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.

Non-proteinogenic amino acids, such as L-citrulline and L-theanine, have garnered attention for their potential health benefits, including enhanced immunity, antioxidant activity, and cardiovascular support. The application of natural amino acids in disease treatment and health supplementation is and will remain a research hotspot in pharmaceutics. Plant-derived L-citrulline and L-theanine have demonstrated multifaceted benefits, primarily through mechanisms involving nitric oxide (NO) bioavailability (for L-citrulline) and mitochondrial regulation or immune modulation (for both). Critical gaps are identified: (1) the role of D-amino acids (e.g., D-citrulline and D-theanine) in health and metabolism remains underexplored, particularly regarding chiral-specific bioactivity; (2) derivatives and co-administration strategies of L-forms warrant systematic evaluation for drug. However, while these compounds show promise, evidence is predominantly from animal and cell studies, with limited long-term human data on efficacy and safety. Potential side effects, dosing limitations, and sourcing challenges are discussed. This review emphasizes the need for cautious interpretation of their benefits, acknowledging that while promising, some effects, such as those on muscle protein synthesis, require further validation compared to established nutrients like branched-chain amino acids. By bridging mechanistic insights with translational challenges, this work aims to guide future research toward sustainable nutraceutical production.

Glycerol fatty acid esters (GFAEs) are recognized for their potential to improve lipid metabolism, energy utilization, and gut health due to their excellent emulsifying and antimicrobial properties. The objective of this research was to investigate the effects of dietary GFAE supplementation on production performance, serum biochemical profiles, and rumen fermentation in beef cattle. Thirty crossbred Simmental bulls, averaging 507.42 ± 9.59 kg in body weight, were assigned to three distinct cohorts, with 10 animals in each cohort. The CON cohort was fed a basal diet devoid of GFAE, whereas the treatment cohorts (GFAE1 and GFAE2) received GFAE supplements at concentrations of 0.1% and 0.2% of the dietary dry matter, respectively. Compared with the control group, supplementation with 0.1% GFAE significantly increased the ADG of beef cattle by 12.14% (p < 0.05); compared with the GFAE2 group, ADG was 7.86% higher (p > 0.05). The digestibility of NDF and ADF was significantly enhanced in the GFAE1 group relative to the control group (p < 0.05). Dietary GFAE supplementation significantly elevated rumen acetate, propionate, and total volatile fatty acid concentrations in both the GFAE1 and GFAE2 groups compared to the control group (p < 0.05). In contrast to the control group, there was a notable rise in serum levels of T-AOC, UREA, and TG in both GFAE1 and GFAE2 groups (p < 0.05). Conversely, the concentration of HDL-C was significantly decreased in the GFAE2 group. Additionally, at the phylum level, the abundance of Fibrobacterota was significantly higher in the GFAE1 group than in the control group (p < 0.01). At the genus level, the proportions of Bacteroides and Fibrobacter were significantly higher in the GFAE1 group compared to the control group (p < 0.05). In conclusion, this study demonstrates that the addition of 0.1% GFAE to beef cattle diets significantly enhances the digestibility of ADF and NDF nutrients, increases serum total antioxidant capacity, urea, and triglycerides, optimizes rumen fermentation parameters and microbial community structure, and ultimately improves production performance. As a result of the findings from this research, it is suggested that 0.1% GFAE be incorporated into the diet for beef cattle.

This study aimed to collaboratively investigate the mechanism of variations in intramuscular fat (IMF) content in Wandong cattle using transcriptomics and metabolomics techniques. Longissimus dorsi (LD) muscle samples were collected from thirteen free-range Wandong cattle in Fengyang County, Anhui Province, China. From this initial cohort, eight animals closely matched in age and body weight were selected. Based on IMF content measured by Soxhlet extraction, these eight cattle were divided into two groups: the high-IMF (HF, n = 4) and low-IMF (LF, n = 4) groups. Subsequent analyses were performed on integrated datasets comprising the transcriptome, metabolome, and fatty acid profile. The results revealed a significant increase in IMF in the HF group compared to the LF group (p < 0.05). Specifically, α-linolenic acid (C18:3n3) and γ-linolenic acid (C18:3n6) were significantly more abundant in the LF group compared to the HF group (p < 0.05), whereas oleic acid (C18:1n9c) and cis-9-palmitoleic acid (C16:1) predominated in the HF group. However, saturated fatty acids (SFAs), such as myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), and Margaric acid (C17:0), did not show significant differences (p > 0.05). A total of 9164 differentially expressed genes (DEGs) were identified via transcriptome analysis, with 2202 genes upregulated and 6962 genes downregulated in the HF group compared to the LF group. The expression profiles exhibited a distinct pattern, characterized by the upregulation of genes such as FABP1, SREBF1, and LIPE, while genes including SCD, PPARGC1A, and LEP were downregulated. GO enrichment analysis demonstrated that the majority of DEGs were predominantly abundant across 25 distinct functional categories distributed across the three primary ontologies. KEGG pathway analysis further identified 341 significantly enriched signaling pathways in the HF group (p < 0.05), predominantly involving metabolic pathways, FoxO, AMPK, and PPAR signaling pathways. Untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) metabolomics analysis revealed 404 differential accumulated metabolites (DAMs), with 187 in positive ion mode and 217 in negative ion mode (p < 0.05). These DAMs were notably enriched in pathways such as glycerophospholipid metabolism, terpene and steroid biosynthesis, fatty acid degradation, and fatty acid metabolism. Notably, C16:1, C18:1n9c, arachidonic acid (peroxide free) (C20:4n6), oleoyl-L-carnitine, and linoleoyl-carnitine were identified as key players in lipid metabolism. Integrating transcriptomics with metabolomics data unveiled significant associations between DAMs linked to lipid metabolism and DEGs. Specifically, C18:1n9c exhibited a positive correlation with LPIN3, while C16:1 showed negative associations with PPAP2B, PPAP2A, CDS2, HADHA, LPL, HSD17B12, ELOVL5, ACSL1, and ACOX1, and positive correlations with PLA2G15, CDIPT, AGPSBG1, and GPD1. In summary, the variation in IMF content in Wandong cattle is co-regulated by key genes (SREBF1, ACSL1, SCD) via the AMPK, PPAR, and FoxO signaling pathways, coupled with alterations in specific fatty acid metabolites such as C18:1n9c, C16:1, and C20:4n6. These findings provide critical molecular insights for the genetic selection and breeding of Wandong cattle, which are renowned for their superior meat quality.

Dabie Mountain cattle are characterized by their ability to tolerate coarse feed, strong disease resistance, and delicious meat. Lower reproductive efficiency has become one of the key factors limiting its development. Therefore, this study investigated the developmental patterns of Dabie Mountain cattle follicles and screened key candidate genes for in vitro experimental validation. Research collected granulosa cells from small follicles (8 mm), followed by RNA extraction for transcriptomic sequencing. A total of 20,775 genes were identified, including 13,777 (66.3%) differentially expressed genes (DEGs). DEGs showing up-regulation and down-regulated in B vs. S, B vs. M, and M vs. S groups were collected. A total of 19 commonly up-regulated DEGs across the three groups were identified, including genes such as DEFB, FAM124A, and RASSF10. Additionally, 227 commonly down-regulated DEGs were identified, including genes such as INSL3, GAS7, and PAQR7. Protein interaction network analysis revealed an interaction between INSL3 and STAR. Bovine ovarian granulosa cells (GCs) were collected to investigate the effect of the INSL3 on GCs proliferation. The results revealed that INSL3 expression was highest in small follicles and was almost absent in big follicles. Subsequently, the INLS3 gene was knocked down in GCs using small interfering RNA. RT-qPCR results demonstrated that both si-INSL3 (239) and si-INSL3 (392) significantly knock down INSL3 expression (p < 0.01), si-INSL3 (239) for follow-up research. CCK-8 was used to assess cell proliferation, revealing that INSL3 knockdown significantly enhanced GCs viability and number at 24, 48, and 72 h (p < 0.05). Flow cytometry was used to detect cell cycle distribution. The results showed that knockdown of INSL3 expression significantly decreased the proportion of G1 phase cells and significantly increased the number of S phase cells (p < 0.01). RT-qPCR was used to detect the expression of cell proliferation-related genes. The results showed that compared with the siNC group, the expression levels of Myc, PCNA, Cytochrome C, and Cyclin D1 were significantly increased in the si-INSL3 group. In conclusion, knockdown of INSL3 affects follicular development in Dabie Mountain cattle by regulating granulosa cell proliferation in the ovaries, providing new insights into the regulatory mechanisms of follicular development in cattle.

Glycerol fatty acid esters (GFAEs) exhibit potential applications in ruminant production, including enhancing animal performance, improving nutrient utilization, and modulating rumen function. However, studies on indigenous Dabieshan beef cattle are lacking. This study aimed to evaluate GFAE’s effects on their performance, meat quality, and rumen function. Thirty 2-year-old cattle (294.73 ± 3.21 kg; mean ± SD), were randomly divided into three groups (n = 10): on a dry matter (DM) basis, CON (basal diet), 0.05 GFAE (basal + 0.05% GFAE), 0.1 GFAE (basal + 0.1% GFAE), fed for 60 days. The crude protein (CP) digestibility of the 0.05 GFAE group showed a significant 4.55% increase compared with the CON group, while that of the 0.1 GFAE group was significantly elevated by 2.76% relative to the CON group. For key meat quality indices of Dabieshan beef cattle, compared with the CON group, the 0.05 GFAE and 0.1 GFAE groups showed increases in L value by 10.14% and 7.11%, respectively (p = 0.042); decreases in shear force by 5.24% and 1.48%, respectively (p = 0.024); and increases in ether extract(EE) content by 10.91% and 2.33%, respectively (p = 0.019). Compared with the CON group, the 0.05 GFAE and 0.1 GFAE groups showed significant alterations in key serum biochemical indices of Dabieshan beef cattle: TP (total protein) levels elevated significantly by 6.44% and 13.04%, respectively (p = 0.010); total antioxidant capacity (T-AOC) increased significantly by 33.96% and 46.23%, respectively (p = 0.001); UREA concentrations decreased significantly, by 22.67% and 33.53%, respectively (p = 0.002); superoxide dismutase (SOD) activity rose significantly, by 7.30% and 7.99%, respectively (p = 0.020); and malondialdehyde (MDA) content declined significantly, by 20.25% and 28.03%, respectively (p = 0.040). Relative to the CON group, dietary supplementation with GFAE significantly increased ruminal butyrate concentrations, with the 0.05 GFAE and 0.1 GFAE supplemented groups exhibiting respective increments of 17.38% and 18.03% (p = 0.025). Both Groups 0.05 GFAE and 0.1 GFAE reduced CH4 emissions (p = 0.005) and elevated Prevotella abundance (p = 0.001). The study findings revealed that dietary supplementation with GFAE at concentrations of 0.05% and 0.1% of dry matter resulted in substantial decreases in daily methane emissions, representing respective reductions of 6.91% and 11.63% compared to the control group (p = 0.005). At the species level of the rumen microbial community, the relative abundance of the genus Prevotella_sp. was significantly elevated by 60.52% and 38.48% in the 0.05 GFAE and 0.1 GFAE groups, respectively, when contrasted with the CON group (p = 0.001). Collectively, these results demonstrate that the inclusion of dietary 0.05% GFAE supplementation conferred multifaceted benefits to Dabieshan beef cattle, thereby highlighting its potential as a viable strategy to enhance the sustainability of beef cattle production systems.