Effects of Caulis Spatholobi Polysaccharide on Immunity, Intestinal Mucosal Barrier Function, and Intestinal Microbiota in Cyclophosphamide-Induced Immunosuppressive Chickens

Protective effects of polysaccharide of Atractylodes macrocephala Koidz and Jiawei Si-jun-zi Decoction on gut health and immune function in cyclophosphamide-treated chicks

The gut serves not only as digestive but also as critical immune organ, playing a vital role in maintaining the growth performance and immune function of poultry. Atractylodes macrocephala Koidz (AMK) is known for its antioxidant, anti-inflammatory and immunomodulatory properties. This study utilized a Cyclophosphamide (CTX)-induced gut injury model to explore the effects of Polysaccharide of Atractylodes macrocephala Koidz (PAMK) and the Jiawei Si-jun-zi Decoction (JSD) on alleviating gut injury and modulating immune function. The experimental results demonstrated that CTX significantly reduced the average daily gain (ADG) and antioxidant capacity of broiler chicks, disrupted intestinal barrier function, and induced gut microbiota dysbiosis. However, supplementation with PAMK and JSD significantly improved ADG, enhanced antioxidant enzyme activity, alleviated oxidative stress, and upregulated the expression of barrier-related genes such as ZO-1 and Occludin. Additionally, PAMK and JSD significantly increased anti-inflammatory cytokines, including IL-10 and TGF-β, improved gut microbiota diversity, enriched beneficial microbial populations, and restored the microbiota balance disrupted by CTX. These findings suggest that PAMK and JSD effectively mitigate CTX-induced intestinal injury by regulating the antioxidant system, strengthening intestinal barrier function, and restoring gut microbiota structure. This study provides a scientific basis for the development of safe and effective feed additives and proposes a novel strategy to reduce antibiotic use in poultry farming.

Selenium Broussonetia papyrifera polysaccharide alleviated cyclophosphamide-induced immune suppression, growth inhibition, intestinal damage, and gut microbiota disorder in yellow-feather broilers

This study aims to investigate the effects of selenium Broussonetia papyrifera polysaccharide (Se-BPP) on growth performance, immune regulation, intestinal barrier function, and gut microbiota in cyclophosphamide (CTX)-induced immunosuppressed chicks. A total of 120 one-day-old male yellow-feathered broilers were randomly divided into five groups: normal control group (NC), model control group (MC), low-dose Se-BPP group (Se-L), high-dose Se-BPP group (Se-H), and Astragalus polysaccharide (APS) group The Se-L and Se-H groups were supplemented with 0.1 % or 0.2 % Se-BPP, respectively, while the APS group was supplemented with 0.2 % APS. On days 22, 24, and 26, the NC group received intramuscular injections of 80 mg/kg saline, while the other groups received the same dose of CTX to induce immunosuppression in the chicks. The results showed that CTX caused growth retardation, immunosuppression, intestinal damage, and alterations in gut microbiota structure. Supplementation with Se-BPP improved average daily gain and reduced feed-to-gain ratio, promoting growth in immunosuppressed chicks. Se-BPP increased the immune organ index and serum content of IgG, IgM, IgA, SOD, GSH-Px, CAT, IL-2, IL-4, IL-6, IL-10, and INF-γ, thus alleviating the immunosuppression and oxidative stress caused by CTX. Additionally, Se-BPP enhanced the mRNA expression levels of ZO-1, Claudin 1, and MUC2 and increased villus height in the jejunum, effectively mitigating intestinal damage induced by CTX. Although the effect of Se-BPP on alpha diversity of the gut microbiota was not significant, it increased the abundance of beneficial bacteria such as Ruminococcus and Lactobacillus. In brief, this study demonstrated that adding Se-BPP to the diet could improve immunosuppression, intestinal damage, and microbiota disturbances in yellow-feather broiler chickens challenged with CTX, enhancing their production performance.

Astragalus polysaccharide mitigates Eimeria tenella-induced damage in laying chicks by modulating immunity, inflammation, and intestine barrier

Astragalus polysaccharides (APS), the main active component of the traditional Chinese medicine Astragalus, exhibit immunomodulatory and antioxidant properties. This study analyzed the preventive and therapeutic effects of APS on chicks infected with Eimeria tenellaE. tenella and its impact on intestinal health. A total of 120 1-d-old Hy-Line Brown chicks were assigned to four groups (2 × 2 factorial): 1) Control (0 mg/L APS + 0 sporulated oocysts/chick), 2) APS (1,000 mg/L APS + 0 sporulated oocysts/chick), 3) E. tenellaE. tenella (0 mg/L APS + 5 × 104 sporulated oocysts/chick), 4) E. tenella + APS (1,000 mg/L APS + 5 × 104 sporulated oocysts/chick). The results showed that the addition of APS to the drinking water increased the average daily gain and body weight (day 25) while reduced feed conversion ratio in E. tenella-infected chicks (P < 0.05). APS mitigated cecal lesions (P < 0.05), decreased oocyst shedding (P < 0.05), lowered spleen index (P < 0.05), and elevated bursa and thymus indices (P < 0.05). Serum total protein and alkaline phosphatase activity increased (P < 0.05). Cecal tissue mRNA expression of IL-2, IgG, IgM, Claudin1, Claudin2, ZO-1, and Occludin were increased (P < 0.05), whereas IL-1β, TNF-α, and NF-κB were decreased (P < 0.05). APS enriched cecal f_Lactobacillaceae, g_Lactobacillus, g_Tuzzerella, g_Oscillospira, and g_UBA1819 (P < 0.05). Furthermore, the anticoccidial index (142.10) indicated low-level efficacy. In conclusion, APS alleviated E. tenella damage by modulating immunity, inflammation, microbiota, and intestinal barriers. Although APS demonstrated limited direct anticoccidial activity, its multifaceted protective effects suggest potential in the prevention and treatment of coccidiosis.

Predicting Pharmacokinetics of Active Constituents in Spatholobi caulis by Using Physiologically Based Pharmacokinetic Models

BACKGROUND/OBJECTIVES

Spatholobi Caulis (SPC) is a medicinal plant that mainly grows in China and Southeast Asian countries and commonly used in clinics; the pharmacokinetic characteristics in humans need to be determined. This study was to establish the physiologically based pharmacokinetic (PBPK) models of multiple active constituents from SPC in rats, and predict the pharmacokinetic properties of rats with different dosages and extrapolated to humans.

METHODS

The parameters were collected based on our previous study and by prediction using ADMET Predictor software predict. The PBPK models for 3'-methoxydadizein (1), 8-O-methylretusin (2), daidzin (3), and isolariciresinol (4) administered orally to rats were established using GastroPlus software. These models were employed to simulate the pharmacokinetic properties in rats across various dosages, and subsequently extrapolated to humans. The calculated parameters including Cmax, Tmax, and AUC were compared with observed values. The accuracy of the PBPK models was assessed using fold-error (FE) values.

RESULT

The FE values ranged from 1.03 to 1.52, meeting the PBPK model regulations where FE should be less than 2. The sensitivity analysis focusing on the absorption amount and AUC0→t of these four constituents in humans was also conducted. These results confirm the successful establishment of PBPK models of these four constituents from SPC in this study, and these models were applicable to predict pharmacokinetics across various doses and extrapolate across species.

CONCLUSIONS

The PBPK models of four constituents can be used to predict the pharmacokinetic characteristics in humans after oral administration of SPC and provide useful data for safe and rational medication in clinical practice.

Progress and prospect of polysaccharides as adjuvants in vaccine development

Vaccines are an effective approach to confer immunity against infectious diseases. Modern subunit vaccines offer more precise target and safe protection compared to traditional whole-pathogen vaccines. However, subunit vaccines require adjuvants to stimulate the immune system due to the less immunogenicity. Adjuvants strengthen immunogenicity by enhancing, modulating, and prolonging the immune response. Unfortunately, few adjuvants have sufficient potency and low enough toxicity for clinical use, highlighting the urgent need for new vaccine adjuvants with the characteristics of safety, efficacy, and cost-effectiveness. Notably, some natural polysaccharides have been approved as adjuvants in human vaccines, owing to their intrinsic immunomodulation, low toxicity, and high safety. Natural polysaccharides are mainly derived from plants, bacteria, and yeast. Partly owing to the difficulty of obtaining them, synthetic polysaccharides emerged in clinical trials. The immune mechanisms of both natural and synthetic polysaccharides remain incompletely understood, hindering the rational development of polysaccharide adjuvants. This comprehensive review primarily focused on several promising polysaccharide adjuvants, discussing their recent applications in vaccines and highlighting their immune-modulatory effects. Furthermore, the future perspectives of polysaccharides offer insightful guidance to adjuvant development and application.

Danggui Buxue decoction regulates the immune function and intestinal microbiota of cyclophosphamide induced immunosuppressed mice

Ethnopharmacological relevance

Danggui Buxue decoction (DBD) is a traditional Chinese herbal formula. According to the theory of traditional Chinese medicine, the combination of Astragali Radix (AR) and Angelica sinensis (AS) is a classic prescription of tonifying qi and enriching blood. DBD has the functions of hematopoietic, immune enhancement and inflammation inhibition, usually used to treat qi and blood deficiency symptoms.

Aim of the study

Cyclophosphamide (CY) can inhibit humoral and cellular immunity, leading to the overall immune disorder of the body, resulting in immunosuppressive (IS). Pre-laboratory studies confirmed the immunomodulatory effects of DBD, but its mechanisms have not been thoroughly studied. In this study, the main purpose was to determine the effects of DBD on the immune function and intestinal mucosal barrier function of IS mice induced by CY, and initially explored the immunomodulatory mechanism of DBD.

Materials and methods

100 g of AR and 20 g of AS were accurately weighed and 0.5 g/mL of the DBD was obtained by boiling, filtration and rotary evaporation. Then, mice in the DBD group were administered 5 g/kg of DBD by gavage, positive group were administered 40 mg/kg of levamisole hydrochloride, whereas those in the control and model groups were given the corresponding volume of normal saline by gavage for 1 week. At the end of the experiment, blood, spleen, thymus, ileum and cecum contents of all the experimental mice were collected aseptically. IS mouse model induced by intraperitoneal injection of 80 mg/kg CY for three consecutive days. Pathomorphology was used to observe the physical barrier of the intestine, flow cytometry to detect splenic lymphocytes, immunohistochemistry to determine the content of intestinal barrier-associated proteins, ELISA to measure the secretion of ileal SIgA, qRT-PCR to detect the mRNA expression of immune-related genes in the intestine, and high-throughput sequencing and analysis of cecum contents.

Results

DBD alleviated spleen tissue damage and restored impaired immune functions, such as increased thymus index and CD4+/CD8+ subsets of spleen lymphocytes. In addition, DBD could increase ileum villi length and the ratio of villi length to crypt depth (V/C), and decrease crypt depth. Moreover, DBD administration up-regulated the expression of ZO-1, Occludin, Claudin-1, MUC-2 mRNA in ileum. And the secretions of sIgA and ZO-1 in ileum were also significantly improved. Furthermore, the administration of DBD can increase the diversity of gut microbiota, improve the composition of intestinal flora and increase the relative abundance of beneficial genus, such as Bacteroides.

Conclusion

DBD alleviated CY-induced immune damage by decreasing the ratio of spleen index to CD4+/CD8+ of T lymphocyte subsets. And the intestinal barrier function of mice was by improves improving the intestinal morphology of the ileum and up-regulating the expression levels of ZO-1, MUC-2 and SIgA. DBD regulates CY-induced gut microbiota dysregulation in mice by increasing species diversity and richness, regulating the phylum, class and order levels of Bacteroidetes.

The Immunomodulatory Function of Assembled Composite Nanopolypeptide Containing Bursal-Derived BP7 (CNPB7) in Promoting the Mucosal Immune Response within Poultry Immunization

Mucosal immunity is the main defense line against respiratory disease pathogens. Newcastle disease and avian infectious bronchitis are common respiratory diseases in poultry. However, the mucosal immune response is not sufficiently activated and thus fails to achieve the ideal immune protection. Therefore, it is important to develop a suitable mucosal immune adjuvant to enhance the immune response of live vaccines. Here, the bursal-derived peptide BP7, β-glucan, and hyaluronic acid were selected as the adjuvant to be assembled into the composite nanopolypeptide adjuvant (CNPB7) with ultrasonic dispersion technology. The results showed that after optimizing assembly conditions, the optimal average particle size of nanoparticle CNPB7 was 514.9 nm and PDI was 0.298. To evaluate the non-specific immune responses of nanoparticle CNPB7, the chickens were immunized only with nanoparticle CNPB7. It was confirmed that nanoparticle CNPB7 enhanced the expression of CD3, CD4, CD80, and CD86 factors in the spleen lymphocyte from the chicken immunized with nanoparticle CNPB7. To investigate the mucosal immune response of nanoparticle CNPB7, the chickens were orally immunized with Newcastle disease virus (NDV)-infectious bronchitis virus (IBV) dual vaccines and CNPB7. The results proved that the levels of immunoglobulin SIgA, IL-4, IFN-γ, and IL-13 in the mucus samples from the respiratory and digestive tract in chicken immunized with nanoparticle CNPB7 and vaccines were significantly increased, compared to that of vaccine control. Finally, it was observed that nanoparticle CNPB7 promoted specific increased antibody productions against NDV and IBV in the immunized chicken. These results proved that the assembled nanoparticle CNPB7 could enhance the vaccination efficacy in chicken, which provided the experimental basis for the development of new adjuvants, and offered technical support for preventing virus transmission of avian diseases.

Mulberry leaf polysaccharide improves cyclophosphamide-induced growth inhibition and intestinal damage in chicks by modulating intestinal flora, enhancing immune regulation and antioxidant capacity

Polysaccharides are generally considered to have immune enhancing functions, and mulberry leaf polysaccharide is the main active substance in mulberry leaves, while there are few studies on whether mulberry leaf polysaccharide (MLP) has an effect on immunosuppression and intestinal damage caused by cyclophosphamide (CTX), we investigated whether MLP has an ameliorative effect on intestinal damage caused by CTX. A total of 210 1-day-old Mahuang cocks were selected for this experiment. Were equally divided into six groups and used to evaluate the immune effect of MLP. Our results showed that MLP significantly enhanced the growth performance of chicks and significantly elevated the secretion of cytokines (IL-1β, IL-10, IL-6, TNF-α, and IFN-γ), immunoglobulins and antioxidant enzymes in the serum of immunosuppressed chicks. It attenuated jejunal damage and elevated the expression of jejunal tight junction proteins Claudin1, Zo-1 and MUC2, which protected intestinal health. MLP activated TLR4-MyD88-NF-κB pathway and enhanced the expression of TLR4, MyD88 and NF-κB, which served to protect the intestine. 16S rDNA gene high-throughput sequencing showed that MLP increased species richness, restored CTX-induced gut microbiome imbalance, and enhanced the abundance of probiotic bacteria in the gut. MLP improves cyclophosphamide-induced growth inhibition and intestinal damage in chicks by modulating intestinal flora and enhancing immune regulation and antioxidant capacity. In conclusion, this study provides a scientific basis for MLP as an immune enhancer to regulate chick intestinal flora and protect chick intestinal mucosal damage.

Preparation and activity study of Ruoqiang jujube polysaccharide copper chelate

Background: Polysaccharide metal chelate exhibit both immunoregulatory activity and metal element supplementation effects. Methods: In this study, Ruoqiang jujube polysaccharide copper chelate (RJP-Cu) was prepared and the preparation conditions were optimized using the response surface method. Subsequently, RJP-Cu was administered to lambs to evaluate its impact on growth performance, copper ion (Cu2+) supplementation, immune enhancement, and intestinal flora was evaluated. Results: The results indicated that optimal RJP-Cu chelation conditions included a sodium citrate content of 0.5 g, a reaction temperature of 50°C, and a solution pH of 8.0, resulting in a Cu2+ concentration of 583°mg/kg in RJP-Cu. Scanning electron microscopy (SEM) revealed significant structural changes in RJP before and after chelation. RJP-Cu displaying characteristic peaks of both polysaccharides and Cu2+ chelates. Blood routine indexes showed no significant differences among the RJP-Cu-High dose group (RJP-Cu-H), RJP-Cu-Medium dose group (RJP-Cu-M), RJP-Cu-low dose group (RJP-Cu-L) and the control group (p > 0.05). However, compared with the control group, the RJP-Cu-H, M, and L dose groups significantly enhanced lamb production performance (p < 0.05). Furthermore, RJP-Cu-H, M, and L dose groups significantly increased serum Cu2+ concentration, total antioxidant capacity (T-AOC), catalase (CAT), and total superoxide dismutase (T-SOD) contents compared with control group (p < 0.05). The RJP-Cu-H group exhibited significant increases in serum IgA and IgG antibodies, as well as the secretion of cytokines IL-2, IL-4, and TNF-α compared to the control group (p < 0.05). Furthermore, RJP-Cu-H group increased the species abundance of lamb intestinal microbiota, abundance and quantity of beneficial bacteria, and decrease the abundance and quantity of harmful bacteria. The RJP-Cu-H led to the promotion of the synthesis of various Short Chain Fatty Acids (SCFAs), improvements in atrazine degradation and clavulanic acid biosynthesis in lambs, while reducing cell apoptosis and lipopolysaccharide biosynthesis. Conclusion: Thus, these findings demonstrate that RJP-Cu, as a metal chelate, could effectively promote lamb growth performance, increase Cu2+ content, and potentially induce positive immunomodulatory effects by regulating antioxidant enzymes, antibodies, cytokines, intestinal flora, and related metabolic pathways.

Protective Effect of Artocarpus heterophyllus Lam. (Jackfruit) Polysaccharides on Liver Injury Induced by Cyclophosphamide in Mice

In recent years, Artocarpus heterophyllus Lam. (jackfruit) polysaccharides (namely JFP-Ps) have attracted much attention due to their multiple biological activities. This study aimed to explore the protective effects and the underlying mechanisms of JFP-Ps on cyclophosphamide (Cp)-induced liver damage. The protective effect of JFP-Ps was evaluated using HE staining, antioxidant testing, enzyme-linked immunosorbent assay (ELISA), real-time quantitative polymerase chain reaction (RT-qPCR), Western blot and ultra-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) metabolomics analysis. The results showed that Cp caused pathological liver damage, activated oxidative stress and downregulated cytokine expression, while JFP-Ps treatment was found to exert antioxidant effects and play immune regulatory roles through mitogen-activated protein kinase/nuclear factor-κB (MAPK/NF-κB) related inflammation and cell apoptosis pathways to protect the Cp-induced liver injury. Metabolomic results showed that the liver-protective effects of JFP-Ps were mainly related to aminoacyl transfer ribonucleic acid (tRNA) biosynthesis, sphingolipid metabolism, purine metabolism and the citrate cycle. These results indicate that JFP-Ps have great potential application in alleviating liver injury.

Spatholobi caulis: A systematic review of its traditional uses, chemical constituents, biological activities and clinical applications

ETHNOPHARMACOLOGICAL RELEVANCE

Spatholobi caulis (SC), the dried vine stem of Spatholobus suberectus Dunn, is known as Ji Xue Teng in China, and has long been used as traditional Chinese medicine (TCM) to treat anaemia, menstrual abnormalities, rheumatoid arthritis, purpura, etc. AIM OF THE REVIEW: The aim of this review is to provide a systematic and updated summary of the traditional uses, chemical constituents, biological activities and clinical applications of SC. In addition, several suggestions for future research on SC are also proposed.

MATERIALS AND METHODS

Extensive information and data on SC were obtained from electronic databases (ScienceDirect, Web of Science, PubMed, CNKI, Baidu Scholar, Google Scholar, ResearchGate, SpringerLink and Wiley Online). Additional information was collected from Ph.D. and MSc dissertations, published books, and classic material medica.

RESULTS

To date, phytochemical studies have revealed that approximately 243 chemical ingredients have been isolated from SC and identified, including flavonoids, glycosides, phenolic acids, phenylpropanoids, volatile oils, sesquiterpenoids and other compounds. Many studies have indicated that extracts and pure constituents from SC possess a wide spectrum of in vitro and in vivo pharmacological effects, such as anti-tumour, haematopoietic, anti-inflammatory, antidiabetic, antioxidant, antiviral and antibacterial effects, as well as other activities. SC could be applied to the treatment of leukopenia, aplastic anemic, endometriosis, etc. according to the clinical reports. The traditional efficacies of SC is due to the biological functions of its chemical compounds, especially flavonoids. However, research investigating the toxicological effects of SC is relatively limited.

CONCLUSIONS

SC is widely used in TCM formulae and its some traditional efficacies has been confirmed by extensive recent pharmacological and clinical studies. Most the biological activities of the SC may be attributed to flavonoids. However, in-depth studies on the molecular mechanisms of the effective ingredients and extracts of SC are limited. Further systematic studies focusing on pharmacokinetics, toxicology and quality control are needed to ensure the effective and safe application of SC.

Ameliorating role of Tetrastigma hemsleyanum polysaccharides in antibiotic-induced intestinal mucosal barrier dysfunction in mice based on microbiome and metabolome analyses

The intestinal mucosal barrier is one of the important barriers to prevent harmful substances and pathogens from entering the body environment and to maintain intestinal homeostasis. This study investigated the reparative effect and possible mechanism of Tetrastigma hemsleyanum polysaccharides (THP) on ceftriaxone-induced intestinal mucosal damage. Our results suggested that THP repaired the mechanical barrier damage of intestinal mucosa by enhancing the expression of intestinal tight junction proteins, reducing intestinal mucosal permeability and improving the pathological state of intestinal epithelial cells. Intestinal immune and chemical barrier was further restored by THP via the increment of the body's cytokine levels, intestinal SIgA levels, intestinal goblet cell number, intestinal mucin-2 levels, and short-chain fatty acid levels. In addition, THP increased the abundance of probiotic bacteria (such as Lactobacillus), reduced the abundance of harmful bacteria (such as Enterococcus) to repair the intestinal biological barrier, restored intestinal mucosal barrier function, and maintains intestinal homeostasis. The possible mechanisms were related to sphingolipid metabolism, linoleic acid metabolism, and d-glutamine and D-glutamate metabolism. Our results demonstrated the potential therapeutic effect of THP against intestinal flora disorders and intestinal barrier function impairment caused by antibiotics.

Progress of Studies on Plant-Derived Polysaccharides Affecting Intestinal Barrier Function in Poultry

As natural bioactive components, plant-derived polysaccharides have many biological functions, such as anti-inflammatory, antioxidant, anticoccidial, and immunity regulation, and have been widely used in poultry production. In this review paper, firstly, the sources and structures of plant-derived polysaccharides are reviewed; secondly, the effects of plant-derived polysaccharides on the intestinal microbiome, permeability, morphology and immune function of poultry are summarized; thirdly, the potential molecular regulation mechanism of plant-derived polysaccharides on the intestinal barrier function of poultry was preliminarily analyzed. The review paper will bring a basis for the scientific utilization of plant-derived polysaccharides in the poultry industry.

Supplementation with honeysuckle extract improves growth performance, immune performance, gut morphology, and cecal microbes in geese

The study aimed to investigate the effects of honeysuckle extract (HE) on growth performance, serum biochemical indexes, immune organ indexes, gut morphology, and gut microbes in geese. A total of 180 28-day-old Holdobaki geese were randomly divided into three groups. Each group contained 6 replicates (10 geese, with 5 males and 5 females). The BD group was fed the basal diet, the HE1 group was fed the basal diet supplemented with 1 g/kg of HE, and the HE2 group was fed the basal diet supplemented with 2 g/kg of HE. The experiment lasted for 42 days. The results showed that, compared with the BD group, the average daily gain (ADG) of the HE1 and HE2 groups tended to increase (0.05 < P < 0.10), but the average daily feed intake (ADFI) and final body weight (BW) did not differ significantly, and the feed/gain ratio (F/G) was significantly lower (P < 0.01). The bursa index and the thymus index tended to increase (0.05 < P < 0.10), and serum immunoglobulin A (IgA) and immunoglobulin G (IgG) levels increased significantly (P < 0.05). In the HE1 and HE2 groups, the crypt depth (CD) in the jejunum tended to decrease (0.05 < P < 0.10), and the villus height/crypt depth ratio (V/C) increased significantly in the jejunum and the ileum (P < 0.05). According to 16sRNA microbial community diversity analysis, Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria were the dominant phyla. The abundance of Firmicutes was significantly decreased (P < 0.01), while that of Bacteroidetes was significantly increased (P < 0.01), in the HE1 and HE2 groups compared with the BD group. Bacteroides barnesiae, Subdoligranulum variabile, Bacteroides plebeius, and Faecalibacterium prausnitzii were the dominant species, and the abundance of B. plebeius and F. prausnitzii was significantly increased (P < 0.05). According to the LEfSe analysis, BD enriched g_Dorea and g_Dehalobacterium; HE1 enriched g_Faecalibacterium, g_Dialister, g_Prevotella, g_Megamonas, g_Phascolarctobacterium, g_Paraprevotella, g_Anaerostipes, g_Staphylococcus, g_Odoribacter, g_Succinivibrio, and g_Sutterella; and HE2 enriched g_Parabacteroides, g_Olsenella, g_human, and g_Rikenella. According to the Spearman correlation analysis, Bacteroides plebeius was positively correlated with final BW, ADG, IgA, IgG, VH (ileum), and V/C (ileum) and was negatively correlated with F/G and CD (ileum); Ruminococcus gnavus was negatively correlated with final BW, ADG, IgA, and IgG. HE supplementation at 1 g/kg improved growth performance, immune performance, gut morphology, and cecal microbes.

Effects of intramuscular fat on meat quality and its regulation mechanism in Tan sheep

Intramuscular fat (IMF) contributes importantly to various aspects of meat quality, and genetic regulation is an effective pathway to improve IMF deposition in sheep. In this study, we systematically explored the effect of IMF content on meat quality in Tan sheep and investigated the regulatory mechanism of flavor precursors metabolism and IMF deposition. The results revealed that IMF significantly affected meat color, total muscle fiber numbers, and muscle fiber types in Tan sheep. Widely-targeted metabolomic analysis showed that amino acids were the main differential flavor precursors between lambs with different IMF content. Importantly, the comparison of fatty acid profiles revealed that saturated fatty acids and monounsaturated fatty acids are beneficial for IMF deposition. Furthermore, integrated analysis between metabolome and transcriptome indicated that MME is a key gene resulting in the reduction of amino acids in lambs with high IMF content; and the joint analysis between fatty acid profiles and transcript profiles showed that ADIPOQ, FABP4, PLIN1, PPARGC1A, SLC2A1 accelerated IMF deposition through positive regulation of saturated fatty acids and monounsaturated fatty acids metabolism. These results revealed key changes in meat quality affected by IMF content and the corresponding genetic mechanism, which may provide a new insight for understanding the IMF differential deposition and for improving meat quality in Tan sheep.