Changjiang Zang

Cotton straw, a major agricultural residue in China, is underutilized for ruminant feed owing to its recalcitrant lignin barrier, which impairs palatability and in vivo digestibil-ity. Solid-state fermentation using ligninolytic fungi provides a sustainable strategy to upgrade this lignocellulosic biomass. Nevertheless, the physiological outcomes of feeding fermented cotton straw to lactating ruminants remain largely unexplored. Herein, we investigated the effects of cotton straw fermented by Penicillium chrysogenum YL-11 on milk production, serum biochemical profiles, and ruminal microbial community composition in Saanen dairy goats, together with a biosafety assessment of the strain using a murine model. A completely randomized design was employed, involving 30 Saanen dairy goats (2–3 parities, initial body weight 48.56 ± 4.74 kg, milk yield 1.03 ± 0.27 kg/d, days in milk 180 ± 5.82 d) randomly assigned to three groups (n = 10): control (CK1, no cotton straw), CK2 (20% unfermented cotton straw), and YL-11 (20% fermented cotton straw). The trial included a 7-day adaptation and a 60-day experimental period. The results demonstrated that YL-11 administration did not adversely affect organ indices, serum biochemistry, or immune parameters in mice (p > 0.05). In dairy goats, YL-11 significantly increased average daily milk yield and 4% fat-corrected milk yield (p < 0.01), while the feed-to-milk ratio was significantly lower than that of the CK2 group (p < 0.01), but did not differ significantly from the CK1 group. Apparent digestibility of crude protein and ash was significantly higher in the YL-11 group than in the CK2 group (p < 0.05), with no significant differences observed between the YL-11 and CK1 groups. Milk fat and lactose percentages were also increased in the YL-11 group compared with both control groups (p < 0.05). Antioxidant enzyme activities (T-AOC, SOD, CAT, GSH-PX) were elevated, whereas MDA, TNF-α, IL-1β, and TGF-β1 were decreased (p < 0.05). Rumen ammonia nitrogen and the acetate/propionate ratio were increased significantly (p < 0.05) and the abundance of fiber-degrading taxa, including Verrucomicrobiota was enriched in the YL-11 group, with five potential biomarkers identified by LEfSe analysis. In conclusion, P.chrysogenum YL-11 is safe and its fermented cotton straw improves lactation performance, rumen fermentation, antioxidant status, and fiber-degrading microbiota in dairy goats, offering a promising strategy for utilizing cotton straw as a feed resource.

Milk urea nitrogen, the primary form of nonprotein nitrogen (N) in milk, is an indirect indicator of N metabolism in dairy cows. The MUN concentrations are modulated by various factors, including dietary composition, physiological status, and environmental conditions. However, the potential roles of host gut microbiota and metabolome in the development of distinct MUN phenotypes remain insufficiently elucidated. Here, we compared fecal microbiota and fecal/serum metabolomes of high-MUN (HMUN) and low-MUN (LMUN) cows (n = 7 per group) under uniform feeding management using 16S rRNA gene sequencing and liquid chromatography-MS-based metabolomics. Compared with that of LMUN cows, the feces of HMUN cows exhibited relatively higher abundances of UCG-009, UCG-002, and Christensenellaceae_R-7_group and lower abundances of Succinivibrio, Lachnospiraceae_NK3A20_group, Acetitomaculum, Prevotellaceae_UCG-001, and norank_f__Bifidobacteriaceae. Metabolomic analysis revealed that HMUN cows had relatively lower levels of hydroxypropionic acid, N-myristoyl arginine, and N-eicosapentaenoyl tryptophan in feces, and reduced amounts of l-serine, linoleic acid, and butyrate in serum. Kyoto Encyclopedia of Genes and Genomes pathway mapping revealed that the metabolites relatively elevated in LMUN cows were primarily involved in the β-alanine metabolism pathway. The UCG-009 and Christensenellaceae_R-7_group were positively correlated with MUN, whereas Succinivibrio, Lachnospiraceae_NK3A20_group, Anaeroplasma, and Acetitomaculum were negatively correlated. These microbial taxa were also significantly associated with several fatty and AA metabolites, including adipic acid, undecenoic acid, dodecanedioic acid, dl-tryptophan, and l-leucine. Collectively, this study revealed certain differences in the gut microbiota and metabolome between cows with high and low MUN levels. These findings suggest that alterations in gut microbial composition and metabolic profiles may contribute to variations in MUN phenotypes and provide new insights into host factors influencing MUN metabolism in dairy cows.

Milk titratable acidity is a key indicator of raw milk freshness and quality, but its variation across different dairy animal species remains incompletely characterized. Based on 16,984 raw milk samples from eight dairy animal species (Holstein cow, goat, buffalo, camel, sheep, yak, donkey, and horse) collected within a retrospective raw milk quality monitoring framework in China from 2016 to 2024, this study provides a large-scale descriptive comparison of milk titratable acidity across species. Distinct titratable acidity profiles were observed among species, with camel and yak milk showing relatively high values, sheep, Holstein, and buffalo milk exhibiting intermediate values, and donkey and horse milk presenting markedly low values. Calendar-season-associated patterns also differed among species. Correlations between titratable acidity and milk components varied by species, with relatively stronger positive associations with protein and solids-not-fat (SNF) in several ruminant milks, suggesting that milk composition may contribute to differences in titratable acidity. However, because this study was based on an unbalanced observational dataset with limited animal-level, farm-level, feeding, management, physiological, and environmental metadata, these observations should be interpreted as descriptive and exploratory patterns rather than causal biological mechanisms. This dataset provides preliminary reference information for future studies on species-associated variation in raw milk titratable acidity and for discussions on species-specific raw milk quality evaluation.

This study was conducted to investigate the effect of different concentrate-to-roughage ratios on the lipid composition of camel milk. Thirty-six Qiangar Bactrian camels were randomly allocated to three groups: the control group (C, grazing plus roughage only), the low-concentrate group (L, grazing plus roughage with 2 kg/d concentrate supplementation), and the high-concentrate group (H, grazing plus roughage with 4 kg/d concentrate supplementation). The trial comprised an 18-day adaptation period followed by a 42-day feeding period (60 days total). A systematic lipidomics approach revealed significant differences in milk lipid profiles among the three dietary treatments. High-concentrate diets markedly remodeled the milk lipidome (especially in positive-ion mode mass spectrometry), with the most pronounced differences detected between the C and H groups. Multivariate analyses (PCA and PLS-DA) confirmed that varying concentrate levels significantly affected milk lipid composition, and the separation between H and C was greater than that between L and C. KEGG annotation and enrichment analysis indicated that lipid-related pathways, notably glycerophospholipid metabolism, were significantly affected by dietary concentrate levels. These findings provide theoretical support for optimizing camel feeding strategies to improve milk nutritional quality and offer scientific guidance for camel husbandry and dairy product development.

This study reveals lipidomic adaptations in camel milk that are crucial for neonatal development in desert environments. Using UHPLC-MS/MS and targeted oxylipidomics, we compared milk from free-grazing camels and cows from the same region. We identified 2460 lipids across 44 subclasses and 11 oxygenated lipids in three groups. Glycerophospholipids (GP) were dominant in both. We found 498 differentially expressed lipids, including potential biomarkers such as phosphatidylinositol (PI 18:0/22:3), phosphatidylethanolamine (PE 18:0/22:3), and two triacylglycerol (TG) species. Camel milk was dominated by phosphatidylcholine (PC, approximately 49%) and PI (approximately 22%), whereas cow milk was predominantly composed of TG (nearly 98%). Pathway analysis showed 11 key altered lipid pathways, mainly glycerophospholipid metabolism. These results define camel milk’s unique lipid profile—linked to desert adaptation—and provide molecular insights into its role in supporting neonatal camels in arid environments.

This study used soybean meal as the substrate and systematically optimized its enzymatic hydrolysis through single-factor experiments and response surface methodology. A predictive model based on a Box–Behnken design was developed to improve protein hydrolysis efficiency and increase the yield of functional products. The optimal conditions were 1.45% enzyme addition, a reaction time of 62 h, a temperature of 36.5 °C, and a moisture content of 35%. Under these conditions, the small-peptide content increased 16.33-fold. Structural analyses showed that enzymatic treatment markedly disrupted the compact surface of soybean meal, converting it into a loose, porous matrix. In addition, enzymolysis altered the protein secondary structure from ordered α-helices and folded conformations to more disordered, flexible forms, thereby improving the molecular-weight distribution. Composition analyses showed an 114.2% increase in total free amino acids, including essential amino acids. Moreover, DPPH radical-scavenging activity increased from 18.37% to 57.99%. Overall, this study optimized the enzymatic hydrolysis conditions for soybean meal and provides valuable insights for the development of high-value protein-peptide products.

This study employed soybean meal as the substrate and systematically optimized its enzymatic hydrolysis process using a combination of single-factor experiments and response surface methodology. A predictive model based on the Box–Behnken design was established to improve protein hydrolysis efficiency and increase the yield of functional products. The optimal conditions identified were 1.45% enzyme addition, a reaction time of 62 h, a temperature of 36.5 °C, and a moisture content of 35%. Under these conditions, the small-peptide content increased by 16.33-fold. Structural analyses showed that enzymatic treatment markedly disrupted the compact surface of soybean meal, converting it into a loose and porous matrix. In addition, enzymolysis altered the protein secondary structure from ordered α-helices and folded conformations to more disordered and flexible forms, thereby improving the molecular-weight distribution. Composition analyses demonstrated a 114.2% increase in total free amino acids, including essential amino acids. Moreover, DPPH radical-scavenging activity increased from 18.37% to 57.99%. Overall, this study optimized the enzymatic hydrolysis conditions for soybean meal and provides valuable insights for the development of high-value protein-peptide products.

The availability of nutrients is closely linked to the protein expression profile of microorganisms. In this study, a comparative investigation has been performed to examine the expression patterns of cell associated proteins and secreted proteins in Staphylococcus aureus cultivated in TSB and milk media at three time points: 3 h, 9 h, and 18 h of the growth stage using proteomic techniques. In TSB medium, cell-associated proteins such as acetyl-CoA acyltransferase, acyl-CoA synthetase, argininosuccinate lyase, and argininosuccinate synthase were detected at higher levels at 9 h and 18 h compared with 3 h, indicating overall increases during growth. While in milk, quinone oxidoreductase 1 and zinc-type alcohol dehydrogenase-like protein SAR2277 exhibited a significant increase across 3, 9 and 18 h. Secretory proteins such as δ-hemolysin, phospholipase C and panton-valentine leukocidin F showed significant increases in both media across 3, 9 and 18 h. Notably, cell associated proteins or secreted proteins such as the leukocidin S subunit and staphopain B were significantly upregulated in TSB medium, while thermonuclease and transcriptional regulator SarA were found to increase in milk. These findings highlight the importance of the culture medium in determining the relative abundances of cell associated proteins and secretory proteins in S. aureus , providing insight into microbial adaptation mechanisms. Furthermore, these up-regulated proteins may serve as potential biomarkers and have practical implications for improving control strategies, leading targeted approaches to reducing S. aureus contamination in milk and dairy products, and eventually contributing to better food safety and quality.

Milk harbors a diverse array of microorganisms; however, the current understanding of the microbial diversity in raw milk from specific geographical origins and milk types remains unclear. To address this knowledge gap, this study employed single-molecule real-time sequencing to analyze the differences in microbial communities across various farms and milk types from different regions, specifically by examining the microbial diversity in Holstein cow milk samples from farms situated in both adjacent and distant regions, and comparing the microbial diversity between Holstein cow milk and non-bovine milk from farms in adjacent regions. The results demonstrated that several genera, such as Lactiplantibacillus , Pseudomonas , Acinetobacter , and Chryseobacterium , exhibited significant differences in Holstein cow milk from adjacent regions. Additionally, genera like Lactiplantibacillus and Chryseobacterium consistently showed substantial variation in Holstein cow milk across distant regions. At the species level, Lactiplantibacillus plantarum , Pseudomonas lurida , and Haloanella gallinarum displayed significant variations in Holstein cow milk from adjacent regions, while Lactiplantibacillus plantarum and Chryseobacterium carnipullorum were significantly more prevalent in distant regions. The bacterial diversity does not have a clear relationship with the geographic proximity of farms, a finding that is consistent with the results of the principal coordinates analysis. Moreover, milk type had a pronounced impact on microbial diversity, with species such as Acinetobacter johnsonii , Pseudomonas fragi , Enterobacter ludwigii , Achromobacter arsenitoxydans , and Leuconostoc mesenteroides exhibiting substantial variations across different milk types. Furthermore, 22 species of lactic acid bacteria were identified in the studied milk samples. Notably, Holstein, donkey, and camel milk exhibited higher lactic acid bacteria diversity compared to buffalo and horse milk. Among these, Lactiplantibacillus plantarum was significantly more abundant in Holstein cow milk, while Lactobacillus helveticus and Leuconostoc mesenteroides were the predominant beneficial species in donkey and camel milk. IMPORTANCE: The data generated through this research present invaluable insights into the intricate microbial ecosystems inhabiting both Holstein and non-bovine milk varieties. These novel findings significantly advance our knowledge and approach toward understanding and managing microorganisms within milk, thereby bolstering their efficient utilization and facilitating the design of enhanced strategies for their prevention and control. This research not only sheds light on the diversity and dynamics of microbial communities in different milk types but also paves the way for more targeted interventions to ensure milk safety and quality across different production systems.

In recent years, in response to the demand for the livestock industry to enhance cattle production performance, scholarly inquiries have centered on elucidating the underlying mechanisms by which feed additives modulate rumen microenvironment and metabolic efficacy, thereby facilitating nutrient absorption and augmenting production performance in cattle. This study was undertaken to evaluate the impacts of surfactant polyacrylamide (PAM) supplementation on digestive processes, metabolic dynamics, and ruminal digestive enzyme activities in cattle. Four ruminally cannulated crossbred cows (~3 years, 350 kg, non-pregnant/lactating) were utilized in a 4 × 4 Latin square design. The animals were fed a basal diet supplemented with polyacrylamide (PAM) at concentrations of 0, 1.0, 2.0, and 6.0 g/kg across four 22-day experimental periods, each consisting of a 16-day adaptation phase and a 6-day sampling phase. Supplementation with polyacrylamide (PAM) at levels ranging from 1.0 to 6.0 g/kg of diet significantly increased voluntary dry matter intake (VFI) in cattle by a maximum of 13.7% (p < 0.05), with peak effects at 2.0 g/kg. The digestibility of dry matter, crude protein, cellulose, and energy was significantly improved (p < 0.05 to p < 0.01), reaching maximum increases by 12.6%, 12.8%, 17.5%, and 11.7%, respectively. Nitrogen, calcium, and phosphorus retention increased substantially (p < 0.01 to p < 0.05), with calcium retention showing the highest improvement (55.7%). Rumen cellulase activities (endocellulase, exocellulase, cellobiase, and xylanase) were significantly enhanced (p < 0.01), peaking at 37.3% for cellobiase. However, pectase, amylase, and protease activities remained unaffected. Optimal benefits were observed at 2.0 g/kg PAM, highlighting its potential to improve feed efficiency and nutrient utilization in cattle.