5 Must-Have Features in a oyster peptide wholesalers

If you want to learn more, please visit our website oyster peptide wholesalers.

Associated Data

Supplementary Materials

nutrients-16--s001.zip

(87K)

GUID: E0E00A99-C0FD-4DD4-80D5-3FFC6FF

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding authors.

Abstract

Ulcerative colitis (UC) is an inflammatory bowel disease with an increasing prevalence year over year, and the medications used to treat patients with UC clinically have severe side effects. Oyster peptides (OPs) have anti-inflammatory and antioxidant properties as functional foods that can alleviate a wide range of inflammatory conditions. However, the application of oyster peptides in ulcerative colitis is not well studied. In this work, an animal model of acute colitis was established using 3% dextran sulfate sodium (DSS), and the impact of OP therapy on colitis in mice was examined. Supplementing with OPs prevented DSS-induced colitis from worsening, reduced the expression of oxidative stress and inflammatory markers, and restored the intestinal barrier damage caused by DSS-induced colitis in mice. The 16S rDNA results showed that the OP treatment improved the gut microbiota structure of the UC mice, including increasing microbial diversity, increasing beneficial bacteria, and decreasing harmful bacteria. In the UC mice, the OP therapy decreased the relative abundance of Family_XIII_AD_group and Prevotella_9 and increased the relative abundance of Alistipes. In conclusion, OP treatment can inhibit the TLR4/NF-κB pathway and improve the intestinal microbiota in UC mice, which in turn alleviates DSS-induced colitis, providing a reference for the treatment of clinical UC patients.

Keywords:

ulcerative colitis, oyster peptide, intestinal barrier, intestinal microbiome

1. Introduction

The common chronic inflammatory illness ulcerative colitis (UC) is characterized by weight loss, diarrhea, and rectal bleeding [1,2]. The frequency and incidence of UC have grown recently on a global scale, progressively turning the illness into a global health issue [3]. The pathogenesis of UC is complex and related to genetics, diet, immune system disorders, and gut microbiota disorders, but the exact pathogenesis of the disease remains unclear [4]. Current therapeutic agents for UC patients, such as corticosteroids, aminosalicylates, and immunosuppressants, frequently produce a wide variety of side effects in the clinic [5]. For example, corticosteroids may cause symptoms such as fever and rash in patients with UC [6]. Therefore, there is an urgent need to develop natural products that do not produce serious side effects as alternative therapies for UC treatment.

The main feature of UC is an impaired intestinal mucosal barrier, including impaired tight junctions, decreased mucus secretion, abnormal inflammatory cells, and an imbalance of intestinal microorganisms [7]. The first line of defense against dangerous chemicals is the intestinal epithelial barrier, which is made up of intestinal epithelial cells and tight junctions [8]. Impairment of intestinal barrier function, characterized by a decrease in tight junction proteins, is one of the pathogenic mechanisms of UC [9]. Moreover, an intestinal microbial community change is a risk factor for patients with UC due to disruption of the intestinal epithelial barrier [10]. It has been shown that the gut microbiota of patients with UC typically has a low abundance of beneficial bacteria and a high abundance of harmful bacteria, which usually leads to intestinal microecological dysbiosis and in turn promotes UC progression [11,12]. Maintaining the integrity of the intestinal barrier, promoting normal development of the mucosal immune system, and lowering pathogen invasion are all facilitated by a healthy gut microbiota [13]. It has been demonstrated that changing the gut microbiota&#;s composition is a successful way to treat UC [10]. DSS-induced UC mouse models exhibit similarities to the disease in humans and are among the most commonly used mouse models in UC [14,15]. Therefore, in order to examine the mechanism of action of OPs in reducing colitis in mice, we constructed an animal model of UC using DSS in this study.

Oysters are rich in vitamins, minerals and proteins and are a great source of high-quality nutrients found in many areas [16]. Oysters have high levels of health benefits as functional products. It has been demonstrated that polysaccharides, taurine, and peptides found in oyster extracts can reduce the symptoms of DSS-induced colitis in mice [17,18]. Among these, oyster polysaccharides modulate the gut microbiota to alleviate DSS-induced colitis and have strong anti-inflammatory activities [19]. Taurine is likewise effective in the alleviation of DSS-induced colitis in mice [20]. In addition, the results of several studies have emphasized the multiple physiological activities of oyster extract peptides, including antioxidant, immunomodulatory, anti-inflammatory, and anti-fatigue effects [21,22,23]. Studies on the function of oyster peptides and their regulatory pathways in the treatment of colitis are still scarce, nevertheless.

In this study, we identified small-molecule peptides in OPs that may play a potential role. An animal model of ulcerative colitis in mice was constructed using 3% DSS. By detecting the symptoms of colitis, the degree of intestinal barrier damage, and the changes of intestinal microbiota in mice, we were able to elucidate the mechanism of action of OPs in alleviating colitis in mice. The results of this study provide insights into the role of OPs in alleviating colitis in mice and provide a theoretical basis for the application of OPs in the prevention and treatment of colitis.

2. Materials and Methods

2.1. Materials and Reagents

DSS was obtained from MP Biomedicals (Irvine, CA, USA). The supplier of the claudin-1 antibody was Affinity (Affinity, Changzhou, China). GAPDH TLR4, p65, and p-p65 antibodies were obtained from Cell Signaling Technology (Cell Signaling Technology, Shanghai, China). OPs were provided by Tiantianhao Biological Products Co., Ltd. (Tiantianhao Biological Products, Wuhan, China) and were obtained by the enzymatic digestion of oysters.

2.2. Analysis of Amino Acid Composition

By adding hydrochloric acid to a final concentration of 6 mol/L, the BCA method was used to first determine the OP concentration. It was hydrolyzed under airtight conditions at 110 °C for 20&#;24 h, evaporated to dryness, and then reintroduced with hydrochloric acid to resolubilize and filter. After adding 10 μL of the hydrolyzed sample to the derivatization tube, 20 μL of the derivatizing agent and 70 μL of boric acid buffer were added one after the other. The sample was then heated for ten minutes at 55 °C in an oven before being utilized for liquid chromatography. The liquid chromatographic conditions were as follows: column temperature, 37 °C; flow rate, 1.0 mL/min; and UV wavelength, 248 nm. Finally, it was passed through an AccQ.

2.3. OP Peptide Identification

The OPs were first fully dissolved in 0.1% trifluoroacetic acid (TFA) to complete the desalting process. After dissolving the peptides with 20 μL of dissolution solution and centrifuging at 13,500 rpm for 20 min, the supernatant was moved to a sample tube so that it could be identified using mass spectrometry.

In the liquid chromatographic test, an 80% acetonitrile (CAN) and a 0.1% formic acid solution made up mobile phase B and mobile phase A, respectively. Gradients of 3&#;8% B over 7 min, 8&#;32% B over 39 min, 32&#;44% B over 5 min, and 44&#;99% B over 5 min were used to separate the samples. The primary mass spectrum had a resolution of 120,000 and a scanning range of 350&#; m/z. The secondary mass spectral resolution was 30,000. Finally, PEAKS Studio 10 software was used for database searching.

2.4. Animals

Liaoning Changsheng Co. (Liaoning Changsheng, Shenyang, China) supplied male BALB/c mice that were 6 weeks old and in good health. The Institutional Animal Care and Use Committee of Jilin University (License No. SY) authorized all experimental protocols. Regarding the choice of OP concentration, we referred to the concentration gradients used in other colitis studies [24], conducted a pilot experiment, and finally chose 500 mg/kg as the treatment concentration for our formal experiment.

Following a week of animal acclimation, the mice were split into three groups at random: (1) Con, the Control group, in which the mice were subjected to gavage with a 0.9% Nacl solution; (2) DSS, the DSS-induced colitis group, which was subjected to gavage with a 0.9% Nacl solution, and in the last week, the DSS was added to the drinking water (3%); (3) OP, the oyster-peptide-treated group, treated with OPs (500 mg/kg/d) by gavage, and DSS was added to drinking water (3%) in the last week. Throughout the previous week, the mice&#;s body weights were noted every day, and following their execution, blood and tissues were gathered.

2.5. Sample Collection, DAI Scoring, and Histopathology

A slice of the colon was removed for staining with H&E and AB-PAS, and two smaller sections were removed for Western blotting and RT-qPCR tests, respectively. Furthermore, the cecum&#;s contents were removed, quickly frozen in liquid nitrogen, and kept at &#;80 °C until additional testing could be conducted. Throughout the trial, the mice&#;s disease activity index (DAI) scores were collected and evaluated every day, and their overall health was checked. The DAI scores were determined by assessing the clinical signs of the mice according to the method described in previous studies [25].

The tissues from the collected mouse colon were sectioned after paraffin embedding, fixed in a 4% paraformaldehyde solution, and stained with hematoxylin and eosin (H&E). Alcian blue (AB) and periodic acid Schiff (PAS) staining were used to identify goblet cells. The pathological evaluation was performed according to previous methods [26], and the histological score was based on mucosal edema, crypt destruction and loss, and inflammatory cell infiltration. The number of goblet cells was measured using ImageJ software (version 1.6.0).

2.6. Enzyme-Linked Immunosorbent Assays (ELISAs)

An IL-6 ELISA kit (YX-E), a TNF-α ELISA kit (YX-E), an IL-1β ELISA kit (YX-E), an LPS ELISA kit (YX-M), an MDA assay kit (YX-E), a SOD assay kit (YX-E), and a T-AOC assay kit (YX-E) were obtained from Shanghai SINO-BESTBIO Co., Ltd. (Shanghai, China). Following the manufacturer&#;s instructions, the levels of cytokines (TNF-α, IL-6, and IL-1β) and oxidative stress factors (SOD, MDA, and T-AOC) were measured in serum and colon samples.

2.7. mRNA Expression Level Measurement

Using a Total RNA Extraction Kit (SM130, Sevenbio, Beijing, China), RNA was isolated from colon tissues. The MonScriptTM RTIII ALL-in-One Mix with dsDNase kit (Monad, Wuhan, China) was used to synthesize first-strand cDNA. A MonAmpTM ChemoHS qPCR Mix (Monad, Wuhan, China) kit was used for RT-qPCR. Supplementary Table S1 contains all of the primer sequences needed for the RT-qPCR procedure.

2.8. Western Blotting

Using a BCA protein assay kit, the total protein content was ascertained after the total protein was isolated from colon tissue. Using the PAGE Gel Rapid Preparation Kit (Yase, Shanghai, China), proteins were isolated and then put onto PVDF (polyvinylidene difluoride) membranes (0.45 μm; Millipore, St. Louis, MO, USA). Specific binding was performed using specific antibody incubation, and sheep anti-rabbit secondary antibody was obtained from Yase (Shanghai, China). Finally, a quantitative analysis was performed using ImageJ software.

2.9. The 16S rDNA Gene Sequencing

After PCR amplification, DNA was extracted from the cecum contents using the CTAB technique and purified using AMPure XT beads (Beckman Coulter Genomics, Danvers, MA, USA). The PCR products were then assessed using Illumina (Kapa Biosciences, Woburn, MA, USA) library quantification kits and an Agilent Bioanalyzer (Agilent, CA, USA). For qualified libraries, optimized data were obtained through quality control, denoising, and splicing. Numerous studies, including species taxonomic, community diversity, and species difference analyses, were carried out using the ASV (feature) feature sequences and ASV (feature) abundance tables as a basis. For Alpha diversity, species richness and evenness were mainly reflected by Chao1, Observed OTU, Shannon, and Simpson indices [27]. For Beta diversity, differences between groups were mainly observed by Principal Component Analysis (PCA), Principal Coordinate Analysis (PCoA), and Non-Multidimensional Scale Analysis (NMDS) [28,29].

2.10. Network Diagram of Correlation Analysis

The correlation analysis methods used here refer to our previous studies [30,31,32]. Briefly, the correlations of DAI scores, body weight changes, differential bacteriophages, inflammation, and oxidative stress metrics in mice were analyzed and network plotted using OmicStudio tools (https://www.omicstudio.cn/tool, accessed on 16 October ).

2.11. Statistical Analysis

In this study, every experiment was conducted at least three times. Two sets of data were compared for significance using GraphPad Prism 9.5 t tests, and multiple comparisons of data significance were examined with a GraphPad Prism 9.5 one-way ANOVA. The means ± standard deviations of three separate biological replicates were used to represent all the data. The results were deemed statistically significant when p < 0.05.

4. Discussion

Globally, the prevalence of UC is increasing year after year, and UC has become a global disease impacting public health [36]. Due to its incurable nature and severe recurrent effects, the quality of life of patients is severely affected [37]. Clinically, antibiotics, immunosuppressants, and glucocorticoids are widely used to alleviate UC; however, prolonged use of these drugs can lead to serious side effects and complications [38]. Marine-derived bioactive peptides have been reported to have high activity, low toxicity, and anti-inflammatory and antioxidant biological functions [39,40]. In the present study, we determined the mitigating effect of oyster peptides on colitis in mice. We found that OPs significantly alleviated the typical pathologic features of colitis in mice, such as weight loss, colon shortening, elevated disease scores, and increased inflammatory response. We also found that OPs restored the number of goblet cells, enhanced mucin expression, and improved the protein level of the tight junction protein claudin-1. Furthermore, feeding mice a meal supplemented with OPs improved the dysbiosis of gut microbiota and decreased the relative presence of the pathogenic bacterium Parasutterella. These findings imply that OP supplementation in the diet can successfully shield mice from DSS-induced colitis.

The intestinal barrier protects the body from invasion by foreign pathogenic microorganisms and reduces colonic injury, and the transmembrane barrier protein claudin-1 is an important component of the intestinal barrier [41,42]. The mucus layer, which is primarily made up of intestinal goblet cells and mucins, is the first physical barrier that bacteria face in the gut, in addition to tight junction proteins [43]. Impaired intestinal barrier function allows bacteria and their harmful substance LPS to enter the bloodstream, which triggers systemic inflammation and can exacerbate UC [44]. Proinflammatory cytokines have been reported to be one of the pathologic factors contributing to intestinal and mucosal inflammation [45]. The results of our study similarly showed that DSS induced inflammatory infiltration in mouse colonic tissues and significantly promoted the expression of proinflammatory cytokines in the colon and serum, whereas the OP treatment suppressed inflammation. Previous studies have shown that many natural marine products, such as oyster polysaccharides, sea cucumber peptides, and tuna bioactive peptides, are able to improve intestinal barrier function and inhibit the inflammatory response to improve colitis [19,24,46]. In this study, OP alleviated the impairment of the intestinal barrier caused by DSS.

Gut microbial disorders are important triggers in the pathogenesis of UC [47]. It has been shown that DSS induces gut microbial dysbiosis in mice, which in turn exacerbates the progression of UC [48]. Typically, Firmicutes and Bacteroidota dominate the gut microbiota, and an abnormal increase in the relative abundance of Proteobacteria c is a sign of an imbalance in gut microbiota [49]. Furthermore, a class of good bacteria called Firmicutes inhabits the gut, and disruption of the gut barrier lowers the relative abundance of Firmicutes [50,51]. In this study, the administration of OPs improved the dysbiosis of the gut microbiota, while the relative abundance of Firmicutes fell and Proteobacteria increased in the DSS group. The abundance of Firmicutes was positively correlated with mouse colon length and T-AOC and negatively correlated with inflammatory factors, DAI scores, and weight loss. Conversely, Proteobacteria was positively correlated with the severity of colitis in mice. Notably, the relative levels of Alistipes were significantly higher in the OP group than in the DSS group. Furthermore, there was a negative correlation between the abundance of Alistipes and inflammatory markers, DAI score, and weight loss, and a positive correlation with colon length and T-AOC. Alistipes has been shown to be not only a beneficial gut microorganism but also a short-chain fatty acid (SCFA)-producing bacterium [52,53]. In addition, many studies have shown that Parasutterella is highly expressed in UC mice and is a potentially harmful class of bacteria, which is consistent with our findings [54,55]. In this study, there were positive and negative correlations found between Parasutterella and colon length and T-AOC, as well as positive correlations with inflammatory markers, DAI score, and weight loss. When the OPs were applied, the relative abundance of Parasutterella was considerably lower than in the DSS group. The aforementioned findings imply that OPs may alleviate colitis by correcting the gut flora&#;s imbalance.

Imbalances in gut microbes usually lead to an increase in harmful bacteria and a decrease in beneficial bacteria [31]. The TLR4/NF-κB signaling pathway plays a critical role in the progression of colitis in mice and can mediate biological processes such as immunity and inflammation [56]. LPS produced by harmful bacteria can bind TLR4 on the cell membrane surface and promote the expression of inflammatory factors by activating the NF-κB signaling pathway [57]. The results of this study showed that the DSS treatment activated the TLR4-NFκB signaling pathway in the mouse colon, while the OP treatment significantly inhibited the pathway. The above results suggest that OPs are able to ameliorate DSS-induced colitis in mice by inhibiting the TLR4/NF-κB signaling pathway and thereby ameliorating DSS-induced colitis.

Bioactive peptides are specific amino acid fragments of proteins that not only have nutritional value but also have beneficial effects on health [58]. For example, wheat peptides were able to alleviate DSS-induced colitis in mice by activating the NRF2-Keap1 signaling pathway and thereby alleviating DSS-induced colitis [30]. Atrial natriuretic peptide was able to attenuate colitis in mice by inhibiting the cGAS-STING pathway [59]. Related studies have focused on exploring the biological activity of individual peptides. For example, the Trichinella matsutake-derived peptide WFNNAGP prevents DSS-induced colitis by improving oxidative stress and intestinal barrier function [60]. The walnut-derived peptide LPF alleviated colitis by reducing apoptosis, reducing inflammation, and modulating the gut microbiota [61]. Numerous bioactive peptides generated from marine food have been shown to exhibit a range of biological properties, including anti-inflammatory, antioxidant, and anti-obesity properties [62]. In the present study, oyster peptides were similarly able to alleviate the symptoms of DSS-induced colitis by maintaining intestinal barrier integrity, modulating the gut microbiota, and inhibiting the TLR4/NF-κB signaling pathway.

5. Conclusions

In this study, we demonstrated that in colitis-affected animals, OPs enhanced the quantity of goblet cells and upregulated the production of mucin and the tight junction protein claudin-1. Additionally, OPs lessen the relative abundance of Proteobacteria, lower the intestinal microbial imbalance brought on by DSS, and lessen the oxidative damage and inflammation in the gut. Furthermore, the OP therapy reduced inflammatory reactions brought on by DSS by blocking the TLR4/NF-κB signaling pathway. In addition, we characterized the peptide composition of the oyster peptides, and in the following studies, we will explore the potential bioactive peptides in the oyster peptides. In summary, the OPs effectively alleviated DSS-induced colitis by improving the intestinal barrier and intestinal microbiota, and the results of this study provide innovative perspectives for the development of marine-food-derived bioactive peptides as functional foods to maintain intestinal health.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10./nu/s1, Table S1: All primers; Table S2: Amino acid composition of OP; Table S3: Peptide identification of OP.

Funding Statement

This work was supported by the Department of Science and Technology of Jilin Province (ZP).

Author Contributions

Conceptualization, W.G. and B.Y.; methodology, H.G.; software, Z.J.; validation, B.Y. and W.X.; formal analysis, W.X. and W.R.; investigation, H.G.; resources, W.X.; data curation, H.G.; writing&#;original draft preparation, W.X.; writing&#;review and editing, Z.J.; visualization, H.G.; supervision, B.W.; project administration, B.Y.; funding acquisition, W.G. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki, and approved by the Laboratory Animal Welfare and Ethics Committee of Jilin University (License No. SY, Approval Date: 2 August ).

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding authors.

Conflicts of Interest

The authors declare no conflicts of interest.

Footnotes

Disclaimer/Publisher&#;s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Fish skin-washing and sterilization- enzymolysis &#; separation- decoloration and deodorization-refined filtration- ultrafiltration- concentration- sterilization- spray drying- inner packing- metal detection- outer packing- inspection- storage

FAQ:

1. Do your company have any certification?

Yes, ISO, MUI, HACCP,HALAL,etc.

2. What is your minimum order quantity?

Usually kg but it is negotiable.

The company is the world’s best edible bird nest extract specifications supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

3. How to ship the goods?

A: Ex-work or FOB, if you have own forwarder in China.

B: CFR or CIF, etc., if you need us to make shipment for you.

C: More options, you can suggest.

4. What kind of payment do you accept?

T/T and L/C.

5. What&#;s your production lead time?

Around 7 to 15 days according to the order quantity and production details.

7. Can you accept customization?

Yes, we offer OEM or ODM service.The recipe and comp

8. Could you provide samples & what&#;s sample delivery time?

Yes, normally we will provide customer free samples we made before, but customer needs to undertake the freight cost.

9. Are you manufacturer or trader?

 We are manufacturer in China and our factory is located in Hainan.Factory visit is welcome!

Contact us to discuss your requirements of elastin peptide suppliers. Our experienced sales team can help you identify the options that best suit your needs.