Protective effect of dihydromyricetin on intestinal epithelium in weaned pigs upon enterotoxigenic Escherichia coli challenge.

Dihydromyricetin (DMY), a natural flavonoid compound, are believed to prevent inflammatory response, dealing with pathogens and repairing the intestinal barrier. The objective of this study was to investigate whether DMY supplementation could attenuate intestinal damage in the context of enterotoxigenic Escherichia coli K88 (ETEC F4+) infection. After weaning, different litters of pigs were randomly assigned to one of the following treatments: (1) non-challenged control (CON, fed with basal diet); (2) ETEC-challenged control (ECON, fed with basal diet); and (3) ETEC challenge + DMY treatment (EDMY, fed with basal diet plus 300 mg kg-1 DMY). We observed a significant reduction in fecal Escherichia coli shedding and diarrhea incidence, but an increase in ADG in pigs of EDMY group compared to the pigs of ECON group. Relative to the pigs of ECON group, dietary DMY treatment decreased (P < 0.05) concentrations of the serum D-xylose, D-lactate and diamine oxidase (DAO), but increased the abundance of zonula occludens-1 (ZO-1) in the jejunum of pigs. In addition, DMY also decreased (P < 0.05) the number of S-phase cells and the percentage of total apoptotic epithelial cells of jejunal epithelium in pigs of the EDMY group compared to the pigs of the ECON group. Furthermore, DMY decreased the mRNA expression levels of critical immune-associated genes TLR4, NFκB, Caspase3, Caspase9, IL-1ß, IL-6, TNF-α and the protein p-NFκB and p-IκBα expressions of intestinal epithelium in pigs of the EDMY group compared to the pigs of the ECON group. Compared to the ECON group, DMY elevated (P < 0.05) the expression levels of ß-defensins PBD1, PBD2, PBD3, PBD129, as well as the abundance of secreted IgA in intestinal mucosae of the EDMY group. Thus, our results indicate that DMY may relieve intestinal integrity damage due to Escherichia coli F4.

Macrogenomes reveal microbial-mediated microplastic degradation pathways in the porcine gut: a hope for solving the environmental challenges of microplastics.

It is increasingly recognized that microplastics (MPs) are being transmitted through the food chain system, but little is known about the microorganisms involved in MP degradation, functional biodegradation genes, and metabolic pathways of degradation in the intestinal tract of foodborne animals. In this study, we explored the potential flora mainly involved in MP degradation in the intestinal tracts of Taoyuan, Duroc, and Xiangcun pigs by macrogenomics, screened relevant MP degradation genes, and identified key enzymes and their mechanisms. The pig colon was enriched with abundant MP degradation-related genes, and gut microorganisms were their main hosts. The fiber diet did not significantly affect the abundance of MP degradation-related genes but significantly reduced their diversity. We identified a total of 94 functional genes for MP degradation and classified them into 27 categories by substrate type, with polystyrene (PS), polyethylene terephthalate (PET), and di(2-ethylhexyl) phthalate (DEHP) were the most predominant degradation types. The MP degradation functional genes were widely distributed in a variety of bacteria, mainly in the phylum Firmicutes and Bacteroidetes. Based on the identified functional genes for MP degradation, we proposed a hypothetical degradation mechanism for the three major MP pollutants, namely, PS, PET, and DEHP, which mainly consist of oxidoreductase, hydrolase, transferase, ligase, laccase, and isomerase. The degradation process involves the breakdown of long polymer chains, the oxidation of short-chain oligomers, the conversion of catechols, and the achievement of complete mineralization. Our findings provide insights into the function of MP degradation genes and their host microorganisms in the porcine colon.

Effect of cordyceps militaris on growth performance, antioxidant capacity, and intestinal epithelium functions in weaned pigs.

To explore the effects of cordyceps militaris (CM) on growth performance and intestinal epithelium functions, 180 weaned pigs were randomly assigned into 5 treatments with 6 replicate pens per treatment (6 pigs per pen). Pigs were fed with basal diet (control) or basal diet supplemented with 100, 200, 400, and 800 mg/kg CM. The trial lasted for 42 d, and pigs from the control and optimal-dose groups (based on growth performance) were picked for blood and tissue collection (n = 6). Results showed that CM elevated the average daily gain (ADG) and decreased the ratio of feed intake to gain (F:G) in the weaned pigs (P < 0.05). CM supplementation at 100 mg/kg improved the digestibilities of dry matter (DM), crude protein (CP), and gross energy (GE) (P < 0.05). CM not only increased the activities of superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) but also increased the concentration of interleukin-10 (IL-10) in serum (P < 0.05). The serum concentrations of malondialdehyde (MDA), d-lactate, and diamine oxidase (DAO) were reduced by CM (P < 0.05). Interestingly, CM elevated the villus height and the ratio of villus height to crypt depth in the duodenum and jejunum and increased the activities of duodenal sucrase and maltase (P < 0.05). Moreover, CM elevated the expression levels of tight-junction proteins ZO-1, claudin-1, and occluding, as well as critical functional genes such as the fatty acid transport protein (FATP1), cationic amino acid transporter 1 (CAT1), and NF-E2-related factor 2 (Nrf2) in the duodenum and jejunum (P < 0.05). Importantly, CM increased the concentrations of acetic acid and butyric acid, and elevated the abundances of Bacillus and Lactobacillus in the cecum and colon, respectively (P < 0.05). These results indicated potential benefits of CM in improving the growth of weaned pigs, and such effect may be tightly associated with improvement in antioxidant capacity and intestinal epithelium functions.

In last decades, antibiotics have been widely used as growth-promoting agents to relieve weaning stress and prevent intestinal injury. However, overdose and misuse of antibiotics led to bacterial resistance and drug residues in animal products. Therefore, the development of healthy alternatives for pork production has attracted considerable research interest worldwide. Cordyceps militaris (CM) is an entomopathogenic fungus with various biological effects, including anti-inflammatory, lipid-lowering, and antioxidant activities. This study was conducted to investigate the effects of dietary CM supplementation on growth performance, antioxidant capacity, and intestinal epithelium functions in weaned pigs. Our results showed that CM supplementation could enhance the growth performance by improving antioxidant capacity and intestinal epithelium functions.

Eugenol mimics exercise to promote skeletal muscle fiber remodeling and myokine IL-15 expression by activating TRPV1 channel.

Metabolic disorders are highly prevalent in modern society. Exercise mimetics are defined as pharmacological compounds that can produce the beneficial effects of fitness. Recently, there has been increased interest in the role of eugenol and transient receptor potential vanilloid 1 (TRPV1) in improving metabolic health. The aim of this study was to investigate whether eugenol acts as an exercise mimetic by activating TRPV1. Here, we showed that eugenol improved endurance capacity, caused the conversion of fast-to-slow muscle fibers, and promoted white fat browning and lipolysis in mice. Mechanistically, eugenol promoted muscle fiber-type transformation by activating TRPV1-mediated CaN signaling pathway. Subsequently, we identified IL-15 as a myokine that is regulated by the CaN/nuclear factor of activated T cells cytoplasmic 1 (NFATc1) signaling pathway. Moreover, we found that TRPV1-mediated CaN/NFATc1 signaling, activated by eugenol, controlled IL-15 levels in C2C12 myotubes. Our results suggest that eugenol may act as an exercise mimetic to improve metabolic health via activating the TRPV1-mediated CaN signaling pathway.

Next-generation probiotic candidates targeting intestinal health in weaned piglets: Both live and heat-killed Akkermansia muciniphila prevent pathological changes induced by enterotoxigenic Escherichia coli in the gut.

The use of next-generation probiotics (NGP) in pigs for combating diseases has been subject to limited research. Here we explored the potential of a well-known NGP candidate Akkermansia muciniphila targeting pig gut health. In the first screening experiment, we found that the abundance of A. muciniphila peaked at 14 d old but decreased at weaning (21 d old; P < 0.05), suggesting the weaning period may be an effective window for A. muciniphila intervention. Following that, 48 crossbred weaned pigs at 28 d old were randomly assigned to five groups: control (CON), high/low live A. muciniphila (HA/LA), and high/low heat-killed A. muciniphila (HIA/LIA). From 1 to 28 d old, the CON group received gastric infusion of anaerobic sterile saline every other day; the HA and LA groups were gavaged every other day with 1 × 1010 CFU/5 mL and 5 × 108 CFU/5 mL live A. muciniphila, respectively; and the HIA and LIA groups were gavaged every other day with 1 × 1010 CFU/5 mL and 5 × 108 CFU/5 mL heat-killed A. muciniphila, respectively. At d 29, pigs in the CON group were randomly and equally divided into two groups, one of which was named the enterotoxigenic Escherichia coli (ETEC) group, and all groups except CON received a 5-d ETEC challenge. The supplementation of A. muciniphila numerically reduced the diarrhea rate of weaned pigs compared to the pigs that only received the ETEC challenge (P = 0.57), but the LIA group had a higher diarrhea rate than the CON group (P < 0.05). Consistent with this, the supplementation of A. muciniphila improved the small intestinal morphology and structure, proportion of CD4+ T lymphocytes in the blood, as well as the expression of genes related to intestinal barrier and antioxidant indices of pigs with ETEC challenge, especially for the LA group (P < 0.05). Meanwhile, A. muciniphila supplementation reduced the expression of ETEC virulence factor genes in the ileum and colon of pigs challenged by ETEC (P < 0.05). Therefore, A. muciniphila may protect the intestinal health of weaned piglets from damage caused by ETEC infection, but the effect may vary depending on the concentration and activity of A. muciniphila.

Genetic- and fiber-diet-mediated changes in virulence factors in pig colon contents and feces and their driving factors.

Virulence factors (VFs) are key factors for microorganisms to establish defense mechanisms in the host and enhance their pathogenic potential. However, the spectrum of virulence factors in pig colon and feces, as well as the influence of dietary and genetic factors on them, remains unreported. In this study, we firstly revealed the diversity, abundance and distribution characteristics of VFs in the colonic contents of different breeds of pigs (Taoyuan, Xiangcun and Duroc pig) fed with different fiber levels by using a metagenomic analysis. The analysis resulted in the identification of 1,236 virulence factors, which could be grouped into 16 virulence features. Among these, Taoyuan pigs exhibited significantly higher levels of virulence factors compared to Duroc pigs. The high-fiber diet significantly reduced the abundance of certain virulence factor categories, including iron uptake systems (FbpABC, HitABC) and Ig protease categories in the colon, along with a noteworthy decrease in the relative abundance of plasmid categories in mobile genetic elements (MGEs). Further we examined VFs in feces using absolute quantification. The results showed that high-fiber diets reduce fecal excretion of VFs and that this effect is strongly influenced by MGEs and short-chain fatty acids (SCFAs). In vitro fermentation experiments confirmed that acetic acid (AA) led to a decrease in the relative abundance of VFs (p < 0.1). In conclusion, our findings reveal for the first time how fiber diet and genetic factors affect the distribution of VFs in pig colon contents and feces and their driving factors. This information provides valuable reference data to further improve food safety and animal health.

Apoptotic vesicles are required to repair DNA damage and suppress premature cellular senescence.

It is well known that DNA damage can cause apoptosis. However, whether apoptosis and its metabolites contribute to DNA repair is largely unknown. In this study, we found that apoptosis-deficient Fasmut and Bim- /- mice show significantly elevated DNA damage and premature cellular senescence, along with a significantly reduced number of 16,000 g apoptotic vesicles (apoVs). Intravenous infusion of mesenchymal stromal cell (MSC)-derived 16,000 g apoVs rescued the DNA damage and premature senescence in Fasmut and Bim-/- mice. Moreover, a sublethal dose of radiation exposure caused more severe DNA damage, reduced survival rate, and loss of body weight in Fasmut mice than in wild-type mice, which can be recovered by the infusion of MSC-apoVs. Mechanistically, we showed that apoptosis can assemble multiple nuclear DNA repair enzymes, such as the full-length PARP1, into 16,000 g apoVs. These DNA repair components are directly transferred by 16,000 g apoVs to recipient cells, leading to the rescue of DNA damage and elimination of senescent cells. Finally, we showed that embryonic stem cell-derived 16,000 g apoVs have superior DNA repair capacity due to containing a high level of nuclear DNA repair enzymes to rescue lethal dose-irradiated mice. This study uncovers a previously unknown role of 16,000 g apoVs in safeguarding tissues from DNA damage and demonstrates a strategy for using stem cell-derived apoVs to ameliorate irradiation-induced DNA damage.

Grape seed proanthocyanidin extract promotes skeletal muscle fiber type transformation through modulation of cecal microbiota and enhanced butyric acid production.

The conversion of fast-twitch fibers into slow-twitch fibers within skeletal muscle plays a crucial role in improving physical stamina and safeguarding against metabolic disorders in individuals. Grape seed proanthocyanidin extract (GSPE) possesses numerous pharmacological and health advantages, effectively inhibiting the onset of chronic illnesses. However, there is a lack of research on the specific mechanisms by which GSPE influences muscle physiology and gut microbiota. This study aims to investigate the role of gut microbiota and their metabolites in GSPE regulation of skeletal muscle fiber type conversion. In this experiment, 54 male BALB/c mice were randomly divided into three groups: basal diet, basal diet supplemented with GSPE, and basal diet supplemented with GSPE and antibiotics. During the feeding period, glucose tolerance and forced swimming tests were performed. After euthanasia, samples of muscle and feces were collected for analysis. The results showed that GSPE increased the muscle mass and anti-fatigue capacity of the mice, as well as the expression of slow-twitch fibers. However, the beneficial effects of GSPE on skeletal muscle fibers disappeared after adding antibiotics to eliminate intestinal microorganisms, suggesting that GSPE may play a role by regulating intestinal microbial structure. In addition, GSPE increased the relative abundance of Blautia, Muribaculaceae, and Enterorhabdus, as well as butyrate production. Importantly, these gut microbes exhibited a significant positive correlation with the expression of slow-twitch muscle fibers. In conclusion, supplementation with GSPE can increase the levels of slow-twitch fibers by modulating the gut microbiota, consequently prolonging the duration of exercise before exhaustion. PRACTICAL APPLICATION: This research suggests that grape seed proanthocyanidin extract (GSPE) has potential applications in improving physical stamina and preventing metabolic disorders. By influencing the gut microbiota and increasing butyric acid production, GSPE contributes to the conversion of fast-twitch muscle fibers into slow-twitch fibers, thereby enhancing anti-fatigue capacity and exercise endurance. While further studies are needed, incorporating GSPE into dietary supplements or functional foods could support individuals seeking to optimize their exercise performance and overall metabolic health.

Leucine alleviates cytokine storm syndrome by regulating macrophage polarization via the mTORC1/LXRα signaling pathway.

Cytokine storms are associated with severe pathological damage and death in some diseases. Excessive activation of M1 macrophages and the subsequent secretion of pro-inflammatory cytokines are a major cause of cytokine storms. Therefore, promoting the polarization of M2 macrophages to restore immune balance is a promising therapeutic strategy for treating cytokine storm syndrome (CSS). This study was aimed at investigating the potential protective effects of leucine on lipopolysaccharide (LPS)-induced CSS in mice and exploring the underlying mechanisms. CSS was induced by LPS administration in mice, which were concurrently administered leucine orally. In vitro, bone marrow derived macrophages (BMDMs) were polarized to M1 and M2 phenotypes with LPS and interleukin-4 (IL-4), respectively, and treated with leucine. Leucine decreased mortality in mice treated with lethal doses of LPS. Specifically, leucine decreased M1 polarization and promoted M2 polarization, thus diminishing pro-inflammatory cytokine levels and ameliorating CSS in mice. Further studies revealed that leucine-induced macrophage polarization through the mechanistic target of rapamycin complex 1 (mTORC1)/liver X receptor α (LXRα) pathway, which synergistically enhanced the expression of the IL-4-induced M2 marker Arg1 and subsequent M2 polarization. In summary, this study revealed that leucine ameliorates CSS in LPS mice by promoting M2 polarization through the mTORC1/LXRα/Arg1 signaling pathway. Our findings indicate that a fundamental link between metabolism and immunity contributes to the resolution of inflammation and the repair of damaged tissues.

L-theanine attenuates H2O2-induced inflammation and apoptosis in IPEC-J2 cells via inhibiting p38 MAPK signaling pathway.

This study investigated the protective effects of L-theanine on hydrogen peroxide (H2O2)-induced intestinal barrier dysfunction in IPEC-J2 cells. Results showed that L-theanine reduced H2O2-induced IPEC-J2 cells inflammation and apoptosis, and decreased protein phosphorylation levels of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor kappa-B (NF-κB). The p38 MAPK inhibitor (SB203580) decreased oxidative stress, the protein expression of phosphorylation of p38 MAPK and NF-κB, the H2O2-induced increase in mRNA expression of pro-apoptotic and pro-inflammatory related genes expression and secretion, and tight junction protein related genes expression, which was similar to the effect of L-theanine. In conclusion, L-theanine inhibited H2O2-induced oxidative damage and inflammatory reaction, eliminated apoptosis, and protected intestinal epithelial barrier damage by inhibiting the activation of p38 MAPK signaling pathway.

All-trans retinoic acid alleviates transmissible gastroenteritis virus-induced intestinal inflammation and barrier dysfunction in weaned piglets.

BACKGROUND: Transmissible gastroenteritis virus (TGEV) is one of the main pathogens causing severe diarrhea of piglets. The pathogenesis of TGEV is closely related to intestinal inflammation. All-trans retinoic acid (ATRA) is the main active metabolite of vitamin A, which has immunomodulatory and anti-inflammatory properties. However, it is unclear whether ATRA can alleviate TGEV-induced intestinal inflammation and barrier dysfunction in piglets. This study aimed to investigate the effects of ATRA on growth performance, diarrhea, intestinal inflammation and intestinal barrier integrity of TGEV-challenged piglets. METHODS: In a 19-d study, 32 weaned piglets were randomly divided into 4 treatments: Control group (basal diet), TGEV group (basal diet + TGEV challenge), TGEV + ATRA5 group (basal diet + 5 mg/d ATRA + TGEV challenge) and TGEV + ATRA15 group (basal diet + 15 mg/d ATRA + TGEV challenge). On d 14, piglets were orally administered TGEV or the sterile medium. RESULTS: Feeding piglets with 5 and 15 mg/d ATRA alleviated the growth inhibition and diarrhea induced by TGEV (P < 0.05). Feeding piglets with 5 and 15 mg/d ATRA also inhibited the increase of serum diamine oxidase (DAO) activity and the decrease of occludin and claudin-1 protein levels in jejunal mucosa induced by TGEV, and maintained intestinal barrier integrity (P < 0.05). Meanwhile, 5 mg/d ATRA feeding increased the sucrase activity and the expressions of nutrient transporter related genes (GLUT2 and SLC7A1) in jejunal mucosa of TGEV-challenged piglets (P < 0.05). Furthermore, 5 mg/d ATRA feeding attenuated TGEV-induced intestinal inflammatory response by inhibiting the release of interleukin (IL)-1ß, IL-8 and tumor necrosis factor-α (TNF-α), and promoting the secretion of IL-10 and secretory immunoglobulin A (sIgA) (P < 0.05). Feeding 5 mg/d ATRA also down-regulated the expressions of Toll-like receptors and RIG-I like receptors signaling pathway related genes (TLR3, TLR4, RIG-I, MyD88, TRIF and MAVS) and the phosphorylation level of nuclear factor-κB-p65 (NF-κB p65), and up-regulated the inhibitor kappa B alpha (IκBα) protein level in jejunal mucosa of TGEV-challenged piglets (P < 0.05). CONCLUSIONS: ATRA alleviated TGEV-induced intestinal barrier damage by inhibiting inflammatory response, thus improving the growth performance and inhibiting diarrhea of piglets. The mechanism was associated with the inhibition of NF-κB signaling pathway mediated by TLR3, TLR4 and RIG-I.

Purine Metabolism and Hexosamine Biosynthetic Pathway Abnormalities in Diarrheal Weaned Piglets Identified Using Metabolomics.

Post-weaning diarrhea significantly contributes to the high mortality in pig production, but the metabolic changes in weaned piglets with diarrhea remain unclear. This study aimed to identify the differential metabolites in the urine of diarrheal weaned piglets and those of healthy weaned piglets to reveal the metabolic changes associated with diarrhea in weaned piglets. Nine 25-day-old piglets with diarrhea scores above 16 and an average body weight of 5.41 ± 0.18 kg were selected for the diarrhea group. Corresponding to the body weight and sex of the diarrhea group, nine 25-month-old healthy piglets with similar sex and body weights of 5.49 ± 0.21 kg were selected as the control group. Results showed that the serum C-reactive protein and cortisol of piglets in the diarrhea group were higher than those in the control group (p < 0.05). The mRNA expression of TNF-α, IFN-γ in the jejunum and colon, and IL-1ß in the jejunum were increased in diarrhea piglets (p < 0.05), accompanied by a reduction in the mRNA expression of ZO-1, ZO-2, and CLDN1 in the jejunum and colon (p < 0.05); mRNA expression of OCLN in the colon also occurred (p < 0.05). Metabolomic analysis of urine revealed increased levels of inosine, hypoxanthine, guanosine, deoxyinosin, glucosamine, glucosamine-1-p, N-Acetylmannosamine, chitobiose, and uric acid, identified as differential metabolites in diarrhea piglets compared to the controls. In summary, elevated weaning stress and inflammatory disease were associated with the abnormalities of purine metabolism and the hexosamine biosynthetic pathway of weaned piglets. This study additionally indicated the presence of energy metabolism-related diseases in diarrheal weaned piglets.

Dietary Ferulic Acid Increases Endurance Capacity by Promoting Skeletal Muscle Oxidative Phenotype, Mitochondrial Function, and Antioxidant Capacity.

SCOPE: Endurance capacity is essential for endurance athletes' achievement and individuals' health. Nutritional supplements are a proven way to enhance endurance capacity. Previous studies have shown that ferulic acid (FA) enhances endurance capacity, but the underlying mechanism is unclear. The study is aimed to investigate the mechanism by which FA increases endurance capacity. METHODS AND RESULTS: Forty mice are divided into control and 0.5% FA-supplemented groups, and an exhaustive swimming test demonstrates increased endurance capacity with FA supplementation. This study investigates the underlying mechanism for this effect of FA. Firstly, RT-PCR and western blot analysis find that FA increases the transformation from fast to slow muscle fiber. Additionally, adenosine triphosphate concentration, metabolic enzyme activity, and mitochondrial DNA analysis find that FA increases mitochondrial biogenesis and activates nuclear factor erythroid 2-related factor (NRF)1 signaling pathway in muscle. Besides, through antioxidant capacity analysis, this study finds that FA activates NRF2 signaling pathway and improves the antioxidant capacity in muscle. Moreover, inhibiting NRF2 eliminates FA's effect on muscle fiber transformation in C2C12 cells. CONCLUSION: Our results suggest that FA increases endurance capacity by promoting skeletal muscle oxidative phenotype, mitochondrial function, and antioxidant capacity, which may be related to the NRF1 and NRF2 signaling pathways.

Dietary short-term supplementation of grape seed proanthocyanidin extract improves pork quality and promotes skeletal muscle fiber type conversion in finishing pigs.

Plant extracts are commonly used as feed additives to improve pork quality. However, due to their high cost, shortening the duration of supplement use can help reduce production costs. In this study, we aimed to investigate the effects of grape seed proanthocyanidin extract (GSPE) on meat quality and muscle fiber characteristics of finishing pigs during the late stage of fattening, which was 30 days in our experimental design. The results indicated that short-term dietary supplementation of GSPE significantly reduced backfat thickness, but increased loin eye area and improved meat color and tenderness. Moreover, GSPE increased slow myosin heavy chain (MyHC) expression and malate dehydrogenase (MDH) activity, while decreasing fast MyHC expression and lactate dehydrogenase (LDH) activity in the Longissimus thoracis (LT) muscle. Additionally, GSPE increased the expression of Sirt1 and PGC-1α proteins in the LT muscle of finishing pigs and upregulated AMP-activated protein kinase α 1 (AMPKα1), AMPKα2, nuclear respiratory factor 1 (NRF1), and calcium/calmodulin-dependent protein kinase kinase ß (CaMKKß) mRNA expression levels. These findings suggest that even during the late stage of fattening, GSPE treatment can regulate skeletal muscle fiber type transformation through the AMPK signaling pathway, thereby affecting the muscle quality of finishing pigs. Therefore, by incorporating GSPE into the diet of pigs during the late stage of fattening, producers can enhance pork quality while reducing production costs.

Oleanolic acid promotes skeletal muscle fiber type transformation by activating TGR5-mediated CaN signaling pathway.

In recent years, the impact of bile acids and their representative G protein-coupled bile acid receptor 1 Takeda-G-protein-receptor-5 (TGR5) signaling pathway on muscle function and metabolic health has gained considerable interest. Increasing the content of slow muscle fibers has been recognized as an effective strategy to improve metabolic health. Oleanolic acid (OA) is a naturally occurring triterpenoid compound derived from plants, which can activate TGR5. The aim of this study was to investigate the effect of OA and TGR5 on muscle fiber types and further explore the underlying TGR5-dependent mechanisms. In this study, mice were divided into three groups and dietary supplementation with 0, 50, or 100 mg/kg OA. In addition, C2C12 cells were treated with OA at concentrations of 0, 5, 10, and 20 µM. Our studies revealed that OA promoted the conversion of fast to slow muscle fibers. In addition, it was found that OA activated the TGR5-mediated calcineurin (CaN)/nuclear factor of activated T cells cytoplasmic 1 (NFATc1) signaling pathway. Further mechanistic investigations demonstrated that inhibiting TGR5 and CaN abolished the effects of OA on muscle fiber types transformation. In conclusion, this study found that OA promotes the transformation of fast muscle fibers to slow muscle fibers through the TGR5-mediated CaN/NFATc1 signaling pathway.

Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness.

The lethality of epithelial ovarian cancer (OC) is largely due to a high rate of recurrence and development of chemoresistance, which requires synergy between cancer cells and the tumor microenvironment (TME) and is thought to involve cancer stem cells. Our analysis of gene expression microarray data from paired primary and recurrent OC tissues revealed significantly elevated expression of the gene encoding periostin (POSTN) in recurrent OC compared to matched primary tumors (p = 0.015). Secreted POSTN plays a role in the extracellular matrix, facilitating epithelial cell migration and tissue regeneration. We therefore examined how elevated extracellular POSTN, as we found is present in recurrent OC, impacts OC cell functions and phenotypes, including stemness. OC cells cultured with conditioned media with high levels of periostin (CMPOSTNhigh) exhibited faster migration (p = 0.0044), enhanced invasiveness (p = 0.006), increased chemoresistance (p < 0.05), and decreased apoptosis as compared to the same cells cultured with control medium (CMCTL). Further, CMPOSTNhigh-cultured OC cells exhibited an elevated stem cell side population (p = 0.027) along with increased expression of cancer stem cell marker CD133 relative to CMCTL-cultured cells. POSTN-transfected 3T3-L1 cells that were used to generate CMPOSTNhigh had visibly enhanced intracellular and extracellular lipids, which was also linked to increased OC cell expression of fatty acid synthetase (FASN) that functions as a central regulator of lipid metabolism and plays a critical role in the growth and survival of tumors. Additionally, POSTN functions in the TME were linked to AKT pathway activities. The mean tumor volume in mice injected with CMPOSTNhigh-cultured OC cells was larger than that in mice injected with CMCTL-cultured OC cells (p = 0.0023). Taken together, these results show that elevated POSTN in the extracellular environment leads to more aggressive OC cell behavior and an increase in cancer stemness, suggesting that increased levels of stromal POSTN during OC recurrence contribute to more rapid disease progression and may be a novel therapeutic target. Furthermore, they also demonstrate the utility of having matched primary-recurrent OC tissues for analysis and support the need for better understanding of the molecular changes that occur with OC recurrence to develop ways to undermine those processes.

Effect of fermented rapeseed meal on growth performance, nutrient digestibility, and intestinal health in growing pigs.

To explore the effects of fermented rapeseed meal (FRSM) on growth performance and intestinal health, a total of 30 growing pigs were randomly allotted to three treatments consisting of corn-soybean meal diet (CSD), rapeseed meal diet (RSD), and fermented rapeseed meal diet (FRSD). Results showed that compared with RSD, FRSD feeding increased the average daily gain and final body weight in pigs (P < 0.01). Compared with RSD feeding, FRSD feeding elevated the apparent digestibility of crude protein, acid detergent fiber, and ether extract in pigs (P < 0.01). Moreover, the FRSD group exhibited greater apparent ileal digestibility of His, Thr, Lys, and Ser than the RSD group (P < 0.01). The digestible energy, metabolic energy, and nitrogen utilization were higher in the FRSD and CSD groups than in the RSD group (P < 0.01). As compared to the RSD, FRSD feeding decreased the serum concentration of leptin but significantly increased the concentrations of immunoglobulin (Ig) A, IgG, ghrelin, and enzyme activities of amylase, lipase, and trypsin in the pancreas (P < 0.05). Interestingly, the villus height, the ratio of villus height to crypt depth, and the activities of brush border enzymes (e.g., maltase and sucrase) in the small intestine were higher in the CSD and FRSD groups than in the RSD group (P < 0.05). As compared to the RSD, the FRSD feeding not only increased the expression level of the occludin in the small intestinal epithelium (P < 0.05) but also elevated the expression levels of claudin-1, MUC1, and PepT1 genes in the duodenum, and elevated the expression levels of SGLT1 and CAT1 genes in the jejunum (P < 0.05). Importantly, FRSD feeding significantly decreased the abundance of Escherichia coli, but increased the abundance of Lactobacillus and the content of butyrate in the cecum and colon (P < 0.05). These results indicated that compared with rapeseed meal, fermented rapeseed meal exhibited a positive effect on improving the growth performance and intestinal health in growing pigs, and the results may also help develop novel protein sources for animal nutrition and the feed industry.

Corrigendum: Combined effects of host genetics and diet on porcine intestinal fungi and their pathogenic genes.

[This corrects the article DOI: 10.3389/fmicb.2023.1192288.].

Genetic- and Fiber-Diet-Mediated Changes in Antibiotic Resistance Genes in Pig Colon Contents and Feces and Their Driving Factors.

Comprehensive studies on the effects of genetics and fiber diets on antibiotic resistance genes (ARGs) remain scarce. In this study, we analyzed the profiles of ARGs in colonic contents and fecal samples of Taoyuan, Duroc, and Xiangcun pigs (n = 10) fed at different fiber levels. Through macrogenomic analysis, we identified a total of 850 unique types of ARGs and classified them into 111 drug resistance classes. The abundance of partially drug-resistant ARGs was higher in the colonic contents of local pig breeds under a large-scale farming model. ARGs were found to be widely distributed among a variety of bacteria, predominantly in the phyla Firmicutes, Proteobacteria, and Bacteroidetes. Fiber diets reduce the abundance of ARGs in colonic contents and feces, and mobile genetic elements (MGEs) and short-chain fatty acids (SCFAs) are important drivers in mediating the effect of fiber diets on the abundance of ARGs. In vitro fermentation experiments confirmed that butyric acid significantly reduced the abundance of ARGs. In summary, the results of this study enhanced our understanding of the distribution and composition of ARGs in the colon of different breeds of pigs and revealed that a fiber diet can reduce ARGs in feces through its Butyric acid, providing reference data for environmental safety.

Effect of Different Dietary Lipid Sources on Growth Performance, Nutrient Digestibility, and Intestinal Health in Weaned Pigs.

To investigate the effects of lipid sources on growth performance and intestinal health, 72 weaned pigs were randomly allocated to three treatments. Pigs were fed with a corn-soybean meal diet containing 2% soybean oil (SO), or fish-palm-rice oil mixture (FPRO), or coconut-palm-rice oil mixture (CPRO). The trial lasted for 28 days; blood and intestinal tissue samples were collected. The results showed that the crude fat digestibility of the FPRO group was higher than that of the SO and CPRO groups (p < 0.05). The FPRO group also had higher digestibility of dry matter, ash, and gross energy than the SO group (p < 0.05); compared to the SO group, the serum interlukin-6 (IL-6) concentration was decreased. Interestingly, the FPRO and CPRO groups had higher villus height than the SO group in the jejunum and ileum, respectively (p < 0.05). Moreover, the FPRO group had higher Lactobacillus abundance than the SO group in the colon and cecum (p < 0.05). Importantly, the expression levels of tight junction protein ZO-1, Claudin-1, and Occludin in the duodenal and ileal mucosa were higher in the FPRO group than in the SO and CPRO groups (p < 0.05). The expression levels of nutrient transporters such as the CAT-1, PepT1, FATP1, and SGLT1 were higher in the FPRO group than in the SO group (p < 0.05). The improved digestibility and intestinal epithelium functions, as well as the reduced inflammatory cytokines, in the FPRO and CPRO group suggest that a mixed lipid source such as the FPRO deserves further attention.