Dietary Supplementation of Inulin Ameliorates Subclinical Mastitis via Regulation of Rumen Microbial Community and Metabolites in Dairy Cows

An Isofibrous Diet with Fiber Konjac Glucomannan Ameliorates Salmonella typhimurium-Induced Colonic Injury by Regulating TLR2-NF-κB Signaling and Intestinal Microbiota in Mice

This study aimed to investigate the hypothesis that dietary konjac glucomannan (KGM) could alleviate Salmonella typhimurium-induced colitis by modulating intestinal microbiota. Mice were fed an isocaloric and isofibrous diet supplemented with either 7% KGM or cellulose and were treated with 5 × 108 CFU of S. typhimurium. The results showed that KGM had an average molecular weight of 936 kDa and predominantly consisted of mannose and glucose at a molar ratio of 1:1.22. In vivo studies demonstrated that dietary KGM effectively mitigated colonic lesions, oxidative stress, disruption of tight junction protein 2 and occludin, and the inflammatory response induced by S. typhimurium. Moreover, KGM administration alleviated the dramatic upregulation of toll-like receptor 2 (TLR2) and phosphonuclear factor κB (NF-κB) protein abundance, induced by Salmonella treatment. Notably, dietary KGM restored the reduced Muribaculaceae and Lactobacillus abundance and increased the abundance of Blautia and Salmonella in S. typhimurium-infected mice. Spearman correlation analysis revealed that the gut microbiota improved by KGM contribute to inhibit inflammation and oxidative stress. These results demonstrated the protective effects of dietary KGM against colitis by modulating the gut microbiota and the TLR2-NF-κB signaling pathway in response to Salmonella infection.

Nutrition, gastrointestinal microorganisms and metabolites in mastitis occurrence and control

Mastitis affects almost all mammals including humans and dairy cows. In the dairy industry, bovine mastitis is a disease with a persistently high incidence, causing serious losses to the health of cows, the quality of dairy products, and the economy of dairy farms. Although local udder infection caused by the invasion of exogenous pathogens into the mammary gland was considered the main cause of mastitis, evidence has been established and continues to grow, showing that nutrition factors and gastrointestinal microbiome (GM) as well as their metabolites are also involved in the development of mammary inflammatory response. Suboptimal nutrition is recognized as a risk factor for increased susceptibility to mastitis in cattle, in particular the negative energy balance. The majority of data regarding nutrition and bovine mastitis involves micronutrients. In addition, the dysbiotic GM can directly trigger or aggravate mastitis through entero-mammary gland pathway. The decreased beneficial commensal bacteria, lowered bacterial diversity, and increased pathogens as well as proinflammatory metabolites are found in both the milk and gastrointestinal tract of mastitic dairy cows. This review discussed the relationship between the nutrition (energy and micronutrient levels) and mastitis, summarized the role of GM and metabolites in regulating mastitis. Meanwhile, several non-antibiotics strategies were provided for the prevention and alleviation of mastitis, including micronutrients, probiotics, short-chain fatty acids, high-fiber diet, inulin, and aryl hydrocarbon receptor.

Antitumor Effect and Gut Microbiota Modulation by Quercetin, Luteolin, and Xanthohumol in a Rat Model for Colorectal Cancer Prevention

Colorectal cancer stands as the third most prevalent form of cancer worldwide, with a notable increase in incidence in Western countries, mainly attributable to unhealthy dietary habits and other factors, such as smoking or reduced physical activity. Greater consumption of vegetables and fruits has been associated with a lower incidence of colorectal cancer, which is attributed to their high content of fiber and bioactive compounds, such as flavonoids. In this study, we have tested the flavonoids quercetin, luteolin, and xanthohumol as potential antitumor agents in an animal model of colorectal cancer induced by azoxymethane and dodecyl sodium sulphate. Forty rats were divided into four cohorts: Cohort 1 (control cohort), Cohort 2 (quercetin cohort), Cohort 3 (luteolin cohort), and Cohort 4 (xanthohumol cohort). These flavonoids were administered intraperitoneally to evaluate their antitumor potential as pharmaceutical agents. At the end of the experiment, after euthanasia, different physical parameters and the intestinal microbiota populations were analyzed. Luteolin was effective in significantly reducing the number of tumors compared to the control cohort. Furthermore, the main significant differences at the microbiota level were observed between the control cohort and the cohort treated with luteolin, which experienced a significant reduction in the abundance of genera associated with disease or inflammatory conditions, such as Clostridia UCG-014 or Turicibacter. On the other hand, genera associated with a healthy state, such as Muribaculum, showed a significant increase in the luteolin cohort. These results underline the anti-colorectal cancer potential of luteolin, manifested through a modulation of the intestinal microbiota and a reduction in the number of tumors.

Intestinal melatonin levels and gut microbiota homeostasis are independent of the pineal gland in pigs

Introduction

Melatonin (MEL) is a crucial neuroendocrine hormone primarily produced by the pineal gland. Pinealectomy (PINX) has been performed on an endogenous MEL deficiency model to investigate the functions of pineal MEL and its relationship with various diseases. However, the effect of PINX on the gastrointestinal tract (GIT) MEL levels and gut microbiome in pigs has not been previously reported.

Methods

By using a newly established pig PINX model, we detected the levels of MEL in the GIT by liquid chromatography-tandem mass spectrometry. In addition, we examined the effects of PINX on the expression of MEL synthesis enzymes, intestinal histomorphology, and the intestinal barrier. Furthermore, 16S rRNA sequencing was performed to analyze the colonic microbiome.

Results

PINX reduced serum MEL levels but did not affect GIT MEL levels. Conversely, MEL supplementation increased MEL levels in the GIT and intestinal contents. Neither PINX nor MEL supplementation had any effect on weight gain, organ coefficient, serum biochemical indexes, or MEL synthetase arylalkylamine N-acetyltransferase (AANAT) expression in the duodenum, ileum, and colon. Furthermore, no significant differences were observed in the intestinal morphology or intestinal mucosal barrier function due to the treatments. Additionally, 16S rRNA sequencing revealed that PINX had no significant impact on the composition of the intestinal microbiota. Nevertheless, MEL supplementation decreased the abundance of Fibrobacterota and increased the abundance of Actinobacteriota, Desulfobacterota, and Chloroflexi.

Conclusion

We demonstrated that synthesis of MEL in the GIT is independent of the pineal gland. PINX had no influence on intestinal MEL level and microbiota composition in pigs, while exogenous MEL alters the structure of the gut microbiota.

Lactobacillus reuteri inhibits Staphylococcus aureus-induced mastitis by regulating oxytocin releasing and gut microbiota in mice

Mastitis is the most frequent disease of cows and has well-recognized detrimental effects on animal wellbeing and dairy farm profitability. With the advent of the postantibiotic era, alternative antibiotic agents, especially probiotics, have received increasing attention in the treatment of mastitis. Based on research showing that Lactobacillus reuteri (L. reuteri) has anti-inflammatory effects, this study explored the protective effects and mechanisms of L. reuteri against mastitis induced by Staphylococcus aureus (S. aureus) in mice. First, mice with S. aureus-induced mastitis were orally administered L. reuteri, and the inflammatory response in the mammary gland was observed. The results showed that L. reuteri significantly inhibited S. aureus-induced mastitis. Moreover, the concentration of oxytocin (OT) and protein expression of oxytocin receptor (OTR) were measured, and inhibition of OTR or vagotomy reversed the protective effect of L. reuteri or its culture supernatant (LCS) on S. aureus-induced mastitis. In addition, in mouse mammary epithelial cells (MMECs), OT inhibited the inflammation induced by S. aureus by inhibiting the protein expression of OTR. It was suggested that L. reuteri protected against S. aureus-induced mastitis by releasing OT. Furthermore, microbiological analysis showed that the composition of the microbiota was altered, and the relative abundance of Lactobacillus was significantly increased in gut and mammary gland after treatment with L. reuteri or LCS. In conclusion, our study found the L. reuteri inhibited the mastitis-induced by S. aureus via promoting the release of OT, and treatment with L. reuteri increased the abundance of Lactobacillus in both gut and mammary gland.

The influence of low-temperature resistant lactic acid bacteria on the enhancement of quality and the microbial community in winter Jerusalem Artichoke (Helianthus tuberosus L.) silage on the Qinghai-Tibet Plateau

Jerusalem Artichoke (Helianthus tuberosus L.), an emerging "food and fodder" economic crop on the Qinghai-Tibet Plateau. To tackle problems such as incomplete fermentation and nutrient loss occurring during the low-temperature ensilage of Jerusalem Artichokes in the plateau's winter, this study inoculated two strains of low-temperature resistant lactic acid bacteria, Lactobacillus plantarum (GN02) and Lactobacillus brevis (XN25), along with their mixed components, into Jerusalem Artichoke silage material. We investigated how low-temperature resistant lactic acid bacteria enhance the quality of low-temperature silage fermentation for Jerusalem Artichokes and clarify its mutual feedback effect with microorganisms. Results indicated that inoculating low-temperature resistant lactic acid bacteria significantly reduces the potential of hydrogen and water-soluble carbohydrates content of silage, while increasing lactic acid and acetic acid levels, reducing propionic acid, and preserving additional dry matter. Inoculating the L. plantarum group during fermentation lowers pH and propionic acid levels, increases lactic acid content, and maintains a dry matter content similar to the original material. Bacterial community diversity exhibited more pronounced changes than fungal diversity, with inoculation having a minor effect on fungal community diversity. Within the bacteria, Lactobacillus remains consistently abundant (>85%) in the inoculated L. plantarum group. At the fungal phylum and genus levels, no significant changes were observed following fermentation, and dominant fungal genera in all groups did not differ significantly from those in the raw material. L. plantarum exhibited a positive correlation with lactic acid and negative correlations with pH and propionic acid. In summary, the inoculation of L. plantarum GN02 facilitated the fermentation process, preserved an acidic silage environment, and ensured high fermentation quality; it is a suitable inoculant for low-temperature silage in the Qinghai-Tibet Plateau.

Evaluation of the Efficacy of a Lactobacilli-Based Teat Detergents for the Microbiota of Cows Teats Using an Untargeted Metabolomics Approach

Teat cleaning pre- and post-milking is important for the overall health and hygiene of dairy cows. The purpose of this research was to evaluate the effectiveness of a teat detergents based on lactic acid bacteria according to changes in somatic cell count and cow-milk metabolites. Sixty-nine raw milk samples were collected from 11 Holstein-Friesian cows in China during 12 days of teat cleaning. An ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry-based untargeted metabolomic approach was applied to detect metabolomic differences after treatment with lactic acid bacteria and chemical teat detergents in cows with subclinical mastitis. The results suggest that the lactobacilli-based teat detergents could reduce somatic cell count and improve microhabitat of cow teat apex by adjusting the composition of metabolites. Furthermore, the somatic cell count could be decreased significantly within 10 days following the cleaning protocol. Lactic acid bacteria have the potential to be applied as a substitution to teat chemical detergents before and after milking for maintenance of healthy teats and breasts. Further, larger scale validation work is required to support the findings of the current study.

Core microbiota for nutrient digestion remained and ammonia utilization increased after continuous batch culture of rumen microbiota in vitro

Introduction

This study aimed to investigate the digestive function, urea utilization ability, and bacterial composition changes in rumen microbiota under high urea (5% urea in diet) over 23 days of continuous batch culture in vitro.

Methods

The gas production, dry matter digestibility, and bacterial counts were determined for the continuously batch-cultured rumen fluid (CRF). The changes in fermentation parameters, NH3-N utilization efficiency, and microbial taxa were analyzed in CRF and were compared with that of fresh rumen fluid (RF), frozen rumen fluid (FRF, frozen rumen fluid at -80°C for 1 month), and the mixed rumen fluid (MRF, 3/4 RF mixed with 1/4 CRF) with in vitro rumen fermentation.

Results

The results showed that the dry matter digestibility remained stable while both the microbial counts and diversity significantly decreased over the 23 days of continuous batch culture. However, the NH3-N utilization efficiency of the CRF group was significantly higher than that of RF, FRF, and MRF groups (p < 0.05), while five core genera including Succinivibrio, Prevotella, Streptococcus, F082, and Megasphaera were retained after 23 days of continuous batch culture. The NH3-N utilization efficiency was effectively improved after continuous batch culture in vitro, and Streptococcus, Succinivibrio, Clostridium_sensu_stricto_1, p.251.o5, Oxalobacter, Bacteroidales_UCG.001, and p.1088.a5_gut_group were identified to explain 75.72% of the variation in NH3-N utilization efficiency with the RandomForest model.

Conclusion

Thus, core bacterial composition and function retained under high urea (5% urea in diet) over 23 days of continuous batch culture in vitro, and bacterial biomarkers for ammonia utilization were illustrated in this study. These findings might provide potential applications in improving the efficiency and safety of non-protein nitrogen utilization in ruminants.

Effects of Flammulina velutipes mushroom residues on growth performance, apparent digestibility, serum biochemical indicators, rumen fermentation and microbial of Guizhou black goat

Introduction

The primary objective of the current study was to evaluate the effects of Flammulina velutipes mushroom residue (FVMR) in a fermented total mixed ration (FTMR) diet on the fattening effect and rumen microorganisms in Guizhou black male goats.

Methods

A total of 22 Guizhou black male goats were allocated into two groups using the Randomized Complete Block Design (RCBD) experimental design. The average initial weight was 22.41 ± 0.90 kg and with 11 goats in each group. The control group (group I) was fed the traditional fermentation total mixed ration (FTMR) diet without FVMR. Group II was fed the 30% FVMR in the FTMR diet.

Results

The results showed that compared with group I, the addition of FVMR in the goat diet could reduce the feed cost and feed conversion ratio (FCR) of group II (p < 0.01). Notably, the apparent digestibility of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and dry matter (DM) were higher in group II (p < 0.01). The levels of growth hormone (GH), immunoglobulin A (IgA), and immunoglobulin M (IgM) in group II were higher than that of group I (p < 0.01), which the level of glutamic oxalacetic transaminase (ALT) and interleukin-6 (IL-6) was noticeably lower than that of group I (p < 0.01). 30% FVMR in FTMR diets had no effect on rumen fermentation parameters and microbial composition at the phylum level of Guizhou black male goats (p > 0.05). However, at the genus level, the relative abundance of bacteroidal_bs11_gut_group, Christensenellaceae_R-7_group and Desulfovibrio in group II was lower than in group I (p < 0.05), and the relative abundance of Lachnospiraceae_ND3007_group was higher than in group I (p < 0.01).

Discussion

In conclusion, the results of the current study indicated that 30% FVMR in the FTMR diet improves rumen fermentation and rumen microbial composition in Guizhou black male goats, which improves growth performance, apparent digestibility, and immunity.

Effects of antioxidant-rich Lactiplantibacillus plantarum inoculated alfalfa silage on rumen fermentation, antioxidant and immunity status, and mammary gland gene expression in dairy goats

BACKGROUND

Milk synthesis in lactating animals demands high energy metabolism, which results in an increased production of reactive oxygen metabolites (ROM) causing an imbalance between oxidants and antioxidants thereby inducing oxidative stress (OS) on the animals. To mitigate OS and postpartum disorders in dairy goats and gain insight into the impact of dietary choices on redox status during lactation, a feeding trial was conducted using alfalfa silage inoculated with a high-antioxidant strain of Lactiplantibacillus plantarum.

METHODS

Twenty-four Guanzhong dairy goats (38.1 ± 1.20 kg) were randomly assigned to two dietary treatments: one containing silage inoculated with L. plantarum MTD/1 (RSMTD-1), and the other containing silage inoculated with high antioxidant activity L. plantarum 24-7 (ES24-7).

RESULTS

ES24-7-inoculated silage exhibited better fermentation quality and antioxidant activity compared to RSMTD-1. The ES24-7 diet elevated the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in milk, serum, and feces of lactating goats (with the exception of T-AOC in milk). Additionally, the diet containing ES24-7 inoculated silage enhanced casein yield, milk free fatty acid (FFA) content, and vitamin A level in the goats' milk. Furthermore, an increase of immunoglobulin (Ig)A, IgG, IgM, interleukin (IL)-4, and IL-10 concentrations were observed, coupled with a reduction in IL-1β, IL-2, IL-6, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α concentrations in the serum of lactating goats fed ES24-7. Higher concentrations of total volatile fatty acid (VFA), acetate, and propionate were observed in the rumen fluid of dairy goats fed ES24-7 inoculated silage. Moreover, the diet containing ES24-7 inoculated silage significantly upregulated the expression of nuclear factor erythroid 2 like 2 (NFE2L2), beta-carotene oxygenase 1 (BCO1), SOD1, SOD2, SOD3, GPX2, CAT, glutathione-disulfide reductase (GSR), and heme oxygenase 1 (HMOX1) genes in the mammary gland, while decreased the levels of NADPH oxidase 4 (NOX4), TNF, and interferon gamma (IFNG).

CONCLUSIONS

These findings indicated that feeding L. plantarum 24-7 inoculated alfalfa silage not only improved rumen fermentation and milk quality in lactating dairy goats but also boosted their immunity and antioxidant status by modulating the expression of several genes related to antioxidant and inflammation in the mammary gland.

Sodium butyrate administration improves intestinal development of suckling lambs

This study was conducted to investigate the effects of sodium butyrate (SB) supplementation on growth performance, intestinal barrier functions, and intestinal bacterial communities in sucking lambs. Forty lambs of 7 d old, with an average body weight (BW) of 4.46 ± 0.45 kg, were allocated into the control (CON) or SB group, with each group having five replicate pens (n = 5). Lambs were orally administered SB at 1.8 mL/kg BW in the SB group or the same volume of saline in the CON group. Treatments were administered from 7 to 35 d of age, when one lamb from each replicate was slaughtered to obtain intestinal tissues and contents. The results showed that supplementation with SB tended to increase the BW (P = 0.079) and the starter intake (P = 0.089) of lambs at 35 d of age. The average daily gain of lambs in the SB group was significantly greater than that in the CON group (P < 0.05). The villus height of jejunum in the SB group was markedly higher (P < 0.05) than that in the CON group. In ileum, lambs in the SB group had lower (P < 0.05) crypt depth and greater (P < 0.05) villus-to-crypt ratio than those in the CON group. Compared with the CON group, the mRNA and protein expressions of Claudin-1 and Occludin were increased (P < 0.05) in the SB group. Supplementation with SB decreased the relative abundances of pathogenic bacteria, including Clostridia_UCG-014 (P = 0.094) and Romboutsia (P < 0.05), which were negatively associated with the intestinal barrier function genes (P < 0.05). The relative abundance of Succiniclasticum (P < 0.05) was higher in the SB group, and it was positively correlated with the ratio of villi height to crypt depth in the jejunum (P < 0.05). Compared with the CON group, the function "Metabolism of Cofactors and Vitamins" was increased in the SB group lambs (P < 0.05). In conclusion, SB orally administration during suckling period could improve the small intestine development and growth performance of lambs by inhibiting the harmful bacteria (Clostridia_UCG-014, Romboutsia) colonization, and enhancing intestinal barrier functions.

Gut/rumen-mammary gland axis in mastitis: Gut/rumen microbiota-mediated "gastroenterogenic mastitis"

BACKGROUND

Mastitis is an inflammatory response in the mammary gland that results in huge economic losses in the breeding industry. The aetiology of mastitis is complex, and the pathogenesis has not been fully elucidated. It is commonly believed that mastitis is induced by pathogen infection of the mammary gland and induces a local inflammatory response. However, in the clinic, mastitis is often comorbid or secondary to gastric disease, and local control effects targeting the mammary gland are limited. In addition, recent studies have found that the gut/rumen microbiota contributes to the development of mastitis and proposed the gut/rumen-mammary gland axis. Combined with studies indicating that gut/rumen microbiota disturbance can damage the gut mucosa barrier, gut/rumen bacteria and their metabolites can migrate to distal extraintestinal organs. It is believed that the occurrence of mastitis is related not only to the infection of the mammary gland by external pathogenic microorganisms but also to a gastroenterogennic pathogenic pathway.

AIM OF REVIEW

We propose the pathological concept of "gastroenterogennic mastitis" and believe that the gut/rumen-mammary gland axis-mediated pathway is the pathological mechanism of "gastroenterogennic mastitis".

KEY SCIENTIFIC CONCEPTS OF REVIEW

To clarify the concept of "gastroenterogennic mastitis" by summarizing reports on the effect of the gut/rumen microbiota on mastitis and the gut/rumen-mammary gland axis-mediated pathway to provide a research basis and direction for further understanding and solving the pathogenesis and difficulties encountered in the prevention of mastitis.

Effects of Dietary Protein Levels on Sheep Gut Metabolite Profiles during the Lactating Stage

Diet-associated characteristics such as dietary protein levels can modulate the gut's primary or secondary metabolites, leading to effects on the productive performance and overall health of animals. Whereas fecal metabolite changes are closely associated with gut metabolome, this study aimed to see changes in the rumen metabolite profile of lactating ewes fed different dietary protein levels. For this, eighteen lactating ewes (approximately 2 years old, averaging 38.52 ± 1.57 kg in their initial body weight) were divided into three groups (n = 6 ewes/group) by following the complete randomized design, and each group was assigned to one of three low-protein (D_I), medium-protein (D_m), and high-protein (D_h) diets containing 8.58%, 10.34%, and 13.93% crude protein contents on a dry basis, respectively. The fecal samples were subjected to untargeted metabolomics using ultra-performance liquid chromatography (UPLC). The metabolomes of the sheep fed to the high-protein-diet group were distinguished as per principal-component analysis from the medium- and low-protein diets. Fecal metabolite concentrations as well as their patterns were changed by feeding different dietary protein levels. The discriminating metabolites between groups of nursing sheep fed different protein levels were identified using partial least-squares discriminant analysis. The pathway enrichment revealed that dietary protein levels mainly influenced the metabolism-associated pathways (n = 63 and 39 in positive as well as negative ionic modes, respectively) followed by protein (n = 15 and 8 in positive as well as negative ionic modes, respectively) and amino-acid (n = 14 and 7 in positive as well as negative ionic modes, respectively) synthesis. Multivariate and univariate analyses showed comparative changes in the fecal concentrations of metabolites in both positive and negative ionic modes. Major changes were observed in protein metabolism, organic-acid biosynthesis, and fatty-acid oxidation. Pairwise analysis and PCA reveal a higher degree of aggregation within the D-h group than all other pairs. In both the PCA and PLS-DA plots, the comparative separation among the D_h/D_m, D_h/D_I, and D_m/D_I groups was superior in positive as well as negative ionic modes, which indicated that sheep fed higher protein levels had alterations in the levels of the metabolites. These metabolic findings provide insights into potentiated biomarker changes in the metabolism influenced by dietary protein levels. The target identification may further increase our knowledge of sheep gut metabolome, particularly regarding how dietary protein levels influence the molecular mechanisms of nutritional metabolism, growth performance, and milk synthesis of sheep.

Hericium erinaceus Extract Exerts Beneficial Effects on Gut-Neuroinflammaging-Cognitive Axis in Elderly Mice

Ageing is a biological phenomenon that determines the impairment of cognitive performances, in particular, affecting memory. Inflammation and cellular senescence are known to be involved in the pathogenesis of cognitive decline. The gut microbiota-brain axis could exert a critical role in influencing brain homeostasis during ageing, modulating neuroinflammation, and possibly leading to inflammaging. Due to their anti-ageing properties, medicinal mushrooms can be utilised as a resource for developing pharmaceuticals and functional foods. Specifically, Hericium erinaceus (He), thanks to its bioactive metabolites, exerts numerous healthy beneficial effects, such as reinforcing the immune system, counteracting ageing, and improving cognitive performance. Our previous works demonstrated the capabilities of two months of He1 standardised extract oral supplementation in preventing cognitive decline in elderly frail mice. Herein, we showed that this treatment did not change the overall gut microbiome composition but significantly modified the relative abundance of genera specifically involved in cognition and inflammation. Parallelly, a significant decrease in crucial markers of inflammation and cellular senescence, i.e., CD45, GFAP, IL6, p62, and γH2AX, was demonstrated in the dentate gyrus and Cornus Ammonis hippocampal areas through immunohistochemical experiments. In summary, we suggested beneficial and anti-inflammatory properties of He1 in mouse hippocampus through the gut microbiome-brain axis modulation.

Enterogenic Stenotrophomonas maltophilia migrates to the mammary gland to induce mastitis by activating the calcium-ROS-AMPK-mTOR-autophagy pathway

BACKGROUND

Mastitis is an inflammatory disease of the mammary gland that has serious economic impacts on the dairy industry and endangers food safety. Our previous study found that the body has a gut/rumen-mammary gland axis and that disturbance of the gut/rumen microbiota could result in 'gastroenterogenic mastitis'. However, the mechanism has not been fully clarified. Recently, we found that long-term feeding of a high-concentrate diet induced mastitis in dairy cows, and the abundance of Stenotrophomonas maltophilia (S. maltophilia) was significantly increased in both the rumen and milk microbiota. Accordingly, we hypothesized that 'gastroenterogenic mastitis' can be induced by the migration of endogenous gut bacteria to the mammary gland. Therefore, this study investigated the mechanism by which enterogenic S. maltophilia induces mastitis.

RESULTS

First, S. maltophilia was labelled with superfolder GFP and administered to mice via gavage. The results showed that treatment with S. maltophilia promoted the occurrence of mastitis and increased the permeability of the blood-milk barrier, leading to intestinal inflammation and intestinal leakage. Furthermore, tracking of ingested S. maltophilia revealed that S. maltophilia could migrate from the gut to the mammary gland and induce mastitis. Subsequently, mammary gland transcriptome analysis showed that the calcium and AMPK signalling pathways were significantly upregulated in mice treated with S. maltophilia. Then, using mouse mammary epithelial cells (MMECs), we verified that S. maltophilia induces mastitis through activation of the calcium-ROS-AMPK-mTOR-autophagy pathway.

CONCLUSIONS

In conclusion, the results showed that enterogenic S. maltophilia could migrate from the gut to the mammary gland via the gut-mammary axis and activate the calcium-ROS-AMPK-mTOR-autophagy pathway to induce mastitis. Targeting the gut-mammary gland axis may also be an effective method to treat mastitis.

Metataxonomic analysis of milk microbiota in the bovine subclinical mastitis

Subclinical mastitis is one of the most widespread diseases affecting dairy herds with detrimental effects on animal health, milk productivity, and quality. Despite its multifactorial nature, the presence of pathogenic bacteria is regarded one of the main drivers of subclinical mastitis, causing a disruption of the homeostasis of the bovine milk microbial community. However, bovine milk microbiota alterations associated with subclinical mastitis still represents a largely unexplored research area. Therefore, the species-level milk microbiota of a total of 75 milk samples, collected from both healthy and subclinical mastitis-affected cows from two different stables, was deeply profiled through an ITS, rather than a traditional, and less informative, 16S rRNA gene microbial profiling. Surprisingly, the present pilot study not only revealed that subclinical mastitis is characterized by a reduced biodiversity of the bovine milk microbiota, but also that this disease does not induce standard alterations of the milk microbial community across stables. In addition, a flow cytometry-based total bacterial cell enumeration highlighted that subclinical mastitis is accompanied by a significant increment in the number of milk microbial cells. Furthermore, the combination of the metagenomic and flow cytometry approaches allowed to identify different potential microbial marker strictly correlated with subclinical mastitis across stables.

Saikosaponin A alleviates Staphylococcus aureus-induced mastitis in mice by inhibiting ferroptosis via SIRT1/Nrf2 pathway

Mastitis is a common and serious bacterial infection of the mammary gland. Saikosaponin A (SSA) is a triterpenoid saponin isolated from Bupleurum falcatum that has the ability to treat various diseases. However, little is known about the role of SSA in achieving mastitis remission. Here, we found that SSA alleviated Staphylococcus aureus (S. aureus)-induced mastitis by attenuating inflammation and maintaining blood-milk barrier integrity. Furthermore, S. aureus activated nuclear factor kappa B (NF-κB) pathway by upregulated p-p65 and p-IκB. S. aureus also induced ferroptosis in mammary gland in mice, mainly characterized by excessive iron accumulation, mitochondrial morphological changes and impaired antioxidant production. However, S. aureus-induced NF-κB activation and ferroptosis were prevented by SSA. Moreover, SAA could upregulate the expression of SIRT1, Nrf2, HO-1 and GPX4. And the inhibitory effects of SAA on inflammation and ferroptosis were reversed by SIRT1 inhibitor EX-527. In conclusion, SAA protected S. aureus-induced mastitis through suppressing inflammation and ferroptosis by activating SIRT1/Nrf2 pathway.

Hexadecanamide alleviates Staphylococcus aureus-induced mastitis in mice by inhibiting inflammatory responses and restoring blood-milk barrier integrity

Subacute ruminal acidosis (SARA) has been demonstrated to promote the development of mastitis, one of the most serious diseases in dairy farming worldwide, but the underlying mechanism is unclear. Using untargeted metabolomics, we found hexadecanamide (HEX) was significantly reduced in rumen fluid and milk from cows with SARA-associated mastitis. Herein, we aimed to assess the protective role of HEX in Staphylococcus aureus (S. aureus)- and SARA-induced mastitis and the underlying mechanism. We showed that HEX ameliorated S. aureus-induced mastitis in mice, which was related to the suppression of mammary inflammatory responses and repair of the blood-milk barrier. In vitro, HEX depressed S. aureus-induced activation of the NF-κB pathway and improved barrier integrity in mouse mammary epithelial cells (MMECs). In detail, HEX activated PPARα, which upregulated SIRT1 and subsequently inhibited NF-κB activation and inflammatory responses. In addition, ruminal microbiota transplantation from SARA cows (S-RMT) caused mastitis and aggravated S. aureus-induced mastitis, while these changes were reversed by HEX. Our findings indicate that HEX effectively attenuates S. aureus- and SARA-induced mastitis by limiting inflammation and repairing barrier integrity, ultimately highlighting the important role of host or microbiota metabolism in the pathogenesis of mastitis and providing a potential strategy for mastitis prevention.

Dynamic changes of rumen bacteria and their fermentative ability in high-producing dairy cows during the late perinatal period

Background

High-producing dairy cows face varying degrees of metabolic stress and challenges during the late perinatal period, resulting in ruminal bacteria abundance and their fermentative ability occurring as a series of changes. However, the dynamic changes are still not clear.

Aims/methods

Ten healthy, high-producing Holstein dairy cows with similar body conditions and the same parity were selected, and ruminal fluid from the dairy cows at postpartum 0, 7, 14, and 21 d was collected before morning feeding. 16S rRNA high-throughput sequencing, GC-MS/MS targeted metabolomics, and UPLC-MS/MS untargeted metabolomics were applied in the study to investigate the dynamic changes within 21 d postpartum.

Results

The results displayed that the structures of ruminal bacteria were significantly altered from 0 to 7 d postpartum (R = 0.486, P = 0.002), reflecting the significantly declining abundances of Euryarchaeota and Chloroflexi phyla and Christensenellaceae, Methanobrevibacter, and Flexilinea genera (P < 0.05) and the obviously ascending abundances of Ruminococcaceae, Moryella, Pseudobutyrivibrio, and Prevotellaceae genera at 7 d postpartum (P < 0.05). The structures of ruminal bacteria also varied significantly from 7 to 14 d postpartum (R = 0.125, P = 0.022), reflecting the reducing abundances of Christensenellaceae, Ruminococcaceae, and Moryella genera (P < 0.05), and the elevating abundances of Sharpea and Olsenella genera at 14 d postpartum (P < 0.05). The metabolic profiles of ruminal SCFAs were obviously varied from 0 to 7 d postpartum, resulting in higher levels of propionic acid, butyric acid, and valeric acid at 7 d postpartum (P < 0.05); the metabolic profiles of other ruminal metabolites were significantly shifted from 0 to 7 d postpartum, with 27 significantly elevated metabolites and 35 apparently reduced metabolites (P < 0.05). The correlation analysis indicated that propionic acid was positively correlated with Prevotellaceae and Ruminococcaceae (P < 0.05), negatively correlated with Methanobrevibacter (P < 0.01); butyric acid was positively associated with Prevotellaceae, Ruminococcaceae, and Pseudobutyrivibrio (P < 0.05), negatively associated with Christensenellaceae (P < 0.01); valeric acid was positively linked with Prevotellaceae and Ruminococcaceae (P < 0.05); pyridoxal was positively correlated with Flexilinea and Methanobrevibacter (P < 0.05) and negatively correlated with Ruminococcaceae (P < 0.01); tyramine was negatively linked with Ruminococcaceae (P < 0.01).

Conclusion

The findings contribute to the decision of nutritional management and prevention of metabolic diseases in high-producing dairy cows during the late perinatal period.

Probiotic Escherichia coli Nissle 1917 protect chicks from damage caused by Salmonella enterica serovar Enteritidis colonization

As a foodborne pathogen of global importance, Salmonella enterica serovar Enteritidis (S. Enteritidis) is a threat to public health that is mainly spread by poultry products. Intestinal Enterobacteriaceae can inhibit the colonization of S. Enteritidis and are regarded as a potential antibiotic substitute. We investigated, in chicks, the anti-S. Enteritidis effects of Escherichia coli (E. coli) Nissle 1917, the most well-known probiotic member of Enterobacteriaceae. Eighty 1-d-old healthy female AA broilers were randomly divided into 4 groups, with 20 in each group, namely the negative control (group P), the E. coli Nissle 1917-treated group (group N), the S. Enteritidis-infected group (group S) and the E. coli Nissle 1917-treated and S. Enteritidis-infected group (group NS). From d 5 to 7, chicks in groups N and NS were orally gavaged once a day with E. coli Nissle 1917 and in groups P and S were administered the same volume of sterile PBS. At d 8, the chicks in groups S and NS were orally gavaged with S. Enteritidis and in groups P and N were administered the same volume of sterile PBS. Sampling was conducted 24 h after challenge. Results showed that gavage of E. coli Nissle 1917 reduced the spleen index, Salmonella loads, and inflammation (P < 0.05). It improved intestinal morphology and intestinal barrier function (P < 0.05). S. Enteritidis infection significantly reduced mRNA expression of angiotensin-converting enzyme 2 (ACE2) and solute carrier family 6-member 19 (SLC6A19) in the cecum and the content of Gly, Ser, Gln, and Trp in the serum (P < 0.05). Pretreatment with E. coli Nissle 1917 yielded mRNA expression of ACE2 and SLC6A19 in the cecum and levels of Gly, Ser, Gln, and Trp in the serum similar to that of uninfected chicks (P < 0.05). Additionally, E. coli Nissle 1917 altered cecum microbiota composition and enriched the abundance of E. coli, Lactobacillales, and Lachnospiraceae. These findings reveal that the probiotic E. coli Nissle 1917 reduced S. Enteritidis infection and shows enormous potential as an alternative to antibiotics.

Research progress on the regulation of production traits by gastrointestinal microbiota in dairy cows

The composition and abundance of microorganisms in the gastrointestinal tract of cows are complex and extensive, and they play a crucial role in regulating nutrient digestion, absorption, maintaining digestive tract stability, and promoting the production and health of the host. The fermentation carried out by these microorganisms in the gastrointestinal tract is fundamental to the health and productivity of cows. Rumen microorganisms produce the majority of enzymes required to break down feed substrates, such as cellulose, protein, lipids, and other plant materials, through fermentation. This process provides energy metabolism substrates that satisfy approximately 70% of the host's energy requirements for physiological activities. Gut microorganisms primarily decompose cellulose that is difficult to digest in the rumen, thereby providing heat and energy to the hosts. Additionally, they have an impact on host health and productivity through their role in immune function. Understanding the composition and function of the cow gut microbiota can help regulate dairy cattle breeding traits and improve their health status. As a result, it has become a popular research topic in dairy cattle breeding. This article provides a review of the composition, structure, physiological characteristics, and physiological effects of the cow gut microbiota, serving as a theoretical foundation for future studies that aim to utilize the gut microbiota for dairy cattle breeding or improving production traits. It may also serve as a reference for research on gut microbiota of other ruminants.

Environmental cadmium exposure alters the internal microbiota and metabolome of Sprague-Dawley rats

Cadmium (Cd) is a toxic element that can negatively affect both humans and animals. It enters the human and animal bodies through the respiratory and digestive tracts, following which it tends to accumulate in different organs, thereby seriously affecting human and animal health, as well as hampering social and economic development. Cd exposure can alter the composition of intestinal microbiota. In addition, it can damage the peripheral organs by causing the translocation of intestinal microbiota. However, the relationship between translocation-induced changes in the composition of microbiome in the blood and metabolic changes remains unclear. In the present study, we investigated the effects of Cd exposure on microbiota and serum metabolism in rats by omics analysis. The results demonstrated that Cd exposure disrupted the balance between the blood and intestinal flora in Sprague-Dawley (SD) rats, with a significant increase in gut microbiota (Clostridia_UCG_014, NK4A214_group) and blood microbiome (Corynebacterium, Muribaculaceae). However, Cd exposure caused the translocation of Corynebacterium and Muribaculaceae from the gut into the blood. In addition, Cd exposure was associated with the up-regulation of serum indoxyl sulfate, phenyl sulfate, and p-cresol sulfate; down-regulation of δ-tocopherol and L-glutamine; and changes in blood microbiome and metabolites. In conclusion, we identified novel metabolic biomarkers for Cd toxicity, which will also expand our understanding of the role of blood microbiome in Cd-induced injury.

Measurement of serum short-chain fatty acid concentrations in cattle after oral administration of difructose anhydride III

Background and Aim

We previously reported the mitigation effects of difructose anhydride III (DFA III) on mycotoxins, such as zearalenon and sterigmatocystin, based on the urinary concentrations of these molecules in calves. This study was aimed at evaluating the effects of dietary supplementation of DFA III and the fermented status of DFA III in the intestine by comparing serum levels of short-chain fatty acid (SCFAs) in DFA III-supplemented cattle with those in non-supplemented control cattle.

Materials and Methods

Serum SCFA concentrations were measured in 30 Japanese Black heifers, aged 9-10 months, from two herds, using gas chromatography on days 0 (before DFA III supplementation), 9, and 14 after DFA III supplementation.

Results

A notably different trend was observed for isobutyric acid and enanthic acid, which may reflect the different fermentation status of supplementary DFA III in the intestine. Our results indicate the possibility that this trend observed in the intestinal tract following DFA III administration is associated with changes in the environment of intestinal bacterial flora, which may partially reflect the effects of DFA III supplementation on cattle.

Conclusion

Difructose anhydride III supplementation for at least 2 weeks affects the trend of blood SCFA concentrations in cattle. Our results provide evidence supporting the effects of DFA III on the intestinal environment and intestinal barrier function.

Mechanism of inulin in colic and gut microbiota of captive Asian elephant

BACKGROUND

Gut microbiota have a complex role on the survivability, digestive physiology, production, and growth performance in animals. Recent studies have emphasized the effects of prebiotics therapy on the gut disease, but the relationship between elephant gut-related diseases and prebiotics remains elusive. Here, a case study was undertaken to evaluate the mechanism of inulin treatment in colic in Asian elephant (Elephas maximus Linnaeus).

METHODS

Fecal samples were collected from a sick elephant and four healthy elephants. Analysis of microbial profile was carried out by 16S rRNA sequencing, and the short chain fatty acids were tested by gas chromatography. The physiological function of "inulin-microbiota" of elephant was verified in mice by fecal microbial transplantation (FMT). The expression of related proteins was determined by Western blotting and qPCR.

RESULTS

(1) Eating inulin can cure gut colic of the sick elephant and changed gut microbiota. (2) It was found that "inulin microbiota" from the post-treatment elephants can promote the proliferation of intestinal cells, increase the utilization of short chain fatty acids (SCFAs), maintain intestinal barrier, and reduce the inflammation in mice. (3) The mechanism was inulin-gut microbiota-SCFAs-immune barrier.

CONCLUSIONS

Inulin contributed to rehabilitate the gut microbiota and gut immune barrier of the elephant with colic. This provides reasonable verification for using prebiotics to treat the colic in captive elephants. Prebiotics will foresure play an increasingly important role in disease prevention and treatment of captive animals in the future. Video Abstract.

Melatonin improves the homeostasis of mice gut microbiota rhythm caused by sleep restriction

Insufficient sleep is regarded as a disruptor of circadian rhythm, and it also contributes to the occurrence of intestinal diseases. The physiological functions of the gut depend on the normal circadian rhythm of the intestinal microbiota. However, how lack of sleep affects intestinal circadian homeostasis is unclear. Therefore, we subjected mice to sleep restriction and found that chronic sleep loss disrupts the pattern of colonic microbial communities and reduces the proportion of gut microbiota with a circadian rhythm, with concomitant changes in the peak phase of the KEGG pathway. We then found that exogenous melatonin supplementation restored the proportion of gut microbiota with a circadian rhythm and increased the KEGG pathway with a circadian rhythm. And we screened for possible circadian oscillation families, Muribaculaceae and Lachnospiraceae, that are sensitive to sleep restriction and can be rescued by melatonin. Our results suggest that sleep restriction disrupts the circadian rhythm of the colonic microbiota. In contrast, melatonin ameliorates disturbances in the circadian rhythm homeostasis of the gut microbiota due to sleep restriction.

Mechanism of Metabolic Response to Hepatectomy by Integrated Analysis of Gut Microbiota, Metabolomics, and Proteomics

Hepatectomy is a common clinical procedure for the treatment of many liver diseases, and the successful recovery of a patient's liver metabolism and function after surgery is crucial for a good prognosis. The objective of this study was to elucidate the metabolic response to hepatectomy using high-throughput sequencing analysis of 16S rRNA gene, metabolomics, and proteomics data. Fecal and serum samples from beagle dogs were collected on day 0 (LH0), day 7 (LH7), and day 28 (LH28) after laparoscopic partial hepatectomy. Liver tissue samples were taken on LH0 and LH7. Dysbiosis in the fecal microbiota was explored, and host-microbiome interactions based on global metabolic and protein profiles and inflammatory processes were determined. Results showed that the relative abundance of Allobaculum and Turicibacter was decreased and that of Escherichia-Shigella was increased after hepatectomy (P < 0.05); the phenylalanine, tyrosine, and tryptophan biosynthetic pathway, along with the phenylalanine and aminoacyl-tRNA biosynthetic pathway, was significantly associated with liver injury. The serum metabolites l-phenylalanine and l-arginine were useful as biomarkers, and the fecal metabolite l-threonine was a signature target monitor for liver recovery. The proteomics profile revealed 412 significantly different proteins and further highlighted two key signaling pathways (mitogen-activated protein kinase [MAPK] and peroxisome proliferator-activated receptor [PPAR]) involved in the response to liver injury. We systematically explored the metabolic mechanism of liver injury and recovery, providing new insights into effective ways to promote recovery after hepatectomy and improve liver function and long-term survival. These fundamental studies on hepatectomy will provide the basis for future advances in treatment and recovery from common liver diseases. IMPORTANCE As the largest parenchymal organ, the liver is a target for bacterial and viral infections, nonalcoholic fatty liver disease (NAFLD), cirrhosis, cancer, and many other diseases, constituting a serious worldwide problem. The treatment for many of these diseases involves hepatectomy. Here, we show that aberrant inflammatory processes after hepatectomy of the liver as reflected in the association between liver metabolism and gut microbiota create a grave risk. This study investigated the mechanisms of gut microbiota and host metabolism involved in liver injury and recovery after hepatectomy, using proteomics to reveal the mechanisms of postoperative liver injury and a comprehensive multi-omics approach to identify changes in metabolism after hepatectomy.

Diets Enriched in Sugar, Refined, or Whole Grain Differentially Influence Plasma Cholesterol Concentrations and Cholesterol Metabolism Pathways with Concurrent Changes in Bile Acid Profile and Gut Microbiota Composition in ApoE-/- Mice

This study aimed to compare the effects of diets enriched in sugar, refined grain (RG), or whole grain (WG) on circulating cholesterol concentrations and established and emerging mechanisms regulating cholesterol metabolism. Forty-four male ApoE^-/- mice aged 8 weeks were randomly fed an isocaloric sugar-, RG-, or WG-enriched diet for 12 weeks. Compared to WG-enriched diet, fasting plasma LDL-C and HDL-C concentrations were higher and the mRNA expression of intestinal LXR-α was lower in sugar- and RG-enriched diets; plasma TC, non-HDL-C, TG and VLDL-C concentrations, and cecal concentrations of lithocholic acid were higher and the mRNA expression of intestinal ABCG5 was lower in sugar-enriched diet, and the mRNA expression of hepatic IDOL and cecal concentrations of lithocholic and deoxycholic acids was higher in RG-enriched diet. The relative abundance of Akkermansia, Clostridia_UCG-014, Alistipes, and Alloprevotella, which were lower in sugar- and/or RG- than in WG-enriched diet, had inverse correlations with fasting plasma cholesterol concentrations or cecal concentrations of secondary bile acids and positive correlations with gene expressions in intestinal cholesterol efflux. Conversely, the relative abundance of Lactobacillus, Lachnoclostridium, Lachnospiraceae_NK4A136_group, Colidextribacter, and Helicobacter had reverse correlations. Both sugar- and RG-enriched diets had unfavorable effects on cholesterol concentrations; yet, their effects on the gene expressions of cholesterol efflux, uptake, bile acid synthesis, and bile acid concentrations were distinctive and could be partially attributable to the concurrent changes in gut microbiota.

Gut microbiota in brain tumors: An emerging crucial player

In recent decades, various roles of the gut microbiota in physiological and pathological conditions have been uncovered. Among the many interacting pathways between the host and gut flora, the gut-brain axis has drawn increasing attention and is generally considered a promising way to understand and treat brain tumors, one of the most lethal neoplasms. In this narrative review, we aimed to unveil and dissect the sophisticated mechanisms by which the gut-brain axis exerts its influence on brain tumors. Furthermore, we summarized the latest research regarding the gastrointestinal microbial landscape and the effect of gut-brain axis malfunction on different brain tumors. Finally, we outlined the ongoing developing approaches of microbial manipulation and their corresponding research related to neuro-malignancies. Collectively, we recapitulated the advances in gut microbial alterations along with their potential interactive mechanisms in brain tumors and encouraged increased efforts in this area.

Remodeling of the gut microbiome by Lactobacillus johnsonii alleviates the development of acute myocardial infarction

Introduction

The gut microbial community, which can be disturbed or repaired by changes in the internal environment, contributes to the development of acute myocardial infarction (AMI). Gut probiotics play a role in microbiome remodeling and nutritional intervention post-AMI. A newly isolated Lactobacillus johnsonii strain EU03 has shown potential as a probiotic. Here, we investigated the cardioprotective function and mechanism of L. johnsonii through gut microbiome remodeling in AMI rats.

Methods

A rat model of left anterior descending coronary artery ligation (LAD)-mediated AMI was assessed with echocardiography, histology, and serum cardiac biomarkers to evaluate the beneficial effects of L. johnsonii. The immunofluorescence analysis was utilized to visualize the intestinal barrier changes. Antibiotic administration model was used for assessing the gut commensals’ function in the improvement of cardiac function post-AMI. The underlying beneficial mechanism through L. johnsonii enrichment was further investigated by metagenomics and metabolomics analysis.

Results

A 28-day treatment with L. johnsonii protected cardiac function, delayed cardiac pathology, suppressed myocardial injury cytokines, and improved gut barrier integrity. The microbiome composition was reprogrammed by enhancing the abundance of L. johnsonii. Microbiome dysbiosis by antibiotics abrogated the improvement of cardiac function post-AMI by L. johnsonii. L. johnsonii enrichment caused remodeling of gut microbiome by increasing the abundance of Muribaculaceae, Lactobacillus, and decreasing Romboutsia, Clostridia UCG-014, which were correlated with cardiac traits and serum metabolic biomarkers 16,16-dimethyl-PGA2, and Lithocholate 3-O-glucuronide.

Conclusion

These findings reveal that gut microbiome remodeling by L. johnsonii ameliorates the cardiac function post-AMI and might advance microbiome-targeted nutritional intervention.

Prodigiosin derived from chromium-resistant Serratia sp. prevents inflammation and modulates gut microbiota homeostasis in DSS-induced colitis mice

Prodigiosin (PG) is a secondary metabolite of microorganisms with anticancer, antimalarial, antibacterial and immunomodulatory effects. However, the modulatory effects on gut microbiome and intestinal immune microenvironment have never been explored in the ulcerative colitis (UC) mice model. In this study, 2.5% dextran sulfate sodium (DSS) induced UC mice model was constructed to investigate the effects of PG derived from a chromium-resistant Serratia sp. on the intestinal flora and inflammatory response. The results showed that prodigiosin administration attenuated the DSS-induced UC symptoms, including preventing the reduction of colonic length and DSS-induced mortality. Furthermore, prodigiosin ameliorated the DSS-induced gut microbiota community dysbiosis by restoring the abundance of Bacteroidota. At the genus level, the declined abundance of Bifidobacterium, Allobaculum and Akkermannia in UC mice was elevated by the treatment of PG. Pathological results by H&E staining showed that PG prevented the appearance of distortion and atrophy of crypt and neutrophil infiltration in a dose-dependent manner. RT-PCR revealed that the expression levels of the inflammatory factors IL-1β, IL-6 and IL-10 were significantly suppressed, and the expression of the intestinal tight junction protein Claudin-1, Occludin and ZO-1 were upregulted in PG-treated UC mice. Conclusively, our results revealed that prodigiosin effectively prevented inflammatory response and protected intestinal barrier integrity of DSS-induced colitis mice via modulating gut microbiota community structure, suppressing inflammatory factors' expression, and accelerating the expression of intestinal tight junction protein. These results will provide new insights into the interaction of prodigiosin with intestinal microbiota homeostasis and its application in clinical against inflammatory bowel disease.

Paeoniflorin alleviates inflammation in bovine mammary epithelial cells induced by Staphylococcus haemolyticus through TLR2/NF-κB signaling pathways

Staphylococcus haemolyticus (S. haemolyticus) is one of the most common coagulase-negative staphylococci (CoNS) isolates from bovine mastitis. Paeoniflorin (PF) shows anti-inflammatory effects on different inflammatory diseases in vitro studies and in vivo animal experiments. In this study, the viability of bovine mammary epithelial cells (bMECs) was detected by the cell counting kit-8 experiment. Subsequently, bMECs were induced with S. haemolyticus, and the induction dosage was determined. The expression of pro-inflammatory cytokines and toll-like receptor (TLR2) and nuclear factor kappa-B (NF-κB) signaling pathway-related genes were investigated by quantitative real-time PCR. The critical pathway proteins were detected by western blot. The results showed that the multiplicity of infection (MOI; the ratio of bacteria to bMECs) 5:1 of S. haemolyticus for 12 h could cause cellular inflammation, which was selected to establish the inflammatory model. Incubation with 50 μg/ml PF for 12 h was the best intervention condition for cells stimulated by S. hemolyticus. Quantitative real-time PCR and western blot analysis showed that PF inhibited the activation of TLR2 and NF-κB pathway-related genes and the expression of related proteins. Western blot results showed that PF suppressed the expression of NF-κB unit p65, NF-κB unit p50, and MyD88 in bMECs stimulated by S. haemolyticus. The inflammatory response pathway and molecular mechanism caused by S. haemolyticus on bMECs are related to TLR2-mediated NF-κB signaling pathways. The anti-inflammatory mechanism of PF may also be through this pathway. Therefore, PF is expected to develop potential drugs against CoNS-induced bovine mastitis.

Microbiota from Exercise Mice Counteracts High-Fat High-Cholesterol Diet-Induced Cognitive Impairment in C57BL/6 Mice

Gut microbes may be the critical mediators for the cognitive enhancing effects of exercise. Via fecal microbiota transplantation (FMT), this study is aimed at determining the mechanism of how voluntary exercise improved learning and memory ability impairment post a high-fat, high-cholesterol (HFHC) diet. The learning and memory abilities assessed via the Morris water maze in the FMT recipient group of voluntary exercising mice were improved compared to sedentary group. 16S rRNA gene sequencing results indicated that exercise-induced changes in gut microbiota distribution were transmissible, mainly in terms of elevated Lactobacillus, Lactobacillus, and Eubacterium nodatum, as well as decreased Clostrida_UCG-014 and Akkermansia after FMT. The neuroprotective effects of FMT were mainly related to the improved insulin signaling pathway (IRS2/PI3K/AKT) and mitochondrial function; inhibition of AQP4; decreased p-Tau at serine 396 and 404; increased BDNF, PSD95, and synaptophysin in the hippocampus; and also decreased HDAC2 and HDAC3 protein expressions in the nuclear and cytoplasmic fractions of the hippocampus. The findings of qRT-PCR suggested that exercise-induced gut microbes, on the one hand, elevated GPR109A and decreased GPR43 and TNF-α in the hippocampus. On the other hand, it increased GPR109A and GPR41 expressions in the proximal colon tissue. In addition, total short-chain fatty acid (SCFA), acetic acid, propionic acid, isobutyric acid, valeric acid, and isovaleric acid contents were also elevated in the cecum. In conclusion, exercise-induced alterations in gut microbiota play a decisive role in ameliorating HFHC diet-induced cognitive deficits. FMT treatment may be a new considerable direction in ameliorating cognitive impairment induced by exposure to HFHC diet.

Effects from supplementary feeding of bamboo powder in perinatal period on farrowing process, serum biochemical indexes, and fecal microbes of sows and offspring piglets

Introduction

This study was conducted to explore the effects of supplementary feeding of bamboo powder on the physical parameters of sows during the perinatal period of 7 days ± in parturition, including farrow duration, serum biochemical indexes, fecal physicochemical indexes, and microbial flora.

Methods

Thirty pregnant sows were randomly divided into three groups: the control group was fed a basal diet, TRE1 group and TRE2 group were fed a basal diet supplemented with 30 g d^-1 and 60 g d^-1 bamboo powder, respectively. Multiple parameters of sows and offspring piglets were determined.

Results

The contents of serum total cholesterol and triglyceride of sows in TRE2 group were significantly lower than those in the control group. The contents of serum malondialdehyde of sows in TRE2 and TRE1 groups were significantly lower than that in control group. The water content of sow feces in TRE2 group was significantly higher than that in control group, and the pH values of sows in TRE2 and TRE1 groups were significantly higher than that in control group. The richness index (Chao) of sow fecal bacterial community in TRE2 group was significantly lower than that of the control group, and the Ace and Sobs indexes tended to be lower than those of the control group. At the phylum level, the relative abundance of Actinobacteriota in the feces of sows in TRE2 group was significantly lower than that of the control group, while that of Fusobacteriota in the feces of suckling piglets in TRE2 group tended to be lower than that of the control group. At the genus level, among the Top10 dominant bacteria, the relative abundance of Tissierella in the feces of sows in TRE2 group was significantly lower than that of the control group while that of Fusobacterium in the feces of suckling piglets in TRE2 group tended to be lower than that of the control group. The relative abundance of Clostridium_sensu_stricto_1, Terrisporobacter, Turicibacter, and Tissierella in the feces of sows in TRE2 group was significantly lower than that of TRE1 group (p < 0.05), while Lactobacillus tended to be higher than that of TRE1 group (p < 0.10).

Discussion

The results suggested that supplementary feeding 60 g d^-1 bamboo powder could increase the water content in the feces of sows, reduce the oxidative damage, and tend to reduce the relative abundance of opportunistic pathogenic Fusobacterium for suckling piglets, while it reduced the fecal microbial diversity of sows.

Chitooligosaccharides Attenuated Hepatic Encephalopathy in Mice through Stabilizing Gut-Liver-Brain Disturbance

SCOPE

Hepatic encephalopathy (HE) refers to neurological dysfunction associated with hepatic inadequacy and gut dysbiosis. Chitooligosaccharides (COS) possesses prominent biological activities including incalculable hepatoprotective, neuroprotective and prebiotic effects. This study evaluates the protective effects of COS on HE from the influence of gut-liver-brain axis in mice.

METHODS AND RESULTS

Hepatic injured mice show minimal symptoms of HE, reflecting in cognitive impairment, and learning and memory retardation, while they are reversed by COS following orally administrated. Furthermore, COS ameliorates brain function through inhibiting microglial and astrocyte activation in cerebral cortex and hippocampus, promoting neuronal regeneration characterized by the increase of neuron-specific marker (neuronal nuclear antigen, NeuN). Concurrently, neuroinflammation and hepatitis are restrained by COS through descending toll-like receptors 4/Nuclear factor kappa B (TLR4/NF-κB) pathway. Additionally, the dysbiosis of the composition and structure of gut microbiota is displayed in mice with HE, while it is modified by COS through decreasing the relative abundances of Muribaculaceae, Lactobacillus, and Enterorhabdus. The enhancement of blood ammonia is crucially slipped to basal levels by COS.

CONCLUSION

The present study shows that COS could prevent the pathological process of HE through regulating the gut-liver-brain cross-talk, which provids new insight into fundamental roles of COS.

Corn Straw Total Mix Dietary Supplementation of Bacillus Subtilis-Enhanced Growth Performance of Lambs by Favorably Modulating Rumen Bacterial Microbiome

In this experiment, B. subtilis was added to pelletized straw-based total mixed ration, and the rumen microbial diversity of house-fed Duhan hybrid sheep was compared. Ten 3-month-old weaned Duhan hybrid lambs were separated into two groups and fattened for 80 days using a single-factor trial design. During the fattening period, the control and the experiment groups were fed with the same ration, except that the experiment group was supplemented with B. subtilis. The results showed that the addition of B. subtilis could significantly increase the daily weight gain, total weight gain, rumen microbial abundance, and rumen microbial diversity of the Duhan lamb. Among them, the proportion of microbial flora such as Bacteroidetes was significantly increased, producing more acetate, iso-butyrate, and butyrate, obtaining higher energy efficiency.

Effects of supplementation of sodium acetate on rumen fermentation and microbiota in postpartum dairy cows

The primary product of rumen fermentation is acetic acid, and its sodium salt is an excellent energy source for post-partum cows to manage negative energy balance (NEB). However, it is unknown how adding sodium acetate (NAc) may affect the rumen bacterial population of post-partum cows. Using the identical nutritional total mixed ration (TMR), this research sought to characterize the impact of NAc supplementation on rumen fermentation and the composition of bacterial communities in post-partum cows. After calving, 24 cows were randomly assigned to two groups of 12 cows each: a control group (CON) and a NAc group (ACE). All cows were fed the same basal TMR with 468 g/d NaCl added to the TMR for the CON group and 656 g/d NAc added to the TMR for the ACE group for 21 days after calving. Ruminal fluid was collected before morning feeding on the last day of the feeding period and analyzed for rumen bacterial community composition by 16S rRNA gene sequencing. Under the identical TMR diet conditions, NAc supplementation did not change rumen pH but increased ammonia nitrogen (NH3-N) levels and microbial crude protein (MCP) concentrations. The administration of NAc to the feed upregulated rumen concentrations of total volatile fatty acids (TVFA), acetic, propionic, isovaleric and isobutyric acids without affecting the molar ratio of VFAs. In the two experimental groups, the Bacteroidota, Firmicutes, Patescibacteria and Proteobacteria were the dominant rumen phylum, and Prevotella was the dominant rumen genus. The administration of NAc had no significant influence on the α-diversity of the rumen bacterial community but upregulated the relative abundance of Prevotella and downregulated the relative abundance of RF39 and Clostridia_UCG_014. In conclusion, the NAc supplementation in the post-peripartum period altered rumen flora structure and thus improved rumen fermentation in dairy cows. Our findings provide a reference for the addition of sodium acetate to alleviate NEB in cows during the late perinatal period.

Dietary Supplementation of Fruit from Nitraria tangutorum Improved Immunity and Abundance of Beneficial Ruminal Bacteria in Hu Sheep

The fruit of Nitraria tangutorum (FNT) is reputed to possess medicinal properties; however, its effect on sheep (Ovis aries) is unknown. The aim of this study was to fill this gap. In a 3 × 3 Latin square design, six 12-month-old rumen-fistulated Hu rams (56.2 ± 8.26 kg; mean ± SD) were penned individually and offered one of three levels of FNT, namely, 0 g/d (control; CON), 16 g/d (N₁₆), and 48 g/d (N₄₈). The concentration of serum immunoglobulin G increased linearly (p = 0.03) with an increasing intake of FNT. The serum concentration of β-hydroxybutyrate in the N₄₈ group was lower than in the CON group (p = 0.01) and decreased linearly with increasing FNT (p = 0.001). The concentration of serum lactate dehydrogenase tended to decrease (p = 0.07) linearly with an increase in FNT intake, while the concentration of glucose did not differ among groups (p = 0.14) but displayed a quadratic curve with an increase in FNT (p = 0.05). The rumen concentration of lipase decreased linearly with increasing FNT (p = 0.04). The rumen fermentation variables were not affected by FNT. The FNT intake increased the abundance of beneficial ruminal bacteria, such as Lachnoclostridium, Rhodocyclaceae, and Candidatus Arthromitus. Prevotella, Rikenellaceae_RC9_gut_group, Ruminococcus, Olsenella, Lachnospiraceae_NK3A20_group, and Quinella were the dominant bacterial genera in all treatments. We conclude that FNT can improve immunity and increase the relative abundance of beneficial ruminal bacteria in sheep.

Effects of supplementary inulin on ewes milk composition and rumen fermentation parameters

This experiment aimed to investigate the effects of inulin supplementation on milk production and composition, feed intake, nutrient digestibility and rumen fermentation parameters in lactating ewes. The experimental treatments were (1) control group (basal diet), (2) basal diet plus 2% inulin (w/w) and (3) basal diet plus 4% inulin (w/w). The experiment was carried out for 21 d in a fully randomized design involving eighteen Ghezel ewes. Production and composition (percentages of fat, protein, lactose and fat-free solids and fatty acid profiles) of milk were measured. Faeces were collected in the last 3 days of the experiment to determine digestibility. On the last day of the experiment, rumen fluid samples were taken from the esophagus 3 h after feeding and fermentation parameters (pH, ammonia nitrogen (N-NH3), volatile fatty acids (VFA) and protozoal population) were examined. Daily milk production was not significantly affected by inulin supplementation, but the fat and protein content of the milk was increased whilst urea nitrogen (MUN) and unsaturated fatty acids were decreased (P < 0.05). The dry matter (DM) intake results showed that there was no significant difference between different diets. The highest digestibility of DM and NDF belonged to the inulin fed group (P < 0.05). Inulin consumption numerically increased the pH of the rumen fluid of the animals and significantly decreased the rumen N-NH3 value (P < 0.05). Inulin supplementation also significantly increased total VFA, acetate, and butyrate levels (P < 0.05). In general, it can be concluded that inulin supplementation can improve rumen fermentation, DM and NDF digestibility,as well as compositional aspects of the ewe's milk production.

Natural shikonin and acetyl-shikonin improve intestinal microbial and protein composition to alleviate colitis-associated colorectal cancer

BACKGROUND

Colorectal cancer (CRC) and inflammatory bowel disease (IBD) are the most common diseases of human digestive system. Nowadays, the influence of the inflammatory microenvironment on tumorigenesis has become a new direction, and the exploration of relative molecular mechanism will facilitate the discovery and identification of novel potential anti-cancer molecules.

METHODS

Natural shikonin (SK) and acetyl-shikonin (acetyl-SK) was administered to azoxymethane (AOM)/dextran sodium sulphate (DSS)-induced colitis-associated colorectal cancer (CAC) mice model by gavage to investigate their therapeutic effects. Moreover, fresh feces and colon tissues were collected for determining the function of SK and acetyl-SK on the gut microbes and protein expression, respectively.

RESULTS

Both SK and acetyl-SK decreased AOM/DSS-induced CAC, and regulated the intestinal flora structure in CAC mouse model. They, especially SK, improved species richness, evenness and diversity of intestinal flora, recovered the upregulated ratio of Firmicutes to Bacteroidota (F/B ratio) which symbolizes gut microbiota dysbiosis. SK and its derivative increased the beneficial bacteria g__norank_f__Muribaculaceae, Lactobacillus, Lachnospiraceae_NK4A136_Group, and reduced those harmful ones including Ileibacterium and Coriobacteriaceae UCG-002. Notably, AOM/DSS caused significant increase in the abundance of Ileibaterium valens and g__norank_f__norank_o__Clostridia_UCG-014, which were not previously reported in studies of colonic inflammation or cancer, and the disorder was reversed by 20 mg/kg of SK. In our current study, the action of SK and acetyl-SK is dose-dependent, and 20 mg/kg SK exhibited the most effective functions, even better than the positive drug mesalazine. Moreover, differential proteomics and ELISA results showed that SK could recover the increase of pro-inflammatory cytokines (including IL-1β, IL-6 and TNF-α), the upregulation of pyruvate kinase isozyme type M2 (PKM2) and some other proteins (mainly concentrated in transcriptional mis-regulation in cancer and IL-17 signaling pathways), and the downregulation of Aldh1b1-Acc3-Maoa and Μgt2b34-Aldh1a1-Aldh1a7 involved in Wnt/β-catenin signaling pathway.

CONCLUSION

Our study identified SK and acetyl-SK, especially SK, as potential preventive agents for CAC through regulating both gut microbes and pathways involved in inflammation and cancer such as Wnt/β-catenin signaling pathway.

The Many Ages of Microbiome–Gut–Brain Axis

Frailty during aging is an increasing problem associated with locomotor and cognitive decline, implicated in poor quality of life and adverse health consequences. Considering the microbiome–gut–brain axis, we investigated, in a longitudinal study, whether and how physiological aging affects gut microbiome composition in wild-type male mice, and if and how cognitive frailty is related to gut microbiome composition. To assess these points, we monitored mice during aging at five selected experimental time points, from adulthood to senescence. At all selected experimental times, we monitored cognitive performance using novel object recognition and emergence tests and measured the corresponding Cognitive Frailty Index. Parallelly, murine fecal samples were collected and analyzed to determine the respective alpha and beta diversities, as well as the relative abundance of different bacterial taxa. We demonstrated that physiological aging significantly affected the overall gut microbiome composition, as well as the relative abundance of specific bacterial taxa, including Deferribacterota, Akkermansia, Muribaculaceae, Alistipes, and Clostridia VadinBB60. We also revealed that 218 amplicon sequence variants were significantly associated to the Cognitive Frailty Index. We speculated that some of them may guide the microbiome toward maladaptive and dysbiotic conditions, while others may compensate with changes toward adaptive and eubiotic conditions.

Comparative Analyses of Production Performance, Meat Quality, and Gut Microbial Composition between Two Chinese Goose Breeds

Simple Summary

Poultry is one of the most frequently consumed meats in the world and plays an important role in the daily life of people. Goose meat is consumed by consumers because it contains a relatively high proportion of polyunsaturated fatty acids. Meat quality traits, production performance, and cecal microbiota diversity in two goose breeds (Zi goose and Xianghai flying goose) were evaluated in this study. Understanding these aspects not only provides a reference for the exploration of the relationship between the cecal microbiota and production performance but also guidelines for the human consumption of healthy poultry meat.

Abstract

Goose meat is consumed by consumers because it contains a relatively high proportion of polyunsaturated fatty acids (PUFAs). This study was conducted to explore the main differences in production performance, breast meat quality traits, and cecal microbiota compositions between the Zi goose (ZG) and Xianghai flying goose (FG). The production performance and breast meat quality trait analyses showed that compared with the ZG, the FG had a higher right breast muscle index, ileum villi height/crypt depth ratio (VH/CD), and cecum fermentation rate (higher short-chain fatty acid (SFCA) concentration); a lower abdominal fat index; a higher proportion of PUFAs; and a lower shear force. Spearman’s correlation coefficients between the cecal microbiota composition and production performance indexes suggested that the genus Faecalibacterium was positively associated with production performance; in contrast, the genus Candidatus Saccharimonas was negatively correlated with production performance; moreover, the Ruminococcus torques group, Parasutterella, and Methanobrevibacter were negatively related to the VH/CD. Taken together, in this particular trial, FG had better production performance, healthier meat quality traits, and better intestinal digestion and absorption capacities than ZG. These results not only provide a useful data reference for the production of healthy geese for human consumption but can also help guide the utilization of goose breed resources.

Testing Two Somatic Cell Count Cutoff Values for Bovine Subclinical Mastitis Detection Based on Milk Microbiota and Peripheral Blood Leukocyte Transcriptome Profile

Somatic cell count (SCC) is an important indicator of the health state of bovine udders. However, the exact cut-off value used for differentiating the cows with healthy quarters from the cows with subclinical mastitis remains controversial. Here, we collected composite milk (milk from four udder quarters) and peripheral blood samples from individual cows in two different dairy farms and used 16S rRNA gene sequencing combined with RNA-seq to explore the differences in the milk microbial composition and transcriptome of cows with three different SCC levels (LSCC: <100,000 cells/mL, MSCC: 100,000−200,000 cells/mL, HSCC: >200,000 cells/mL). Results showed that the milk microbial profiles and gene expression profiles of samples derived from cows in the MSCC group were indeed relatively easily discriminated from those from cows in the LSCC group. Discriminative analysis also uncovered some differentially abundant microbiota at the genus level, such as Bifidobacterium and Lachnospiraceae_AC2044_group, which were more abundant in milk samples from cows with SCC below 100,000 cells/mL. As for the transcriptome profiling, 79 differentially expressed genes (DEGs) were found to have the same direction of regulation in two sites, and functional analyses also showed that biological processes involved in inflammatory responses were more active in MSCC and HSCC cows. Overall, these results showed a similarity between the milk microbiota and gene expression profiles of MSCC and HSCC cows, which presented further evidence that 100,000 cells/ml is a more optimal cut-off value than 200,000 cells/mL for intramammary infection detection at the cow level.

Changes in the Profile of Fecal Microbiota and Metabolites as Well as Serum Metabolites and Proteome After Dietary Inulin Supplementation in Dairy Cows With Subclinical Mastitis

The occurrence and development of mastitis is linked to dysbiostic gastrointestinal microbiota. Inulin is a dietary prebiotic that improves the profile of intestinal flora. Our previous study showed that inulin supplementation could improve the ruminal microbes of subclinical mastitis (SCM) cows. The current study attempted to further investigate the response of hindgut (fecal) microbiome and metabolites, serum metabolism, and protein expression to inulin in the in SCM cows. Different levels of inulin (0, 100, 200, 300, and 400 g/day per cow) were supplemented in SCM cows. Compared with control group, Bacteroides and Bifidobacteria were increased, and Paeniclostridium, Ruminococcaceae, Coprococcus, and Clostridia were decreased in the feces of inulin groups, and accompanied with elevated propionate and butyrate concentrations, while secondary bile acid (SBA) metabolites were increased and proinflammatory lipid oxidation products were dropped in both feces and serum. In serum, inulin intake suppressed the levels of triglyceride (TG) and low-density lipoprotein (LDL). Serum proteome analysis found that CD44 antigen, phosphatidylinositol-glycan-specific phospholipase D, apolipoprotein A-II, and superoxide dismutase [Cu-Zn] were upregulated, while cathelicidin-1, haptoglobin, serpin A3, inter-alpha-trypsin inhibitor heavy chain H4 were downregulated in inulin groups. These findings suggested further evidence for inulin supplementation in amelioration of inflammatory symptoms in SCM cows, which might provide alternative treatment for mastitis.

Calcium Propionate Supplementation Has Minor Effects on Major Ruminal Bacterial Community Composition of Early Lactation Dairy Cows

Calcium propionate is one kind of good source for preventing and treating hypocalcemia and ketosis for dairy cows in early lactation. However, little is known about the effects of different feeding levels of calcium propionate on the ruminal bacterial community of early lactation dairy cows. This study aimed to explore the effects of different calcium propionate feeding levels on the ruminal fermentation and bacterial community composition of early lactation dairy cows. Twenty-four multiparous cows were randomly allocated into control (CON), low calcium propionate (LCaP), medium calcium propionate (MCaP), and high calcium propionate (HCaP) groups with six cows per group after calving. The CON group cows were fed the normal total mixed ration (TMR), and the cows of the LCaP, MCaP, and HCaP groups were fed TMR supplemented with 200, 350, and 500 g/day calcium propionate for 35 days after calving, respectively. The rumen fermentation parameters were measured every week, and the ruminal bacterial community composition of the last week was analyzed by 16S rRNA gene sequencing. Under the same diet, the rumen pH showed no difference among the four groups, but the content of microbial crude protein (MCP) and ammonia nitrogen quadratically decreased and linearly increased with calcium propionate supplementation, respectively. The feeding of calcium propionate linearly increased the concentrations of total volatile fatty acid (VFA), acetate, propionate, butyrate, iso-valerate, and valerate in the rumen. In all the treatment groups, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla, and Prevotella_1 and Succiniclasticum were the dominant genera in the rumen. Compared with the CON group, the addition of calcium propionate to the early lactation dairy cows quadratically improved the alpha diversity index of Chao1 estimator and observed species, but had little effect on the relative abundance of the major bacterial at phyla and genera level. These results suggested different levels of calcium propionate supplementation improved the rumen fermentation and the ruminal bacterial diversity but had little impact on the major ruminal bacterial community composition of dairy cows in early lactation.

Angelica sinensis polysaccharide improves rheumatoid arthritis by modifying the expression of intestinal Cldn5, Slit3 and Rgs18 through gut microbiota

Rheumatoid arthritis (RA) is an autoimmune disease with a high incidence. Recent studies have demonstrated that diet can contribute to the development and progression of RA. Indeed, non-starch polysaccharides (NSPs) were known to be related to the improvement of RA. In this study, the collagen-induced rats were administrated with Angelica sinensis polysaccharide (ASP) at 200 mg/kg (L), 400 mg/kg (M), or 800 mg/kg (H). Results showed that ASP could reduce joint swelling and significantly inhibit anti-CII-antibodies and pro-inflammatory factors in RA, H group showed the best treatment among them. Further analysis using 16S rDNA sequencing suggested that ASP could shape the gut microbiota composition. Several key bacteria, including norank_f__norank_o__Clostridia_UCG-014, Lactobacillus, norank_f__Oscillospiraceae, and norank_f__Desulfovibrionaceae, were found to be related to the development of RA. The colonic transcriptome showed that ASP could restore RA-induced intestinal dysfunction, such as tight junction disarrangement, by upregulating Cldn5. The balance between osteoblasts and osteoclasts might be modified by regulating the expression of Slit3 and Rgs18 to alleviate RA, which may be correlated with gut microbiota. Our results suggested that ASP improved RA by regulating gut microbiota and gene expression, revealing a positive relationship between dietary patterns and RA.

Contribution of Ruminal Bacteriome to the Individual Variation of Nitrogen Utilization Efficiency of Dairy Cows

High nitrogen utilization efficiency (NUE) is important for increasing milk protein production and decreasing the feed nitrogen cost and nitrogen emission to the environment. Currently, there is a limited whole picture of the relationship between ruminal bacteriome and the NUE of dairy cows, even though some information has been revealed about the bacteriome and milk or milk protein production of dairy cows. The purpose of this study was to compare the rumen bacterial community in dairy cows with different nitrogen utilization efficiency under the same diet. The natural abundance of 15N between the animal proteins and diet (Δ15N) was used as a simple, non-invasive, and accurate biomarker for NUE in ruminants to mark the individual variation. Dairy cows with high NUE (HE_HP, n = 7), medium NUE (ME_MP, n = 7), and low NUE (LE_LP, n = 7) were selected from 284 Holstein dairy cows with the same diet. Measurement of the rumen fermentation indices showed that the proportion of propionate was higher in HE_HP cows and ME_MP cows than in LE_LP cows (P < 0.05). The diversity of rumen bacterial community was higher in LE_LP cows than in ME_MP cows and HE_HP cows by 16S rRNA sequencing analysis (P < 0.05). Moreover, at the genus level, the relative abundances of Succinivibrionaceae_UCG_001, uncultured_Selenomonadaceae, and Acidaminococcus were higher in HE_HP cows than in LE_LP cows (P < 0.05). Interestingly, we found that these bacteria were positively correlated with milk protein yield and negatively correlated with Δ15N (P < 0.05). However, Clostridia_UCG_014, Saccharofermentans, Bacilli_RF39, and Desulfovibrio were lower in HE_HP cows and ME_MP cows than in LE_LP cows (P < 0.05), which were negatively correlated with milk protein yield and positively correlated with Δ15N (P < 0.05). In conclusion, the study showed that the diversity and relative abundances of rumen bacteria differed among different NUE cows, indicating that rumen bacteriome contributes to nitrogen metabolism in dairy cows.

The Rumen Microbiota Contributes to the Development of Mastitis in Dairy Cows

Mastitis, a highly prevalent disease in dairy cows, is commonly caused by local infection of the mammary gland. Our previous studies have suggested that the gut microbiota plays an important role in the development of mastitis in mice. However, the effects of rumen microbiota on bovine mastitis and the related mechanisms remain unclear. In this study, we assessed the effects and mechanisms of rumen microbiota on bovine mastitis based on the subacute rumen acidosis (SARA) model induced by feeding Holstein Frisian cows a high-concentrate diet for 8 weeks. Then, the inflammatory responses in the mammary gland and the bacterial communities of rumen fluid, feces, and milk were analyzed. The results showed that SARA induced mastitis symptoms in the mammary gland; activated a systemic inflammatory response; and increased the permeability of the blood-milk barrier, gut barrier, and rumen barrier. Further research showed that lipopolysaccharides (LPS), derived from the gut of SARA cows, translocated into the blood and accumulated in the mammary glands. Furthermore, the abundance of Stenotrophomonas was increased in the rumen of SARA cows, and mastitis was induced by oral administration of Stenotrophomonas in lactating mice. In conclusion, our findings suggested that mastitis is induced by exogenous pathogenic microorganisms as well as by endogenous pathogenic factors. Specifically, the elevated abundance of Stenotrophomonas in the rumen and LPS translocation from the rumen to the mammary gland were important endogenous factors that induced mastitis. Our study provides a foundation for novel therapeutic strategies that target the rumen microbiota in cow mastitis. IMPORTANCE Mastitis is a common and frequently occurring disease of humans and animals, especially in dairy farming, which has caused huge economic losses and brought harmful substance residues, drug-resistant bacteria, and other public health risks. The traditional viewpoint indicates that mastitis is mainly caused by exogenous pathogenic bacteria infecting the mammary gland. Our study found that the occurrence of mastitis was induced by the endogenous pathway. Evidence has shown that rumen-derived LPS enters the mammary gland through blood circulation, damaging the blood-milk barrier and then inducing inflammation of the mammary gland in cows. In addition, a higher abundance of Stenotrophomonas in the rumen was closely associated with the development of mastitis. This study provides a basis for novel therapeutic strategies that exploit the rumen microbiota against mastitis in cows.

Consumption of Supplementary Inulin Modulates Milk Microbiota and Metabolites in Dairy Cows with Subclinical Mastitis

The milk microbiota and mediated metabolites directly affect the health of the udder in dairy cows. Inulin, a dietary prebiotic, can modulate the profile of gastrointestinal microbiota. However, whether the inulin intake affects the milk microbial population and metabolites remains unknown. In this study, 40 subclinical mastitis (SCM) cows were randomly divided into 5 groups. Five inulin addition doses, 0, 100, 200, 300, and 400 g/day per cow, based on the same basal diet, were supplemented. The experiments lasted for 8 weeks. The results showed lower relative abundance of mastitis-causing and proinflammation microbes in milk (i.e., Escherichia-Shigella, Pseudomonas, Rhodococcus, Burkholderia-Caballeronia-Paraburkholderia, etc.) and higher abundances of probiotics and commensal bacteria, such as Lactobacillus, Bifidobacterium, etc., in the cows fed 300 g/day inulin compared to that in the control group. Meanwhile, the levels of arachidonic acid proinflammatory mediators (leukotriene E3, 20-carboxy-leukotriene B4, and 12-Oxo-c-LTB3) and phospholipid metabolites were reduced, and the levels of compounds with antibacterial and anti-inflammatory potential (prostaglandin A1, 8-iso-15-keto-prostaglandin E2 [PGE2], etc.) and participating energy metabolism (citric acid, l-carnitine, etc.) were elevated. These data suggested that inulin intake might modulate the microflora and metabolite level in extraintestinal tissue, such as mammary gland, which provided an alternative for the regulation and mitigation of SCM. IMPORTANCE The profile of the microbial community and metabolic activity in milk are the main determinants of udder health status and milk quality. Recent studies have demonstrated that diet could directly modulate the mammary gland microbiome. Inulin is a probiotic dietary fiber which can improve the microbiota population in the gastrointestinal tract. However, whether inulin intake can further regulate the profile of the microbiota and metabolic activities in milk remains unclear. In subclinical mastitic cows, we found that inulin supplementation could reduce the abundance of Escherichia-Shigella, Pseudomonas, Rhodococcus, and Burkholderia-Caballeronia-Paraburkholderia and the levels of (±)12, 13-DiHOME, leukotriene E3 and 20-carboxy-leukotriene B4 etc., while it elevated the abundance of Lactobacillus, Bifidobacterium, and Muribaculaceae, as well as the levels of prostaglandin A1 (PGA1), 8-iso-15-keto-PGE2, benzoic acid, etc. in milk. These data suggest that inulin intake affects the profile of microorganisms and metabolites in milk, which provides an alternative for the regulation of mastitis.