Iron oxide nanozyme suppresses intracellular Salmonella Enteritidis growth and alleviates infection in vivo

Rosmarinic Acid Attenuates Salmonella enteritidis-Induced Inflammation via Regulating TLR9/NF-κB Signaling Pathway and Intestinal Microbiota

Salmonella enteritidis (SE) infection disrupts the homeostasis of the intestinal microbiota, causing an intestinal inflammatory response and posing a great threat to human and animal health. The unreasonable use of antibiotics has led to an increase in the prevalence of drug-resistant SE, increasing the difficulty of controlling SE. Therefore, new drug strategies and research are urgently needed to control SE. Rosmarinic acid (RA) is a natural phenolic acid with various pharmacological activities, including antioxidant, anti-inflammatory and antibacterial properties. However, the protective effects and mechanism of RA on intestinal inflammation and the gut microbial disorders caused by SE have not been fully elucidated. In this study, RAW264.7 cells, MCECs and BALB/c mice were challenged with SE to assess the protective effects and mechanisms of RA. The results showed that RA enhanced the phagocytic ability of RAW264.7 cells, reduced the invasion and adhesion ability of SE in MCECs, and inhibited SE-induced inflammation in cells. Moreover, RA inhibited the activation of the NF-κB signaling pathway by upregulating TLR9 expression. Importantly, we found that RA provided protection against SE and increased the diversity and abundance of the intestinal microbiota in mice. Compared with infection control, RA significantly increased the abundance of Firmicutes and Acidibacteria and decreased the abundance of Proteobacteria, Epsilonbacteraeota and Bacteroidota. However, RA failed to alleviate SE-induced inflammation and lost its regulatory effects on the TLR9/NF-κB signaling pathway after destroying the gut microbiota with broad-spectrum antibiotics. These results indicated that RA attenuated SE-induced inflammation by regulating the TLR9/NF-κB signaling pathway and maintaining the homeostasis of the gut microbiota. Our study provides a new strategy for preventing SE-induced intestinal inflammation.

Advancements in wound management: integrating nanotechnology and smart materials for enhanced therapeutic interventions

Wound management spans various techniques and materials tailored to address acute and chronic non-healing wounds, with the primary objective of achieving successful wound closure. Chronic wounds pose additional challenges, often necessitating dressings to prepare the wound bed for subsequent surgical procedures like skin grafting. Ideal dressing materials should not only expedite wound healing but also mitigate protein, electrolyte, and fluid loss while minimizing pain and infection risk. Nanotechnology has emerged as a transformative tool in wound care, revolutionizing the landscape of biomedical dressings. Its application offers remarkable efficacy in accelerating wound healing and combating bacterial infections, representing a significant advancement in wound care practices. Integration of nanotechnology into dressings has resulted in enhanced properties, including improved mechanical strength and controlled drug release, facilitating tailored therapeutic interventions. This review article comprehensively explores recent breakthroughs in wound healing therapies, with a focus on innovative medical dressings such as nano-enzymes. Additionally, the utilization of smart materials, like hydrogels and electroactive polymers, in wound dressings offers dynamic functionalities to promote tissue regeneration. Emerging concepts such as bio-fabrication, microfluidic systems, bio-responsive scaffolds, and personalized therapeutics show promise in expediting wound healing and minimizing scarring. Through an in-depth exploration of these advancements, this review aims to catalyze a paradigm shift in wound care strategies, promoting a patient-centric approach to therapeutic interventions.

Nanozymes and their biomolecular conjugates as next-generation antibacterial agents: A comprehensive review

Antimicrobial resistance (AMR), the ability of bacterial species to develop resistance against exposed antibiotics, has gained immense global attention in the past few years. Bacterial infections are serious health concerns affecting millions of people annually worldwide. Therefore, developing novel antibacterial agents that are highly effective and avoid resistance development is imperative. Among various strategies, recent developments in nanozyme technology have shown promising results as antibacterials in several antibiotic-sensitive and resistant bacterial species. Nanozymes offer several advantages over corresponding natural enzymes, such as inexpensive, stable, multifunctional, tunable catalytic properties, etc. Although the use of nanozymes as antibacterial agents has provided promising results, the specific biomolecule-conjugated nanozymes have shown further improvement in catalytic performance and associated antibacterial efficacy. The exclusive design of functional nanozymes with theranostic potential is found to simultaneously inhibit the growth and image of AMR bacterial species. This review comprehensively summarizes the history of nanozymes, their classification, biomolecules conjugated nanozyme, and their mechanism of enzyme-mimetic activity and associated antibacterial activity in antibiotic-sensitive and resistant species. The futureneeds to effectively engineer the existing or new nanozymes to curb AMR have also been discussed.

Combinatorial therapeutic enzymes to combat multidrug resistance in bacteria

AIMS

Antibiotic resistance including multidrug resistance (MDR) is a negative symbol to the human health system because it loses the capability to treat infections. Unfortunately, the available antibiotics do not show an effective therapeutic response against bacterial infections. In the situation of global antibiotic unresponsiveness, enzymatic therapy especially in combinatorial form seems an effective approach to control bacterial infection and combat resistance. The article is important because it focuses on combinatorial enzymatic therapy that has multiple properties (effective antibacterial performances, antibiofilm capacity, immunomodulators, targeted actions, synergistic actions, multiple targeting, and resistance-proof properties) and can address antibiotic resistance effectively.

MATERIALS AND METHODS

We searched the related topics with Pubmed, Scopus, and Google Scholar databases and finally 73 relevant papers were reviewed in detail and cited in this article.

KEY FINDINGS

Discusses properties of combinatorial therapeutic enzymes made it an accomplished means over antibiotic therapy. This article discusses the need for combinatorial enzymatic therapy against bacterial infection, its distinguished features, and properties with multi-mechanistic antibacterial action. It discussed the European Medicine Agency and Food and Drug Administration-approved therapeutic enzymes (antibacterial and antibiofilm).

SIGNIFICANCE

This article provided the possible combination of the enzyme that may be used as an antibacterial agent along with limitations and future scope of combinatorial antibacterial enzymatic agents. This article could draw the attention of researchers to combinatorial therapeutic enzymatic molecules as effective and futuristic therapy to overcome the problem of multiple antibiotic resistance in bacteria.

Nanozybiotics: Advancing Antimicrobial Strategies Through Biomimetic Mechanisms

Infectious diseases caused by bacterial, viral, and fungal pathogens present significant global health challenges. The rapid emergence of antimicrobial resistance exacerbates this issue, leading to a scenario where effective antibiotics are increasingly scarce. Traditional antibiotic development strategies are proving inadequate against the swift evolution of microbial resistance. Therefore, there is an urgent need to develop novel antimicrobial strategies with mechanisms distinct from those of existing antibiotics. Nanozybiotics, which are nanozyme-based antimicrobials, mimic the catalytic action of lysosomal enzymes in innate immune cells to kill infectious pathogens. This review reinforces the concept of nanozymes and provides a comprehensive summary of recent research advancements on potential antimicrobial candidates. Initially, nanozybiotics are categorized based on their activities, mimicking either oxidoreductase-like or hydrolase-like functions, thereby highlighting their superior mechanisms in combating antimicrobial resistance. The review then discusses the progress of nanozybiotics in treating bacterial, viral, and fungal infections, confirming their potential as novel antimicrobial candidates. The translational potential of nanozybiotic-based products, including hydrogels, nanorobots, sprays, bandages, masks, and protective clothing, is also considered. Finally, the current challenges and future prospects of nanozybiotic-related products are explored, emphasizing the design and antimicrobial capabilities of nanozybiotics for future applications.

Nanomaterials with Enzyme-like Properties for Combatting Foodborne Pathogen Infections: Classifications, Mechanisms, and Applications in Food Preservation

During the transportation and storage of food, foodborne spoilage caused by bacterial and biofilm infection is prone to occur, leading to issues such as short shelf life, economic loss, and sensory quality instability. Therefore, the development of novel and efficient antibacterial agents capable of efficiently inhibiting bacteria throughout various stages of food processing, transportation, and storage is strongly recommended by researchers. The emergence of nanozymes is considered to be an effective candidate for inhibiting foodborne bacteria agents in the food industry. As potent antibacterial agents, nanozymes have the advantages of low cost, high stability, strong broad-spectrum antibacterial ability, and biocompatibility. Herein, we aim to summarize the classification status of various nanozymes. Furthermore, the general catalytic bacteriostatic mechanism of nanozymes against intracellular bacteria, planktonic bacteria, and biofilm activities are highlighted, mainly concerning the destruction of cell walls and/or membranes, reactive oxygen species regulation, HOBr/Cl generation, damage of intracellular components, and so forth. In particular, the review focuses on the pivotal role of nanozymes as antibacterial agents and delivery vehicles in the fields of food preservation applications. We look forward to the future prospects, especially in the field of food preservation, to promote broader applications based on antimicrobial nanozymes.

A Comparative Analysis of the Antibacterial Spectrum of Ultrasmall Manganese Ferrite Nanozymes with Varied Surface Modifications

Bacterial infectious diseases pose a significant global challenge. However, conventional antibacterial agents exhibit limited therapeutic effectiveness due to the emergence of drug resistance, necessitating the exploration of novel antibacterial strategies. Nanozymes have emerged as a highly promising alternative to antibiotics, owing to their particular catalytic activities against pathogens. Herein, we synthesized ultrasmall-sized MnFe2O4 nanozymes with different charges (MnFe2O4-COOH, MnFe2O4-PEG, MnFe2O4-NH2) and assessed their antibacterial capabilities. It was found that MnFe2O4 nanozymes exhibited both antibacterial and antibiofilm properties attributed to their excellent peroxidase-like activities and small sizes, enabling them to penetrate biofilms and interact with bacteria. Moreover, MnFe2O4 nanozymes effectively expedite wound healing within 12 days and facilitate tissue repair and regeneration while concurrently reducing inflammation. MnFe2O4-COOH displayed favorable antibacterial activity against Gram-positive bacteria, with 80% bacterial removal efficiency against MRSA by interacting with phosphatidylglycerol (PG) and cardiolipin (CL) of the membrane. By interacting with negatively charged bacteria surfaces, MnFe2O4-NH2 demonstrated the most significant and broad-spectrum antibacterial activity, with 95 and 85% removal efficiency against methicillin-resistant Staphylococcus aureus (MRSA) and P. aeruginosa, respectively. MnFe2O4-PEG dissipated membrane potential and reduced ATP levels in MRSA and P. aeruginosa, showing relatively broad-spectrum antibacterial activity. To conclude, MnFe2O4 nanozymes offer a promising therapeutic approach for treating wound infections.

Comparative efficacy of difloxacin and nano-emulsion difloxacin as antibacterial agents against Salmonella enterica Serovar enteritidis in chickenss

Background

Avian salmonellosis is a group of diseases caused by bacteria from the genus Salmonella with a negative impact on poultry, particularly chickens. In addition, salmonellosis is a global food-borne infection.

Aim

The aim of this study was to evaluate the effect of nano-emulsion difloxacin (NED) and commercial difloxacin (CD) water supplement on broiler's growth, feed intake, and body weight, weight gain, growth rate, feed conversion ratio (FCR), and mortality rate (MR). The antibiotic sensitivity was determined both in-vivo and in-vitro for NED against Salmonella enterica Serovar enteritidis in chickens.

Methods

1500 one-day of age chicks were grouped into five groups as follows: group 1 (G1) control negative group, G2 control positive group (infected and not treated), G3 (infected and treated with CD, and G4 and G5 (infected and treated with NED at different doses). Samples, including the intestine, liver, and spleen were collected. Agar well diffusion test and minimum inhibitory concentrations were adopted. Histopathological lesions on different tissues were studied. During 35 days of the experiment, the feed intake, growth rate, growth gain, FCR, and MR were recorded daily. In addition, a variety of analytical techniques including transmission electron microscopic analysis, dynamic light scattering, UV-visible spectroscopy, and zeta-potential analysis were applied to characterize NED.

Results

The agar well diffusion test indicated that NED was in-vitro effective against S. enteritidis isolates than CD. The minimum inhibitory concentration was recorded as NED inhibited bacterial growth till well 8 at a concentration of 0.78 µg/ml; on the other hand, the CD inhibited bacterial growth till well 6 at a concentration of 0.62 µg/ml. Growth performance and MRs in the groups treated with NED are significantly reduced.

Conclusion

Treatment of broiler's drinking water with NED at doses of 0.5 and 1 ml instead of pure CD was able to enforce a new perspective, antibacterial efficacy, enhancing the productive performance, and reducing the MRs of broilers.

Advancing biofilm management through nanoformulation strategies: a review of dosage forms and administration routes

Biofilms are complex microbial communities formed by the attachment of bacteria or fungi to surfaces encased in a self-produced polymeric matrix. These biofilms are highly resistant to conventional antimicrobial therapies. The resistance mechanisms exhibited by biofilms include low antibiotic absorption, sluggish replication, adaptive stress response, and the formation of dormant-like phenotypes. The eradication of biofilms requires alternative strategies and approaches. Nanotechnological drug delivery systems allow excellent control over the drug chemistry, surface area, particle size, particle shape, and composition of nanostructures. Nanoformulations can enhance the efficacy of antimicrobial agents by improving their bioavailability, stability, and targeted delivery to the site of infection that helps biofilm eradication more effectively. In addition to nanoformulations, the route of administration and choice of dosage forms play a crucial role in treating biofilm infections. Systemic administration of antibiotics is effective in controlling systemic infection and sepsis associated with biofilms. Alternative routes of administration, such as inhalation, vaginal, ocular, or dermal, have been explored to target biofilm infections in specific organs. This review primarily examines the utilisation of nanoformulations in various administration routes for biofilm management. It also provides an overview of biofilms, current approaches, and the drawbacks associated with conventional methods.

Sodium Humate-Derived Gut Microbiota Ameliorates Intestinal Dysfunction Induced by Salmonella Typhimurium in Mice

Salmonella is a foodborne pathogen that is one of the main causes of gastroenteric disease in humans and animals. As a natural organic substance, sodium humate (HNa) possesses antibacterial, antidiarrheal, and anti-inflammatory properties. However, it is unclear whether the HNa and HNa-derived microbiota exert alleviative effects on Salmonella enterica serovar Typhimurium-induced enteritis. We found that treatment with HNa disrupted the cell wall of S. Typhimurium and decreased the virulence gene expression. Next, we explored the effect of HNa presupplementation on S. Typhimurium-induced murine enteritis. The results revealed that HNa ameliorated intestinal pathological damage. In addition, we observed that presupplementation with HNa enhanced intestinal barrier function via modulating gut microbiota, downregulating toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) and NOD-like receptor protein 3 (NLRP3) signaling pathways, regulating intestinal mucosal immunity, and enhancing tight junction protein expression. To further validate the effect of HNa-derived microbiota on S. Typhimurium-induced enteritis, we performed fecal microbiota transplantation and found that HNa-derived microbiota also alleviated S. Typhimurium-induced intestinal damage. It is noteworthy that both HNa and HNa-derived microbiota improved the liver injury caused by S. Typhimurium infection. Collectively, this is the first study to confirm that HNa could alleviate S. Typhimurium-induced enteritis in a gut microbiota-dependent manner. This study provides a new perspective on HNa as a potential drug to prevent and treat salmonellosis. IMPORTANCE Salmonella Typhimurium is an important zoonotic pathogen, widely distributed in nature. S. Typhimurium is one of the leading causes of foodborne illnesses worldwide, and more than 350,000 people died from Salmonella infection each year, which poses a substantial risk to public health and causes a considerable economic loss. Here, we found that the S. Typhimurium infection caused severe intestinal and liver damage. In addition, we first found that sodium humate (HNa) and HNa-derived gut microbiota can alleviate S. Typhimurium infection-induced intestinal damage. These findings extend the knowledge about the public health risk and pathogenic mechanisms of S. Typhimurium.

Nanomaterials for the treatment of bacterial infection by photothermal/photodynamic synergism

In the past few decades, great progress has been made in the field of nanomaterials against bacterial infection. However, with the widespread emergence of drug-resistant bacteria, people try their best to explore and develop new antibacterial strategies to fight bacteria without obtaining or increasing drug resistance. Recently, multi-mode synergistic therapy has been considered as an effective scheme for the treatment of bacterial infections, especially the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) with controllable, non-invasive, small side effects and broad-spectrum antibacterial characteristics. It can not only improve the efficiency of antibiotics, but also do not promote antibiotic resistance. Therefore, multifunctional nanomaterials which combine the advantages of PTT and PDT are more and more used in the treatment of bacterial infections. However, there is still a lack of a comprehensive review of the synergistic effect of PTT and PDT in anti-infection. This review first focuses on the synthesis of synergistic photothermal/photodynamic nanomaterials and discusses the ways and challenges of photothermal/photodynamic synergism, as well as the future research direction of photothermal/photodynamic synergistic antibacterial nanomaterials.

Synthesis of Ti3C2T x /MnO2 composites for synergistic catalytic/photothermal-based bacterial inhibition

Human inflammation caused by bacterial infection threatens global public health. The abuse of antibiotics often leads to the development of drug resistance in bacteria. To address this issue, nanozymes with peroxidase-like (POD-like) activity have often been reported for bacteriostasis with the assistance of catalytic substrate hydrogen peroxide (H2O2). However, it is difficult to achieve efficient bactericidal outcomes only through exertion of the POD-like activity of nanozymes. Here, MnO2 loaded Ti3C2T x (Ti3C2T x /MnO2) was prepared by a two-step reaction method, in which MnO2 showed high oxidase-like (OXD-like) activity to elevate the levels of reactive oxygen species (ROS) without H2O2 and Ti3C2T x exhibited high photothermal conversion efficiency to induce hyperthermia. Thus, the obtained Ti3C2T x /MnO2 realized synergistic catalytic/photothermal-based bacterial inhibition, including for Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and methicillin-resistant Staphylococcus aureus. Importantly, Ti3C2T x /MnO2 with near-infrared light irradiation successfully promoted Staphylococcus aureus-infected wound healing in mouse models, representing an alternative treatment to fight against bacterial infection.

Metal-Based Nanozymes with Multienzyme-Like Activities as Therapeutic Candidates: Applications, Mechanisms, and Optimization Strategy

Most nanozymes in development for medical applications only exhibit single-enzyme-like activity, and are thus limited by insufficient catalytic activity and dysfunctionality in complex pathological microenvironments. To overcome the impediments of limited substrate availabilities and concentrations, some metal-based nanozymes may mimic two or more activities of natural enzymes to catalyze cascade reactions or to catalyze multiple substrates simultaneously, thereby amplifying catalysis. Metal-based nanozymes with multienzyme-like activities (MNMs) may adapt to dissimilar catalytic conditions to exert different enzyme-like effects. These multienzyme-like activities can synergize to realize "self-provision of the substrate," in which upstream catalysts produce substrates for downstream catalytic reactions to overcome the limitation of insufficient substrates in the microenvironment. Consequently, MNMs exert more potent antitumor, antibacterial, and anti-inflammatory effects in preclinical models. This review summarizes the cellular effects and underlying mechanisms of MNMs. Their potential medical utility and optimization strategy from the perspective of clinical requirements are also discussed, with the aim to provide a theoretical reference for the design, development, and therapeutic application of their catalytic effects.

Prospects of coupled iron-based nanostructures in preclinical antibacterial therapy

Bacterial infections can threaten human health. Drug-resistant bacteria have become a challenge because of the excessive use of drugs. We summarize the current metallic antibacterial materials, especially Fe-based materials, for efficiently killing bacteria. The possible antibacterial mechanisms of metallic antibacterial agents are classified into interactions with bacterial proteins, iron metabolism, catalytic activity, and combinations of magnetic, photodynamic, and photothermal effects. This review will inspire the development of novel Fe-based antibacterial agents for clinical settings.

The DNA adenine methylase of Salmonella Enteritidis promotes their intracellular replication by inhibiting arachidonic acid metabolism pathway in macrophages

Macrophages can participate in immune responses by altering their metabolism, and play important roles in controlling bacterial infections. However, Salmonella Enteritidis can survive and proliferate in macrophages. After the deletion of DNA adenine methylase (Dam), the proliferation of Salmonella Enteritidis in macrophages decreased, the molecular mechanism is still unclear. After infecting macrophages with Salmonella Enteritidis wild type and dam gene deletion strains, intracellular metabolites were extracted and detected by non-targeted metabolomics and fatty acid targeted metabolomics. We found Dam had significant effects on arachidonic acid and related metabolic pathways in macrophages. The dam gene can promote the proliferation of Salmonella Enteritidis in macrophages by inhibiting the metabolic pathway of cytosolic phospholipase A2-mediated arachidonic acid production and conversion to prostaglandin E2 in macrophages, reducing the secretion of the pro-inflammatory factors IL-1β and IL-6. In addition, inhibition of arachidonic acid-related pathways in macrophages by Arachidonyl trifluoromethyl ketone could restore the proliferation of dam gene deletion strains in macrophages. This study explored the role of Dam in the process of Salmonella Enteritidis invading host cells from the perspective of host cell metabolism, and provides new insights into the immune escape mechanism of Salmonella Enteritidis.

Nanomaterials against intracellular bacterial infection: from drug delivery to intrinsic biofunction

Fighting intracellular bacteria with strong antibiotics evading remains a long-standing challenge. Responding to and regulating the infectious microenvironment is crucial for treating intracellular infections. Sophisticated nanomaterials with unique physicochemical properties exhibit great potential for precise drug delivery towards infection sites, along with modulating infectious microenvironment via their instinct bioactivity. In this review, we first identify the key characters and therapeutic targets of intracellular infection microenvironment. Next, we illustrate how the nanomaterials physicochemical properties, such as size, charge, shape and functionalization affect the interaction between nanomaterials, cells and bacteria. We also introduce the recent progress of nanomaterial-based targeted delivery and controlled release of antibiotics in intracellular infection microenvironment. Notably, we highlight the nanomaterials with unique intrinsic properties, such as metal toxicity and enzyme-like activity for the treatment of intracellular bacteria. Finally, we discuss the opportunities and challenges of bioactive nanomaterials in addressing intracellular infections.

Sodium humate alters the intestinal microbiome, short-chain fatty acids, eggshell ultrastructure, and egg performance of old laying hens

This study investigated the effect of sodium humate supplementation on changes in the intestinal microbiome, intestinal short-chain fatty acids production, and trace element absorption in older laying hens, with consequent effects on egg performance and shell quality. We used the same hens as their own control; a total of 720 laying hens aged 422 days were randomly divided into three replicates, with the CON group fed a commercial diet at 422–441 days of age and the HANa group fed a commercial diet supplemented with 0.05% sodium humate at 442–461 days of age. Compared with the CON group, in the HANa group, Bacteroidetes and Actinobacteria were significantly increased, whereas, Firmicutes was significantly decreased. Further, Veillonella, Enterococcus, Lactobacillus, and Turricibacter significantly decreased, and Peptoniphilus, Helcococcus, GW-34, Psychrobacter, Anaerococcus, Corynebacterium, Facklamia, Trichococcus, Gallicola, Clostridium, and Oscillospira were significantly increased. The results showed that sodium humate significantly altered the alpha and beta diversity and changed the structure of the intestinal microbiome. Acetic acid, isovaleric acid, and isobutyric acid, among short-chain fatty acids were significantly increased in the HANa group, whereas trace elements such as Mn, Zn, and Fe were significantly reduced. The eggshell strength and ultrastructure were significantly altered. In this study, sodium humate was found to alter the intestinal microbiome structure of aged hens, change the production of short-chain fatty acids, and promote the absorption of trace elements to keep aged hens from experiencing a decrease in egg production performance.

Supplementation with paraformic acid in the diet improved intestinal development through modulating intestinal inflammation and microbiota in broiler chickens

The aim of this study was to explore the effects of supplementing paraformic acid (PFA) to the diet of broiler chickens on intestinal development, inflammation, and microbiota. A total of 378 healthy 1-day-old Arbor Acres broilers with similar birth weight were used in this study, and randomly assigned into two treatment groups. The broiler chickens were received a basal diet or a basal diet supplemented with 1,000 mg/kg PFA. Results showed that PFA supplementation increased (P < 0.05) small intestinal villus height and villus height/crypt depth ratio, elevated intestinal mucosal factors (mucin 2, trefoil factor family, and zonula occludens-1) concentrations, and upregulated mNRA expression of y + L amino acid transporter 1. Moreover, PFA supplementation decreased (P < 0.05) the concentrations of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-10), activities of caspase-3 and caspase-8, and mNRA expressions of Toll-like Receptor 4, nuclear factor-kappa B, Bax, and Bax/Bcl-2 ratio in small intestinal mucosa. Dietary PFA supplementation also increased (P < 0.05) alpha diversity of cecal microbiota and relative abundance of Alistipes. The present study demonstrated that supplementation of 1,000 mg/kg PFA showed beneficial effects in improving intestinal development, which might be attributed to the suppression of intestinal inflammation and change of gut microbiota composition in broiler chickens. These findings will aid in our knowledge of the mechanisms through which dietary PFA modulates gut development, as well as support the use of PFA in poultry industry.

Tannic Acid Extracted from Galla chinensis Supplementation in the Diet Improves Intestinal Development through Suppressing Inflammatory Responses via Blockage of NF-κB in Broiler Chickens

The objective of this study was to investigate the effects of adding tannic acid (TA) extracted from Galla chinensis to the diet of broiler chickens on intestinal development. A total of 324 healthy 1-day-old broilers were used in a 42 d study, and divided into two treatment groups at random (six replicates per group). Broilers were either received a basal diet or a basal diet supplemented with 300 mg/kg microencapsulated TA extracted from Galla chinensis. The results showed that dietary supplemented with 300 mg/kg TA from Galla chinensis improved intestinal morphology, promoted intestinal mucosal barrier integrity, and elevated mucosal expressions of nutrients transporters and tight junction protein CLDN3 in broilers. Besides, 300 mg/kg TA from Galla chinensis supplementation decreased the concentrations of inflammatory cytokines in serum and intestinal mucosa and reduced the mRNA expression of NF-κB in intestinal mucosa. Above all, supplementation of 300 mg/kg microencapsulated TA extracted from Galla chinensis showed beneficial effects in improving intestinal development, which might be attributed to the suppression of inflammatory responses via blockage of NF-κB in broiler chickens. These findings will support the use of TA sourced from Galla chinensis in poultry industry.

Emerging nanozyme-based multimodal synergistic therapies in combating bacterial infections

Pathogenic infections have emerged as major threats to global public health. Multidrug resistance induced by the abuse of antibiotics makes the anti-infection therapies to be a global challenge. Thus, it is urgent to develop novel, efficient and biosafe antibiotic alternatives for future antibacterial therapy. Recently, nanozymes have emerged as promising antibiotic alternatives for combating bacterial infections. More significantly, the multimodal synergistic nanozyme-based antibacterial systems open novel disinfection pathways. In this review, we are mainly focusing on the recent research progress of nanozyme-based multimodal synergistic therapies to eliminate bacterial infections. Their antibacterial mechanism, the synergistic antibacterial systems are systematically summarized and discussed according to the combination of mechanisms and the purpose to improve their antibacterial efficiency, biosafety and specificity. Finanly, the current challenges and prospects of the multimodal synergistic antibacterial systems are proposed.

Effects of Dietary Macleaya cordata Extract Containing Isoquinoline Alkaloids Supplementation as an Alternative to Antibiotics in the Diets on Growth Performance and Liver Health of Broiler Chickens

This study aimed to investigate the effects of dietary supplementation with Macleaya cordata extract (MCE) containing protopine and allotypotopine on the growth performance and liver health in broiler chickens. A total of 486 1-day-old male AA broiler chickens were randomly assigned to the following three groups: (1) control (CON) group, broiler chickens fed a basal diet; (2) AGP group (positive control), broiler chickens fed a basal diet supplemented with 50 mg/kg aureomycin; (3) MCE group, broiler chickens fed a basal diet supplemented with 0.6 mg/kg MCE including 0.4 mg/kg protopine and 0.2 mg/kg allotypotopine. The results showed that the MCE group had significantly higher final body weight and average daily gain from d 0 to 42 than the other groups (p < 0.05), and groups MCE and AGP both had significantly lower feed-to-gain ratio from d 0 to 42 than the CON group (p < 0.05). Serum total protein, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, glucose, immunoglobulin A, immunoglobulin M, and complements (C3, C4) concentrations in the MCE group were significantly higher than in the CON group (p < 0.05). Dietary MCE or aureomycin supplementation significantly reduced the hepatic contents of 8-hydroxy-2'-deoxyguanosine, malondialdehyde, interleukin (IL)-1β, IL-6, NLRs family pyrin domain containing 3 (NLRP3), and caspase-1 in the liver (p < 0.05). Moreover, MCE or aureomycin supplementation significantly inhibited mRNA expressions of Toll-like receptor 4, myeloid differentiation factor 88, nuclear factor-κB, and NLRP3, as well as the expression ratio of Bax to Bcl-2 mRNA (p < 0.05). Therefore, our study suggested that dietary supplementation with 0.6 mg/kg MCE containing protopine and allocryptopine improved growth performance and benefited liver health in broiler chickens possibly through inhibiting caspase-1-induced pyroptosis by inactivating TLR4/MyD88/NF-κB/NLRP3 signaling pathway, and provided support for the application of MCE containing protopine and allocryptopine as an alternative to antibiotics in the feed industry.

Immobilization of Superoxide Dismutase in Mesoporous Silica and its Applications in Strengthening the Lifespan and Healthspan of Caenorhabditis elegans

Senescence is a major inductive factor of aging-related diseases in connection with an accumulation of reactive oxygen species (ROS). Therefore, it is important to maintain ROS at an appropriate level to keep homeostasis in organisms. Superoxide dismutase (SOD) is a vital enzyme in defending against oxidative damage in vivo. Because of the defects in the direct application of SOD and SOD mimics, mounting delivery systems have been developed for the efficient applications of SOD to realize antioxidant treatment. Among these systems, mesoporous silica nanoparticles (MSNs) have been widely studied because of various advantages such as desirable stability, low toxicity, and adjustable particle sizes. Herein, SOD was immobilized on MSNs using a physical absorption strategy to construct the nanosystem SOD@MSN. The nematode Caenorhabditis elegans (C. elegans) was selected as the model organism for the subsequent antioxidant and anti-aging studies. The research results suggested the nanosystem could not only be effectively internalized by C. elegans but could also protect the nematode against external stress, thus extending the lifespan and healthspan of C. elegans. Therefore, SOD@MSN could be applied as a promising medicine in anti-aging therapeutics.

Responses of Combined Non-starch Polysaccharide Enzymes and Protease on Growth Performance, Meat Quality, and Nutrient Digestibility of Yellow-Feathered Broilers Fed With Diets With Different Crude Protein Levels

The aim of this study was to investigate the responses of non-starch polysaccharide (NSP) enzymes and protease combination on growth performance, meat quality, and nutrients digestibility of yellow-feathered broilers fed with corn-soybean meal basal diets with normal and subnormal crude protein (CP) levels. The experimental design was completely randomized with a 2 × 2 factorial arrangement of treatments, including six replicates of 20 birds per pen. Two basal diets were formulated with normal CP level as positive control (PC) and subnormal CP level without extra essential amino acid (AA) supplementation as negative control (NC). The basal diets were supplemented without or with NSP enzymes and protease. Broilers fed with the NC diet had lower (P < 0.05) final body weight (BW), average daily weight gain (ADG) on days 1–21, 22–56 and 1–56 and higher (P < 0.05) feed-to-gain ratio (F/G) on day 22–56 than those fed with PC diet. The broilers fed with the NC diet had higher (P < 0.05) L^* and b^* values in thigh muscle, crypt depth in the duodenum, and dry matter (DM) digestibility as well as lower (P < 0.05) villus height, musculature thicknesses, and villus height: crypt depth in the duodenum than those fed with the PC diet. Dietary NSP enzymes and protease combination increased (P < 0.05) the ADG and F/G of the broilers on days 1–56, and pH values in breast and thigh muscles as well as the digestibility of DM, gross energy (GE), CP and most AAs of the broilers on day 56. Compared with the PC diet, the combination of NSP enzymes and protease exhibited greater (P < 0.05) improvements in the digestibility of DM, CP, and some AAs (Asp, Ile, and Leu) in the broilers fed with the NC diet. In conclusion, reducing CP diet without essential AA supplementation impaired the growth performance and meat color of the thigh muscles of the broilers. The combination of NSP enzymes and protease effectively improved the growth performance, meat quality, and nutritional values of the broilers. In terms of the digestibility of DM, CP, and some AAs, the magnitude of response to the addition of NSP enzymes and protease was greater in the low nutritional-quality diet with a subnormal CP level.

Maternal Dietary Forsythia suspensa Extract Supplementation Induces Changes in Offspring Antioxidant Status, Inflammatory Responses, Intestinal Development, and Microbial Community of Sows

This experiment aims to investigate the effect of maternal diet supplemented with Forsythia suspensa extract (FSE) on the performance, antioxidant status, inflammatory responses, intestinal development, and microbial community of sows. A total of 24 gestating sows (Landrace × Yorkshire) were assigned to 2 treatments with 12 sows per treatment. From d 107 of gestation to d 21 of lactation, sows were supplemented with a basal diet as control (CON) or an FSE diet (basal diet + 100 mg/kg FSE). Compared with CON, sows fed FSE showed lower (P &lt; 0.05) wean-to-estrus interval, body weight loss, and higher (P &lt; 0.05) average daily gain of suckling piglet. Sows fed FSE had reduced (P &lt; 0.05) serum malondialdehyde (MDA) content and enhanced (P &lt; 0.05) catalase and glutathione peroxidase (GSH-Px) contents at farrowing and weaning compared with CON. The suckling piglets of FSE-fed sows had increased (P &lt; 0.05) mRNA expressions of nuclear factor erythroid-2 related factor 2, heme oxygenase-1 in the liver, and lower (P &lt; 0.05) serum MDA content on d 0, 7, and 14 of lactation. Sows fed FSE had lower (P &lt; 0.05) serum tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) contents at farrowing and reduced (P &lt; 0.05) serum IL-6 and IL-8 contents at weaning compared with CON. Piglets from FSE-fed sows had enhanced (P ≤ 0.05) villus height and villus height to crypt depth ratio in the jejunum, and higher (P &lt; 0.05) protein expression of Occludin in jejunal mucosa compared with CON. Sows fed FSE tended to have higher (P = 0.09) relative abundance of Lactobacillus at genus level in feces at weaning compared with CON. Our results showed maternal diet supplemented with FSE in lactating sows could effectively induce improvement of performance, antioxidant status, anti-inflammatory function, intestinal morphology, barrier function, and microbial community.

Quercetin Alleviates Lipopolysaccharide-Induced Inflammatory Response in Bovine Mammary Epithelial Cells by Suppressing TLR4/NF-κB Signaling Pathway

Bovine mastitis is one of the most common clinical diseases in dairy cows, causing huge economic losses to the dairy industry. Quercetin is an important flavonoid existing in many food resources, which has attracted widespread attention as a potential anti-inflammatory and antioxidant. However, the molecular mechanism of quercetin on inflammatory responses and oxidative stress in bovine mammary epithelial cells (BMECs) induced by lipopolysaccharide (LPS) remains unknown. The objective of this study was to investigate the effects of quercetin on inflammation responses, oxidative stress, and barrier function of BMEC induced by LPS. Our results showed that BMEC viability was not affected by treatment with 50 and 100 μg/ml of quercetin and 1 μg/ml of LPS compared with control group. The results of oxidative stress indicators and related genes of barrier function indicated that 100 μg/ml of quercetin effectively protected the BMECs from damage of oxidative and barrier induced by 1 μg/ml of LPS. Moreover, the messenger RNA (mRNA) expressions of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and chemokines CXCL2, CXCL5, CCL5, and CXCL8 were markedly decreased in the LPS-treated bovine retinal endothelial cells (BRECs) with 100 μg/ml of quercetin relatively to LPS alone. More importantly, the mRNA expressions of toll-like receptor 4 (TLR4), CD14, myeloid differential protein-2 (MD2), and myeloid differentiation primary response protein (MyD88) genes involved in TLR4 signal pathway were significantly attenuated by the addition of quercetin in LPS-treated BMEC, suggesting that quercetin can inhibit the TLR4 signal pathway. In addition, immunocytofluorescence showed that quercetin significantly inhibited the nuclear translocation of NF-κB p65 in BMEC induced by LPS. Therefore, the protective effects of quercetin on inflammatory responses in LPS-induced BMEC may be due to its ability to suppress the TLR4-mediated NF-κB signaling pathway. These findings suggest that quercetin can be used as an anti-inflammatory reagent to treat mastitis induced by exogenous or endogenous LPS release.

The Effect of Bone Morphogenetic Protein 2 or Extracellular Signal-Regulated Kinase 1 Silencing on Phosphorus Utilization and Related Parameters in Primary Broiler Osteoblasts

Two experiments were conducted to study the effect of bone morphogenetic protein 2 (BMP2) or extracellular signal-regulated kinase 1 (ERK1) silencing on phosphorus (P) utilization and related parameters in primary broiler osteoblasts. Experiment 1 was carried out to select the most efficacious siRNAs against BMP2 or ERK1 for the subsequent experiment. In experiment 2, with or without the siRNA against BMP2 or ERK1, primary broiler osteoblasts were incubated in the medium supplemented with 0.0 or 2.0 mmol/L of P as NaH₂PO₄ for 12 days. The osteoblastic P utilization and related parameters were determined. The results showed that the si980 and si1003 were the most effective (P < 0.05) in inhibiting BMP2 and ERK1 expressions, respectively. The BMP2 silencing reduced (P < 0.004) the osteoblastic P retention rate, alkaline phosphatase (ALP) activity, BMP2 mRNA and protein expressions. Supplemental P increased (P = 0.0008) ALP activity. Significant interactions (P < 0.04) between the gene silencing and supplemental P level were observed in both mineralization formation and bone gal protein (BGP) content. The BMP2 silencing decreased (P < 0.05) mineralization formation at both 0.0 and 2.0 mmol/L of added P levels, but the decreased degree was greater at 2.0 mmol/L of added P level, while BMP2 silencing reduced (P < 0.05) BGP content at only 2.0 mmol/L of added P level. The ERK1 silencing decreased (P < 0.004) mineralization formation, ALP activity, BGP content, ERK1 mRNA, ERK1 and p-ERK1 protein expressions. Supplemental P increased (P < 0.03) mineralization formation, ALP activity, BGP content and p-ERK1 protein expression, but inhibited (P = 0.014) ERK1 protein expression. There was an interaction (P < 0.03) between the gene silencing and supplemental P level in the osteoblastic P retention rate. The ERK1 silencing decreased (P < 0.05) it regardless of 0.0 or 2.0 mmol/L of added P level, but the reduced degree was greater at 2.0 mmol/L of added P level. It was concluded that either BMP2 or ERK1 silencing suppressed P utilization, and thus either of them participated in regulating P utilization in primary broiler osteoblasts.

Emerging Prospects of Nanozymes for Antibacterial and Anticancer Applications

The ability of some nanoparticles to mimic the activity of certain enzymes paves the way for several attractive biomedical applications which bolster the already impressive arsenal of nanomaterials to combat deadly diseases. A key feature of such 'nanozymes' is the duplication of activities of enzymes or classes of enzymes, such as catalase, superoxide dismutase, oxidase, and peroxidase which are known to modulate the oxidative balance of treated cells for facilitating a particular biological process such as cellular apoptosis. Several nanoparticles that include those of metals, metal oxides/sulfides, metal-organic frameworks, carbon-based materials, etc., have shown the ability to behave as one or more of such enzymes. As compared to natural enzymes, these artificial nanozymes are safer, less expensive, and more stable. Moreover, their catalytic activity can be tuned by changing their size, shape, surface properties, etc. In addition, they can also be engineered to demonstrate additional features, such as photoactivated hyperthermia, or be loaded with active agents for multimodal action. Several researchers have explored the nanozyme-mediated oxidative modulation for therapeutic purposes, often in combination with other diagnostic and/or therapeutic modalities, using a single probe. It has been observed that such synergistic action can effectively by-pass the various defense mechanisms adapted by rogue cells such as hypoxia, evasion of immuno-recognition, drug-rejection, etc. The emerging prospects of using several such nanoparticle platforms for the treatment of bacterial infections/diseases and cancer, along with various related challenges and opportunities, are discussed in this review.

Comparative Study on Jejunal Immunity and Microbial Composition of Growing-Period Tibetan Pigs and Duroc × (Landrace × Yorkshire) Pigs

The gut microbiota plays vital roles in metabolizing nutrient, maintaining the intestinal epithelial barrier but also in modulating immunity. Host genetics and the pig breed are implicated in shaping gut microbiota. Tibetan pig is a unique native Chinese breed and has evolved to manifest a strong disease resistance. However, the immunity and microbiota of growing Tibetan (TP) pigs were still rarely understood. The jejunal immunity phenotype and microbial composition of TP and Duroc × (Landrace × Yorkshire) (DLY) pigs were explored through immunohistochemistry and 16S rRNA sequencing. Higher scores of clusters of differentiation 4 (CD4+) and Toll-like receptor 9 (TLR9) were observed in TP pigs than those of DLY pigs (p &lt; 0.05), as were Interleukin 10 (IL-10) and zonular occludens 1 (ZO-1) (p &lt; 0.01). Similar levels of bacterial richness and diversity were found in the jejunal microbiota of the TP and DLY pigs. However, the TP pigs showed a significantly different microbiome compared to DLY pigs at the genus level (ANOSIM; p &lt; 0.05). Pseudomonas, Stenotrophomonas, Phenylobacterium, and Sandaracinobacter were enriched in DLY pigs (p &lt; 0.05), while the Lactobacillus and Solibacillus had higher abundances in TP pigs than DLY pigs (p &lt; 0.05). Tibetan pigs have “healthier” intestinal microbial communities than DLY pigs. Close relationships were found between jejunal immune performance and the differential bacteria, Lactobacillus can enhance porcine jejunal immunity, while Stenotrophomonas will have a negative impact on porcine gut immunity.

Metastable Iron Sulfides Gram-Dependently Counteract Resistant Gardnerella Vaginalis for Bacterial Vaginosis Treatment

Bacterial vaginosis (BV) is the most common vaginal infection found in women in the world. Due to increasing drug-resistance of virulent pathogen such as Gardnerella vaginalis (G. vaginalis), more than half of BV patients suffer recurrence after antibotics treatment. Here, metastable iron sulfides (mFeS) act in a Gram-dependent manner to kill bacteria, with the ability to counteract resistant G. vaginalis for BV treatment. With screening of iron sulfide minerals, metastable Fe3 S4 shows suppressive effect on bacterial growth with an order: Gram-variable G. vaginalis >Gram-negative bacteria>> Gram-positive bacteria. Further studies on mechanism of action (MoA) discover that the polysulfide species released from Fe3 S4 selectively permeate bacteria with thin wall and subsequently interrupt energy metabolism by inhibiting glucokinase in glycolysis, and is further synergized by simultaneously released ferrous iron that induces bactericidal damage. Such multiple MoAs enable Fe3 S4 to counteract G. vaginalis strains with metronidazole-resistance and persisters in biofilm or intracellular vacuole, without developing new drug resistance and killing probiotic bacteria. The Fe3 S4 regimens successfully ameliorate BV with resistant G. vaginalis in mouse models and eliminate pathogens from patients suffering BV. Collectively, mFeS represent an antibacterial alternative with distinct MoA able to treat challenged BV and improve women health.

Associations of the T329S Polymorphism in Flavin-Containing Monooxygenase 3 With Atherosclerosis and Fatty Liver Syndrome in 90-Week-Old Hens

This study aimed to evaluate the effects of the spontaneous genetic mutation T329S in flavin-containing monooxygenase 3 (FMO3) on atherosclerosis (AS), fatty liver syndrome (FLS), and adiposity in 90-week-old layers. At 90 weeks of age, 27 FMO3 genotyped Rhode Island White chickens (consisting of nine AA hens, nine AT hens, and nine TT hens) with normal laying performance were selected. The AS lesions, incidence of FLS, fat deposition, metabolic characteristics, and production performance of these egg-layers with different FMO3 genotypes were assessed. The T329S mutation in TT hens reduced the AS lesions (P < 0.01) and altered the plasma metabolic indices more than it did in the AA and AT hens. Furthermore, it reduced the incidence of FLS, hepatic triglyceride deposition (P < 0.05), liver indices (P < 0.05), and fat deposition (P < 0.05) in the subcutis and abdomen of TT hens compared to those of AA and AT hens. Moreover, as an effect of T329S, TT hens laid a higher than average number of eggs and maintained a higher egg-laying rate from 68 to 90 weeks than AA and AT hens. Our study confirmed that the T329S mutation in FMO3 could reduce the development of AS lesions, the incidence of FLS, and fat deposition, which are associated with changes in plasma and hepatic metabolic indices and improvements in the laying performance of older layers. Our results may provide a new strategy for using the T329S mutation to improve the health status and production performance of layers during the late laying period.

Preparation, Antibacterial Potential, and Antibacterial Components of Fermented Compound Chinese Medicine Feed Additives

This experiment was conducted to compare the antibacterial ability and to identify the antibacterial components of different fermented compound Chinese medicine feed additives in order to develop one fermented compound Chinese medicine feed additive product that can effectively alleviate metritis, vaginitis, and mastitis of sows. The Oxford cup method and double dilution method were used to compare the antibacterial ability of three fermented compound Chinese medicine feed additives (A, B, and C). UHPLC-QE-MS-based untargeted metabolomics was used to identify the antibacterial components of fermented compound Chinese medicine feed additives. Results showed that among fermented compound Chinese medicine feed additives A, B, and C, additive A had the strongest ability to inhibit the growth of Staphylococcus aureus, Salmonella cholerae suis, Escherichia coli, and Streptococcus agalactiae. The MIC and MBC of additive A were the lowest for Staphylococcus aureus compared to that for the other three pathogens. The concentrations of 23 Chinese medicine ingredients (ellagic acid, guanine, camphor, L-valine, sinapine, dipropylphthalate, 3-hydroxy-5-isopropylidene-3,8-dimethyl-2,3,3a,4,5,8a-hexahydro-6(1H)-azulenone, 7-dihydroxy-2-(4-hydroxyphenyl)-8-[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]-6-(3,4,5-trihydroxyoxan-2-yl)chromen-4-one, acetylcholine, farrerol, pyrogallol, ethyl gallate, demethylwedelolactone, methyl gallate, kaempferide, gallic acid, eriodictyol, threonic acid, inositol, 3′,4′,7-trihydroxyflavanone, taxifolin, asiatic acid, and isorhamnetin) in additive A were significantly (p &lt; 0.05 or p &lt; 0.01) higher than those in additive B, respectively. It is concluded that the mixture composed of 23 active components in fermented compound Chinese medicine feed additive A plays an important role in inhibiting the growth of Staphylococcus aureus, Salmonella cholerae suis, Escherichia coli, and Streptococcus agalactiae.

Effects of Catalase on Growth Performance, Antioxidant Capacity, Intestinal Morphology, and Microbial Composition in Yellow Broilers

The objective of this experiment was to study the effects of catalase (CAT) on growth performance, antioxidant capacity, intestinal morphology, and microbial composition of yellow broilers. Male Lingnan yellow broilers (360), aged 1 day, were randomly divided into control group (CON) (fed with a basic diet), R1 group (fed with basic diet + 150 U/kg catalase), and R2 group (fed with basic diet + 200 U/kg catalase). Each group had 8 replicates and 15 chickens in each replicate. The test is divided into the early stage (1–30 days) and the later stage (31–60 days). The results showed that compared with the control group, groups R1 and R2 significantly (p < 0.05) increased the weight gain and reduced (p < 0.05) the ratio of feed to gain in the early and the whole stages; prominently increased (p < 0.05) the concentration of total antioxidant capacity (T-AOC), the activities of CAT, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in livers, the activities of CAT and GSH-Px in serum, and CAT in the jejunum in the early and the later stages; markedly increased (p < 0.05) the villus height and the ratio of villus height to crypt depth of the duodenum in the early and the later stages, the villus height and the villus height:crypt depth ratio of the jejunum and ileum in the early stage, and significantly lowered (p < 0.05) the crypt depth of the duodenum (in the early and the later stages), jejunum, and ileum (in early stage); memorably (p < 0.05) increased the number of total bacteria and Bacteroidetes in ceca, as well as the number of Lactobacillus in the jejunum (p < 0.05) on the 30th; significantly (p < 0.05) increased the mRNA expression of junction adhesion molecule 2 (JAM2), mucin 2 (MCU2), and occlusal protein (occludin) in the duodenum in the early stage, and increased (p < 0.05) the mRNA expression of JAM2 in the jejunum in the later stage. Collectively, adding catalase (CAT) to the diet of yellow broilers can improve the growth performance and the antioxidant capacity, promoting the integrity of intestinal morphology, optimizing the composition of intestinal microorganisms, and upregulating the mRNA expression of tight junction protein.

Nanozybiotics: Nanozyme-Based Antibacterials against Bacterial Resistance

Infectious diseases caused by bacteria represent a global threat to human health. However, due to the abuse of antibiotics, drug-resistant bacteria have evolved rapidly and led to the failure of antibiotics treatment. Alternative antimicrobial strategies different to traditional antibiotics are urgently needed. Enzyme-based antibacterials (Enzybiotics) have gradually attracted interest owing to their advantages including high specificity, rapid mode-of-action, no resistance development, etc. However, due to their low stability, potential immunogenicity, and high cost of natural enzymes, enzybiotics have limitations in practical antibacterial therapy. In recent years, many nanomaterials with enzyme-like activities (Nanozymes) have been discovered as a new generation of artificial enzymes and perform catalytic antibacterial effects against bacterial resistance. To highlight the progress in this field of nanozyme-based antibacterials (Nanozybiotics), this review discussed the antibacterial mechanism of action of nanozybiotics with a comparison with enzybiotics. We propose that nanozybiotics may bear promising applications in antibacterial therapy, due to their high stability, rapid bacterial killing, biofilm elimination, and low cost.

Development of an Au-anchored Fe Single-atom nanozyme for biocatalysis and enhanced tumor photothermal therapy

Near-infrared light-induced photothermal therapy (PTT) can achieve effective tumor ablation, but the associated hyperthermic temperatures result in off-target inflammatory damage to proximal tissues. Therefore, killing the tumor at a lower temperature is vital to improving the clinical effect of PTT. In this study, an Au-integrated Fe single-atom nanozyme (FeSAzyme) was developed through the immobilization of an ultrasmall Au nanozyme within a metal-organic framework via an in situ reduction approach. The nanozyme was found to exhibit favorable glucose oxidase- (GOD) like activity and photosensitizing properties to better achieve low-temperature PTT. The Au-carbon nanozyme was able to markedly inhibit tumor growth both in vitro and in vivo due to its GOD-like activity and enhanced photodynamic and photothermal properties. In addition, the integration of the Au nanozyme enhanced the FeSAzyme's peroxidase activity and catalyzed endogenous H₂O₂ species to generate reactive oxide species, thereby facilitating chemodynamic therapy. Furthermore, its integration markedly enhanced the PTT performance of the FeSAzyme, which achieved pronounced synergistic anti-tumor efficacy. The enzymatic activity and photothermal/photosensitive properties of the Au-FeSAzyme may help to overcome traditional therapeutic limitations, indicating its potential for catalytic cascade nanozymes in biomedical applications.

Catalytic antimicrobial therapy using nanozymes

Nanozymes are nanomaterials with enzyme-like characteristics, which catalyze the conversion of enzyme substrates and follow enzymatic kinetics under physiological conditions. As a new generation of artificial enzymes, nanozymes provide alternative approaches for those upon enzymatic catalysis. Compared with natural enzymes, nanozymes have the advantages of simple preparation, good stability and low cost, which makes nanozymes promising for application in many fields, such as antimicrobial infection treatment. Many studies have reported that nanozymes are capable of killing a number of pathogenic bacteria with resistance, fungi as well as viruses, and have shown great curative effects for diseases caused by these pathogens. Herein, we summarize the application of nanozymes for antibacterial, antiviral, and antifungal therapies and outline the issues needing resolution in the future. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Functionalized Mn3 O4 Nanosheets with Photothermal, Photodynamic, and Oxidase-Like Activities Triggered by Low-Powered Near-Infrared Light for Synergetic Combating Multidrug-Resistant Bacterial Infections

Multidrug-resistant (MDR) pathogenic bacterial infections have become a major danger to public health. Synergetic therapy through multiple approaches is more powerful than the respective one alone, but has been rarely achieved in defeating MDR bacterial infections so far. Herein, indocyanine green-functionalized Mn₃ O₄ nanosheets are engineered as an efficient and safe antibacterial agent with photothermal, photodynamic, and oxidase-like activities, which display powerful ability in treating MDR bacterial infections. Therein, photothermal and photodynamic activities can be triggered by a single low-powered near-infrared laser (808 nm, 0.33 W cm^-2 ), resulting in the generation of localized hyperthermia (photothermal conversion efficiency, 67.5%) and singlet oxygen. Meanwhile, oxidase-like activity of this material further leads to the generation of hydroxyl radical as well as superoxide radical. Sheet-like structure with rough surfaces make them tends to adhere on bacterial surface and thus damage membrane system as well as influence bacterial metabolism. As a result, Gram-positive and Gram-negative bacteria can both be eradicated. Animal experiments further indicate that the functionalized Mn₃ O₄ nanosheets can effectively treat methicillin-resistant Staphylococcus aureus-infected wounds through the triple synergetic therapy. Moreover, toxicity evaluation in vitro and in vivo has proved the superior biosafety of this material, which is promising to apply in clinical anti-infective therapy.

Spherical mesoporous Fe-N-C single-atom nanozyme for photothermal and catalytic synergistic antibacterial therapy

Nanozyme has been regarded as an efficient antibiotic to kill bacteria using the reactive oxygen species (ROS) generated by Fenton-like reaction. However, its activity is still unsatisfied and requires large amount of hydrogen peroxide with side effects toward normal tissues. Herein, spherical mesoporous Fe-N-C single-atom nanozyme (SAzyme) is designed for antibacterial therapy via photothermal treatment enhanced Fenton-like catalysis process. Due to the large pore size (4.0 nm), high specific surface area (413.9 m² g^-1) and uniform diameter (100 nm), the catalytic performance of Fe-N-C SAzyme is greatly improved. The Michaelis-Menten constant (K_m) is 4.84 mmol L^-1, which is similar with that of horseradish peroxidase (3.7 mmol L^-1). Moreover, mesoporous Fe-N-C SAzyme shows high photothermal conversion efficiency (23.3 %) owing to the carbon framework. The catalytic activity can be enhanced under light irradiation due to the elevated reaction temperature. The bacteria can also be killed via physical heat effect. Due to the synergistic effect of nanozyme catalysis and photothermal treatment, the antibacterial performance is much higher than that using single antibacterial method. This work provides an alternative for combined antibacterial treatment via photothermal treatment assisted catalytic process using spherical mesoporous single-atom nanozyme as an antibiotic.

Biological Function of Plant Tannin and Its Application in Animal Health

Plant tannins are widely found in plants and can be divided into hydrolyzed tannins and condensed tannins. In recent years, researchers have become more and more interested in using tannin-rich plants and plant extracts in ruminant diets to improve the quality of animal products. Some research results show that plant tannins can effectively improve the quality of meat and milk, and enhance the oxidative stability of the product. In this paper, the classification and extraction sources of plant tannins are reviewed, as well as the biological functions of plant tannins in animals. The antioxidant function of plant tannins is discussed, and the influence of their structure on antioxidation is analyzed. The effects of plant tannins against pathogenic bacteria and the mechanism of action are discussed, and the relationship between antibacterial action and antioxidant action is analyzed. The inhibitory effect of plant tannins on many kinds of pathogenic viruses and their action pathways are discussed, as are the antiparasitic properties of plant tannins. The anti-inflammatory action of tannins and its mechanism are analyzed. The function of plant tannins in antidiarrheal action and its influencing factors are discussed. In addition, the effects of plant tannins as feed additives on animals and the influencing factors are reviewed in this paper to provide a reference for further research.

Recent Advances in Nanozymes for Bacteria-Infected Wound Therapy

Bacterial-infected wounds are a serious threat to public health. Bacterial invasion can easily delay the wound healing process and even cause more serious damage. Therefore, effective new methods or drugs are needed to treat wounds. Nanozyme is an artificial enzyme that mimics the activity of a natural enzyme, and a substitute for natural enzymes by mimicking the coordination environment of the catalytic site. Due to the numerous excellent properties of nanozymes, the generation of drug-resistant bacteria can be avoided while treating bacterial infection wounds by catalyzing the sterilization mechanism of generating reactive oxygen species (ROS). Notably, there are still some defects in the nanozyme antibacterial agents, and the design direction is to realize the multifunctionalization and intelligence of a single system. In this review, we first discuss the pathophysiology of bacteria infected wound healing, the formation of bacterial infection wounds, and the strategies for treating bacterially infected wounds. In addition, the antibacterial advantages and mechanism of nanozymes for bacteria-infected wounds are also described. Importantly, a series of nanomaterials based on nanozyme synthesis for the treatment of infected wounds are emphasized. Finally, the challenges and prospects of nanozymes for treating bacterial infection wounds are proposed for future research in this field.

What are the inorganic nanozymes? Artificial or inorganic enzymes!

The research on inorganic nanozymes remains very active since the first paper on the “intrinsic peroxidase-like properties of ferromagnetic nanoparticles” was published in Nature Nanotechnology in 2007. However, there is...

Effects of Dietary Ginsenoside Rg1 Supplementation on Growth Performance, Gut Health, and Serum Immunity in Broiler Chickens

The restriction and banning of antibiotics in farm animal feed has led to a search for promising substitutes for antibiotics to promote growth and maintain health for livestock and poultry. Ginsenoside Rg1, which is one of the most effective bioactive components in ginseng, has been reported to have great potential to improve the anti-inflammatory and anti-oxidative status of animals. In this study, 360 Chinese indigenous broiler chickens with close initial body weight were divided into 5 groups. Each group contained 6 replicates and each replicate had 12 birds. The experimental groups were: the control group, fed with the basal diet; the antibiotic group, fed basal diet + 300 mg/kg 15% chlortetracycline; and three Rg1 supplementation groups, fed with basal diet + 100, 200, and 300 mg/kg ginsenoside Rg1, respectively. The growth performance, immune function, and intestinal health of birds were examined at early (day 1-28) and late (day 29-51) stages. Our results showed that dietary supplementation of 300 mg/kg ginsenoside Rg1 significantly improved the growth performance for broilers, particularly at the late stage, including an increase in final body weight and decrease of feed conversion ratio (P < 0.05). Additionally, the integrity of intestinal morphology (Villus height, Crypt depth, and Villus height/Crypt depth) and tight junction (ZO-1 and Occludin), and the secretion of sIgA in the intestine were enhanced by the supplementation of Rg1 in chicken diet (P < 0.05). The immune organ index showed that the weight of the thymus, spleen, and bursa was significantly increased at the early stage in ginsenoside Rg1 supplementation groups (P < 0.05). Our findings might demonstrate that ginsenoside Rg1 could serve as a promising antibiotic alternative to improve the growth performance and gut health for broiler chickens mainly through its amelioration of inflammatory and oxidative activities.

The Effect of Exogenous Bile Acids on Antioxidant Status and Gut Microbiota in Heat-Stressed Broiler Chickens

Bile acids are critical for lipid absorption, however, their new roles in maintaining or regulating systemic metabolism are irreplaceable. The negative impacts of heat stress (HS) on growth performance, lipid metabolism, and antioxidant status have been reported, but it remains unknown whether the bile acids (BA) composition of broiler chickens can be affected by HS. Therefore, this study aimed to investigate the modulating effects of the environment (HS) and whether dietary BA supplementation can benefit heat-stressed broiler chickens. A total of 216 Arbor Acres broilers were selected with a bodyweight approach average and treated with thermal neutral (TN), HS (32°C), or HS-BA (200 mg/kg BA supplementation) from 21 to 42 days. The results showed that an increase in average daily gain (P < 0.05) while GSH-Px activities (P < 0.05) in both serum and liver were restored to the normal range were observed in the HS-BA group. HS caused a drop in the primary BA (P = 0.084, 38.46%) and Tauro-conjugated BA (33.49%) in the ileum, meanwhile, the secondary BA in the liver and cecum were lower by 36.88 and 39.45% respectively. Notably, results were consistent that SBA levels were significantly increased in the serum (3-fold, P = 0.0003) and the ileum (24.89-fold, P < 0.0001). Among them, TUDCA levels (P < 0.01) were included. Besides, BA supplementation indeed increased significantly TUDCA (P = 0.0154) and THDCA (P = 0.0003) levels in the liver, while ileal TDCA (P = 0.0307), TLCA (P = 0.0453), HDCA (P = 0.0018), and THDCA (P = 0.0002) levels were also increased. Intestinal morphology of ileum was observed by hematoxylin and eosin (H&E) staining, birds fed with BA supplementation reduced (P = 0.0431) crypt depth, and the ratio of villous height to crypt depth trended higher (P = 0.0539) under the heat exposure. Quantitative RT-PCR showed that dietary supplementation with BA resulted in upregulation of FXR (P = 0.0369), ASBT (P = 0.0154), and Keap-1 (P = 0.0104) while downregulation of iNOS (P = 0.0399) expression in ileum. Moreover, 16S rRNA gene sequencing analysis and relevance networks revealed that HS-derived changes in gut microbiota and BA metabolites of broilers may affect their resistance to HS. Thus, BA supplementation can benefit broiler chickens during high ambient temperatures, serving as a new nutritional strategy against heat stress.

Progress on Gut Health Maintenance and Antibiotic Alternatives in Broiler Chicken Production

The perturbation of gut health is a common yet unresolved problem in broiler chicken production. Antibiotics used as growth promoters have remarkably improved the broiler production industry with high feed conversion efficiency and reduced intestinal problems. However, the misuse of antibiotics has also led to the increase in the development of antibiotic resistance and antibiotic residues in the meat. Many countries have enacted laws prohibiting the use of antibiotics in livestock production because of the increasing concerns from the consumers and the public. Consequently, one of the most significant discussions in the poultry industry is currently antibiotic-free livestock production. However, the biggest challenge in animal husbandry globally is the complete removal of antibiotics. The necessity to venture into antibiotic-free production has led researchers to look for alternatives to antibiotics in broiler chicken production. Many strategies can be used to replace the use of antibiotics in broiler farming. In recent years, many studies have been conducted to identify functional feed additives with similar beneficial effects as antibiotic growth promoters. Attention has been focused on prebiotics, probiotics, organic acids, emulsifiers, enzymes, essential oils, tributyrin, and medium-chain fatty acids. In this review, we focused on recent discoveries on gut health maintenance through the use of these functional feed additives as alternatives to antibiotics in the past 10 years to provide novel insights into the design of antibiotic-free feeds.

Inorganic Nanozymes: Prospects for Disease Treatments and Detection Applications

In recent years, with the development of nanomaterials, a slice of nanomaterials has been demonstrated to possess high catalytic activity similar to natural enzymes and counter the dilemmas including easy inactivation and low yield natural of enzymes, which are labeled as nanozymes. The catalytic activity of nanozymes could be easily regulated by size, structure, surface modification and other factors. In comparison with natural enzymes, nanozymes featured with a more stable structure, economical preparation and preservation, diversity of functions and adjustable catalytic activity, thus becoming the potentially ideal substitute for natural enzymes. Generally, the are mainly three types containing metal oxide nanozymes, noble metal nanozymes and carbon-based nanozymes, owing various applications in biomedical, energy and environmental fields. In this review, to summarize the recent representative applications of nanozymes, and potentially explore the scientific problems in this field at the same time, we are going to discuss the catalytic mechanisms of diverse nanozymes, with the emphasis on their applications in the fields of tumor therapy, anti-inflammatory and biosensing, hoping to help and guide the future development of nanozymes.

Gastrointestinal Development and Microbiota Responses of Geese to Honeycomb Flavonoids Supplementation

Background: Geese are conventionally considered to be herbivorous, which could also be raised with concentrate feeding diets without green grass because of the similar gastrointestinal tract with other poultry. However, the geese gut microbiota profiles and their interactions with epithelial cells are still of limited study. Flavonoids were well-documented to shape gut microbiota and promote epithelial barrier functions individually or cooperatively with other metabolites. Therefore, in the present study, honeycomb flavonoids (HF) were supplemented to investigate the effects on growth performances, intestinal development, and gut microbiome of geese.

Material and Methods: A total of 400 1-day-old male lion-head geese with similar birth weight (82.6 ± 1.4 g) were randomly divided into five treatments: the control treatment (CON) and the HF supplementation treatments, HF was supplemented arithmetically to increase from 0.25 to 1%. Growth performance, carcass performances, and intestines' development parameters were measured to determine the optimum supplement. Junction proteins including ZO-1 and ZO-2 and cecal microbiota were investigated to demonstrate the regulatory effects of HF on both microbiota and intestinal epithelium.

Results: Results showed that 0.5% of HF supplement had superior growth performance, carcass performance, and the total parameters of gastrointestinal development to other treatments. Further research showed that tight junction proteins including ZO-1 and ZO-2 significantly up-regulated, while Firmicutes and some probiotics including Clostridiales, Streptococcus, Lachnoclostridium, and Bifidobacterium, remarkably proliferated after HF supplement. In conclusion, HF supplement in concentrate-diet feeding geese effectively increased the growth performances by regulating the gut microbiota to increase the probiotic abundance to promote the nutrient digestibility and fortify the epithelial development and barrier functions to facilitate the nutrient absorption and utilization.

Nanomedicines for the Efficient Treatment of Intracellular Bacteria: The "ART" Principle

Infections induced by bacteria at present are a severe threat to public health. Compared with extracellular bacteria, intracellular bacteria are harder to get rid of and readily induce chronic inflammation as well as autoimmune disorders. As the development of new antibiotics becomes more and more difficult, the construction of new antibiotic dosage forms is one of the optimal choices for the elimination of intracellular bacteria, and, to date, various nanomedicines have been exploited. However, current nanomedicines have limited treatment efficiency for intracellular bacteria due to the multiple biological barriers. Here in this short review, we focus on systemically administered nanomedicines and divide the treatment of intracellular bacteria with nanomedicines into three steps: 1) Accumulation at the infection site; 2) Recognition of infected cells; 3) Targeting of intracellular bacteria. Furthermore, we summarize how nanomedicines are elaborately designed to achieve the "ART" principle and discuss the problems of experimental models construction. Through this review, we want to remind that the golden approach for the building of cell and animal experimental models should be established, and nanomedicines should be also endowed with the versatility to follow the "ART" principle, efficiently improving the treatment efficiency of nanomedicines for intracellular bacteria.

Nanozymes Regulate Redox Homeostasis in ROS-Related Inflammation

Reactive oxygen species (ROS), in moderate amounts, play an essential role in regulating different physiological functions in organisms. However, increased amounts of ROS may cause oxidative stress and damage to biomolecules, leading to a variety of diseases including inflammation and even cancer. Therefore, ROS scavenging reagents are needed to maintain healthy levels of ROS. With considerable advances in nanotechnology, nanozymes possess SOD or CAT-like activities with outstanding free radical scavenging activity, facile synthesis conditions, and excellent biocompatibility. Based on these extraordinary properties, nanozymes has been used to modulate the redox homeostasis and relieve the ROS-related injury. This has led to the emergence of nanozyme-based therapies. In the current review, we presented recently developed applications of nanozymes to treat ROS-dependent disorders with an emphasis on inflammatory and brain diseases.

Effects of Adding Eubiotic Lignocellulose on the Growth Performance, Laying Performance, Gut Microbiota, and Short-Chain Fatty Acids of Two Breeds of Hens

Eubiotic lignocellulose is a new and useful dietary fiber source for chickens. However, few studies have been undertaken on the impacts of its use as a supplement in different chicken breeds. In this experiment, 108 Chinese native breed Bian hens (BH) and 108 commercial breed ISA Brown hens (IBH) were chosen. They were randomly divided into three groups, and 0, 2, or 4% eubiotic lignocellulose was added to their feed during the growing periods (9-20 weeks), respectively. We aimed to observe the impacts of adding eubiotic lignocellulose on the growth and laying performance, gut microbiota, and short-chain fatty acid (SCFA) of two breeds of hens. In this study, the addition of eubiotic lignocellulose had no significant effect on the growth performance and gut microbial diversity in the two breeds of chickens (P > 0.05). Compared with the control group, adding 4% eubiotic lignocellulose significantly increased the cecum weight, laying performance (P < 0.05), but had no significant effect on the SCFA of BH (P > 0.05); however, adding 4% significantly inhibited the intestinal development, laying performance, butyrate concentration, and SCFA content of IBH (P < 0.05). Moreover, the relative abundances of the fiber-degrading bacteria Alloprevotella and butyrate-producing bacteria Fusobacterium in the 4% group of BH were significantly higher than those in the 4% group of IBH (P < 0.05), resulting in the concentration of butyrate was significantly higher than those in it (P < 0.05). Combining these results suggests that the tolerance of BH to a high level of eubiotic lignocellulose is greater than that of IBH and adding 2-4% eubiotic lignocellulose is appropriate for BH, while 0-2% eubiotic lignocellulose is appropriate for IBH.