Human milk fat globule delivers entrapped probiotics to the infant's gut and acts synergistically to ameliorate oxidative and pathogenic stress.

The human milk fat globule membrane (hMFGM) and Lactobacillus modulate the infant's gut and benefit health. Hence, the current study assesses the probiotic potential of Lactiplantibacillus plantarum (MRK3), Limosilactobacillus ferementum (MK1) isolated from infant feces, and its interaction with hMFGM during conditions mimicking infant digestive tract. Both strains showed high tolerance to gastrointestinal conditions, cell surface hydrophobicity, and strong anti-pathogen activity against Staphylococcus aureus. During digestion, hMFGM significantly exhibited xanthine oxidase activity, membrane roughness, and surface topography. In the presence of hMFGM, survival of MRK3 was higher than MK1, and electron microscopic observation revealed successful entrapment of MRK3 in the membrane matrix throughout digestion. Interestingly, probiotic-membrane matrix interaction showed significant synergy to alleviate oxidative stress and damage induced by cell-free supernatant of Escherichia coli in Caco-2 cells. Our results show that a probiotic-encapsulated membrane matrix potentially opens the functional infant formula development pathway.

Study on the mechanism of SAR1B in sodium acetate promoting milk fat synthesis.

Acetate can promote milk fat synthesis in dairy cow mammary epithelial cells (BMECs). In this study, gene function analysis was used to explore the role of Ras family secretion-related GTP binding protein 1B (SAR1B) in milk fat synthesis of BMECs and its role and molecular mechanism in acetate-promoted milk fat synthesis. We found that the synthesis of lipid droplets and triglycerides was inhibited, and the expression levels of key genes and proteins in milk fat synthesis such as FASN and ACC were decreased in SAR1B knockout, which was reversed by overexpression of SAR1B. Addition of sodium acetate in BMECs can promote the expression of SAR1B, and SAR1B plays an important role in the synthesis of milk fat promoted by sodium acetate. We further investigated the underlying mechanism of SAR1B upregulation by sodium acetate, and found that sodium acetate could affect SAR1B expression through the positive regulation of SAR1B gene promoter activity by C/EBPß and PPARγ. In conclusion, the results suggest that SAR1B can promote milk fat synthesis in BMECs, while C/EBPß and PPARγ play important roles in sodium acetate to promote the expression of SAR1B.

Modifying physicochemical properties, rheology, and creaming stability of milk fat globule and membrane through ultrasound treatment.

The healthy benefits of milk fat globules and membrane (MFGs/MFGM) ingredients are increasingly recognized in the dairy industry. In this research, we examined the effects of ultrasonic treatment on the physicochemical and rheological properties, as well as the emulsions stability of MFGs/MFGM derived from bovine raw milk. Fresh milk was subjected to sonication at frequencies of 20 kHz and 40 kHz, either individually or simultaneously, for durations of 5 min or 15 min, using work/rest cycles of 5 s on and 3 s off. Bovine milk, without any treatment, served as the control. Regardless of the intensity difference, ultrasonic treatment for 5 min resulted in more pronounced changes in the regions of Amide Ⅱ (1600-1500 cm-1), Amide Ⅲ (1500-1200 cm-1), and fingerprint region (1200-1900 cm-1) compared to both the 15 min treatments and control MFGs/MFGM. Principal component analysis (PCA) conducted on the entire spectra, as well as in the regions of Amide Ⅰ, Amide Ⅱ, and the fingerprint spectra, clustered the 5 min treatment distinctly from the control and MFGs/MFGM ultrasonically treated for 15 min. MFGs/MFGM samples following 20 kHz and 40 kHz synchronous treatment for 15 min exhibited lower absorbance bands at 1727-1726 cm-1, whereas a higher content at 1740 cm-1 was observed compared to control MFGs/MFGM. Additionally, a more significant reduction in the intramolecular ß-sheet content in 20 + 40 kHz/ 15 min treatment was observed. According to the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) patterns, a diminished intensity of Periodic Acid Schiff 6/7 (PAS 6/7) bands was observed across all the MFGs/MFGM. Ultrasonic treatment retained more caseins while reducing the ß -LG levels compared to the controls, enhancing the stability of MFGs/MFGM, except in MFGs/ MFGM subjected to 20 and 40 kHz simultaneously treated for 15 min. The irregular sphericity of fat globules was noted particularly in MFGs/MFGM treated at 20 kHz independently or in combination with 40 kHz for 15 min. According to the confocal laser scanning microscopy (CLSM), ultrasonic treatment facilitated the binding of caseins or whey proteins to the MFGs surface and induced flocculation of membrane proteins. Hierarchical cluster analysis (HCA) heat map further underscored the impact of ultrasonic treatments on the structural and compositional changes, as well as rheology and emulsions stability, of MFGs/MFGM.

Improvement in probiotic intestinal survival by electrospun milk fat globule membrane-pullulan nanofibers: Fabrication and structural characterization.

Studies have demonstrated the protective effect of milk fat globule membrane (MFGM) on probiotics in harsh environments. However, currently, there are no reports on the encapsulation of probiotics using MFGM. In this study, MFGM and pullulan (PUL) polysaccharide fibers were prepared by electrostatic spinning and used to encapsulate probiotics, with whey protein isolates (WPI)/PUL as the control. The morphology, physical properties, mechanical properties, survival, and stability of the encapsulated Lacticaseibacillus rhamnosus GG (LGG) were studied. The results showed that the MFGM/PUL solution had significant effects on pH, viscosity, conductivity, and stability. Electrostatic spinning improved the mechanical properties and encapsulation ability of the polymer formed by MFGM/PUL. LGG encapsulated in MFGM/PUL nanofibers survived rate was higher than WPI/PUL nanofibers in mimic intestinal juice, which could be attributed to the phospholipid content contained in MFGM. These results demonstrate that MFGM is a promising material for probiotic encapsulation, providing an important basis for the potential use of MFGM/PUL nanofibers as a robust encapsulation matrix.

Small extracellular vesicles derived from adipose mesenchymal stem cells alleviate intestinal fibrosis by inhibiting the FAK/Akt signaling pathway via MFGE8.

BACKGROUND: Intestinal fibrosis is one of the most frequent and severe complications of Crohn's disease. Accumulating studies have reported that adipose mesenchymal stem cell-derived small extracellular vesicles (AMSC-sEVs) could alleviate renal fibrosis, hepatic fibrosis, etc., while their potential for treating intestinal fibrosis remains uncertain. Therefore, this study aims to determine the therapeutic effects of AMSC-sEVs on intestinal fibrosis and identify the mechanisms underlying these effects. METHODS: AMSC-sEVs were characterized using transmission electron microscopy, nanoparticle tracking analysis, and western blot. Whether AMSC-sEVs exert antifibrotic effects was investigated in two different murine models of intestinal fibrosis. Besides, AMSC-sEVs were co-cultured with primary human fibroblasts and CCD18co during transforming growth factor (TGF)-ß1 stimulation. Label-free proteomics and rescue experiments were performed to identify candidate molecules in AMSC-sEVs. Transcriptome sequencing revealed changes in mRNA levels among different groups. Lastly, proteins related to relevant signaling pathways were identified by western blotting, and their expression and activation status were assessed. RESULTS: AMSC-sEVs positively expressed CD63 and Alix and presented a classical "rim of a cup" and granule shape with approximately 43-100 nm diameter. AMSCs significantly alleviated intestinal fibrosis through secreted sEVs in vitro and in vivo. The milk fat globule-EGF factor 8 (MFGE8) was stably enriched in AMSC-sEVs and was an active compound contributing to the treatment of intestinal fibrosis by AMSCs. Mechanistically, AMSC-sEV-based therapies attenuated intestinal fibrosis by inhibiting the FAK/Akt signaling pathway. CONCLUSIONS: MFGE8-containing AMSC-sEVs attenuate intestinal fibrosis, partly through FAK/Akt pathway inhibition.

Ubiquitination and De-Ubiquitination in the Synthesis of Cow Milk Fat: Reality and Prospects.

Ubiquitination modifications permit the degradation of labelled target proteins with the assistance of proteasomes and lysosomes, which is the main protein degradation pathway in eukaryotic cells. Polyubiquitination modifications of proteins can also affect their functions. De-ubiquitinating enzymes reverse the process of ubiquitination via cleavage of the ubiquitin molecule, which is known as a de-ubiquitination. It was demonstrated that ubiquitination and de-ubiquitination play key regulatory roles in fatty acid transport, de novo synthesis, and desaturation in dairy mammary epithelial cells. In addition, natural plant extracts, such as stigmasterol, promote milk fat synthesis in epithelial cells via the ubiquitination pathway. This paper reviews the current research on ubiquitination and de-ubiquitination in dairy milk fat production, with a view to providing a reference for subsequent research on milk fat and exploring new directions for the improvement of milk quality.

Infant Milk Formula Enriched in Dairy Cream Brings Its Digestibility Closer to Human Milk and Supports Intestinal Health in Pre-Clinical Studies.

Human breast milk (HBM) is the "gold standard" for infant nutrition. When breast milk is insufficient or unavailable, infant milk formula (IMF) can provide a safe and nutritious alternative. However, IMFs differ considerably from HBM in composition and health function. We compared the digestibility and potential health functions of IMF containing low cream (LC-) or high cream (HC-) with pooled HBM. After simulated infant digestion of these samples, the bioavailability of key nutrients and immunomodulatory activities were determined via cell-based in vitro assays. A Caenorhabditis elegans leaky gut model was established to investigate cream effects on gut health. Distinct differences were observed in peptide diversity and sequences released from HC-IMF compared with LC-IMF during simulated digestion (p < 0.05). Higher levels of free fatty acids were absorbed through 21-day differentiated Caco-2/HT-29MTX monolayers from HC-IMF, compared with LC-IMF and HBM (p < 0.05). Furthermore, the immune-modulating properties of HC-IMF appeared to be more similar to HBM than LC-IMF, as observed by comparable secretion of cytokines IL-10 and IL-1ß from THP-1 macrophages (p > 0.05). HC-IMF also supported intestinal recovery in C. elegans following distortion versus LC-IMF (p < 0.05). These observations suggest that cream as a lipid source in IMF may provide added nutritional and functional benefits more aligned with HBM.

Substitutive Effects of Milk vs. Vegetable Milk on the Human Gut Microbiota and Implications for Human Health.

Background: In the last two decades, the consumption of plant-based dairy substitutes in place of animal-based milk has increased in different geographic regions of the world. Dairy substitutes of vegetable origin have a quantitative composition of macronutrients such as animal milk, although the composition of carbohydrates, proteins and fats, as well as bioactive components, is completely different from that of animal milk. Many milk components have been shown to have relevant effects on the intestinal microbiota. Methods: Therefore, the aim of this review is to compare the effects obtained by previous works on the composition of the gut microbiota after the ingestion of animal milk and/or vegetable beverages. Results: In general, the results obtained in the included studies were very positive for animal milk intake. Thus, we found an increase in gut microbiota richness and diversity, increase in the production of short-chain fatty acids, and beneficial microbes such as Bifidobacterium, lactobacilli, Akkermansia, Lachnospiraceae or Blautia. In other cases, we found a significant decrease in potential harmful bacteria such as Proteobacteria, Erysipelotrichaceae, Desulfovibrionaceae or Clostridium perfingens after animal-origin milk intake. Vegetable beverages have also generally produced positive results in the gut microbiota such as the increase in the relative presence of lactobacilli, Bifidobacterium or Blautia. However, we also found some potential negative results, such as increases in the presence of potential pathogens such as Enterobacteriaceae, Salmonella and Fusobacterium. Conclusions: From the perspective of their effects on the intestinal microbiota, milks of animal origin appear to be more beneficial for human health than their vegetable substitutes. These different effects on the intestinal microbiota should be considered in those cases where the replacement of animal milks by vegetable substitutes is recommended.

The impact of genetic variants related to the fatty acid metabolic process pathway on milk production traits in Jersey cows.

The synthesis of fatty acids plays a critical role in shaping milk production characteristics in dairy cattle. Thus, identifying effective haplotypes within the fatty acid metabolism pathway will provide novel and robust insights into the genetics of dairy cattle. This study aimed to comprehensively examine the individual and combined impacts of fundamental genes within the fatty acid metabolic process pathway in Jersey cows. A comprehensive phenotypic dataset was compiled, considering milk production traits, to summarize a cow's productivity across three lactations. Genotyping was conducted through PCR-RFLP and Sanger sequencing, while the association between genotype and phenotype was quantified using linear mixed models. Moderate biodiversity and abundant variation suitable for haplotype analysis were observed across all examined markers. The individual effects of the FABP3, LTF and ANXA9 genes significantly influenced both milk yield and milk fat production. Additionally, this study reveals novel two-way interactions between genes in the fatty acid metabolism pathway that directly affect milk fat properties. Notably, we identified that the GGAAGG haplotype in FABP3×LTF×ANXA9 interaction may be a robust genetic marker concerning both milk fat yield and percentage. Consequently, the genotype combinations highlighted in this study serve as novel and efficient markers for assessing the fat content in cow's milk.

The Ruminal Microbiome Alterations Associated with Diet-Induced Milk Fat Depression and Milk Fat Globule Size Reduction in Dairy Goats.

The aim of this study was to evaluate the effect of conjugated linoleic acid (CLA) on milk fat globule (MFG) size and the ruminal microbiome of goats. Twenty-four mid-lactation Saanen dairy goats weighing 49 ± 4.5 kg (168 ± 27 d in milk, 1.2 ± 0.1 kg milk/d, 2-3 years old) were randomly divided into four groups-a control (CON) group, which was fed a basal diet, and three CLA supplementation groups, in which 30 g CLA (low-dose group, L-CLA), 60 g CLA (medium-dose group, M-CLA), or 90 g CLA (high-dose group, H-CLA) was added to the basal diet daily. The experiment lasted for 21 days, during which time goat milk was collected for composition and MFG size analysis. On day 21 of feeding, ruminal fluid was collected from the CON and H-CLA groups for analysis of the changes in microorganismal abundance. The results showed that CLA supplementation did not affect milk production, milk protein, or lactose content in the dairy goats (p > 0.05), but significantly reduced the milk fat content (p < 0.01) compared with the CON group. The CLA supplementation significantly decreased the D[3,2] and D[4,3] of the MFGs in a dose-dependent manner (p < 0.01). Moreover, dietary CLA inclusion increased the proportion of small-sized MFGs and decreased that of large-sized ones. The results of 16S rRNA gene sequencing showed that CLA-induced milk fat depression in dairy goats was accompanied by significant changes in the relative abundance of ruminal bacterial populations, most of which belonged to the Firmicutes and Bacteroidetes phyla. The relative abundance of Rikenellaceae_RC9_gut_group and Prevolellaceae_UCG-003 in Bacteroidetes and UCG-002, Succiniclasticum, and norank_f__norank_o__Clostridia_vadinBB60_group in Firmicutes was significantly higher in the CON group than in the H-CLA group. In contrast, the relative abundance of norank_f__UCG-011, norank_f_Eubacterium_coprostanoligenes_group, unclassified_f__Lachnospiraceae, and UCG-001 in Firmicutes and norank_f__Muribaculaceae in Bacteroidetes was significantly higher in the H-CLA group than in the CON group. Correlation analysis showed that the milk fat content was negatively correlated with the relative abundance of some bacteria, including members of Firmicutes and Bacteroidetes. Similarly, MFG size (D[3,2] and D[4,3]) was negatively correlated with several members of Firmicutes and Bacteroidetes, including Lachnospiraceae, norank_f__UCG-011, UCG-001, norank_f__Eubacterium_coprostanoligenes_group (Firmicutes), and norank_f__Muribaculaceae (Bacteroidetes), while positively correlated with the relative abundance of some members of Firmicutes and Bacteroidetes, including Mycoplasma, Succiniclasticum, norank_f__norank_o__Clostridia_vadinBB60_group, UCG-002 (Firmicutes), and Rikenellaceae_RC9_gut_group (Bacteroidetes). Overall, our data indicated that CLA treatment affected milk fat content and MFG size in dairy goats, and these effects were correlated with the relative abundance of ruminal bacterial populations. These results provide the first evidence to explain the mechanism underlying diet-induced MFG from the perspective of the ruminal microbiome in dairy goats.