IntroductionMicrobial additives can improve silage quality in lowland areas. However, Saccharomyces cerevisiae and Lactic Acid Bacteriacan efficacy on whole-plant maize silage under Tibet’s hypoxic and cold environment, have not been explored.MethodsIn this experiment, whole corn plants cultivated in Dazi District, Lhasa City, Xizang (Tibet) Autonomous Region, were selected as silage raw materials. The treatment group was added 0.5 kg of microbial additives per ton of silage. The addition levels for both Saccharomyces cerevisiae and Lactic Acid Bacteria were ≥ 1 × 107 CFU·g-1 FM). The quality of silage and its in vitro fermentation characteristics were determined on 0, 30 and 60 days of fermentation, respectively. Subsequently, dairy cows were fed with silage after 60 days of fermentation to evaluate milk production and milk quality.ResultsThe results indicated that the lactic acid content in the treatment group was increased significantly on 30 and 60 days of fermentation (p < 0.05). In addition to Simpson’s index, alpha diversity was significantly affected by the fermentation day × treatment interaction (p < 0.05). At 60 days of fermentation, the abundance of Firmicutes phylum in the treatment group was significantly higher than that in the control group (p < 0.05). The abundance of genera such as Acetobacter and Latilactobacillus was significantly decreased (p < 0.05), while the abundance of the genus Weissella was significantly increased (p < 0.05). Dairy cows were fed 60-day maize silage, the milk protein content and total solid content in the treatment group were significantly higher than that in the control group (p < 0.05). The levels of dry matter degradation rate, ammonia nitrogen and total volatile fatty acids in the in vitro fermentation of maize silage in the treatment group on the 60th day of fermentation were significantly higher than that in the control group (p < 0.05).ConclusionIn Xizang (Lhasa, China), the addition of microbial additives has significantly improved the quality and nutritional value of whole corn silage plants and enhanced the milk quality of local dairy cows. This provides a theoretical basis for the application of microbial additives from the Qinghai-Tibet Plateau to agricultural crops.

This research aimed to explore the effect and mechanism of dietary methionine and lysine deficiency on autophagy of gastrointestinal tract and liver tissues. Thirty goats were divided into three groups: control (Con), methionine deficiency (MD), and lysine deficiency (LD) groups. The expression levels of autophagy marker proteins LC3 and p62 were analyzed by immunohistochemistry (n = 5), and mRNA expression levels of autophagy-related genes ATF4, FOXO3, Beclin-1, Atg13 and eIF2α were analyzed through qPCR. No significant differences were found for LC3, but optical density for p62 of jejunal mucosa in LD was significantly higher (P < 0.01) than Con and MD. The mRNA expression level of rumen epithelial ATF4 in LD was significantly higher compared to control and MD, but FOXO3 in LD was significantly higher than control (P < 0.01). In the jejunal mucosa, LD had the highest ATF4 mRNA expression level, while Beclin-1 mRNA expression level was lowest (P < 0.01) compared to control. Metabolomics of jejunal mucosa showed that sorbitol and N-acetylglucosamine in MD and DL-Homocystine and eight other metabolites in LD were significantly increased compared to control. Overall, the degradation process of autophagy was blocked in the jejunum when the diet was lacking of lysine in jejunum, and ATF4 was upregulated to maintain the metabolic balance of amino acids in rumen, jejunum and ileum. However, dietary MD primarily affected metabolic pathways rather than autophagy.

The experiment aimed to investigate the effects of replacing soybean meal with extruded soybean and cottonseed meal in the diet on the nutrient apparent digestibility, milk quality, serum biochemical indices, rumen fermentation parameters, and rumen microbiota of lactating Sanhe cattle. Twenty-four healthy, high-yielding lactating Sanhe cattle with the same parity and similar calving dates were randomly divided into two groups, with 12 replicates per group and one cow per replicate. The control group was fed a basal diet, while the experimental group, the diet was formulated under the condition of equal nitrogen content, with expanded soybeans and cottonseed meal replacing the soybean meal in the concentrate. The pre-test period was seven days, and the formal test period was 45 days. The results showed that compared with the control group, the experimental group had extremely decreased dry matter intake and feed-to-milk ratio (P<0.01), and significantly increased lactose percentage (P<0.05). The apparent digestibility of crude protein was significantly increased in the experimental group (P<0.05), while the apparent digestibility of acid detergent fiber was significantly decreased (P<0.05). Serum concentrations of total protein and glucose were significantly increased in the experimental group (P<0.05), non-esterified fatty acid content was significantly decreased (P<0.05), and blood ammonia content was extremely decreased (P<0.01). In the rumen, the concentrations of valeric acid, propionic acid, and total volatile fatty acids were extremely increased in the experimental group (P<0.01), the concentrations of butyric acid and ammonia nitrogen were significantly increased (P<0.05), and the microbial protein content was significantly decreased (P<0.05). At the phylum level, the relative abundances of Actinobacteria, Chloroflexi, and Acidobacteria in the rumen of the experimental group were extremely increased (P<0.01), while the relative abundances of Firmicutes and Spirochaetes were significantly decreased (P<0.05). At the genus level, the relative abundance of Prevotella_7 of the experimental group was extremely increased (P<0.01), while the relative abundances of Rikenellaceae_RC9_gut_group was significantly decreased (P<0.05). The study shows that replacing soybean meal with extruded soybean and cottonseed meal in the diet not only improved feed utilization efficiency, feed-to-milk ratio, serum biochemical indices, and milk quality of Sanhe cattle, but also target-regulated specific rumen bacterial genera and improved rumen fermentation patterns, indicating high application value and development potential in the breeding of lactating Sanhe cattle.

The gut-liver nexus is a critical regulator of metabolic homeostasis, and its disruption drives the progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Among gut microbes, Akkermansia muciniphila has emerged as a key modulator of host-microbiome interactions at the intestinal barrier. Here, we synthesize current mechanistic and clinical evidence linking A. muciniphila to the regulation of the gut-liver nexus. We highlight how defined microbial effectors, including both the outer membrane protein Amuc_1100 and extracellular vesicles, orchestrate a multidimensional defense encompassing epithelial integrity, hepatic lipid metabolism, and immune responses. While preclinical studies provide strong mechanistic support, emerging clinical trials indicate that therapeutic responses are context dependent and influenced by baseline microbiome composition. We discuss current challenges in translating A. muciniphila into clinical interventions and outline strategies for next-generation microbiome therapeutics, including postbiotic and precision approaches. This framework provides a strategic blueprint for leveraging A. muciniphila as a cornerstone of next-generation hepatology, transforming this functional microbe into a definitive therapeutic pillar across the MASLD-to-carcinoma spectrum.

IntroductionIn areas affected by heavy metal contamination, the potential transfer of these metals from feed into animal products during digestion is a major concern.MethodsTwenty-four Xiangdong black male goats were equally assigned to three experimental groups (8 goats per group) using a completely randomized design for 60 days. The experimental groups were formulated by incorporating Paddy A, B, and C (containing low [LHM], medium [MHM], and high [HHM] levels of heavy metals, respectively) at 33% of the total diet.ResultsThe results revealed a nonsignificant decrease (p > 0.05) in the digestibility and absorption of Mn, Ca, Fe, Zn and Cr through the gastrointestinal tract, whereas the absorption of Cd and Pb significantly increased (p < 0.05), and that of Ni decreased in the HHM and MHH groups compared with those in the control group. The contents of heavy metals and essential metals in different tissues changed according to the type and function of the organ, and the contents of heavy metals in various tissues (spleen, lung, liver, kidney, rumen, ileum, cecum, colon, rectum, fat, muscles and hair) remained within internationally recognized safety limits for human consumption, as established by Codex and/or the European Commission Regulation. Moreover, meat quality and carcass characteristics were not affected (p > 0.05) by increasing heavy metal contents in the diets of goats.ConclusionThis study demonstrates that, under the current experimental conditions, incorporating paddy cultivated in soils contaminated with heavy metals into Xiangdong black male goat diets for short periods (60 days), without adverse effects on productive performance or health status, and the resulting animal products remained safe for human consumption. However, long-term studies involving different animal species under diverse climatic conditions are required to validate these findings before considering any practical application in livestock production systems.

An inadequate amino acid (AA) supply in animals under protein-restricted conditions can slow skeletal muscle growth. Protein translation can be activated by short-term leucine (Leu) stimulation; however, whether muscle mass increases under long-term Leu supplementation and how the gut and muscle respond to Leu supplementation are largely unknown. In this study, we investigated if muscle mass increases with long-term Leu supplementation under protein-restricted conditions. We identified changes in the link between the gut and muscles under different amino acid supply conditions, using goats as the study object. A total of 27 Xiangdong black male goats with average initial body weight (BW) of 10.88 ± 1.22 kg were randomly divided into three dietary treatments: a normal protein diet (NP, 14.24% crude protein [CP]); a low protein diet (LP, 8.27% CP with supplemental 1.66% rumen-protected lysine [RPLys] and 0.09% rumen-protected methionine [RPMet]); and LP diet with rumen-protected Leu (RPLeu) (LP + RPLeu, 8.75% CP with supplemental 1.66% RPLys, 0.09% RPMet and 1.46% RPLeu). The animal trial lasted for 110 d, consisting of 20 d of adaptation and a 90 d of experimental period. The results showed that long-term protein restriction increased gut tryptophan hydroxylase 1 (TPH1) activity (P < 0.001), tryptophan (Trp) catabolism (P < 0.001), and 5-Hydroxytryptamine (5-HT) synthesis (P < 0.001), which all subsequently reduced goat appetite. Long-term Leu supplementation inhibited 5-HT synthesis (P < 0.001), decreased Trp catabolism in the gut, and increased appetite in goats. Long-term protein restriction enhanced jejunal and ileal branched-chain amino acid transferase (BCAT) (P < 0.001) and branched-chain α-Keto acid dehydrogenase (BCKD) (P = 0.048) activities, which increased branched-chain amino acid (BCAA) catabolism. Immunofluorescence results showed that protein restriction decreased the intestinal mucosal expression of solute carrier family 1 member 5 (SLC1A5) (P = 0.032) and solute carrier family 7 member 5 (SLC7A5) (P < 0.001), reduced BCAA transport from the mucosa to the blood, lowered BCAA levels in the blood (P < 0.001). Western blot results showed that protein restriction inhibited mammalian target of rapamycin (mTOR) pathway activation in goat muscles. Leu supplementation increased BCAA translocation from the intestine to the blood and promoted activation of the muscle mTOR pathway and protein synthesis. In conclusion, our results suggest that Leu supplementation in low-protein diets improves appetite and alleviates the inhibition of muscle protein synthesis in goats.

This study aimed to investigate the effects of ginger straw as a replacement of peanut straw on the growth, meat quality, rumen fermentation, and immunity of goats. In this study, 40 Huanghuai male goats, weighing 30 ± 0.5 kg at six months of age, were selected and randomly divided into four treatments: ginger straw 0% (G0), 5% (G5), 10% (G10) and 20% (G20) replacing peanut straw, with 10 goats in each treatment. Goat dry matter intake (DMI) improved as the proportion of peanut straws replaced with ginger straws increased (linear, P < 0.001, quadratic, P < 0.001). The highest average daily gain (ADG) and the lowest feed-to-gain ratio (F/G) were observed in G5 goats (P < 0.001). The digestibilities of neutral detergent fibre (NDF, P = 0.031) and acid detergent fibre (ADF, P = 0.014) were higher in the G5 group than in G10 and G20. With increasing ginger straw replacement, the plasma interleukin-10 (IL-10) levels increased (linear, P = 0.035, quadratic, P = 0.041). The microbial protein (MCP) increased as the proportion of ginger straw increased (linear, P = 0.034, quadratic, P = 0.041). The butyrate was increased (linear, P = 0.028, quadratic, P = 0.035) at all levels of ginger straw inclusion into the diet. A linear (P < 0.001) increase in the height of the jejunal mucosal villi was observed as the proportion of ginger straw in the diet increased. The tight junction protein 1 (TJP1) and claudin-1 mRNA expression in the jejunal mucosa were significantly higher in groups G5, G10, and G20 than in the G0 group (P < 0.001). In general, substituting peanut straw with ginger straw in goat diets promoted rumen fermentation and produced more volatile fatty acids and microbial proteins to meet the needs of goats for improved growth performance. Substituting ginger straw for peanut straw improved immunity and the intestinal barrier in goats and did not adversely affect meat quality. Replacing peanut straw with 5% ginger straw in the goat diet resulted in higher NDF digestibility and growth performance. Therefore, the replacement of peanut straw with 5% ginger straw in goat diets is recommended.

Successfully navigating the periparturient period poses significant challenges for dairy cows in plateau environment. Brassica rapa L., a common crop in plateau regions, is rich in bioactive compounds and provides multiple benefits, including protection against altitude sickness, antioxidant effects, and immune regulation. This study investigated the effects of Brassica rapa L. supplementation on lactation performance, serum oxidative stress, and ruminal microbiotametabolite interactions in periparturient dairy cows living at high altitudes. Thirty Holstein cows, all in their first pregnancy with similar milk yields, diet, and body weights, were randomly assigned to three groups: a Control (Con) group following NRC standards feeding, a Brassica rapa L. group (Bra) supplemented with 20 g / per cow / day of Bra, and an N-Carbamylglutamate (NCG) group received 20 g / per cow / day of NCG. The trial lasted 45 days. Milk production was recorded monthly, and milk fat and protein contents were determined from pooled samples collected during the final month. In addition, ruminal fluid and blood were collected on the first day after the experiment to analyse oxidative stress indicators, ruminal microbiota, and secondary metabolites. Brassica rapa L. significantly increased milk yield (March) and milk protein content, while both Bra and NCG groups showed elevated serum glutathione peroxidase and reduced malondialdehyde levels, indicating enhanced antioxidant capacity. 16S rRNA sequencing revealed that Bra supplementation enriched cellulose-degrading bacteria such as Fibrobacter, Treponema, and Prevotella, which were positively correlated with elevated levels of acetate, propionate, and butyrate in the rumen. Using LC-MS/MS metabolomics, it was showed that Bra upregulated metabolites like dehydroepiandrosterone sulfate and raffinose, and enriched arginine biosynthesis while downregulating arachidonic acid metabolism. Supplementation with NCG increased the abundance of Lachnospiraceae (e.g., Anaerovibrio, Coprococcus, Moryella), elevated levels of butyrate, and enhanced TCA cycle activity. Correlation analyses confirmed strong links between altered microbiota, metabolites, and host performance. These findings demonstrate that Brassica rapa L. and NCG can alleviate oxidative stress, enhance milk production, and improve energy and nitrogen metabolism in periparturient cows through targeted modulation of ruminal microbial and metabolic networks, offering potential for improving dairy cow resilience in plateau environments.

Utilizing straw feed is an effective strategy to optimize straw resource utilization by incorporating microbial degradation agents to expedite lignocellulose breakdown and enhance feed efficiency. Lignocellulose-degrading species and microbial communities are present in various Earth ecosystems, including the rumen of ruminants, insect digestive tracts, forest soil, and microbial populations in papermaking processes. The rumen of ruminants harbors a diverse range of microbial species, making it a promising source of lignocellulose-degrading microorganisms. Exploring alternative systems like insect intestines and forest soil is essential for future research. Current studies primarily rely on traditional microbial isolation techniques to identify lignocellulose-degrading strains, underscoring the necessity to transition to utilizing microbial culturomics and genome-editing technologies for discovering and manipulating cellulose-degrading microbes. This review provides an overview of lignocellulose-degrading microbial communities from diverse environments, encompassing bacterial and fungal populations. It also delves into the use of metagenomic, metatranscriptomic, and metaproteomic approaches to pinpoint highly efficient cellulase genes, along with the application of genome-editing tools for engineering lignocellulose-degrading microorganisms. The primary objective of this review is to offer insights for further exploration of potential lignocellulose-degrading microbial resources and high-performance cellulase genes to enhance roughage utilization in ruminant rumen ecosystems.

Previous studies have discussed the association between serum metabolism and lactation performance among Sanhe and Holstein cows of different parities and found that the metabolic profiles of these two breeds vary differently with parity. Since the rumen is the central organ for nutrient absorption and production transformation in dairy cows, it remains unknown whether the differences observed under the same dietary conditions are related to the structure of the rumen microbiome. This study measured the apparent digestibility and rumen fermentation parameters of Sanhe cows (S1/S2/S3/S4) and Holstein cows (H1/H2/H3/H4) across four parities and generated a comprehensive rumen microbiome dataset using high-throughput sequencing technology. Significant differences in dry matter digestibility (p = 0.001) and ammonia nitrogen (p = 0.024) were observed among the S groups, with higher trends of various VFA contents in S1 (0.05 < p < 0.1). The H group showed significant differences in crude protein digestibility (p = 0.001), higher isovaleric acid content in H1 (p = 0.002), and the lowest acetate to propionate ratio (p = 0.002) in H3. Metagenomic sequencing results indicated consistency between rumen microbiome patterns and metabolic changes, with S1 distinctly different from S2/S3/S4, and H1 and H2 different from H3 and H4. The species composition of the rumen microbiome was similar between Sanhe and Holstein cows, but differences in abundance were noted. Rhizophagus , Neocallimastix, and Piromyces were more abundant in S1, H1, and H2, and pathways such as autophagy-animal, plant-pathogen interaction, and endocytosis were significantly enriched in these parities. Multiparous Sanhe cows had higher abundances of ATP-binding cassette transporters pathways. Additionally, CAZymes such as GH84 and GH37 were significantly associated with differential physiological indicators and milk traits. In conclusion, this study reveals the complex relationship between rumen microbiota and metabolic characteristics in Sanhe and Holstein cows of different parities, indicating that changes in the structure of the rumen microbiome may be key factors affecting lactation performance and metabolic differences in dairy cows.

The maturation of the gastrointestinal tract and its interconnected microbial consortia in various ruminant species is essential for their survival and productivity, as this symbiotic group plays a key role in metabolizing phyto-derived feeds into bioavailable nutrients. The rumen mucosa serves as a crucial conduit for complex host-microbiota interplay, while scarce knowledge is available regarding their co-oscillation patterns from birth to puberty. Here, we characterized th overall interaction of five age groups, from 1-day-old to 90-day-old goats. The findings indicated that the composition of the mucosa-attached microbiota underwent significant changes, with Mannheimia, Porphyromonas and Streptococcus taking the lead as the dominant genera at day 1, Akkermansia muciniphila and Lactobacillus amylovorus dominated at day 10, and a mature microbiota characterized by Succiniclasticum ruminis, Ruminococcus albus, Succinivibrio dextrinosolvens, and Fibrobacter succinogenes until day 90. Additionally, the rumen mucosa underwent a three-phase temporal shift during early life, from digestive system to immune development, and finally to nutrient metabolism. Furthermore, the integration of mucosal microbiome and host gene expression profiles uncovered a phase-specific interaction between the microbial community and host epithelium, with the early phase emphasizing digestive and immune development and the later phase focusing on enhanced nutrient metabolism. Collectively, microbiome-host co-oscillation in the rumen mucosa shaped the ruminal ecosystem during early life.

As an important feed source for ruminants, alfalfa’s rational and efficient utilization is of great significance for the production and economic benefits of pastures. This study focuses on Sanhe dairy cows and includes a control group (CON group, alfalfa in the diet is hay) and an experimental group (AS group, alfalfa silage partially replaces alfalfa hay of equal dry weight). The feeding experiment lasted for 60 days. The results revealed that, compared with the CON group, the AS group exhibited increased milk yield, milk protein, and milk fat. There were no significant differences in apparent digestibility, serum biochemical indicators, and volatile fatty acid (VFA) levels between the two groups. However, the microbial composition of the rumen differed significantly between the two groups of cows based on β-diversity. On the genus level, compared with the CON group, the relative abundance of Erysipelatoclostridium, Pseudoflavonifractor, and Candidatus Saccharimonas in the AS group was significantly reduced. In summary, partially replacing alfalfa hay with alfalfa silage feed is beneficial for improving the production performance of cows and changing rumen microbial diversity. These findings provide a basis for the effective utilization of alfalfa.

Methane is considered as a potent greenhouse gas, emitted from ruminants through enteric fermentation. Several methane mitigation strategies have been proposed and reported, however, role of aromatic herbs and their bioactive components on reduction of methane is still unclear. Mint (Mentha canadensis L.), turmeric (Curcuma longa L.), eupatorium (Eupatorium fortunei Turcz.) and dandelion (Taraxacum officinale) were selected for two separate in vitro fermentation, at first as substrates and then additives with TMR (control) at the level of 1 % and 3 %, and assessed in terms of conventional nutrients, fermentation characteristics, metabolomics and microbial diversity. The experiment was conducted by a completely randomized block design, which included three runs with each treatment, whereas treatments are considered fixed effects and runs as a random effect. Turmeric contained more CP and less NDF, ADF showed higher IVDMD (g/kg), total VFA (mM) but produced less CH4 (ml/g) both as substrates or additives. Eupatorium produced more H2 (ml/g) and CH4 (ml/g), contained less propionate content (P < 0.05). Flavone, succinate, 2-hydroxycinnamic acid were the common metabolites present in all four herbs. Lachnospiraceae, Prevotellaceae, Succinivibrionaceae, Oscillospiraceae and Selenomonadaceae were most dominant families. Succinivibrionaceae in turmeric-treated rumen fluid, used H2 to produce propionate, thus, amount of H2 available for methanogenesis is decreased, capacitated this herb to reduce more methane than other herbs. Overall, 3 % inclusion of turmeric with TMR is best both in terms of dry matter degradation and methane mitigation potentiality.

The substances in ecosystems flow along the food chain. Therefore, we should establish a monitoring system for antibiotic resistance genes (ARGs) in fertilizer products as soon as possible to regulate the use of fertilizers. In this study, three groups of cattle manure organic fertilizers were set up according to the ratio of straw addition, namely CK: cattle manure: straw = 6:4; M1: cattle manure = 100%; M2: cattle manure: straw = 8:2. All groups were supplemented with microbial agents. Their effects on ARGs, class 1 integron integrase genes (intI1) and bacterial communities were investigated. At the end of composting, the relative abundance of sul1, sul2, tetG, and intI1 in M1 and M2 were significantly lower than that in the CK group, and most of the ARGs in each group were removed. The changes in the relative abundance of ARGs are related to changes in microbial community structure. The establishment of temperature conditions is a key factor affecting the structure of microbial communities. Bacillus may play an important role in controlling the relative abundance of ARGs. We found that the most suitable ratio of cattle manure to straw was 8:2 among the three groups, which not only ensured the balanced nutritional composition of organic fertilizers, but also effectively reduced the abundance of ARGs.

This experiment aimed to investigate the effects of dietary supplemented with rosemary extract on the lactation performance, serum biochemical indexes, rumen fermentation parameters, and microbial community in dairy cows. A total of 30 healthy, freshly calved Holstein cows with good physical condition, the same parity, and in the lactation period were selected and randomly divided into two groups, with 15 replicates per group and one cow per replicate. The control group was fed a basal diet, while the experimental group received the basal diet supplemented with 20 g/(head·d) of rosemary extract. The pre-trial period was 18 days, and the formal trial period was 30 days. The results showed that compared with the control group, there were no significant differences in milk yield, milk fat percentage, milk protein percentage, lactose percentage, and somatic cell count in the experimental group (P>0.05). The levels of urea nitrogen (BUN), glucose (GLU), and blood ammonia (BA) were significantly reduced (P<0.05), and triglyceride (TG) was extremely reduced (P<0.01), and the non-esterified fatty acid (NEFA) content in the serum of the experimental group was extremely increased (P<0.01). The propionic acid content in the rumen fluid of the experimental group was significantly increased (P<0.05), while the acetic acid content and acetic acid to propionic acid ratio were significantly decreased (P<0.05). There was no significant difference in alpha diversity between the two groups (P>0.05). At the genus level, the relative abundance of Rikenella in the experimental group was significantly increased (P<0.05), while the relative abundances of Lentimicrobium and Eisenbergiella were significantly decreased (P<0.05). The study shows that dietary supplementation with rosemary extract can improve rumen fermentation function and lipid metabolism of dairy cow by modulating the rumen microbial structure.

In recent years, the rapid development of the ruminant feeding industry and the limited availability and rising prices of traditional protein feed ingredients have renewed the focus on protein feeds in ruminant diets. Plant protein feeds are a core component of protein feeds for ruminants; however, the utilisation of both conventional and non-conventional plant protein feeds is limited by the presence of anti-nutritional factors (ANFs). In order to maximise the use of plant protein feeds and to promote their application in ruminant production, it is important to have a comprehensive understanding of the types and nature of their ANFs, their anti-nutritional mechanisms, and current effective methods of eliminating ANFs. Therefore, the types, anti-nutritional mechanisms, and elimination methods of ANFs in major plant protein feeds for ruminants are initially summarised in this review, which provides a reference for anti-nutritional factor elimination and the production of full-price compound feeds for ruminants.

Rosemary (Rosmarinus officinalis L.) is renowned for its wide array of bioactive compounds, such as phenolic acids, terpenoids, and flavonoids. Alongside its role as a natural antioxidant, rosemary extract demonstrates anti-inflammatory, antimicrobial, and growth-promoting effects, making it a promising feed supplement for sustainable animal production. Recent research has highlighted its potential to enhance rumen fermentation, improve meat quality, and bolster immune responses in various livestock and poultry species. In dairy cattle, supplementation with rosemary extract elevates milk nutritional quality and antioxidant levels while decreasing methane emissions during rumen fermentation. However, much of the current literature focuses on mixed extracts or in vitro models, with limited exploration of its specific in vivo mechanisms of action. This review systematically outlines recent advances in rosemary extract research, emphasizing its biological functions and practical applications in livestock and poultry production. Challenges related to standardizing its chemical composition and characterizing its functionality are discussed, along with suggestions for future studies utilizing omics technologies to elucidate its mechanisms and optimize its utility as a plant-derived feed additive.

As a low-cost, high-fibre biomass resource, Phragmites australis (reed) has significant potential for feed applications, particularly as a partial replacement for conventional roughage in ruminant diets. This study investigated the effects of integrating Bacillus subtilis (B. subtilis BNCC109047) with homofermentative/ heterofermentative lactic acid bacteria (LAB) consortia on the fermentation and nutritional quality of Phragmites australis (reed) silage. Five treatments were evaluated: a Control (CK, without inoculum) and four inoculants-LAB (1.5 × 108 CFU/kg LAB, 1:4 homofermentative (Lentilactobacillus plantarum BNCC 336421 and Pediococcus pentosaceus BNCC 135034 in a ratio of 1:1): heterofermentative (L. buchneri BNCC 187961) ratio), LAB-BS2.5 (LAB plus 2.5 × 107 CFU/kg B. subtilis), LAB-BS5.0 (LAB plus 5.0 × 107 CFU/kg B. subtilis), and LAB-BS10.0 (LAB plus 1.0 × 108 CFU/kg B. subtilis)-with triplicate samples per group. Silage fermentation was conducted for 90 days. LAB-BS10.0 demonstrated superior fermentation outcomes, achieving the highest lactic acid-to-total acid ratio (62.3%, p < 0.05) and the lowest ammonia nitrogen (NH3-N) content (0.60 ± 0.09 g/kg, p < 0.05). Acetic and butyric acid concentrations were significantly reduced (p < 0.05), while neutral detergent fiber (NDF) decreased by 5.9% compared to the Control. Ether extract (EE) increased to 4.76% (p < 0.01), highlighting enhanced lipid preservation. These results emphasize the synergistic potential of B. subtilis and LAB to optimize P. australis silage, providing a sustainable strategy to enhance forage quality and tackle global feed shortages.

Rosemary extract (RE) has shown potential as a plant-derived feed additive, but its effects on Sanhe dairy cows are still unknown. In this study, 30 multiparous Sanhe dairy cows (days in milk 171 ± 17 days) with similar body condition were randomly divided into two groups: the RE group (n = 15) was fed the basal diet plus 20 g RE/d, and the CON group (n = 15) was fed only the basal diet. The experiment lasted for 57 days, including a one-week adaptation period. Compared with the CON group, milk yield (P = 0.022) increased significantly with RE supplementation, while milk fat (P = 0.071) also tended to increase. Milk urea nitrogen (P = 0.003) and serum urea nitrogen (P = 0.013) contents were significantly reduced in the RE group compared with the CON group. In rumen fermentation, the content of butyric acid (P = 0.035) in RE group was significantly increased, while valeric acid (P = 0.080) content had an increasing trend. In addition, RE supplementation improved the antioxidant capacity of Sanhe dairy cows by significantly increasing the serum total antioxidant capacity (P < 0.001), superoxide dismutase activity (P = 0.001), immunoglobulin A content (P < 0.001), and immunoglobulin G content (P = 0.005), while decreasing serum malondialdehyde content (P < 0.001), to improve immunity and also affect the composition of serum free amino acids. Metabolomic results showed that a total of 13 co-differential metabolites were identified in rumen and serum, including ursolic acid, a major component of RE, which was higher in both rumen and serum. The milk metabolome analysis identified glycerides, glycerophospholipids, and sphingolipids as the three lipid types that exhibited higher identification intensity in RE. Rumen metagenomic results showed that RE supplementation affected the composition of rumen microorganisms, and differential microbial Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses revealed that the RE group was significantly enriched in the fatty acid biosynthesis pathway and the glycerophospholipid metabolism pathway; two pathways related to lipid synthesis. By associating the genus-level differential microorganisms in the rumen with the “rumen-serum-milk” metabolome and mapping the correlation network, it was found that g_Sharpea, g_Tistlia, and g_Acetobacter, which were more abundant in RE, correlated with more differential metabolites and clustered in the same module. Among the 10 microbial biomarkers screened in the rumen, g_Acetobacter and g_Prevotella were more abundant in the RE, and Mantel's analysis showed that they correlated with rumen fermentation parameters and oxidative and immunological indicators in serum. These results reveal the regulatory mechanism of RE supplementation feeding to enhance milk production and improve milk quality by improving oxidative stress capacity and immunity and reducing nitrogen loss in Sanhe dairy cows, suggesting that RE has the potential as a feed additive for dairy cows.