Undernutrition Disrupts Cecal Microbiota and Epithelium Interactions, Epithelial Metabolism, and Immune Responses in a Pregnant Sheep Model

Undernutrition disrupts jejunal and ileal microbiota and epithelial tissue homeostasis in a pregnant sheep model

Nutrition consistently affects microbe-host interactions in the gastrointestinal tract. This study aimed to unravel how undernutrition reshapes the microbial composition and the homeostasis of epithelium in the jejunum and ileum. Sixteen late-gestation Hu-sheep were randomly assigned to the control group (n = 8, 100% ad libitum feeding levels) or the undernutrition group (n = 8, which received 30% ad libitum feeding levels). After 15-d treatment, all ewes were slaughtered, and jejunal and ileal digesta and epithelium samples were collected for 16S rRNA gene sequencing and transcriptome sequencing, respectively. Results indicated that undernutrition decreased the jejunal and ileal tissue weights (P = 0.005 and P = 0.022) and the levels of volatile fatty acids (P = 0.019 and P = 0.007) and microbial protein levels (P = 0.019 and P = 0.031) in jejunal and ileal digesta. The relative abundance of acetate producing microbiota, including Clostridia UCG-014 norank, Ruminococcus, [Ruminococcus] gauvreauii, and Lachnospiraceae _Blautia, were significantly reduced (P < 0.05) in the jejunum and ileum. Undernutrition up-regulated (P < 0.05) the expression of genes involved in amino acid synthesis and fatty acid oxidation, but down-regulated (P < 0.05) the expression of genes associated with amino acid degradation, fatty acid synthesis, and extracellular structures in jejunal and ileal epithelium. In the jejunal epithelium, genes associated with extracellular matrix-receptor interactions, cell growth, and immune response were down-regulated (P < 0.05) upon undernutrition. Taken together, undernutrition changed the microbial community in the jejunum and ileum, which altered the fermentation mode and the production of volatile fatty acids and microbial protein. These affected the energy and protein system in the epithelium and reprogrammed substance metabolism and extracellular structures, which probably further influenced cell growth and immune response. These insights provide a foundation for completely clarifying the crosstalk between small intestinal microbiota and the host.

Dietary and environmental factors affecting the dynamics of the gut bacteria in Tibetan Awang sheep (Ovis aries) across divergent breeding models

Introduction

Tibetan Awang sheep (Ovis aries), indigenous to the Qinghai-Tibet Plateau, are highly adapted to high-altitude environment. However, knowledge regarding their gut bacterial composition remains limited.

Methods

A comprehensive 16S rRNA highthroughput sequencing was performed on fecal samples from 15 Awang sheep under pure grazing, semi-captivity, and full captivity breeding models.

Results

Our results revealed that Firmicutes and Bacteroidetes were the most abundant bacterial phyla, while Christensenellaceae_R-7_group, Romboutsia, Rikenellaceae_RC9_gut_group, Ruminococcus, and Bacteroides were prevalent genera in the gut microbiota of Awang sheep. Meanwhile, the predominant presence of Bacteroides with increasing altitude of breeding locations indirectly demonstrates its crucial role in mediating energy acquisition among Awang sheep at high altitudes. Furthermore, PCoA and ANOSIM analysis exhibited significant differences in bacterial composition across all breeding models (r > 0.6, p < 0.001). Christensenellaceae_R-7_group, Romboutsia, and Ruminococcus were significantly abundant in the pure grazing breeding model, while Rikenellaceae_RC9_gut_group and Bacteroides were more abundant in the semi-captivity breeding model. An abnormally high abundance of Acinetobacter indicated a potential risk of Acinetobacter infection in the fully captive group. The environmental association analysis exhibited that meadows diet (R 2 = 0.938, Pr[>r] = 0.001) and altitude (R 2 = 0.892, Pr[>r] = 0.001) had significant effects on the dominant genera, explaining a substantial proportion of the total variation in community composition.

Discussion

Our study indicated that breeding conditions significantly impact the gut microbiota of Awang sheep. The environmental association analysis underscores the importance of diet and altitude in shaping the gut microbiota of Awang sheep. The present findings provide insights into the microbiota dynamics of Awang sheep and offer guidance for their scientific husbandry management.

Cecum microbiota composition, fermentation characteristics, and immunometabolic biomarkers of Yunshang black goat fed varying dietary energy and protein levels

Introduction

Ruminants including goats have diverse microcosms of microbiota involved in diet digestion, absorption, and assimilation. Moreover, it is well known that changes in dietary regimens including nutrient levels result in varied gut microbiota composition, and ultimately, the performance and health of these animals.

Methods

The current study examined the effects of varying dietary energy and protein levels on the cecal fermentation, immune biomarkers, and microbiota characteristics of 80 male Yunshan Black Goats (6 months, ~35.82 ± 2.79 kg), divided into four diets: 1) High Energy-High Protein (HEHP), 2) High Energy-Low Protein (HELP), 3) Low Energy-High Protein (LEHP), and 4) Low Energy-Low Protein (LELP). Twenty goats (five from each treatment group) were randomly slaughtered after a 50-day feeding trial, and cecal digesta and tissue were sampled for microbial analysis.

Results

The cecal content revealed that the high-energy groups (HEHP, HELP) had lower pH levels than the LEHP group (p < 0.05) and significantly higher valeric and isovaleric acid concentrations in HEHP. Although species richness (Chao1 index) remained consistent, the HEHP group showed higher diversity (Shannon and Simpson indices) than LEHP (p < 0.05). Dominant phyla included Bacteroidetes and Firmicutes; LEHP and LELP had significantly higher Bacteroidetes abundance than HELP, while HELP had higher Firmicutes abundance than LEHP (p < 0.05). Verrucomicrobia abundance was lower in LEHP than in HELP and LELP (p < 0.05). At the genus level, 311 genera were identified, with Clostridium, Prevotella, unidentified_BS11, and others showing significant variation. The HELP group had lower unidentified_BS11 than LEHP and LELP, and higher unidentified_Ruminococcaceae, Clostridium, and Lachnospiraceae than LEHP (p < 0.05). VFA metabolism, absorption, cytokine expression, and tight junction protein mRNA in cecal tissue were also analyzed. Genes like MCT-1 and SLC16A4, linked to VFA absorption, positively correlated with Paludibacter, which was associated with immune markers (TLR-3, TLR-4, IFN-γ) and Occludin expression. In contrast, VFA-related genes and tight junction proteins negatively correlated with unidentified Fibrobacterales, suggesting a microbial role in adaptive immunity.

Conclusion

This study demonstrated that dietary energy and protein levels significantly influenced cecal fermentation, immune biomarkers, and microbiota composition in Yunshan Black Goats.

Undernutrition affects metabolism and immune response in subcutaneous adipose tissue of pregnant ewes

Pregnant ewes mobilize body fat to increase energy supply for fetal growth and development upon undernutrition, which disrupts the metabolic homeostasis of the body. However, the comprehensive metabolic changes in subcutaneous adipose tissue upon undernutrition are poorly understood. In this study, an undernutrition sheep model was established to investigate the effects of undernutrition on metabolic changes, immune response, and inflammation in subcutaneous fat through transcriptome, RT-qPCR, and metabolome analysis. Results showed that undernutrition changed the total transcriptional and metabolic profiles of adipose tissue. Compared to the controls, differentially expressed genes (DEGs) involved in fatty acid synthesis, triglyceride genesis, and lipid transport were downregulated in undernourished ewes, while DEGs related to fatty acid and triglyceride degradation were upregulated. Almost all lipid-related differential metabolites (DMs) were downregulated. DEGs and DMs involved in glucose metabolism and glycogen degradation were downregulated, while glycogen synthesis and carbohydrate transport were upregulated. DEGs linked to amino acid degradation were upregulated and some amino acids and derivatives were downregulated. KEGG pathway analysis showed complement and coagulation cascades were enriched significantly by DEGs, and DEGs related to coagulation, macrophage, and inflammation were upregulated while DEGs associated with the complement system were downregulated. Undernutrition during late gestation disrupted the metabolism of lipids, carbohydrates, and amino acids in adipose tissue, which weakened the complement system and immune response and may have ultimately led to inflammation.

Response of the gut microbiota to changes in the nutritional status of red deer during winter

Unravelling abrupt alterations in the gut microbiota of wild species associated with nutritional stress is imperative but challenging for wildlife conservation. This study assessed the nutritional status of wild red deer during winter on the basis of changes in faecal nitrogen (FN) and urea nitrogen/creatinine (UN: C) levels and identified gut microbes associated with nutritional status via nutritional control experiments and metagenomic sequencing. The FN of wild red deer in winter 2022 was significantly lower than that in winter 2021 (p < 0.05, winter 2021: 1.37 ± 0.16% and winter 2022: 1.26 ± 0.22%), and the UN: C ratio increased (winter 2021: 2.19 ± 1.65 and winter 2022: 3.05 ± 3.50). Similar trends were found in late winter, which indicated greater nutritional pressure in winter (2022) and late winter. Compared with winter 2021, abundances of Ructibacterium and Butyrivibrio significantly increased, and Acetatifactor and Cuneatibacter significantly decreased during winter 2022 (p < 0.05). Compared with early winter, the cell growth and death pathways increased and lipid metabolism and its subpathway of secondary bile acid synthesis (ko00121) significantly decreased during late winter (p < 0.05), which was similar to the changes in malnourished experimental red deer. Abrupt alterations in the gut microbiota should receive increased attention when monitoring the nutritional health of wild ungulates. This study provides new insights and critical implications for the conservation of wild ungulate populations.

Functional analysis of microorganisms and metabolites in the cecum of different sheep populations and their effects on production traits

The purpose of this study was to investigate the effects of intestinal microbiota on the growth and production performance of different groups of sheep, focusing on the role of cecal microbiota in regulating intestinal function, enhancing digestion and absorption, and improving feed utilization. The production performance of MG × STH (Mongolia × Small Tailed Han) F1 hybrids and purebred STH (Small Tailed Han) sheep by measuring various factors, including enzyme activities and VFAs (volatile fatty acids), to analyze changes in cecal fermentation parameters across different sheep groups. Metagenomic and metabolomic sequencing combined with bioinformatics to analyze the cecal contents of the two sheep populations. The study findings indicated that the MG × STH F1 hybrids outperformed the purebred STH in terms of body weight, height, oblique body length, and VFAs (p < 0.05). Additionally, the MG × STH F1 higher levels of protease and cellulase in the cecum compared to the purebred sheep (p < 0.05). Metagenomic analysis identified 4,034 different microorganisms at the species level. Five differential organisms (Akkermansiaceae bacterium, Escherichia coli, unclassified p Firmicutes, Streptococcus equinus, Methanobrevibacter millerae) positively regulated sheep performance. Metabolomics identified 822 differential metabolites indoleacetaldehyde, 2-aminobenzoic acid, phenyl-Alanine, enol-phenylpyruvate and n-acetylserotonin were associated with improved performance of sheep. The combined results from the metagenomic and metabolomic studies suggest a positive correlation between specific microbes and metabolites and the performance of the sheep. In conclusion, the MG × STH F1 hybrids demonstrated superior growth performance compared to the purebred STH sheep. The identified microorganisms and metabolites have promising roles in positively regulating sheep growth and can be considered key targets for enhancing sheep performance.

Mixed probiotics modulated gut microbiota to improve spermatogenesis in bisphenol A-exposed male mice

Bisphenol A (BPA), an environmental endocrine disruptor (EDC), has been implicated in impairing intestinal and male reproductive dysfunction. The efficacy of gut microbiota modulation for BPA-exposed testicular dysfunction has yet to be verified through research. Therefore, this study explored the potential of mixed probiotics in restoring spermatogenesis damage through the gut-testis axis under BPA exposure. We selected two probiotics strains (Lactobacillus rhamnosus and Lactobacillus plantarum) with BPA removal properties in vitro and the BPA-exposed male mice model was established. The probiotics mixture effectively reduced BPA residue in the gut, serum, and testis in mice. Through 16 S rDNA-seq and metabolomics sequencing, we uncovered that vitamin D metabolism and bile acid levels in the gut was abolished under BPA exposure. This perturbation was linked to an increased abundance of Faecalibaculum and decreased abundance of Lachnospiraceae_NK4A136_group and Ligilactobacillus. The probiotics mixture restored this balance, enhancing intestinal barrier function and reducing oxidative stress. This improvement was accompanied by a restored balance of short-chain fatty acids (SCFAs). Remarkably, the probiotics ameliorated testicular dysfunction by repairing structures of seminiferous tubules and reversing arrested spermiogenesis. Further, the probiotics mixture enhanced testosterone-driven increases in spermatogonial stem cells and all stages of sperm cells. Testicular transcriptome profiling linked these improvements to fatty acid degradation and peroxisome pathways. These findings suggest a significant interplay between spermatogenesis and gut microbiota, demonstrating that probiotic intake could be a viable strategy for combating male subfertility issues caused by BPA exposure.

The Role and Mechanism of Retinol and Its Transformation Product, Retinoic Acid, in Modulating Oxidative Stress-Induced Damage to the Duck Intestinal Epithelial Barrier In Vitro

This study aimed to investigate the effects and mechanisms of retinol and retinoic acid on primary duck intestinal epithelial cells under oxidative stress induced by H2O2. Different ratios of retinol and retinoic acid were used for treatment. The study evaluated the cell morphology, viability, antioxidative capacity, and barrier function of cells. The expression of genes related to oxidative stress and the intestinal barrier was analyzed. The main findings demonstrated that the treated duck intestinal epithelial cells exhibited increased viability, increased antioxidative capacity, and improved intestinal barrier function compared to the control group. High retinoic acid treatment improved viability and gene expression, while high retinol increased antioxidative indicators and promoted intestinal barrier repair. Transcriptome analysis revealed the effects of treatments on cytokine interactions, retinol metabolism, PPAR signaling, and cell adhesion. In conclusion, this study highlights the potential of retinol and retinoic acid in protecting and improving intestinal cell health under oxidative stress, providing valuable insights for future research.

Effects of Diets Containing Different Levels of Copper, Manganese, and Iodine on Rumen Fermentation, Blood Parameters, and Growth Performance of Yaks

Copper, manganese, and iodine are part of a yak's required trace elements. However, knowledge about their dietary requirements is scarce. Therefore, an experiment was conducted to evaluate rumen fermentation, blood parameters, and growth performance and screen out the optimum levels of trace elements in yaks' diet. Here, 18 three-year-old castrated yaks were randomly divided into four groups, which fed with diets containing basal (CON: 4.40, 33.82, and 0 mg/kg) and low-level (LL: 10.00, 40.00, and 0.30 mg/kg), middle-level (ML: 15.00, 50.00, and 0.50 mg/kg), and high-level (HL: 20.00, 60.00, and 0.70 mg/kg) copper, manganese, and iodine for 30 days. With the increase in trace elements, yaks' daily weight gain (DWG), rumen pH, ammonia nitrogen, microbial protein (MCP), and volatile fatty acids levels and serum triglycerides and urea nitrogen levels showed firstly increasing and then decreasing trends and reached the highest values in ML, and serum ceruloplasmin and total superoxide dismutase (T-SOD) activities showed continuously increasing trends. Yaks' DWG, rumen MCP, butyrate, and valerate levels and serum triglycerides, urea nitrogen, ceruloplasmin, and T-SOD levels in ML were significantly higher than CON. Therefore, the recommended levels of copper, manganese, and iodine in growing yaks' diet are 15.00, 50.00, and 0.50 mg/kg (ML), respectively.