Antimicrobial peptides as a feed additive alternative to animal production, food safety and public health implications: An overview

Dietary supplementation with antibacterial peptide microcin J25 improved antioxidant capacity and intestinal health of pigeons

Introduction

The present study aimed to evaluate the potential of antimicrobial peptide microcin J25 (MccJ25) as a feed additive for pigeons.

Methods

A total of 28-day-old pigeons were allocated to four groups and fed a basal diet (CON) or a basal diet supplemented with 100, 200, or 300 mg/kg MccJ25 (ABP100, ABP200, and ABP300) for 8 weeks.

Results

Dietary MccJ25 supplementation significantly improved survival rates in the ABP200 group compared to the control (p < 0.05). Serum analysis revealed that ABP200 and ABP300 groups exhibited increased levels of total protein (TP), globulin (GLB), immunoglobulin A (IgA), and immunoglobulin G (IgG), alongside reduced aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), and triglyceride (TG) concentrations (p < 0.05). Furthermore, MccJ25 supplementation enhanced duodenal maltase and trypsin activity (p < 0.05) and upregulated intestinal and hepatic antioxidant capacity, as evidenced by elevated glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity (p < 0.05). Intestinal morphology improvements were observed in the jejunum and ileum, with increased villus height-to-crypt depth ratios (VH/CD) (p < 0.05). Additionally, ABP200 and ABP300 groups demonstrated significant upregulation of intestinal barrier-related genes occludin (OCLN), claudin 1 (CLDN1), zonula occluden protein 1 (ZO1), mucin 2 (MUC2), superoxide dismutase 1, 2 (SOD1, 2), and catalase (CAT) in duodenum (p < 0.05).

Discussion

These findings indicate that MccJ25 supplementation improves systemic metabolism, enhances antioxidant defenses, strengthens intestinal barrier integrity, and ultimately promotes pigeon health and survival. This study supports the application of MccJ25 as a functional feed additive in poultry production.

Expression of recombination antimicrobial protein PIL22-PBD-2 in Pichia pastoris and verification of its biological function in vitro

Finding suitable alternatives to antibiotics as feed additives is challenging for the livestock industry. Porcine beta-defensin 2 (PBD-2) is an endogenous antimicrobial peptide produced by pigs. Due to its broad-spectrum antibacterial activity against various microorganisms and its low tendency for drug resistance, it is considered a potential substitute for antibiotics. Additionally, given its strong ability to repair intestinal epithelial damage and maintain intestinal mucosal barrier function, porcine interleukin-22 (PIL-22) is a potential feed additive to combat intestinal damage caused by intestinal pathogens in piglets. In this study, the amino acid sequences of PBD-2 and PIL-22 were combined to express the fusion protein in Pichia pastoris, and its biological activity was evaluated in vitro. Our results showed that the PIL22-PBD-2 exhibits broad-spectrum antibacterial activity against multidrug-resistant enterotoxigenic Escherichia coli O8 (ETEC O8), Escherichia coli (E. coli), Salmonella typhimurium, and Staphylococcus aureus (S. aureus). PIL22-PBD-2 demonstrated wound repair capability through a healing assay in the intestinal porcine epithelial cell line-J2 (IPEC-J2). Furthermore, PIL22-PBD-2 significantly enhanced the expression of the major intercellular junction-associated proteins ZO-1 and E-cadherin in IPEC-J2. It is important to note that PIL22-PBD-2 reduced intestinal epithelial cell apoptosis (p < 0.05) considerably and decreased bacterial adhesion (p < 0.05) in ETEC O8-challenged IPEC-J2. We also found that the PIL22-PBD-2 treatment attenuated ETEC O8-induced inflammatory responses in IPEC-J2 by exerting antibacterial activity, increasing the expression of endogenous antimicrobial peptides, and significantly decreasing the mRNA expression levels of IL-6 and TNF-α (p < 0.05). In conclusion, our studies demonstrate that PIL22-PBD-2 has a positive effect on inhibiting pathogenic bacteria and repairing intestinal damage.

Effects of Diet Xylooligosaccharide Supplementation on Growth Performance, Carcass Characteristics, and Meat Quality of Hu Lambs

In this study, we examined the effect of xylooligosaccharide (XOS) supplementation on the growth performance, carcass characteristics, and meat quality of Hu lambs. In total, 60 Hu lambs (two months old and weighing 17.32 ± 0.81 kg) were randomly assigned to four treatment groups, each with three replicates and five lambs per replicate. The lambs were fed basal diets supplemented with 0, 1.5, 3, or 4.5 g/kg XOSs in a basal diet for 60 days, with the groups designated XOS0%, XOS1.5%, XOS3%, and XOS4.5%, respectively. The results revealed, compared to theXOS0% group, the XOS3% group presented a lower F:G during 31 to 45 d (p = 0.06). By the 60th day, the body length indices of groups XOS3% and XOS4.5% increased compared to the XOS0% group, with a significant increase observed in group XOS4.5% (p < 0.05). Additionally, the GR values of the XOS1.5%, XOS3%, and XOS4.5% groups increased significantly, and the rumen fluid pH values of the XOS3% and XOS4.5% groups increased significantly (p < 0.01). The crude fat content in the XOS1.5% and XOS4.5% groups were significantly lower (p < 0.05). The hardness, adhesiveness, elasticity, cohesiveness, and chewiness of the mutton in the XOS1.5%, XOS3%, and XOS4.5% groups were increased, although the differences were not statistically significant (p > 0.05). Correlation analysis indicates that there is a significant correlation between growth performance, carcass traits, and meat quality (p < 0.05). The factors influencing meat quality originate from the growth period and the slaughtering phase, which can be attributed to the effects of xylooligosaccharides. In conclusion, XOS had positive effects on the growth performance, carcass characteristics, and meat quality of Hu lambs. The comprehensive effect of group XOS3% was best. Considering the production cost, the 3 g/kg XOSs is identified as the optimal supplementation level for sheep.

Exploring Tenebrio molitor as a source of low-molecular-weight antimicrobial peptides using a n in silico approach: correlation of molecular features and molecular docking

BACKGROUND

Yellow mealworm (Tenebrio molitor) larvae are increasingly recognized as a potential source of bioactive peptides due to their high protein content. Antimicrobial peptides from sustainable sources are a research topic of interest. This study aims to characterize the peptidome of T. molitor flour and an Alcalase-derived hydrolysate, and to explore the potential presence of antimicrobial peptides using in silico analyses, including prediction tools, molecular docking and parameter correlations.

RESULTS

T. molitor protein was hydrolysed using Alcalase, resulting in a hydrolysate (TMH10A) with a 10% degree of hydrolysis. The peptidome was analysed using LC-TIMS-MS/MS, yielding over 6000 sequences. These sequences were filtered using the PeptideRanker tool, selecting the top 100 sequences with scores >0.8. Bioactivity predictions indicated that specific peptides, particularly WLNSKGGF and GFIPYEPFLKKMMA, showed significant antimicrobial potential, particularly against bacteria, fungi and viruses. Correlations were found between antifungal activity and physicochemical properties such as net charge, hydrophobicity and isoelectric point.

CONCLUSIONS

The study identified specific T. molitor-derived peptides with strong predicted antimicrobial activity through in silico analysis. These peptides, particularly WLNSKGGF and GFIPYEPFLKKMMA, might offer potential applications in food safety and healthcare. Further experimental validation is required to confirm their efficacy. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Antimicrobial Peptides: A Promising Alternative to Conventional Antimicrobials for Combating Polymicrobial Biofilms

Polymicrobial biofilms adhere to surfaces and enhance pathogen resistance to conventional treatments, significantly contributing to chronic infections in the respiratory tract, oral cavity, chronic wounds, and on medical devices. This review examines antimicrobial peptides (AMPs) as a promising alternative to traditional antibiotics for treating biofilm-associated infections. AMPs, which can be produced as part of the innate immune response or synthesized therapeutically, have broad-spectrum antimicrobial activity, often disrupting microbial cell membranes and causing cell death. Many specifically target negatively charged bacterial membranes, unlike host cell membranes. Research shows AMPs effectively inhibit and disrupt polymicrobial biofilms and can enhance conventional antibiotics' efficacy. Preclinical and clinical research is advancing, with animal studies and clinical trials showing promise against multidrug-resistant bacteria and fungi. Numerous patents indicate increasing interest in AMPs. However, challenges such as peptide stability, potential cytotoxicity, and high production costs must be addressed. Ongoing research focuses on optimizing AMP structures, enhancing stability, and developing cost-effective production methods. In summary, AMPs offer a novel approach to combating biofilm-associated infections, with their unique mechanisms and synergistic potential with existing antibiotics positioning them as promising candidates for future treatments.

Dietary supplementation of compound probiotics to improve performance, egg quality, biochemical parameters and intestinal morphology of laying hens

The purpose of this study was to investigate the effects of dietary supplementation of compound probiotics on the performance, egg quality, biochemical parameters and intestinal morphology of laying hens. A total of 180 healthy 200-day-old Hyline Brown laying hens with similar initial laying rate (87.5% ± 0.2%) were randomly divided into the control group and the treatment group. Each group included 6 replicates and each replicate included 15 laying hens. The control group was provided a basal diet, while the treatment group received the basal diet supplemented with compound probiotics. The experiment lasted for 52 days. The study indicated the following outcomes: (1) The laying rate (LR) and average egg weight (AEW) of laying hens in the treatment group were significantly higher than those of the control group (p < 0.05), whereas the feed-to-egg ratio (F/E) was significantly lower (p < 0.05); (2) The yolk weight (YW), egg shape index (ESI) and albumen height (AH) were significantly higher (p < 0.05), whereas the eggshell percentage (EP) was significantly lower (p < 0.05) after the dietary supplementation of compound probiotics; (3) The treatment group significantly decreased in total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), immunoglobulin A (IgA), and immunoglobulin G (IgG) levels in serum compared to the CON group (p < 0.05). Additionally, serum levels of total protein (TP), globulin (GLB), albumin (ALB), high-density lipoprotein (HDL), alkaline phosphatase (ALP), and total antioxidant capacity (T-AOC) were significantly higher in the treatment group (p < 0.05); (4) The supplementation of compound probiotics to laying hen diets led to a significant reduction in crypt depth (CD) and the ratio of villus height to crypt depth (V/C) in the jejunum compared to the CON group (p < 0.05). In conclusion, the supplementation of compound probiotics can regulate the body metabolism and improve the intestinal morphology, thus enhancing the antioxidant capacity and immune function of the body, which in turn improves the performance and egg quality of laying hens.

UniBioPAN: A Novel Universal Classification Architecture for Bioactive Peptides Inspired by Video Action Recognition

The classification of bioactive peptides is of great importance in protein biology, but there is still a lack of a universal and effective classifier. Inspired by video action recognition, we developed the UniBioPAN architecture to create a universal peptide classifier to solve this problem. The architecture treats the peptide sequence as a video sequence and the molecular image of each amino acid in the peptide sequence as a video frame, enabling feature extraction and classification using convolutional neural networks, bidirectional long short-term memory networks, and fully connected networks. As a novel peptide classification architecture, UniBioPAN significantly outperforms other universal architecture in ACC, AUC and MCC across 11 data sets, and F1 score in 9 data sets. UniBioPAN is available in three ways: python script, jupyter notebook script and web server (https://gzliang.cqu.edu.cn/software/UniBioPAN.html). In summary, UniBioPAN is a universal, convenient, and high-performance peptide classification architecture. UniBioPAN holds significant importance in the discovery of bioactive peptides and the advancement of peptide classifiers. All the codes and data sets are publicly available at https://github.com/sanwrh/UniBioPAN.

Method validation and antioxidant activities of Hyperacanthus amoenus and Carissa bispinosa

Plant foliages used as feed additives pose a health risk due to high oxidant concentrations. Oxidants cause oxidative stress and high rate of morbidities and mortalities. Hence, the aim of the study was to validate the methods to quantify gallic acid (GA) and quercetin (Q) as putative antioxidants, and to evaluate antioxidant activities in feed (F), Hyperacanthus amoenus (HA) and Carissa bispinosa (CB) extracts. Extraction was carried out with 62.5% methanol. Method validations for linearity, accuracy and precision were performed on high performance liquid chromatography. Quantitative analysis of GA and Q and testing of 2,2-diphenyl-2-picrylhydrazyl (DPPH) scavenging activities in the extracts were performed. The lowest limit of detection (LOD) and limit of quantitation (LOQ) of 0.011 µg/mL and 0.032 µg/mL were determined in HA, respectively. The methods were accurate and precise as the relative standard deviations (%RSD) were less than 15%. The GA concentrations in CB and HA extracts were statistically significant (p  0.05) and their values were 0.65 ± 0.03 x 106 µg/kg dry weight (DW) (0.13%) and 0.28 ± 0.06 x 106 µg/kg DW (0.002%), respectively. All extracts showed very strong radical scavenging activities with their IC50 values ranging between 5.87 µg/mL and 6.86 µg/mL.Contribution: These accurate, repeatable, precise and reliable methods can be used to provide a valuable basis for GA and Q analysis in various shrub foliages. Though high GA concentrations have potential to act as antioxidants, they may have adverse health and growth performance effects when used as feed additives, while lower Q concentrations may have no effects on livestock.

The Effects of Octapeptin Supplementation on Growth Performance, Serum Biochemistry, Serum Immunity, and Gut Microbiota in Weaned Piglets

With the prohibition of antibiotics in animal feed, the livestock industry faces significant challenges, including increased morbidity and mortality rates and reduced farming efficiency. Developing green, natural, and safe antibiotic alternatives has become a research hotspot. This study evaluated the effects of octapeptin as a feed additive on growth performance, diarrhea incidence, serum biochemistry, serum immune factors, and gut microbiota of weaned piglets. Seventy-two weaned piglets were randomly assigned to three groups based on body weight and sex, with each group receiving different dietary treatments: a negative control group (CON, basal diet), a positive control group (MC, basal diet + 5 mg/kg Microcin C7), and an octapeptin supplement group (OP, basal diet + 40 mg/kg octapeptin). After 28 days of feeding experimental diets, the results demonstrated that supplementing the diet of weaned piglets with octapeptin significantly improved the feed conversion ratio compared to the control group (p < 0.05) over the entire experimental period. Furthermore, a reduction in diarrhea incidence was observed during the late nursery period (14-28 d), resulting in an overall improvement in diarrhea compared to the other two groups (p < 0.01). Serum biochemical analysis results revealed a trend towards decreased alanine aminotransferase level in the octapeptin group, with no significant differences in other indicators, suggesting potential improvements in liver function without causing liver damage. In addition, compared to the control group, octapeptin enhanced mucosal immunity by decreasing TNF-α level (p < 0.05). Fecal microbiota analysis results showed a significant increase in beneficial bacteria such as Collinsella and Olsenella in the octapeptin group compared to the other two groups (p < 0.05), indicating a positive impact on gut health. These findings supported the potential of octapeptin as an alternative to antibiotic growth promoters in weaned piglets' diets.

Dietary apidaecin Api-PR19 addition enhances growth performance by regulating gut health and microbiota in broilers

OBJECTIVE

This study investigated the effects of Apidaecin Api-PR19 as feed additive on growth performance, intestinal health, and small intestinal microbiota of broilers.

METHODS

A total of 360 1-d-old Arbor Acres broilers were randomly assigned to 3 groups with 6 replicates including control group with basal diet (CON), antibiotic growth promotor group with basal plus 10 mg/kg colistin sulfate and 50 mg/kg roxarsone (AGP), and antibacterial peptide group with basal diet plus 330 mg/kg Apidaecin Api-PR19 (ABP). The trial lasted 35 d.

RESULTS

Results showed that dietary Api-PR19 addition increased (p<0.05) the average daily feed intake, average daily gain and decreased (p<0.05) feed conversion ratio (FCR) during 1 to 21 d compared with the CON group. The digestibility of dry matter and crude protein were higher in AGP and ABP groups (p<0.05) where greater trypsin activity was detected in duodenum (p<0.05). The ratio of villus height to crypt depth (V/C) in duodenum and jejunum was increased at 35 d when broilers were given diets with ABP or AGP (p<0.05). Besides, ABP treatments up-regulated (p<0.05) the mRNA expression of EAAT3, GLUT2, ZO-1, and Claudin-1 in duodenum of broilers at 35 d of age. The results of immunohistochemistry showed that ABP treatment significantly increased (p<0.05) duodenal secretory immunoglobulin A (sIgA) content. In addition, 16S rRNA gene sequencing revealed that there were differences in the intestinal microbiota diversity and composition among three groups. Notably, the linear discriminant analysis effect size showed that p_Firmicutes, g_Enterococcus, g_Carnobacterium, g_Kitasatospora, and g_Acidaminococcus were dominant in ABP group. Redundancy analysis showed that these changes in gut microbiota in ABP group had correlation with growth performance, intestinal morphology, and content of sIgA.

CONCLUSION

In general, these results indicated that dietary 330 mg/kg Apidaecin Api-PR19 supplementation promoted growth performance of broilers by improving intestinal development, nutrients absorption, immune function and modulating intestinal microbiota.

Development strategies and application of antimicrobial peptides as future alternatives to in-feed antibiotics

The use of in-feed antibiotics has been widely restricted due to the significant environmental pollution and food safety concerns they have caused. Antimicrobial peptides (AMPs) have attracted widespread attention as potential future alternatives to in-feed antibiotics owing to their demonstrated antimicrobial activity and environment friendly characteristics. However, the challenges of weak bioactivity, immature stability, and low production yields of natural AMPs impede practical application in the feed industry. To address these problems, efforts have been made to develop strategies for approaching the AMPs with enhanced properties. Herein, we summarize approaches to improving the properties of AMPs as potential alternatives to in-feed antibiotics, mainly including optimization of structural parameters, sequence modification, selection of microbial hosts, fusion expression, and industrially fermentation control. Additionally, the potential for application of AMPs in animal husbandry is discussed. This comprehensive review lays a strong theoretical foundation for the development of in-feed AMPs to achieve the public health globally.

Pap12-6: A host defense peptide with potent immunomodulatory activity in a chicken hepatic cell culture

In the fight against antimicrobial resistance, host defense peptides (HDPs) are increasingly referred to as promising molecules for the design of new antimicrobial agents. In terms of their future clinical use, particularly small, synthetic HDPs offer several advantages, based on which their application as feed additives has aroused great interest in the poultry sector. However, given their complex mechanism of action and the limited data about the cellular effects in production animals, their investigation is of great importance in these species. The present study aimed to examine the immunomodulatory activity of the synthetic HDP Pap12-6 (PAP) solely and in inflammatory environments evoked by lipoteichoic acid (LTA) and polyinosinic-polycytidylic acid (Poly I:C), in a primary chicken hepatocyte-non-parenchymal cell co-culture. Based on the investigation of the extracellular lactate dehydrogenase (LDH) activity, PAP seemed to exert no cytotoxicity on hepatic cells, suggesting its safe application. Moreover, PAP was able to influence the immune response, reflected by the decreased production of interleukin (IL)-6, IL-8, and "regulated on activation, normal T cell expressed and secreted"(RANTES), as well as the reduced IL-6/IL-10 ratio in Poly I:C-induced inflammation. PAP also diminished the levels of extracellular H2O2 and nuclear factor erythroid 2-related factor 2 (Nrf2) when applied together with Poly I:C and in both inflammatory conditions, respectively. Consequently, PAP appeared to display potent immunomodulatory activity, preferring to act towards the cellular anti-inflammatory and antioxidant processes. These findings confirm that PAP might be a promising alternative for designing novel antimicrobial immunomodulatory agents for chickens, thereby contributing to the reduction of the use of conventional antibiotics.

Bioinspired silver nanoparticle-based nanocomposites for effective control of plant pathogens: A review

Plant pathogens, including bacteria, fungi, and viruses, pose significant challenges to the farming community due to their extensive diversity, the rapidly evolving phenomenon of multi-drug resistance (MDR), and the limited availability of effective control measures. Amid mounting global pressure, particularly from the World Health Organization, to limit the use of antibiotics in agriculture and livestock management, there is increasing consideration of engineered nanomaterials (ENMs) as promising alternatives for antimicrobial applications. Studies focusing on the application of ENMs in the fight against MDR pathogens are receiving increasing attention, driven by significant losses in agriculture and critical knowledge gaps in this crucial field. In this review, we explore the potential contributions of silver nanoparticles (AgNPs) and their nanocomposites in combating plant diseases, within the emerging interdisciplinary arena of nano-phytopathology. AgNPs and their nanocomposites are increasingly acknowledged as promising countermeasures against plant pathogens, owing to their unique physicochemical characteristics and inherent antimicrobial properties. This review explores recent advancements in engineered nanocomposites, highlights their diverse mechanisms for pathogen control, and draws attention to their potential in antibacterial, antifungal, and antiviral applications. In the discussion, we briefly address three crucial dimensions of combating plant pathogens: green synthesis approaches, toxicity-environmental concerns, and factors influencing antimicrobial efficacy. Finally, we outline recent advancements, existing challenges, and prospects in scholarly research to facilitate the integration of nanotechnology across interdisciplinary fields for more effective treatment and prevention of plant diseases.

Effects of cyclic antimicrobial lipopeptides from Bacillus subtilis on growth performance, intestinal morphology, and cecal gene expression and microbiota community in broilers

This study investigated the effects of cyclic antimicrobial lipopeptides (CLPs) from Bacillus subtilis on the growth performance, gut morphology, and cecal gene expression and microbiota in broilers; 120 1-day-old unsexed Arbor Acres chicks were randomly divided into four groups, with six replicates in each group and five broilers per cage. These groups were fed a basal diet (C), basal diet plus 10-mg enramycin/kg (E), and basal diet plus 51-mg CLPs/kg (L) or 102-mg CLPs/kg (H). The results indicated that CLP supplementation linearly increased the body weight compared with the C group at 35 days of age. Between 15 and 35 days and 1 and 35 days of age, CLP supplementation linearly increased the average daily gain compared with the C group. The duodenal villus height was significantly increased in the H group compared with the C and E groups. In the cecum, CLP supplementation linearly increased SOD and ZO-1 mRNA expression compared with the C group. β diversity of microbiota indicated distinct clusters between the groups. CLP supplementation linearly increased the abundance of the genus Lactobacillus in the cecal digesta compared with the C group. These results demonstrate that B. subtilis-produced CLPs dose-dependently increase broilers' growth performance, improve their gut morphology, and modulate their gut microbiota.

Nanopeptide CI20 remarkably enhances growth performance and disease resistances by improving the mucosal structure, antioxidant capacity, and immunity in mandarin fish (Siniperca chuatsi)

Soybean meal, excessively used in place of fish meal (FM) in aquaculture, has a detrimental impact on fish. In this study, the nanopeptide CI20, which was created by conjugating antimicrobial peptide gcIFN-20H and CMCS, were evaluated the feeding effect in mandarin fish (Siniperca chuatsi). Compared with the control group, 150 mg/kg C-I20-fed fish showed the second highest growth performance with no significant changes in body composition. C-I20-fed fish showed more goblet cells and thicker mucin after feeding. The 150 mg/kg CI20 diet boosted the antioxidant capacity, immunity, and digestive enzymes. After Aeromonas hydrophila and infection spleen and kidney necrosis virus infection, the survival rates in the 150 mg/kg CI20 group were highest. Meanwhile, many tissues in the 150 mg/kg CI20 group had significantly lower pathogen loads than the other groups. Treatment with 150 mg/kg CI20 was effective in increasing antioxidant capacity and immunity. The minimum tissue lesions were observed in the 150 mg/kg CI20 group. The goblet cell number and mucin thickness were significantly increased by CI20 treatment after infection. The study results herein showed that a reasonable dietary concentration of CI20 feed promoted growth performance and disease resistances in fish, suggesting a prospective nano antimicrobial peptide for the aquaculture.

Fermented Chinese Herbs Improve the Growth and Immunity of Growing Pigs through Regulating Colon Microbiota and Metabolites

(1) Background: the development of new antibiotic substitutes to promote pig growth and health has become an important way to solve the current dilemma and promote the pig industry. (2) Methods: to assess the effects of a fermented Chinese herbal (FCH) formula on the growth and immunity of growing pigs, 100 Duroc × Landrace × Yorshire three-way crossed growing pigs were randomly divided into control and treatment groups that were fed a basal diet, and a basal diet with 1% (group A), 2% (group B), and 3% (group C) FCH formulas, respectively. A sixty-day formal experiment was conducted, and their growth and serum indices, colonic microbiota, and metabolites were analyzed. (3) Results: the daily gain of growing pigs in groups A, B, and C increased by 7.93%, 17.68%, and 19.61%, respectively, and the feed-to-gain ratios decreased by 8.33%, 15.00%, and 14.58%, respectively. Serum immunity and antioxidant activities were significantly increased in all treatment groups. Particularly, adding a 2% FCH formula significantly changed the colon's microbial structure; the Proteobacteria significantly increased and Firmicutes significantly decreased, and the metabolite composition in the colon's contents significantly changed. (4) Conclusions: these results indicate that the FCH formula is a good feed additive for growing pigs, and the recommended addition ratio was 3%.

Mesobiliverdin IXα-enriched microalgae feed additive eliminates reliance on antibiotic tylosin to promote intestinal health of weaning piglets

Weaning is a critical period in raising pigs. Novel animal feed additives that promote gut health and regulate immune function of piglets without antibiotics are needed. In this study, we aimed to test the ability of mesobiliverdin IXα-enriched microalgae (MBV IXα-enriched microalgae) to eliminate reliance on antibiotics to promote intestinal health in piglets. Eighty 28-day-old weaned piglets were randomly allocated to four groups each with four replicate pens and five piglets per pen. The dietary treatments were a basal diet as control (NC), basal diet plus 0.05% tylosin (PC), basal diet plus 0.1% or 0.5% MBV IXα-enriched microalgae as low (MBV-SP1) or high (MBV-SP2) dose respectively. All treated animals showed no significant differences in live weight, average daily gain and feed efficiency compared to control animals. Histological examination showed that MBV-SP1 and particularly MBV-SP2 increased the ratio of villus height to crypt depth in the jejunum and ileum compared to NC (p < 0.05). Similarly, tylosin treatment also increased villi lengths and the ratio of villus height to crypt depth in the jejunum and ileum compared to the NC (p < 0.05). MBV-SP1 and particularly MBV-SP2 reduced the levels of inflammatory cytokines interleukin-6 and tumour necrosis factor-alpha in the small intestine. MBV-SP2 and tylosin similarly reduced the lipid peroxidation marker (TBARS value) in the duodenum and ileum. In conclusion, feed supplementation with MBV IXα-enriched microalgae improved gut health by villus height and production of immunomodulators that correlated with down-regulated secretion of inflammatory cytokines.

Advances in Diagnostics and Drug Discovery against Resistant and Latent Tuberculosis Infection

Latent tuberculosis infection (LTBI) represents a subclinical, asymptomatic mycobacterial state affecting approximately 25% of the global population. The substantial prevalence of LTBI, combined with the risk of progressing to active tuberculosis, underscores its central role in the increasing incidence of tuberculosis (TB). Accurate identification and timely treatment are vital to contain and reduce the spread of the disease, forming a critical component of the global strategy known as "End TB." This review aims to examine and highlight the most recent scientific evidence related to new diagnostic approaches and emerging therapeutic treatments for LTBI. While prevalent diagnostic methods include the tuberculin skin test (TST) and interferon gamma release assay (IGRA), WHO's approval of two specific IGRAs for Mycobacterium tuberculosis (MTB) marked a significant advancement. However, the need for a specific test with global application viability has propelled research into diagnostic tests based on molecular diagnostics, pulmonary immunity, epigenetics, metabolomics, and a current focus on next-generation MTB antigen-based skin test (TBST). It is within these emerging methods that the potential for accurate distinction between LTBI and active TB has been demonstrated. Therapeutically, in addition to traditional first-line therapies, anti-LTBI drugs, anti-resistant TB drugs, and innovative candidates in preclinical and clinical stages are being explored. Although the advancements are promising, it is crucial to recognize that further research and clinical evidence are needed to solidify the effectiveness and safety of these new approaches, in addition to ensuring access to new drugs and diagnostic methods across all health centers. The fight against TB is evolving with the development of more precise diagnostic tools that differentiate the various stages of the infection and with more effective and targeted treatments. Once consolidated, current advancements have the potential to transform the prevention and treatment landscape of TB, reinforcing the global mission to eradicate this disease.

Feeding Behavior, Growth Performance and Meat Quality Profile in Broiler Chickens Fed Multiple Levels of Xylooligosaccharides

A total of 240 1-day-old Arbor Acres broiler chickens were randomly distributed to 4 treatment groups with 6 replicates and 10 birds per replicate. Chickens were fed with corn-soybean meal diet supplementation with additions of 0, 150, 300, and 450 mg/kg XOS for 42 days. At 4 weeks of age, the average feeding time was reduced in the 450 mg/kg XOS group (p < 0.05), and the percentage of feeding time was increased in the 300 mg/kg XOS group (p < 0.05). At 5 weeks of age, broilers fed with 300 mg/kg XOS had increased the percentage of feeding time (p < 0.05), and 450 mg/kg XOS had increased the feeding frequency and percentage of feeding time (p < 0.05). At 6 weeks of age, the feeding frequency was highest in the 450 mg/kg XOS group (p < 0.05). During 4 to 6 weeks of age, the average feeding time was increased in 300 mg/kg XOS group (p < 0.05), the frequency was improved in the 450 mg/kg XOS group (p < 0.05), and the percentage of feeding time was longer in the XOS group than that in the control group (p < 0.05). The average daily gain was improved during days 22-42 and days 1-42 in the 150 mg/kg XOS group (p < 0.05). Broilers fed with 300 mg/kg XOS had an increased eviscerated rate (p < 0.05). The pH45min of breast muscle was highest in the 450 mg/kg XOS group (p < 0.05), as well as the pH45min and pH24h of thigh muscle, which improved in the 300 mg/kg and 450 mg/kg XOS groups (p < 0.05). In addition, the cooking loss of thigh muscle was reduced in the 300 mg/kg XOS group (p < 0.05). In conclusion, dietary supplementation with XOS had positive effects on the feeding behavior, growth performance, and meat quality of broiler chickens.

Nanopeptide C-I20 as a novel feed additive effectively alleviates detrimental impacts of soybean meal on mandarin fish by improving the intestinal mucosal barrier

Antibacterial peptide has been widely developed in cultivation industry as feed additives. However, its functions in reducing the detrimental impacts of soybean meal (SM) remain unknown. In this study, we prepared nano antibacterial peptide CMCS-gcIFN-20H (C-I20) with excellent sustained-release and anti-enzymolysis, and fed mandarin fish (Siniperca chuatsi) with a SM diet supplemented with different levels of C-I20 (320, 160, 80, 40, 0 mg/Kg) for 10 weeks. 160 mg/Kg C-I20 treatment significantly improved the final body weight, weight gain rate and crude protein content of mandarin fish and reduced feed conversion ratio. 160 mg/Kg C-I20-fed fish maintained appropriate goblet cells number and mucin thickness, as well as improved villus length, intestinal cross-sectional area. Based on these advantageous physiological changes, 160 mg/Kg C-I20 treatment effectively reduced multi-type tissue (liver, trunk kidney, head kidney and spleen) injury. The addition of C-I20 did not change the muscle composition and muscle amino acids composition. Interestingly, dietary 160 mg/Kg C-I20 supplementation prevented the reduction in myofiber diameter and change in muscle texture, and effectively increased polyunsaturated fatty acids (especially DHA + EPA) in muscle. In conclusion, dietary C-I20 in a reasonable concentration supplementation effectively alleviates the negative effects of SM by improving the intestinal mucosal barrier. The application of nanopeptide C-I20 is a prospectively novel strategy for promoting aquaculture development.

Antimicrobial peptides as drugs with double response against Mycobacterium tuberculosis coinfections in lung cancer

Tuberculosis and lung cancer are, in many cases, correlated diseases that can be confused because they have similar symptoms. Many meta-analyses have proven that there is a greater chance of developing lung cancer in patients who have active pulmonary tuberculosis. It is, therefore, important to monitor the patient for a long time after recovery and search for combined therapies that can treat both diseases, as well as face the great problem of drug resistance. Peptides are molecules derived from the breakdown of proteins, and the membranolytic class is already being studied. It has been proposed that these molecules destabilize cellular homeostasis, performing a dual antimicrobial and anticancer function and offering several possibilities of adaptation for adequate delivery and action. In this review, we focus on two important reason for the use of multifunctional peptides or peptides, namely the double activity and no harmful effects on humans. We review some of the main antimicrobial and anti-inflammatory bioactive peptides and highlight four that have anti-tuberculosis and anti-cancer activity, which may contribute to obtaining drugs with this dual functionality.

Evaluation of antibacterial efficacy of garlic (Allium sativum) and ginger (Zingiber officinale) crude extract against multidrug-resistant (MDR) poultry pathogen

Objective

The study is aimed to understand the antibacterial sensitivity of native and Indian varieties of garlic (Allium sativum) and ginger (Zingiber officinale) crude extracts against multidrug-resistant (MDR) poultry pathogen (Escherichia coli and Salmonella sp.).

Materials and Methods

Thin layer chromatography (TLC) is used to identify the target spices' bioactive antibacterial compounds. MDR E. coli and Salmonella sp. were isolated from poultry. The TLC-Bioautography technique was applied to explore the antibacterial potentiality of garlic and ginger.

Results

Inhibitory activities of garlic were Zone of inhibition (ZI) = 14.03 ± 0.15 mm and 19.70 ± 0.36 mm, Minimum inhibitory concentration (MIC): 0.625 and 0.325 mg/ml, and ginger were ZI = 14.63 ± 0.30 mm and 11.56 ± 0.51mm, MIC: 9.0 mg/ml against E. coli and Salmonella sp., respectively. Two bands of garlic (Rf value = 0.31 and 0.50) and one band of ginger (Rf value = 0.71) showed inhibitory potential in TLC-Bioautography against both MDR isolates.

Conclusion

Garlic and ginger were effective against MDR E. coli and Salmonella sp. These spices could be a suitable alternative during the antibiotic void.

Screening of a short chain antimicrobial peptide-LKLHI and its application in hydrogels for wound healing

Antibacterial peptides have been widely used in the field of antibacterial due to their biocompatibility. In this work, owing to quickly screen out peptides with antibacterial effects, the bacterial membranes of E. coli and S. aureus were extracted and fixed on self-made silica gel microspheres to prepare bacterial membrane chromatography stationary phase. We successfully screened antimicrobial peptides from a peptide library composed of one-bead-one-compound by bacterial membrane chromatography. The antibacterial peptide has an effective defense effect on gram-positive bacteria, gram-negative bacteria, and fungi. In addition, the antibacterial peptide has almost no hemolysis and cytotoxicity and other excellent biocompatibility and has excellent properties such as stability, broad-spectrum antibacterial, and promotion of wound healing，and HA hydrogel carrier loaded with antimicrobial peptides was prepared, which provided the application direction of antimicrobial dressings for antimicrobial peptides. In summary, this method can screen out polypeptides with antibacterial effects, and the screened-out antibacterial peptides are expected to be applied in clinical applications.

Early weaning causes small intestinal atrophy by inhibiting the activity of intestinal stem cells: involvement of Wnt/β-catenin signaling

BACKGROUND

Early weaning and shorter breastfeeding duration are applied by a proportion of young mothers, especially in the social spheres of poverty-stricken areas. Early childhood is a critical period for intestinal development, which is driven by intestinal stem cells (ISCs). However, how early weaning practice affects the function of ISCs to mediate intestinal development remains unclear.

METHODS

We established an excellent early weaning mice model that has significant intestinal atrophy and growth arrest symptoms to explore the responses of ISCs to early weaning. The primary and passaged intestinal organoids from the suckling or early weaning mice were cultured to explore the underlying mechanism of early weaning affecting the ISCs.

RESULTS

Early weaning depressed the self-renewal of ISCs and attenuated the activity of ISCs-driven intestinal epithelial regeneration and crypt expansion in vivo and ex-vivo. Further results showed that early weaning retarded the differentiation of ISCs into transit-amplifying cells and Paneth cells, and accelerated the apoptosis of villous epithelial cells, jointly leading to intestinal epithelial atrophy. Mechanistically, early weaning inhibited Wnt signaling in ISCs, while an exogenous Wnt amplifier restored ISCs' function in ex-vivo.

CONCLUSION

Our findings indicate that early weaning depresses the activity of ISCs via attenuating Wnt/β-catenin signaling and triggers the proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-17 in jejunum, thereby impeding ISCs-driven epithelial regeneration and intestinal growth, which may provide a basal theory for the development of infant nutrients targeting stem cells to alleviate early weaning-induced intestinal problems.

Bioactive Antimicrobial Peptides from Food Proteins: Perspectives and Challenges for Controlling Foodborne Pathogens

Bioactive peptides (BAPs) derived from food proteins have been extensively studied for their health benefits, majorly exploring their potential use as nutraceuticals and functional food components. These peptides possess a range of beneficial properties, including antihypertensive, antioxidant, immunomodulatory, and antibacterial activities, and are naturally present within dietary protein sequences. To release food-grade antimicrobial peptides (AMPs), enzymatic protein hydrolysis or microbial fermentation, such as with lactic acid bacteria (LAB), can be employed. The activity of AMPs is influenced by various structural characteristics, including the amino acid composition, three-dimensional conformation, liquid charge, putative domains, and resulting hydrophobicity. This review discusses the synthesis of BAPs and AMPs, their potential for controlling foodborne pathogens, their mechanisms of action, and the challenges and prospects faced by the food industry. BAPs can regulate gut microbiota by promoting the growth of beneficial bacteria or by directly inhibiting pathogenic microorganisms. LAB-promoted hydrolysis of dietary proteins occurs naturally in both the matrix and the gastrointestinal tract. However, several obstacles must be overcome before BAPs can replace antimicrobials in food production. These include the high manufacturing costs of current technologies, limited in vivo and matrix data, and the difficulties associated with standardization and commercial-scale production.

Antibiotic Resistance and Food Safety: Perspectives on New Technologies and Molecules for Microbial Control in the Food Industry

Antibiotic resistance (ABR) has direct and indirect repercussions on public health and threatens to decrease the therapeutic effect of antibiotic treatments and lead to more infection-related deaths. There are several mechanisms by which ABR can be transferred from one microorganism to another. The risk of transfer is often related to environmental factors. The food supply chain offers conditions where ABR gene transfer can occur by multiple pathways, which generates concerns regarding food safety. This work reviews mechanisms involved in ABR gene transfer, potential transmission routes in the food supply chain, the prevalence of antibiotic residues in food and ABR organisms in processing lines and final products, and implications for public health. Finally, the paper will elaborate on the application of antimicrobial peptides as new alternatives to antibiotics that might countermeasure ABR and is compatible with current food trends.

Comparison of the Effects between Tannins Extracted from Different Natural Plants on Growth Performance, Antioxidant Capacity, Immunity, and Intestinal Flora of Broiler Chickens

In this study, four plant tannins, including AT (Acacia mearnsii tannin, 68%), CT (Castanea sativa tannin, 60%), QT (Schinopsis lorenzii tannin, 73%) and TT (Caesalpinia spinosa tannin, 50%) were added to broiler diets for 42 days to evaluate and compare their effects on growth performance, antioxidant capacity, immune performance and gut microbiota in broilers. The results showed that the supplementation of five tannins could increase the production of T-AOC, GSH-Px, SOD and CAT and reduce the production of MDA in the serum of broilers (p < 0.01), but the antioxidant effect of the AT group was lower than that of the other three groups (p < 0.01). All four tannins decreased the level of the pro-inflammatory factor IL-1β and increased the level of the anti-inflammatory factor IL-10 (p < 0.01). CT, QT and TT decreased the levels of pro-inflammatory factors IL-6 and TNF-α (p < 0.01), while AT and CT increased the level of IL-2 in serum (p < 0.01). Supplementation with four tannins also increased the levels of IgG, IgM, IgA and sIgA in serum (p < 0.01) and the levels of ZO-1, claudin-1 and occludin in the jejunum (p < 0.01). The detection results of ALT and AST showed that CT, QT and TT decreased the concentrations of ALT and AST in serum (p < 0.01). The results of the gut microbiota showed that the abundance of Clostridia and Subdoligranulum increased, and the abundance of Oscillospiraceae decreased, compared to the control group after adding the four tannins to the diets (p > 0.05). In addition, CT, QT and TT decreased the abundance of Lactobacillus and increased the abundance of Bacteroides compared to the control group, while AT showed the opposite result (p > 0.05). Overall, our study shows that tannins derived from different plants have their own unique effects on broilers. AT and CT can promote broilers' growth better than other tannins, CT has the best ability to improve immune and antioxidant properties, and QT and TT have the best effect on broilers' liver protection.

Prospects of antimicrobial peptides as an alternative to chemical preservatives for food safety

Antimicrobial peptides (AMPs) are a potential alternative to antimicrobial agents that have got considerable research interest owing to their significant role in the inhibition of bacterial pathogens. These AMPs can essentially inhibit the growth and multiplication of microbes through multiple mechanisms including disruption of cellular membranes, inhibition of cell wall biosynthesis, or affecting intracellular components and cell division. Moreover, AMPs are biocompatible and biodegradable therefore, they can be a good alternative to antimicrobial agents and chemical preservatives. A few of their features for example thermostability and high selectivity are quite appealing for their potential use in the food industry for food preservation to prevent the spoilage caused by microorganisms and foodborne pathogens. Despite these advantages, very few AMPs are being used at an industrial scale for food preservation as these peptides are quite vulnerable to external environmental factors which deter their practical applications and commercialization. The review aims to provide an outline of the mechanism of action of AMPs and their prospects as an alternative to chemical preservatives in the food industry. Further studies related to the structure-activity relationship of AMPs will help to expand the understanding of their mechanism of action and to determine specific conditions to increase their stability and applicability in food preservation.

A review on biofilms and the currently available antibiofilm approaches: Matrix-destabilizing hydrolases and anti-bacterial peptides as promising candidates for the food industries

Biofilms are communities of microorganisms that can be harmful and/or beneficial, depending on location and cell content. Since in most cases (such as the formation of biofilms in laboratory/medicinal equipment, water pipes, high humidity-placed structures, and the food packaging machinery) these bacterial and fungal communities are troublesome, researchers in various fields are trying to find a promising strategy to destroy or slow down their formation. In general, anti-biofilm strategies are divided into the plant-based and non-plant categories, with the latter including nanoparticles, bacteriophages, enzymes, surfactants, active peptides and free fatty acids. In most cases, using a single strategy will not be sufficient to eliminate biofilm, and consequently, two or more strategies will inevitably be used to deal with this unwanted phenomenon. According to the analysis of potential biofilm inhibition strategies, the best option for the food industry would be the use of hydrolase enzymes and peptides extracted from natural sources. This article represents a systematic review of the previous efforts made in these directions.

Antimicrobial monoglycerides for swine and poultry applications

The development of natural, broadly acting antimicrobial solutions to combat viral and bacterial pathogens is a high priority for the livestock industry. Herein, we cover the latest progress in utilizing lipid-based monoglycerides as feed additives to address some of the biggest challenges in animal agriculture. The current industry needs for effective antimicrobial strategies are introduced before discussing why medium-chain monoglycerides are a promising solution due to attractive molecular features and biological functions. We then critically analyze recent application examples in which case monoglycerides demonstrated superior activity to prevent feed transmission of viruses in swine and to mitigate bacterial infections in poultry along with gut microbiome modulation capabilities. Future innovation strategies are also suggested to expand the range of application possibilities and to enable new monoglyceride delivery options.

Functionality of dietary antimicrobial peptides in aquatic animal health: Multiple meta-analyses

Effects of antimicrobial peptides (AMP) added to diets on aquatic animal health and body function are influenced by multiple factors such as animal species, initial body weight, the dosage of AMP and feeding duration. However, there is limited knowledge on the relationship between these factors and the body function of aquatic animals. Here, we aimed to perform multiple meta-analyses to investigate the effects of dietary AMP on growth performance (feed conversion ratio [FCR], specific growth rate [SGR]), enzyme activity (superoxide dismutase activity [SOD], lysozyme activity [LSA]), disease resistance (cumulative survival rate [CSR], the expression of immune-related genes [GENE]) and the abundance of gut microbiota (MICRO) from a pool of empirical studies. Additionally, the dose-effect model was applied to determine the optimal AMP dose, initial body weight and feeding duration to maximize body function. To conduct the meta-analyses, we included 34 publications that estimated 705 effect sizes across 21 fish, 2 shrimp and 2 shellfish species. The results confirmed that the inclusion of AMP in the diet can significantly improve SGR, SOD, LSA, CSR and GENE and decrease FCR for aquatic animals. Interestingly, our findings implied a slight positive effect of AMP on MICRO albeit with a limited number of studies available on fish gut microbial communities. Although no significant linear or quadratic relationship was predicted by meta-regression, the dose-effect indicated that the optimal AMP doses for FCR, SGR, SOD and LSA were 707.5, 750.0, 1,050.0 and 937.5 mg/kg, respectively. Taken together, fish with an initial body weight of 30 g could be fed with a dose of 600 to 800 mg/kg for 2 mo when AMP-supplemented diets were applied in aquaculture, which can effectively improve body function and health while lowering aquafeed costs. In addition, more studies should address fish gut microbiota to delimitate the influence of dietary AMP on MICRO in the future.

Dietary supplementation of Macleaya cordata extract and Bacillus in combination improve laying performance by regulating reproductive hormones, intestinal microbiota and barrier function of laying hens

BACKGROUND

This study aimed to investigate whether the combination of Macleaya cordata extract (MCE) and Bacillus could improve the laying performance and health of laying hens better.

METHODS

A total of 360 29-week-old Jingbai laying hens were randomly divided into 4 treatments: control group (basal diet), MCE group (basal diet + MCE), Probiotics Bacillus Compound (PBC) group (basal diet + compound Bacillus), MCE + PBC group (basal diet + MCE + compound Bacillus). The feeding experiment lasted for 42 d.

RESULTS

The results showed that the laying rate and the average daily egg mass in the MCE + PBC group were significantly higher than those in the control group (P < 0.05) and better than the MCE and PBC group. Combination of MCE and Bacillus significantly increased the content of follicle-stimulating hormone (FSH) in the serum and up-regulated the expression of related hormone receptor gene (estrogen receptor-β, FSHR and luteinizing hormone/choriogonadotropin receptor) in the ovary of laying hens (P < 0.05). In the MCE + PBC group, the mRNA expressions of zonula occluden-1, Occludin and mucin-2 in jejunum was increased and the intestinal epithelial barrier detected by transmission electron microscopy was enhanced compared with the control group (P < 0.05). In addition, compared with the control group, combination of MCE and Bacillus significantly increased the total antioxidant capacity and catalase activity (P < 0.05), and down-regulated the mRNA expressions of inflammation-related genes (interleukin-1β and tumor necrosis factor-α) as well as apoptosis-related genes (Caspase 3, Caspase 8 and P53) (P < 0.05). The concentration of acetic acid and butyric acid in the cecum content of laying hens in the MCE + PBC group was significantly increased compared with the control group (P < 0.05).

CONCLUSIONS

Collectively, dietary supplementation of 600 μg/kg MCE and 5 × 108 CFU/kg compound Bacillus can improve laying performance by improving microbiota to enhance antioxidant capacity and intestinal barrier, regulate reproductive hormones and the concentration of cecal short-chain fatty acids of laying hens, and the combined effect of MCE and Bacillus is better than that of single supplementation.

Zambrano-Rodríguez P. The Use of Peptides in Veterinary Serodiagnosis of Infectious Diseases: A Review

Peptides constitute an alternative and interesting option to develop treatments, vaccines, and diagnostic tools as they demonstrate their scope in several health aspects; as proof of this, commercial peptides for humans and animals are available on the market and used daily. This review aimed to know the role of peptides in the field of veterinary diagnosis, and include peptide-based enzyme-linked immunosorbent assay (pELISA), lateral flow devices, and peptide latex agglutination tests that have been developed to detect several pathogens including viruses and bacteria of health and production relevance in domestic animals. Studies in cattle, small ruminants, dogs, cats, poultry, horses, and even aquatic organisms were reviewed. Different studies showed good levels of sensitivity and specificity against their target, moreover, comparisons with commercial kits and official tests were performed which allowed appraising their performance. Chemical synthesis, recombinant DNA technology, and enzymatic synthesis were reviewed as well as their advantages and drawbacks. In addition, we discussed the intrinsic limitations such as the small size or affinity to polystyrene membrane and mention several strategies to overcome these problems. The use of peptides will increase in the coming years and their utility for diagnostic purposes in animals must be evaluated.

Detecting the Mechanism of Action of Antimicrobial Peptides by Using Microscopic Detection Techniques

Increasing antibiotic resistance has shifted researchers’ focus to antimicrobial peptides (AMPs) as alternatives to antibiotics. AMPs are small, positively charged, amphipathic peptides with secondary helical structures. They have the ability to disrupt the bacterial membrane and create wedges due to electrostatic differences. Water molecules enter the pathogens through those wedges and disrupt their normal cellular functioning, eventually causing the death of the pathogens. Keeping in mind the importance of AMPs, this review compiles recent data and is divided into three parts. The first part explains the AMP structure and properties, the second part comprises the spectroscopy techniques currently used for evaluating the AMP-bacterial targeting mechanism as well as its structure and safety; and the third part describes the production of AMPs from an animal source (whey protein). Most of the peptides that were used in recent studies have been either the precursors of a natural peptide or synthetic peptides with some modifications, but data on the exploitation of dairy protein are scarce. Among the little-studied milk proteins and peptides, in the last three years, whey protein has been studied the least based on the reported data. Because whey protein is a leftover part of cheese making that often drains out as cheese waste, causing soil and environmental pollution, today, the need of the hour is to produce safe AMPs from whey protein. The use of whey protein that is based on hydrolyzing lactic acid bacteria with some structural modifications can increase AMPs’ potency, stability, and safety, and it can also help to avoid soil and environmental pollution as a result of whey drainage.

Beta-lactam resistance and the effectiveness of antimicrobial peptides against KPC-producing bacteria

Bacterial resistance is a problem that is giving serious cause for concern because bacterial strains such as Acinetobacter baumannii and Pseudomonas aeruginosa are difficult to treat and highly opportunistic. These bacteria easily acquire resistance genes even from other species, which confers greater persistence and tolerance towards conventional antibiotics. These bacteria have the highest death rate in hospitalized intensive care patients, so strong measures must be taken. In this review, we focus on the use of antimicrobial peptides (AMPs) as an alternative to traditional drugs, due to their rapid action and lower risk of generating resistance by microorganisms. We also present an overview of beta-lactams and explicitly explain the activity of AMPs against carbapenemase-producing bacteria as potential alternative agents for infection control.

Conjugation of Ctx(Ile21)-Ha Antimicrobial Peptides to Chitosan Ultrathin Films by N-Acetylcysteine Improves Peptide Physicochemical Properties and Enhances Biological Activity

The importance of obtaining new compounds with improved antimicrobial activity is a current trend and challenge. Some polymers such as chitosan have shown promising bactericidal properties when they are structurally modified, which is due to the binding versatility provided by their free amines. Likewise, antimicrobial peptides (AMPs) have received attention in recent years because of their bactericidal activity that is similar to or even better than that of conventional drugs, and they exhibit a low induction rate of antimicrobial resistance. Herein, the modified AMP Ctx(Ile²¹)-Ha-Ahx-Cys was conjugated to chitosan using N-acetylcysteine as an intermediate by the carbodiimide method. Films were prepared using protonated chitosan in 1% acetic acid and Ctx(Ile²¹)-Ha-Ahx-Cys AMP dissolved in N-acetylcysteine-chitosan; 1.6 mmol of ethylcarbodiimide hydrochloride, 1.2 mmol of N-hydroxysulfosucchimide, and 0.1 mol L ^-1of N-morpholino)ethanesulfonic acid buffer at pH 6.5 by continuous stirring at 100 × g for 10 min at 37 °C. Physicochemical properties were evaluated by Fourier-transform infrared spectroscopy, differential scanning calorimetry/thermogravimetric analysis, and X-ray diffraction to determine the mechanical properties, solubility, morphology, and thickness. Furthermore, the antimicrobial activities of chitosan-based conjugated films were evaluated againstStaphylococcus aureus,Pseudomonas aeruginosa,SalmonellaTyphimurium, andEscherichia coli. The results showed that the conjugation of a potent AMP could further increase its antibacterial activity and maintain its stable physicochemical properties. Therefore, the developed peptide-chitosan conjugate could be applied as an additive in surgical procedures to prevent and combat bacterial infection.

Plant-Derived Antimicrobial Peptides: Novel Preservatives for the Food Industry

Food spoilage is a widespread issue brought on by the undesired growth of microbes in food products. Thousands of tons of usable food or food products are wasted every day due to rotting in different parts of the world. Several food preservation techniques are employed to prevent food from rotting, including the use of natural or manufactured chemicals or substances; however, the issue persists. One strategy for halting food deterioration is the use of plant-derived antimicrobial peptides (AMPs), which have been investigated for possible bioactivities against a range of human, plant, and food pathogens. The food industry may be able to benefit from the development of synthetic AMPs, produced from plants that have higher bioactivity, better stability, and decreased cytotoxicity as a means of food preservation. In order to exploit plant-derived AMPs in various food preservation techniques, in this review, we also outline the difficulties in developing AMPs for use as commercial food preservatives. Nevertheless, as technology advances, it will soon be possible to fully explore the promise of plant-derived AMPs as food preservatives.

Scientists’ Assessments of Research on Lactic Acid Bacterial Bacteriocins 1990–2010

The antimicrobial activity of bacteriocins from lactic acid bacteria has constituted a very active research field within the last 35 years. Here, we report the results of a questionnaire survey with assessments of progress within this field during the two decades of the 1990s and the 2000s by 48 scientists active at that time. The scientists had research positions at the time ranging from the levels of Master’s and Ph.D. students to principal investigators in 19 Asian, European, Oceanian and North American countries. This time period was evaluated by the respondents to have resulted in valuable progress regarding the basic science of bacteriocins, whereas this was not achieved to the same degree with regard to their applications. For the most important area of application, food biopreservation, there were some success stories, but overall the objectives had not been entirely met due to a number of issues, such as limited target spectrum, target resistance, poor yield as well as economic and regulatory challenges. Other applications of bacteriocins such as enhancers of the effects of probiotics or serving as antimicrobials in human clinical or veterinary microbiology, were not evaluated as having been implemented successfully to any large extent at the time. However, developments in genomic and chemical methodologies illustrate, together with an interest in combining bacteriocins with other antimicrobials, the current progress of the field regarding potential applications in human clinical microbiology and food biopreservation. In conclusion, this study illuminates parameters of importance not only for R&D of bacteriocins, but also for the broader field of antimicrobial research.

Insights in the Development and Uses of Alternatives to Antibiotic Growth Promoters in Poultry and Swine Production

The overuse and misuse of antibiotics has contributed to the rise and spread of multidrug-resistant bacteria. To address this global public health threat, many countries have restricted the use of antibiotics as growth promoters and promoted the development of alternatives to antibiotics in human and veterinary medicine and animal farming. In food-animal production, acidifiers, bacteriophages, enzymes, phytochemicals, probiotics, prebiotics, and antimicrobial peptides have shown hallmarks as alternatives to antibiotics. This review reports the current state of these alternatives as growth-promoting factors for poultry and swine production and describes their mode of action. Recent findings on their usefulness and the factors that presently hinder their broader use in animal food production are identified by SWOT (strength, weakness, opportunity, and threat) analysis. The potential for resistance development as well as co- and cross-resistance with currently used antibiotics is also discussed. Using predetermined keywords, we searched specialized databases including Scopus, Web of Science, and Google Scholar. Antibiotic resistance cannot be stopped, but its spreading can certainly be hindered or delayed with the development of more alternatives with innovative modes of action and a wise and careful use of antimicrobials in a One Health approach.

Antimicrobial Peptides Controlling Resistant Bacteria in Animal Production

In the last few decades, antimicrobial resistance (AMR) has been a worldwide concern. The excessive use of antibiotics affects animal and human health. In the last few years, livestock production has used antibiotics as food supplementation. This massive use can be considered a principal factor in the accelerated development of genetic modifications in bacteria. These modifications are responsible for AMR and can be widespread to pathogenic and commensal bacteria. In addition, these antibiotic residues can be dispersed by water and sewer water systems, the contamination of soil and, water and plants, in addition, can be stocked in tissues such as muscle, milk, eggs, fat, and others. These residues can be spread to humans by the consumption of water or contaminated food. In addition, studies have demonstrated that antimicrobial resistance may be developed by vertical and horizontal gene transfer, producing a risk to public health. Hence, the World Health Organization in 2000 forbid the use of antibiotics for feed supplementation in livestock. In this context, to obtain safe food production, one of the potential substitutes for traditional antibiotics is the use of antimicrobial peptides (AMPs). In general, AMPs present anti-infective activity, and in some cases immune response. A limited number of AMP-based drugs are now available for use in animals and humans. This use is still not widespread due to a few problems like in-vivo effectiveness, stability, and high cost of production. This review will elucidate the different AMPs applications in animal diets, in an effort to generate safe food and control AMR.

Natural Polyphenols for the Preservation of Meat and Dairy Products

Food spoilage makes foods undesirable and unacceptable for human use. The preservation of food is essential for human survival, and different techniques were initially used to limit the growth of spoiling microbes, e.g., drying, heating, salting, or fermentation. Water activity, temperature, redox potential, preservatives, and competitive microorganisms are the most important approaches used in the preservation of food products. Preservative agents are generally classified into antimicrobial, antioxidant, and anti-browning agents. On the other hand, artificial preservatives (sorbate, sulfite, or nitrite) may cause serious health hazards such as hypersensitivity, asthma, neurological damage, hyperactivity, and cancer. Thus, consumers prefer natural food preservatives to synthetic ones, as they are considered safer. Polyphenols have potential uses as biopreservatives in the food industry, because their antimicrobial and antioxidant activities can increase the storage life of food products. The antioxidant capacity of polyphenols is mainly due to the inhibition of free radical formation. Moreover, the antimicrobial activity of plants and herbs is mainly attributed to the presence of phenolic compounds. Thus, incorporation of botanical extracts rich in polyphenols in perishable foods can be considered since no pure polyphenolic compounds are authorized as food preservatives. However, individual polyphenols can be screened in this regard. In conclusion, this review highlights the use of phenolic compounds or botanical extracts rich in polyphenols as preservative agents with special reference to meat and dairy products.

Antimicrobial Peptides as an Alternative for the Eradication of Bacterial Biofilms of Multi-Drug Resistant Bacteria

Bacterial resistance is an emergency public health problem worldwide, compounded by the ability of bacteria to form biofilms, mainly in seriously ill hospitalized patients. The World Health Organization has published a list of priority bacteria that should be studied and, in turn, has encouraged the development of new drugs. Herein, we explain the importance of studying new molecules such as antimicrobial peptides (AMPs) with potential against multi-drug resistant (MDR) and extensively drug-resistant (XDR) bacteria and focus on the inhibition of biofilm formation. This review describes the main causes of antimicrobial resistance and biofilm formation, as well as the main and potential AMP applications against these bacteria. Our results suggest that the new biomacromolecules to be discovered and studied should focus on this group of dangerous and highly infectious bacteria. Alternative molecules such as AMPs could contribute to eradicating biofilm proliferation by MDR/XDR bacteria; this is a challenging undertaking with promising prospects.

HPMCAS-Coated Alginate Microparticles Loaded with Ctx(Ile21)-Ha as a Promising Antimicrobial Agent against Salmonella Enteritidis in a Chicken Infection Model

Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) in poultry is most often transmitted by the fecal-oral route, which can be attributed to high population density. Upon encountering the innate immune response in a host, the pathogen triggers a stress response and virulence factors to help it survive in the host. The aim of this study was to evaluate the effect of hypromellose acetate/succinate (HPMCAS)-coated alginate microparticles containing the Ctx(Ile²¹)-Ha antimicrobial peptide (AMP) on both intestinal colonization and systemic infection of laying hens challenged with S. Enteritidis. The applied AMP microsystem reduced the bacterial load of S. Enteritidis in the liver, with a statistical significance between groups A (control, no Ctx(Ile²¹)-Ha peptide) and B (2.5 mg of Ctx(Ile²¹)-Ha/kg) at 2 days postinfection (dpi), potentially indicating the effectiveness of Ctx(Ile²¹)-Ha in the first stage of infection by S. Enteritidis. In addition, the results showed a significant decrease in the S. Enteritidis counts in the spleen and cecal content at 5 dpi; remarkably, no S. Enteritidis counts were observed in livers at 5, 7, and 14 dpi, regardless of the Ctx(Ile²¹)-Ha dosage (p-value <0.0001). Using the Chi-square test, the effect of AMP microparticles on S. Enteritidis fecal excretion was also evaluated, and a significantly lower bacterial excretion was observed over 21 days in groups B and C, in comparison with the untreated control (p-value <0.05). In summary, the use of HPMCAS-Ctx(Ile²¹)-Ha peptide microcapsules in laying hens drastically reduced the systemic infection of S. Enteritidis, mainly in the liver, indicating a potential for application as a feed additive against this pathogen.

Perspective, Opportunities and Challenges in Using Fennel (Foeniculum vulgare) in Poultry Health and Production as an Eco-Friendly Alternative to Antibiotics: A Review

Following the European Union’s restriction on antibiotic growth promoters, research on enhancing gut health has been accelerated. As the poultry industry is facing issues that were previously managed by antimicrobial growth promoters, the hunt for the best remedies continues to find suitable alternatives. Simultaneously, social pressure is mounting to reduce the usage of antibiotics and replace them with other feed additives. Consumers believe a number of accessible options to be safe, with phytogenics playing a crucial role. This review describes how the use of fennel seeds could be beneficial for poultry. An overview of the broad chemical diversity of fennel is presented together with their physicochemical and biological properties. According to investigations, fennel seeds have a variety of biological effects in birds, including improved performance, higher immune cell proliferation, reduced oxidative stress, and boosted antibody titers against infectious diseases. The efficacy of poultry outcomes is determined by the stage and age of the plants, the extraction process, the geographical location, the chicken species, management techniques, and the concentrations administered. The present review focuses on the effects of fennel seeds as a feed additive on poultry growth, carcass quality, blood biochemistry, antioxidant activity, immunity, and microbiological aspects.

Haematological Profile of Dairy Cattle Fed with A Diet Supplemented with Depolarized Katuk Leaf (Sauropus androgynus)

This study was aimed to assess the health status of dairy cows after consuming depolarized katuk leaves (Sauroupus androgynus) as a feed additive by measuring their hematological profile. Nine Friesian-Holstein cows were divided into three groups based on their diet: complete feed (control), complete feed plus depolarized katuk leaf powder (P1; 100 g per day), and complete feed plus depolarized katuk leaf pellet (P2; 100 g per day). Supplementation of depolarizing katuk leaves in the diet started two weeks before parturition until three months of lactation. Blood sampling was carried out during the 10th week of lactation. The analysis of hematological profiles includes total erythrocytes, hematocrit, hemoglobin, total leukocytes, stress index (neutrophil-lymphocyte ratio), total platelets, and total protein. There were no significant differences in total erythrocytes, hematocrit, total leukocytes, stress index, total platelets, and total protein in groups P1 and P2 compared to controls. The hemoglobin levels of dairy cows in groups P1 and P2 were significantly lower (P<0.05) compared to controls, although these levels were still within normal limits. In conclusion, there was no negative impact of depolarizing katuk leaf supplementation in the ratio on the health status of lactating dairy cows based on the hematological profile.

Multiple roles of ribosomal antimicrobial peptides in tackling global antimicrobial resistance

In the last century, conventional antibiotics have played a significant role in global healthcare. Antibiotics support the body in controlling bacterial infection and simultaneously increase the tendency of drug resistance. Consequently, there is a severe concern regarding the regression of the antibiotic era. Despite the use of antibiotics, host defence systems are vital in fighting infectious diseases. In fact, the expression of ribosomal antimicrobial peptides (AMPs) has been crucial in the evolution of innate host defences and has been irreplaceable to date. Therefore, this valuable source is considered to have great potential in tackling the antimicrobial resistance (AMR) crisis. Furthermore, the possibility of bacterial resistance to AMPs has been intensively investigated. Here, we summarize all aspects related to the multiple applications of ribosomal AMPs and their derivatives in combating AMR.

Pharmacological Applications and Action Mechanisms of Phytochemicals as Alternatives to Antibiotics in Pig Production

Antibiotics are widely used for infectious diseases and feed additives for animal health and growth. Antibiotic resistant caused by overuse of antibiotics poses a global health threat. It is urgent to choose safe and environment-friendly alternatives to antibiotics to promote the ecological sustainable development of the pig industry. Phytochemicals are characterized by little residue, no resistance, and minimal side effects and have been reported to improve animal health and growth performance in pigs, which may become a promising additive in pig production. This paper summarizes the biological functions of recent studies of phytochemicals on growth performance, metabolism, antioxidative capacity, gut microbiota, intestinal mucosa barrier, antiviral, antimicrobial, immunomodulatory, detoxification of mycotoxins, as well as their action mechanisms in pig production. The review may provide the theoretical basis for the application of phytochemicals functioning as alternative antibiotic additives in the pig industry.

Bioactive Peptides: A Promising Alternative to Chemical Preservatives for Food Preservation

Bioactive peptides used for food preservation can prolong the shelf life through bacteriostasis and antioxidation. On the one hand, bioactive peptides can inhibit lipid oxidation by scavenging free radicals, interacting with metal ions, and inhibiting lipid peroxidation. On the other hand, bioactive peptides can fundamentally inhibit the growth and reproduction of microorganisms by destroying their cell membranes or targeting intracellular components. Besides, bioactive peptides are biocompatible and biodegradable in vivo. Therefore, they are regarded as a promising alternative to chemical preservatives. However, bioactive peptides are easily affected by the external environment in practical application, which hinders their commercialization. Currently, the studies to overcome the weakness focus on encapsulation and chemical synthesis. Bioactive peptides have been applied to the preservation of various foods in experimental research, with good results. In the future, with the deepening understanding of their safety and structure-activity relationship, there may be more bioactive peptides as food preservatives.