Yeast culture repairs rumen epithelial injury by regulating microbial communities and metabolites in sheep

Yeast Culture Supplementation Improves Meat Quality by Enhancing Immune Response and Purine Metabolism of Small-Tail Han Sheep (Ovis aries)

Yeast culture is widely used in ruminants to improve gut health, immunity, and productivity; however, its impact on meat quality remains unclear. This study aimed to investigate the effects of yeast culture supplementation in the basic diet on meat quality of Small-tail Han sheep. A total of 40 Small-tail Han sheep (17.5 ± 1.2 kg) were randomly assigned to two treatment groups, with 20 sheep in each group. The sheep were fed either a basic diet (CON) or the basic diet supplemented with 1% yeast culture (YSD) for 90 days. At the end of the trial, the Longissimus dorsi muscle (LOD) of the sheep was collected for meat quality evaluation, as well as transcriptome and metabolome analyses. Meat quality data were analyzed using t-tests, while transcriptome and metabolome data were analyzed using bioinformatics tools. The results showed that YSD supplementation significantly reduced carcass fat content (p < 0.05) and increased the pH values (p < 0.05) of LOD compared to the CON group. Multi-omics analysis revealed significant changes in the levels of 349 transcripts and 149 metabolites (p < 0.05) in the YSD group relative to the CON group. These changes were primarily associated with immune response pathways and purine metabolism. Further integrated transcriptomics and metabolomics analysis identified significant alterations in the expression of adenylate kinase 4 (AK4) and ribonucleotide reductase M2 (RRM2), which influenced purine metabolites, such as ADP, GMP, 3'-AMP, 3'-GMP, dGDP, adenine, guanosine, and guanine. These metabolites were markedly upregulated in the LOD of the sheep supplemented with yeast culture. In conclusion, yeast culture supplementation improved the meat quality of Small-tail Han sheep, potentially through the enhancement of immune response and purine metabolism. These findings offer valuable insights into the molecular mechanisms underlying the effects of yeast culture on animal health and meat quality.

Rhodotorula Yeast Culture Improved the Antioxidant Capacity, Lipid Metabolism, and Immunity of Sheep Livers

There is currently no research on the application evaluation of R. mucilaginosa yeast culture (RYC) in animal production. Therefore, this study investigated the effects of RYC on the antioxidant capacity, lipid metabolism, and immunity of sheep livers. Twenty-four 3-month-old Duhan male sheep (36 ± 4 kg) were divided into four groups. The control group received a basal diet, the L group received a basal diet + 10 g/sheep/day RYC, the M group received a basal diet + 20 g/sheep/day RYC, and the H group received a basal diet + 40 g/sheep/day RYC. The trial lasted for 75 days. The results showed that the content of glutathione peroxidase in the livers of sheep in group M was significantly increased by 26.6%, and the content of malondialdehyde was significantly decreased by 38% (p < 0.05). Additionally, the serum levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol significantly decreased; the liver content of C16:0 decreased; and the levels of C18:2n6C and C20:1 increased (p < 0.05). Furthermore, the contents of cytokines TNF-α and IFN-γ in sheep livers from the M group were also significantly decreased by 20% and 24.8%, respectively (p < 0.05). These findings suggest that supplementation with 20 g/sheep/day RYC can enhance antioxidant capacity, improve lipid metabolism, and reduce inflammation in sheep livers, which is advantageous for farming healthy sheep.

Effects of Yeast Culture on Lamb Growth Performance, Rumen Microbiota, and Metabolites

The effects of incorporating yeast culture (YC) into pelleted feeds on sheep production and the potential impact on rumen microbial populations, microbial metabolism, and fermentation have not been extensively studied. This study aimed to evaluate the effect of YC on growth performance, rumen tissue development, rumen fermentation, and rumen microflora in sheep and to explore the potential microbial mechanisms involved. Fifty healthy 3-month-old male lambs of small-tailed Han sheep, with an average weight of 28.44 ± 0.63 kg, were randomly divided into five groups: control (0% YC), 3% YC, 6% YC, 9% YC, and 12% YC. The pre-feeding period lasted for 15 days, followed by an official feeding period of 60 days. On the last day of the formal feeding period, six lambs that exhibited the best growth performance were randomly selected from the control group and the 9% YC group. These sheep were slaughtered, then the rumen epithelial tissue and rumen contents were collected for the measurement of rumen fermentation, microbial populations, and metabolites. Compared to the control group, the YC-treated groups showed higher daily and final body weight gains, as well as increased levels of propionic acid, butyric acid, and total volatile fatty acids (p < 0.05). YC supplementation also enhanced rumen papilla length and width (p < 0.05). Additionally, YC increased the relative abundance of certain microbial species (p < 0.05). These results suggest that supplementing 9% YC in pelleted diets for small-tailed Han sheep may enhance growth performance and improve the rumen environment.

Transcriptomic characterization of the functional and morphological development of the rumen wall in weaned lambs fed a diet containing yeast co-cultures of Saccharomyces cerevisiae and Kluyveromyces marxianus

Introduction

In lambs, the function of the rumen is incompletely developed at weaning, and the inclusion of yeast cultures in the diet can profoundly influence the morphological and functional development of the rumen.

Methods

In this study, the effects of Saccharomyces cerevisiae and Kluyveromyces marxianus (NM) yeast co-cultures on ruminal histomorphology were assessed, and corresponding transcriptomic changes within the rumen epithelium were identified. In total, 24 lambs were grouped into four groups of six lambs including a control (C) group fed a basal diet, and N, M, and NM groups in which lambs were fed the basal diet, respectively, supplemented with Saccharomyces cerevisiae yeast cultures (30 g/d per head), Kluyveromyces marxianus yeast cultures (30 g/d per head), and co-cultures of both yeasts (30 g/d per head), the experiment lasted for 42 d.

Results

In morphological analyses, lambs from the NM group presented with significant increases in papilla length, papilla width, and epithelial thickness in the rumen relative to lambs in the C group (p < 0.05). Transcriptomic analyses revealed 202 genes that were differentially expressed between samples from the C and NM groups, with the largest proportion of these genes being associated with the oxidative phosphorylation pathway. In a weighted gene coexpression network analysis, a positive correlation was observed between the MEgreen and MEpurple modules and rumen morphology. Of these modules, the MEgreen module was found to be more closely linked to fatty acid metabolism and oxidative phosphorylation, whereas the MEpurple module was linked to oxidative phosphorylation and fatty acid degradation. Ultimately, these results suggest that dietary supplementation with NM has driven the degradation of fatty acids, the induction of oxidative phosphorylation, the acceleration of lipid metabolism, the production of ATP to sustain ruminal growth, and the maintenance of intracellular NADH/NAD+ homeostasis on weaned lambs and is superior to single yeast fermentation.

Discussion

These results thus offer a theoretical foundation for further studies examining the mechanisms through which NM cultures can influence ruminal development in lambs.

Effects of Saccharomyces cerevisiae and Bacillus subtilis on in vitro fermentation in the rumen of Hu sheep

BACKGROUND

The demand for animal products is increasing in developing countries due to population growth. However, livestock production contributes significantly to global warming, accounting for 25%. Probiotics can help improve livestock efficiency by enhancing gut microbes and fat metabolism. They can modify rumen populations, enhance fermentation, reduce methane emissions and improve feed digestion. In this study, the goal was to determine the most effective method of reducing methane emissions in the rumen of sheep in vitro by adding different concentrations of Saccharomyces cerevisiae and Bacillus subtilis.

RESULTS

Adding 8 × 106 CFU g-1 S. cerevisiae during fermentation reduced pH levels after 48 h. This also increased the concentrations of NH3-N, microbial protein and total gas production. At the same time, it decreased methane emissions. Furthermore, adding 20 × 106 CFU g-1 B. subtilis to the mixture increased total gas production (TGP) and methane production, with the highest production observed after 48 h. However, it did not affect pH levels after 48 h.

CONCLUSION

It can be concluded that S. cerevisiae had significantly increased microbial protein and NH3-N concentrations after fermentation without altering pH. Additionally, the addition of S. cerevisiae enhanced TGP and reduced methane emissions. It is worth noting that TGP increased because B. subtilis was added at a concentration of 20 × 106 CFU g-1, with no significant differences between concentrations. Therefore, we recommend adding S. cerevisiae and B. subtilis to the diet at doses of 8 and 20 × 106 CFU g-1, as it resulted in higher TGP and reduced methane emissions. © 2024 Society of Chemical Industry.

Effects of yeast cultures on meat quality, flavor composition and rumen microbiota in lambs

Since the banning of antibiotics, the use of feed additives to improve meat quality to satisfy people's pursuit of high quality has become a research hotspot. Yeast culture (YC) is rich in proteins, mannan oligosaccharides, peptides, and yeast cell metabolites, etc., and its use as a feed additive has a positive impact on improving meat quality. So the study aimed to provide a theoretical basis for YC improving mutton flavor and quality by detecting and analyzing the effects of YC on muscle physicochemical properties, amino acids, fatty acids, flavor composition, expression of related genes, and rumen microbiota of lambs. A total of 20 crossbred F1 weaned lambs (Australian white sheep♂ × Hu sheep♀; average 23.38 ± 1.17 kg) were randomly assigned to 2 groups, the control group (CON) and the 1.0% YC supplemented group (YC) (n = 10), and were reared in separate pens. The experiment had a pre-feeding period of 10 d and a treatment period of 60 d. After the experiment, 6 lambs in each group were randomly selected for slaughtering. The results showed that dietary YC supplementation increased rumen total VFA and acetate concentrations (p < 0.05), and muscle carcass fat (GR), a∗ value, intramuscular fat (IMF), lysine (Lys), arginine (Arg), nonessential amino acid (NEAA), oleic acid (C18:1n9c), and eicosanoic acid (C20:1) contents were significantly increased (p < 0.05), while cooking loss and γ-linolenic acid (C18: 3n6) were decreased (p < 0.05). Furthermore, we found that dietary YC improved the types of flavor compounds, and the key flavor substances such as hexanal, nonanal, styrene, benzaldehyde, p-xylene, and 1-octen-3-ol contents were changed (p < 0.05). Additionally, the expression of fat metabolism related genes PPARγ, FASN, and FABP4 were increased. Adding 1% YC to lamb diets increased profits by 47.70 CNY per sheep after 60 d of fattening. All of which indicated that YC could improve meat quality, especially flavor, which may be related to the regulation of the relative abundance of rumen microorganisms Bacteroidota, Prevotella_7, Succiniclasticum and Lachnospiraceae_NK3A20_group.

Effect of Adding Yeast Cultures to High-Grain Conditions on Production Performance, Rumen Fermentation Profile, Microbial Abundance, and Immunity in Goats

It is a common practice among farmers to utilize high-grain diets with the intention of promoting ruminant growth. However, this approach bears the risk of inducing rumen disorders and nutrient metabolism diseases. Yeast culture (YC) showed advantages in ruminant applications. The objective of this study was to evaluate the effects of adding two different types of YC to high-grain conditions on production performance, rumen fermentation profile, microbial abundance, and immunity in goats. A total of 30 male goats with similar body condition were randomly distributed into 3 dietary treatments with 10 replicates per treatment as follows: basic diet group (CON); basic diet + 0.5% yeast culture 1 (YC1) group; basic diet + 0.5% yeast culture 2 (YC2) group. The trial lasted for 36 days. The results demonstrated that dietary YC supplementation led to an increase in the average daily gain and a reduction in feed intake and weight gain ratio in goats. It increased the apparent digestibility of crude protein, NDF, and ADF (p < 0.05). The serum concentrations of interleukin (IL)-1β, IL-6, and Tumor Necrosis Factor-α in the control group were significantly higher than those of the YC groups (p < 0.05). The serum concentrations of Immunoglobulin (Ig)A and IgG in the control group were significantly lower than those in the YC groups (p < 0.05). The rumen concentration of microbial protein (MCP) in the control group was significantly lower than that in the YC groups (p < 0.05). There was a negative correlation between the concentration of IL-10 and Bacteroidota, Spirochaetota, and Succinivibrio, while there was a positive correlation between concentrations of IL-10 and Firmicutes. Nevertheless, discrepancies were observed in the impact of the two different types of YC on the physiological and biochemical indicators of the animals. The concentration of triglyceride in the YC1 group was significantly higher than that of the CON and YC2 groups, while the concentration of urea in the YC2 group was significantly higher than that of the CON and YC1 groups (p < 0.05). At the phylum level, the addition of YC2 to the diet significantly increased the relative abundance of Bacteroidota and Fibrobacterota and significantly decreased Firmicutes compared to the control. At the genus level, the addition of YC1 to the HGD significantly reduced the relative abundance of Rikenellaceae_RC9_gut_group, while the addition of YC2 to the HGD significantly increased the relative abundance of Prevotellace-ae_UCG-001, Fibrobacter, and Prevotellaceae_UCG-003 (p < 0.05). The addition of YC significantly improved growth performance, increased nutrient digestibility, beneficially manipulated ruminal fermentation and microbial diversity, and improved immune function. The choice of yeast cultures can be customized according to specific production conditions.

Prickly ash seeds can promote healthy production of sheep by regulating the rumen microbial community

This study aimed to investigate the effect of prickly ash seeds (PAS) on the microbial community found in rumen microbes of Hu sheep by adding different percentages of prickly ash seeds and to carry out research on the relation between rumen flora and production performance. Twenty-seven male lambs of Hu sheep were classified into three groups based on the content of prickly ash seeds (PAS) fed for 90 days, i.e., 0%, 3%, and 6%. At the end of the feeding trial, rumen fluid samples were collected from six sheep in each group for 16S amplicon sequencing. The results showed that the addition of prickly ash seeds significantly increased both Chao1 and ACE indices (P < 0.05), and the differences between groups were greater than those within groups. The relative content of Bacteriodota decreased, and the relative content of Fusobacteriota, Proteobacteria, Acidobacteriota, and Euryarchaeota increased. The relative content of Papillibacter and Saccharofermentans was increased at the genus level, and the relative content of Bacteroides and Ruminococcus was decreased. The test group given 3% of prickly ash seeds was superior to the test group given 6% of prickly ash seeds. In addition, the addition of 3% of prickly ash seeds improved the metabolism or immunity of sheep. Fusobacteriota and Acidobacteriota were positively correlated with total weight, dressing percentage, and average daily gain (ADG) and negatively correlated with average daily feed intake (ADFI), feed-to-gain ratio (F/G), and lightness (L*). Methanobrevibacter and Saccharofermentans were positively correlated with ADG and negatively correlated with ADFI and L*. In conclusion, under the present experimental conditions, the addition of prickly ash seeds increased the abundance and diversity of rumen microorganisms in Hu sheep and changed the relative abundance of some genera. However, the addition of 6% prickly ash seeds may negatively affect the digestive and immune functions in sheep rumen.

Rumen Development of Tianhua Mutton Sheep Was Better than That of Gansu Alpine Fine Wool Sheep under Grazing Conditions

The purpose of this experiment was to investigate the differences in rumen tissue morphology, volatile fatty acid content, and rumen microflora between Tianhua mutton sheep and Gansu alpine fine wool sheep under the same grazing conditions. Twelve 30-day-old lambs were randomly selected from two different flocks in Duolong Village and grazed together for a period of 150 days. The rumen tissue was fixed with 4% paraformaldehyde and brought back to the laboratory for H&E staining, the volatile fatty acid content of the rumen contents was detected by gas chromatography, and the rumen flora structure was sequenced by full-length sequencing of the bacterial 16S rRNA gene using the PacBio sequencing platform. The acetic acid and total acid contents of the rumen contents of Tianhua mutton sheep were significantly higher than those of Gansu alpine fine wool sheep (p < 0.05). The rumen papillae height of Tianhua mutton sheep was significantly higher than that of Gansu alpine fine wool sheep (p < 0.05). The diversity and richness of the rumen flora of Tianhua mutton sheep were higher than those of Gansu alpine fine wool sheep, and Beta analysis showed that the microflora structure of the two fine wool sheep was significantly different. At the phylum level, Firmicutes and Bacteroidetes dominated the rumen flora of Tianhua mutton sheep and Gansu alpine fine wool sheep. At the genus level, the dominant strains were Christensenellaceae_R_7_group and Rikenellaceae_RC9_gut_group. LEfSe analysis showed that Prevotella was a highly abundant differential species in Tianhua mutton sheep and lachnospiraccac was a highly abundant differential species in Gansu alpine fine wool sheep. Finally, both the KEGG and COG databases showed that the enrichment of biometabolic pathways, such as replication and repair and translation, were significantly higher in Tianhua mutton sheep than in Gansu alpine fine wool sheep (p < 0.05). In general, there were some similarities between Tianhua mutton sheep and Gansu alpine fine wool sheep in the rumen tissue morphology, rumen fermentation ability, and rumen flora structure. However, Tianhua mutton sheep had a better performance in the rumen acetic acid content, rumen papillae height, and beneficial bacteria content. These differences may be one of the reasons why Tianhua mutton sheep are more suitable for growing in alpine pastoral areas than Gansu alpine fine wool sheep.