Salt and heat stresses often occur simultaneously in arid regions, restricting the distribution and productivity of alfalfa (Medicago sativa L.). However, the mechanisms underlying alfalfa responses to combined salt and heat stress remain unclear. Here, we integrated phenotypic, physiological, transcriptomic, and metabolomic analyses to investigate the regulatory mechanisms involved in combined stress responses. Combined stress more strongly inhibited plant height, stem diameter, fresh weight, net photosynthetic rate, and transpiration rate than single stresses. Salt stress had a predominant effect on several agronomic and physiological traits, whereas heat stress mainly affected chloroplast ultrastructure. Multiomics analysis identified flavonoid metabolism, linoleic acid metabolism, and amino acid biosynthesis as key pathways associated with combined stress responses. Moreover, CHS, CHR, P5CS, and LOX genes expression was closely correlated with metabolites such as naringenin, naringenin chalcone, and proline. These findings provide insights into alfalfa adaptation to multiple abiotic stresses.

Paper mulberry (Broussonetia papyrifera) is a high-protein forage, but its high buffering capacity and low water-soluble carbohydrate (WSC) content hinder silage fermentation. This study evaluated the effect of tea tree (Melaleuca alternifolia) essential oil (TTO) as a natural additive for paper mulberry silage. TTO was added at 0 (CK), 500 (CSD), and 1000 mg/kg (CSG) fresh weight, with samples collected on days 7, 15, 30, and 90. After 90 days, CSD had the lowest pH and the highest lactic acid content. NH3-N/TN was significantly lower than in CK (p < 0.05), and the retention of dry matter, crude protein and water-soluble carbohydrate was improved (p < 0.05). Compared with CK, CSD exhibited the highest lactic acid bacteria (LAB) counts, along with the lowest mold and aerobic bacterial counts (p < 0.05). However, CSG did not further improve fermentation quality, and most of the indicators were not significantly different from CSD (p > 0.05). The in vitro gas production test showed that CSD significantly increased the theoretical maximum gas production and the maximum gas production rate (p < 0.05). Additionally, 16S rRNA sequencing revealed a distinct bacterial succession in CSD, which enriched beneficial lactic acid bacteria (LAB) such as Pediococcus while outcompeting less competitive taxa. This microbial reshaping redirected the community toward acidification and nutrient retention. Collectively, these results demonstrate that TTO at 500 mg/kg is a promising natural additive for improving paper mulberry silage quality through selective reshaping of the bacterial community.

IntroductionSaline-alkali soil significantly inhibits the growth and development of Leymus chinensis, and root exudates are vital components in plant responses to abiotic stress. At present, whether L. chinensis accumulates specific root exudates to adapt to saline-alkali environments remains poorly understood.MethodsTherefore, in this study, the relatively saline-alkali-tolerant L. chinensis cultivar 'Huise' (HS) and the relatively saline-alkali-sensitive cultivar 'Dongbei' (DB) were selected as experimental materials. Three saline-alkali stress treatments were established: non-saline-alkali soil (Control, CK), moderate saline-alkali soil (MS), and severe saline-alkali soil (ES), to explore cultivar differences in physiological characteristics and root exudate metabolism under saline-alkali stress.ResultsThe results showed that cultivar differences in aboveground biomass were observed between HS and DB L. chinensis under saline-alkali stress. Intracellular Na+ accumulation and K+ decline occurred, which aggravated membrane lipid peroxidation and a 31-38% decrease in root vitality. Compared with HS, DB suffered more severe membrane lipid damage and a larger decline in root vitality. The two cultivars alleviated saline-alkali stress by simultaneously increasing the activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) and accumulating proline (Pro), soluble sugars (SS), and soluble protein (SP). In total, 5014 metabolites were identified using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Thirteen differentially accumulated metabolite (DAM) markers (including [8]-Shogaol, Pikuroside, L-dihydroanticapsin) were screened. Distinct cultivar differences were also observed in the number of differential root exudate metabolites under saline-alkali stress. KEGG pathway enrichment analysis revealed that the pentose phosphate pathway (PPP) and the tricarboxylic acid cycle (TCA) were significantly enriched in L. chinensis under saline-alkali stress. Compared with the DB cultivar, relevant biosynthetic pathways for leucine and glycine were additionally enriched in the HS cultivar.DiscussionThis study identifies inter-cultivar differences in the content, composition and enriched metabolic pathways of root exudates in L. chinensis. These findings offer fundamental references for further exploring how saline-alkali stress correlates with physiological traits, growth performance and root exudate profiles of regreening stage L. chinensis.

Sediment microbial communities in arid inland rivers are important for biogeochemical cycling, but the assembly mechanisms and network responses across the transition from irrigated oases to desert margins remain unclear. We investigated bacterial and fungal communities in Yarkand River sediments along salinity and nutrient gradients using 16S rRNA and ITS sequencing, sediment chemistry, iCAMP null-model analysis, and co-occurrence networks. Downstream increases in electrical conductivity, total nitrogen, and pH were associated with reduced bacterial α-diversity and turnover from nutrient-responsive Pseudomonadota in the oasis midstream to stress-tolerant Chloroflexota and Actinomycetota in the desert downstream. Fungal diversity showed high inter-site variability without a linear decline. Despite strong physicochemical gradients, ecological drift dominated assembly in both kingdoms, while desert networks showed higher connectivity. These findings support a hierarchical assembly model in which salinity filters community composition, but stochastic processes and network densification shape benthic microbiota in arid river sediments.

Lactic acid bacteria (LAB) and cellulase have been used as additives to improve the fermentation quality of mulberry silage. This study investigated the dynamics of fermentation characteristics and bacterial communities during 60-day ensiling through three established treatment groups: Control (no inoculation), Lactiplantibacillus plantarum (LP) inoculation as well as combination of L. plantarum and cellulase inoculation group (LPC). The results showed that compared with the Control group, the LP and LPC treatments significantly reduced the loss of dry matter, soluble carbohydrates, and crude protein (p < 0.05), effectively promoted the accumulation of lactic acid and acetic acid (p < 0.05), but significantly elevated ammonia nitrogen (NH3-N) production. Inoculation was beneficial to the stability of the bacterial community in mulberry branch and leaf silage because it can maintain a high level of beneficial bacteria (Lactiplantibacillus) and inhibit the growth of harmful bacteria (Escherichia-Shigella). The combination of the inoculation of L. plantarum and cellulase may improve the quality of mulberry branch silage.

ABSTRACT Nettle showed several benefits for animals as an unconventional feed source, but it is difficult to ensile in order to be better utilized. Recently, nettle has been utilized to alternate alfalfa as ruminant feed, but it is usually poor in ensiling quality. To determine the endogenous component influencing ensiling, we investigated the effect of Pediococcus on the characteristics of nettle silage and the mechanism of action of these substances against Pediococcus. Inoculation with Pediococcus pentosaceus decreased the relative abundance of Clostridium sensu stricto 15 by 85.95% in the middle fermentation stage of nettle silage (30 d), with a 24.74% decrease in the ammonia content (P＜0.05). In the correlation analysis, 4-pentenoic acid showed an extremely significant negative correlation with Pediococcus spp. in nettle silage (P < 0.001). After 4-pentenoic acid treatment, the most downregulated proteins were involved in the ribosome pathway (30 differentially expressed proteins), and then in the glycolysis/gluconeogenesis, pyruvate metabolism, and fatty acid synthesis pathways (particularly for accA, accD, and fabG). The mechanism of action of 4-pentenoic acid against P. pentosaceus mainly involves inhibition of fatty acid synthesis and decreased the expression of acid tolerance proteins. The present study will give new insights into silage fermentation and provide new clues for better ensiling of nettle.IMPORTANCENettle has attracted the attention of scientists due to its several benefits for animals as non-conventional feed sources. However, as for challenge, nettle is difficult to ensile (poor quality), which is an obstacle for nettle use. In the present manuscript, we investigated the effect of Pediococcus on the characteristics of nettle silage and clarified the mechanisms of 4-pentenoic acid against Pediococcus. Our findings suggested that P. pentosaceus could improve nettle silage quality at a significant level through decreased production of ammonia (decline percentage was 21.41%–31.73%) during ensiling, while it could not well improve the quality of nettle silage due to the interference effect of 4-pentenoic acid as an antibacterial substance. The mechanism of 4-pentenoic acid against P. pentosaceus was mainly through inhibition of fatty acid synthesis (fabG) and expression of acid tolerance protein (accA), resulting in destruction of the cell wall in P. pentosaceus. Our finding could give a new clue for better use of nettle silage.

Numerous studies have demonstrated that Broussonetia papyrifera is an unconventional feed resource with significant developmental potential. This research aimed to explore the effects of Broussonetia papyrifera silage on the growth performance, blood parameters, immunity, antioxidation, cytokine levels, and rumen bacterial composition of Kazakh lamb. Forty healthy male Kazakh lambs, aged 5 months and weighing 30.12 ± 1.14 kg, were randomly divided into control and experimental groups, each consisting of four replicates (five lambs per replicate). The control group was fed a basal diet, while the experimental group received a diet supplemented with 20% Broussonetia papyrifera silage (dry matter basis). Following a 10-day pre-feeding period, a 60-day formal experiment was conducted. The results indicated no significant difference in growth performance between the experimental and control groups. However, compared to the control group, the use of Broussonetia papyrifera silage significantly reduced (p < 0.05) neutrophil, lymphocyte, and eosinophil counts, as well as creatinine levels in the blood. Furthermore, Broussonetia papyrifera silage (p < 0.01) enhanced total serum antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase, immunoglobulin A, immunoglobulin M, immunoglobulin G, interleukin-2, interleukin-6, and interleukin-8, and decreased malondialdehyde and interleukin-4 levels. Additionally, the use of Broussonetia papyrifera silage increased the diversity and richness of the rumen bacterial community, notably enhancing the relative abundance of Firmicutes such as Rikenellaceae_RC9_gut_group and Christensenellaceae_R-7_group. In conclusion, feeding Kazakh lamb with Broussonetia papyrifera silage (20% DM) did not adversely affect their growth performance but improved their immunity and antioxidant capacity and enhanced the relative abundance of beneficial bacteria in the rumen, thereby promoting animal health.

Hybrid Broussonetia papyrifera shows great promise for use in antibiotic-free feed, potentially contributing to the green and sustainable development of the animal husbandry industry. In this study, we investigated the impact of Broussonetia papyrifera silage on the intestinal health of Kazakh sheep. Forty healthy male Kazakh sheep, aged 5 months and weighing an average of 28.28 ± 1.14 kg, were randomly assigned to either a control or an experimental group, each comprising four replicates, with five sheep per replicate. The control group was fed a basal diet, while the experimental group received a diet supplemented with 20% Broussonetia papyrifera silage (dry matter basis). The 70-day experiment included a 10-day adaptation phase followed by a 60-day feeding trial. The results showed that there was no significant difference in growth performance or apparent nutrient digestibility between the experimental and control groups (p > 0.05). However, the experimental group exhibited significantly greater total antioxidant capacity, alongside higher contents of superoxide dismutase, catalase, glutathione peroxidase, immunoglobulins A, M, and G, and interleukins-2, −6, and −8 in the intestinal mucosa; in contrast, malondialdehyde and interleukin-4 contents were significantly reduced (p < 0.01). Furthermore, the dietary inclusion of Broussonetia papyrifera silage resulted in a reduction in the relative abundance of the bacterial genera Turicibacter and Romboutsia (p < 0.05). In conclusion, the feeding of Broussonetia papyrifera silage to Kazakh sheep significantly enhanced immune function, increased antioxidant capacity, and reduced the relative abundance of potentially pathogenic bacteria in the sheep without negatively impacting their growth or nutrient digestion, thus supporting the overall health of the animals.

Photosynthesis is essential for the accumulation of organic compounds in plant leaves. Study of photosynthesis in the leaves of Broussonetia papyrifera is crucial for enhancing its biomass production, growth, and development. Here, we cloned the SikPsaF gene associated with photosynthesis from Saussurea involucrata and constructed a vector that was introduced into B. papyrifera to generate a transgenic strain. We then assessed various photosynthesis-related parameters in the transgenic plants and examined the function of this gene and its expression patterns under cold stress. The results showed that SikPsaF was localized to chloroplasts. Its expression was induced by light, and its expression was higher in the leaves than in other tissues. Furthermore, SikPsaF expression increased significantly under cold stress. The biomass of transgenic lines was greater than that of wild-type plants. Overexpression of this gene led to increases in the chlorophyll content and photosynthetic indices, which mitigated cell membrane damage and reduced reactive oxygen species (ROS) accumulation. SikPsaF overexpression also helped maintain high antioxidant enzyme activity and a high content of osmoregulatory substances during stress; the increased enzyme activities were due to up-regulated gene expression. Overexpression of SikPsaF has a major effect on growth and development by enhancing photosynthetic efficiency, improving yield, conferring cold resistance, and reducing damage to the cell membrane and ROS accumulation at low temperatures. In summary, our findings indicate that these transgenic plants have enhanced photosynthetic efficiency and resilience against biotic stresses.

The utilization of nettle (Urtica cannabina) as feed is restricted by its material properties (antibacterial activity and high buffering capacity). This study hypothesized that the use of lactic acid bacteria (LAB) attached to nettles can improve these problems. Lactococcus garvieae (LG), Pediococcus pentosaceus (PP), and LG + PP (LP) isolated from nettles were inoculated into nettle silage to explore nutrient retention and the microbial community structure. The results showed that inoculation significantly delayed dry matter and crude protein loss, inhibited neutral detergent fiber and acid detergent fiber degradation, and reduced ammonia nitrogen (NH3-N) accumulation. There was a significant increase in Firmicutes abundance after inoculation, and the dominant genus, Aerococcus, was negatively correlated with NH3-N accumulation. In the later stages of the PP treatment, Atopistipes synergistically inhibited Clostridia with acetic acid. However, the high buffering capacity and antibacterial components of raw nettle led to increased pH values during the later fermentation stages, limiting sustained acid production by LAB. These results confirm that nettle-derived LAB can effectively improve the quality of silage by regulating the microbial community and the acidification process; however, they must be combined with pretreatment strategies or optimized composite microbial agents to overcome raw material limitations. This study provides a theoretical basis and technical support for the utilization of nettle as feed.

Background: Nettle is a potential non-conventional feed resource due to its high level of crude protein content, and ensiling is better for utilization in the animal industry. Previous integrated analysis (microbiome and metabolome) suggested that 4-pentenoic acid and malic acid in ensiled nettle may inhibit harmful microorganisms within the system. The present study investigated the effects of these two acids on nettle silage quality through the addition of 1% fresh weight of these acids, then analyzed the characteristics and bacterial communities during 60 days of nettle ensiling. Results: The addition of 4-pentenoic acid increased the content of crude protein (CP) and acetic acid (AA) compared with both control and malic acid-treated groups during 30 to 60 days of ensiling (p < 0.05). Lactic acid (LA) content was highest in the malic acid-treated group (4.21%, dry matter, DM based) compared to the control and 4-pentenoic acid-treated groups after 7 days of nettle ensiling (p < 0.05), but lower compared with the 4-pentenoic acid-treated group after 30 days of nettle ensiling (p < 0.05), and it was not detected in all groups after 60 days of silage. The contents of butyric acid (BA) and ammonia (AN) were the lowest (2.92–4.39% of DM and 9.94–24.28% of total nitrogen, respectively) in the 4-pentenoic-treated group compared with both control and malic acid-treated groups during 30 to 60 days of ensiling (p < 0.05). Both acids increased the relative abundance of Weissella after 30 days of nettle ensiling, with 4-pentenoic acid showing a higher inhibitory capacity. Both acids showed a trend to inhibit the relative abundance of Clostridium sensu stricto 15 after 30 days of nettle ensiling. Clostridium sensu stricto 15 showed significant positive correlation with BA and AN (p < 0.05). Conclusions: The results of the present study suggested that the addition of 4-pentenoic could improve the quality of silage by reducing levels of protein degradation, probably resulting from its inhibited activity against Clostridium spp. However, malic acid was less effective than 4-pentenoic acid in suppressing Clostridium spp. activity and the associated production of BA and AN, resulting in inferior preservation of CP.

Broussonetia papyrifera is an important source of unconventional feed. However, freezing injuries in winter are a considerable threat to the popularization and application of B. papyrifera. Notably, the use of anthocyanins is a promising approach for enhancing plant stress resistance. However, B. papyrifera contains low levels of anthocyanins, and the anthocyanin synthesis process in this plant remains unclear. In this study, the one-month-old cuttings of B. papyrifera were grown at low (4 °C) and average (25 °C) temperatures. After 3 weeks, petioles and veins from different growth environments were harvested for transcriptome and anthocyanin-targeted metabolome analyses. The targeted metabolome analysis revealed that following cold treatment, the levels of cyanidin-3-O-galactoside, cyanidin-3-O-rutinoside, cyanidin-3-O-(6-O-p-coumaroyl)-glucoside and cyanidin chloride increased by 756.22, 306.87, 222.28, and 776.67 times, respectively. Transcriptome analysis revealed 17 pivotal anthocyanin-related differentially expressing genes (DEGs), among which chalcone synthase 2 (BpCHS2) was significantly upregulated at low temperatures. The combined transcriptome and metabolome disclosed an apparent positive correlation between BpCHS2 and cyanidin derivatives (R2 ≥ 0.99). Transgenic experiments demonstrated that overexpression of BpCHS2 in tobacco markedly increased the expression of anthocyanin-related genes, promoted anthocyanin accumulation, and enhanced the activities of peroxidase, superoxide dismutase, and catalase. These results suggest that the expression of BpCHS2 is markedly increased in B. papyrifera under low-temperature stress, improving anthocyanin accumulation and cold tolerance.

Broussonetia papyrifera is an important native tree species in China, and CL is a cold-tolerant cultivar. Under cold stress, CL leaves and veins show distinct color changes, but the molecular mechanisms are unclear. This study investigates the regulatory pathways of anthocyanin accumulation in CL under cold stress. After 21 days of 4°C treatment, anthocyanins accumulated significantly in veins, while leaves remained green. Broad-spectrum targeted metabolomics identified the differential metabolites mainly as flavonoids and saccharides, which were enriched under cold stress. These compounds support plant survival and serve as precursors for anthocyanin synthesis. Anthocyanin targeted metabolomics revealed that most anthocyanin substances significantly accumulated in CL-V-DW, among which cyanidin-3-O-rutinoside was the main chromogenic metabolite in CL-V-DW. Transcriptome analysis indicated that differentially expressed genes were enriched in saccharides metabolism, anthocyanin synthesis, and photosynthesis. Through correlation analysis and WGCNA, the associations between key genes and anthocyanin and saccharides metabolism were further revealed. The study found that in a cold stress, BpETR2 could promote saccharides synthesis, providing carbon source support for anthocyanin production; BpC4H, BpbHLH, BpADH1 and BpGPATCH11 could promote anthocyanin accumulation; meanwhile, the activation of BpGST might enhance the transport efficiency of anthocyanins. In contrast, BpSnRK and BpMYBS3 inhibited sucrose accumulation, and BpMYBS3 also negatively regulated the synthesis of cyanidin-3-O-rutinoside. In summary, this study systematically clarified the molecular basis of the color difference between the veins and leaves of CL under cold stress and provided strong evidence for the supporting role of saccharides in anthocyanin synthesis.

The antibacterial mechanism of condensed tannins (CTs) obtained from tea has been elucidated, but the mechanism of legume-derived CTs remains unclear. The mechanisms of legume- and tea-derived CTs probably differ due to the diverse compositions of CTs. Previous research found that sainfoin CTs directly inhibited the growth of Pediococcus. The present study investigated the inhibition mechanism of CTs against Pediococcus pentosaceus SF11 (SF11) through proteomic analysis. The results showed that the minimum inhibitory concentration (MIC) of CTs against SF11 was 1500 mg/L and that CTs increased cell membrane permeability in a dose-dependent manner. In total, 418 differentially expressed proteins (DEPs) were identified between the CT treatment and the control, among which 341 were down-regulated and 77 were up-regulated in the CT treatment. The protein interaction network showed that the expression of only two DEPs was highly different between CT treated and control (|log2FC|> 2); the atpD protein was up-regulated in the CT-treated group, which was involved in ATP synthesis; down-regulated DEPs were most involved in lipoteichoic acid synthesis, peptidoglycan synthesis, and glycine metabolism. Twenty-seven proteins were not detected after CT treatment, which were involved in functions including fatty acid synthesis, RNA synthesis and translation, drug resistance, and cell membrane permeability in SF11. Therefore, the findings suggest that the inhibition mechanism of CTs may be related to cell membrane damage and inhibition of cell reproduction.

Background The antibacterial mechanisms of action of condensed tannins (CTs) obtained from tea are well known. However, the antibacterial mechanism of CTs from legumes, such as sainfoin, against to Pediococcus pentosaceus was still unclear. Using Pediococcus pentosaceus SF11 as a model organism, this study investigated the antibacterial mechanism of CTs (extract from sainfoin by 70% acetone aqueous solution). Methods The mechanism of CTs against Pediococcus pentosaceus was investigated though determined the minimal inhibitory concentration (MIC) of CTs, effects of CTs on cell membrane, scanning and transmission electron microscopy analysis and global transcriptome analysis, et al. Results The results showed that CTs decreased the activities of enzymes such as lactic dehydrogenase, and inhibited the pentose phosphate (PP)/glycolytic pathway. The content of hydrogen peroxide produced by CTs was increased in P. pentosaceus SF11, and antibacterial activity partly occurred due to this hydrogen peroxide. The global transcriptome analysis showed that CTs upregulated the expression of 187 genes, most of which were involved in hypothetical protein, followed by the PTS (phosphotransferase system) system, while three genes were involved in oxidative stress. The expression of 161 genes was downregulated, most of which were involved in the phosphate ABC transporter system. Conclusion These findings suggest that the mechanism of antibacterial action of sainfoin CTs mainly operates through the inhibition of protease activity, and is partly associated with oxidative stress induced by hydrogen peroxide. Graphical Abstract

BackgroundIn this study, we aimed to address the low utilization of straw and poor fermentation quality of paper mulberry silage (under natural fermentation conditions). Straw was combined with paper mulberry for ensiling, and the fermentation characteristics, bacterial community, and metabolite composition of the mixed straw and paper mulberry silage were investigated. Four treatment groups were established: corn-straw treatment 2 (3:7 ratio of corn straw to paper mulberry), corn-straw treatment 3 (5:5 ratio of corn straw to paper mulberry), wheat-straw treatment 2 (3:7 ratio of wheat straw to paper mulberry), wheat-straw treatment 3 (5:5 ratio of wheat straw to paper mulberry), and a control group (ensiling of paper mulberry alone).ResultsThe control group demonstrated the highest pH and ammonia (AN) and acetic acid (AA) content compared with all the treatment groups. Corn-straw treatment 2 had the highest lactic acid content (54.70 g/kg dry weight) compared with the control and other treatment groups. The relative abundance of Enterobacter (7.085%) was the lowest in the control than in the other treatment groups (p < 0.05). The relative abundance of Enterococcus was higher in both the control and wheat-straw treatment 2 (22.03% and 21.29%, respectively) than in other treatment groups. The relative abundance of Lactococcus was highest in wheat-straw treatment 3 (15.83%) compared with the control and other treatment groups. Corn-straw treatments 2 and 3 demonstrated the same metabolite composition but were clearly different from the wheat-straw treatment 2, wheat-straw treatment 3, and the control. Diacetoxyscirpenol (DAS) belongs to the Fusarium metabolite type A trichothecenes, which were not detected in corn or wheat silage. DAS was downregulated in the wheat-straw treatment 3 and both corn-straw treatments compared with the control, which indicates that the addition of straw decreased mycotoxin production. Lactococcus was significantly and positively correlated with gluconic acid content (R2 = 0.5166).ConclusionOur results suggest that straw treatment can improve the nutritional value of paper mulberry silage by decreasing mycotoxin production, pH value, and AN content and increasing lactic acid production.

This study aimed to investigate the morphological characteristics of fruits and seeds from Diptychocarpus strictus, a plant species inhabiting the cold desert pastoral area of China. Furthermore, this study sought to evaluate the germination potential of these seeds following digestion by sheep. This study employed the sheep rumen fistula method to simulate rumen digestion at various time intervals. Subsequently, an in vitro simulation method was utilized to simulate true gastric and intestinal digestion after rumen digestion. Paper germination tests were then conducted to assess the impact of the digestive process on the heteromorphic seed morphology and germination. During rumen digestion, the seeds were protected by wide wings. The results revealed a highly significant negative correlation (p < 0.01) between seed wing length and digestion time. Post-rumen digestion, variations in the germination rate among seeds from fruits at different locations were observed. Indicators, such as germination rate, exhibited a highly significant negative correlation with rumen digestion time (p < 0.01). In vitro simulated digestion tests demonstrated that Diptychocarpus strictus seeds retained their ability to germinate even after complete digestion within the livestock’s digestive tract. The polymorphic nature of Diptychocarpus strictus seeds, coupled with their capacity to survive and germinate through the digestive tract, facilitates the spread of these seeds. This finding has implications for mitigating desert grassland degradation and promoting sustainable ecological development.

(1) Background: Previous studies have indicated that proteolysis is inhibited by the condensed tannins (CTs) that are present during sainfoin ensiling. Whether inhibiting this effect of CTs on proteolysis is functional during aerobic exposure is still unclear.(2) Methods: the present study investigated the effect of CTs on metabolite composition during the aerobic exposure of sainfoin silage via the use of polyethylene glycol (PEG), leading to the inactivation of CTs.(3) Results: The neutral detergent-insoluble protein (NDIP) and acid detergent-insoluble protein concentrations were both more concentrated in the control group than in the PEG-treated group. There were 587 and 651 different metabolites present in the control and PEG-treated groups after 3 and 7 days, respectively, of aerobic exposure of silage. Flavonoids (72 metabolites) were the most abundant among these different metabolites. The addition of PEG upregulated histidine, threonine, asparagine, tryptophan, and glutamine, but downregulated phenylalanine. The relative abundances of Lactococcus, Fructobacillus, Enterobacter, Cutibacterium, Citrobacter, and Rosenbergiella differed significantly between the control and PEG-treated groups (p < 0.05); all of these bacteria showed significant correlation with some of the 50 most abundant metabolites.(4) Conclusions: the results suggest that the antioxidant status of the silage increased and inhibited the activity of a variety of bacteria that coexist with CTs, and decreased the production of certain amino acids after the aerobic exposure of silage.

This experiment was conducted to study the effects of different lactic acid bacteria treatments on nutritional quality,fermentation characteristics and aerobic stability of hybrid Broussonetia papyrifera silage,and to provide technical reference for the development and utilization of hybrid Broussonetia papyrifera. There were7 treatments as follows:the CK treatment was supplemented 10 mL/kg deionized water,the LP treatment was supplemented 5×106CFU/g FM Lactobacillus plantarum,the LB treatment was supplemented 5×106CFU/g FM Lactobacillus brevis,the EF treatment was supplemented 5 × 106CFU/g FM Enterococcus faecalis,the LP+EF treatment was compound supplemented 5×106CFU/g FM Lactobacillus plantarum and Enterococcus faecalis（1∶1）,the LP+LB treatment was compound supplemented 5×106CFU/g FM Lactobacillus plantarum and Lactobacillus brevis（1∶1）,and the LP+LB+EF treatment was compound supplemented 5×106CFU/g FM Lactobacillus plantarum,Lactobacillus brevis and Enterococcus faecalis（1∶1∶1）,each treatment contained 5replicates,fermentation for 60 days. The results showed as follows:1)the dry matter content of LP and LP+LB+EF treatments was significantly higher than that of CK treatment（P＜0.05）. The neutral detergent fiber content of LP,LB,EF,LP+LB and LP+LB+EF treatments was significantly lower than that of CK treatment（P＜0.05）. The crude protein content of EF and LP+LB+EF treatments was significantly higher than that of CK treatment（P＜0.05）. The water-soluble carbohydrates content of LP,LB and EF treatments was significantly lower than that of CK treatment（P＜0.05）. 2)The pH of LP and LP+LB+EF treatments was significantly lower than that of CK treatment（P＜0.05）. The ammoniacal nitrogen content of CK treatment was significantly higher than that of other treatments（P＜0.05）. The lactic acid content of LP treatment was significantly higher than that of EF,LP+LB and CK treatments（P＜0.05）. The acetic acid content of LB and LP+LB treatment was significantly higher than that of other treatments except LP+LB+EF treatment（P＜0.05）.The propionic acid content of LP,LB and LP+LB treatment was significantly lower than that of CK treatment（P＜0.05）. The lactic acid bacteria population of LP+LB treatment was significantly higher than that of other treatments（P＜0.05）. 3)After 5 days of aerobic exposure,the mold population of LP+LB treatment was the lowest,and the aerobic bacteria population of LP+LB+EF treatment was the lowest. The aerobic stability order from high to low was LB treatment ＞ LP+LB treatment ＞ LP+LB+EF treatment ＞ CK,LP,EF and LP+EF treatments. To sum up,adding epiphytic lactic acid bacteria to hybrid Broussonetia papyrifera silage obviously improve the nutritional quality,fermentation characteristics and aerobic stability.[Chinese Journal of Animal Nutrition,2023,35（4）:2702-2710]