are gaps to understand in depth the issues on the precise requirement, metabolic processes and physiological functions of VD in fish. In this study, we investigated the effects of VD on the growth, intestinal health, host immunity and metabolism in turbot (Scophthalmus maximus L.), one important commercial carnivorous fish in aquaculture, through the supplementation of different doses of dietary VD3 (0, 200, 400, 800 and 1600 µg VD3/kg diet). According to our results, the optimal VD3 level in the feed for turbot growth was estimated to be around 400 IU/kg, whereas VD3 deficiency or overdose in diets induced the intestinal inflammation, lowered the diversity of gut microbiota and impaired the host resistance to bacterial infection in turbot. Moreover, the level of 1α,25(OH)2D3, the active metabolite of VD3, reached a peak value in the turbot serum in the 400 µg group, although the concentrations of Ca and phosphate in the turbot were stable in all groups. Finally, the deficiency of dietary VD3 disturbed the nutritional metabolism in turbot, especially the metabolism of lipids and glucose. In conclusion, this study evaluated the optimal dose of dietary VD3 for turbot and provided the evidence that VD has a significant impact on intestinal health, host immunity and nutritional metabolism in fish, which deepened our understanding on the physiological functions and metabolism of VD3 in fish.