Metabonomic analysis of human and 12 kinds of livestock mature milk

Label-free quantitative proteomic analysis of functional changes of goat milk whey proteins subject to heat treatments of ultra-high-temperature and the common low-temperature

This work investigated the functional changes in whey proteins obtained from goat milk subject to various temperature treatments. Ultra-high temperature instantaneous sterilization (UHTIS) caused less damage than the common low-temperature, whereas spray-drying treatment had the opposite effect. A total of 426 proteins were identified in UHTIS and control treatment groups, including 386 common proteins and 16 and 14 unique proteins. The UHTIS treatment upregulated 55 whey proteins while down-regulated 98. The UHTIS-treated whey proteins may upregulate three metabolic pathways but downregulate one. Overall, UHTIS only slightly impacted the composition and functions of whey proteins from goat milk compared to the common low-temperature treatments.

Common proteins analysis of different mammals' mature milk by 4D-Label-Free

The milk proteins from samples of 13 different animals were identified utilizing 4D-Label-Free proteomics technology, leading to the identification of a substantial number of proteins. Among the various samples, Chinese people (CHP) milk proteins exhibited the highest count, with 1149 distinct proteins. Simultaneously, we identified common proteins present in these animal milk. It's notable presence in goat milk contributes to enhancing infant infection resistance, showcasing the beneficial role of lactoperoxidase. Galectin-3 binding protein (Gal-3BP) and tetraspanin in human milk are significantly higher than those in other animals, which determine the prominent antiviral effect of human milk and the important processes related to cell transduction. Furthermore, human milk, camel milk, goat milk and sheep milk proved to be rich sources of milk fat globule membrane (MFGM) proteins. The insights obtained from this study can serve as a foundational framework for exploring the role of different animal milk proteins in disease treatment and the composition of infant formula.

Multiomics analysis revealed that the metabolite profile of raw milk is associated with lactation stage of dairy cows and could be affected by variations in the ruminal microbiota

The nutritional components and quality of milk are influenced by the rumen microbiota and its metabolites at different lactation stages. Hence, rumen fluid and milk samples from 6 dairy cows fed the same diet were collected during peak, early mid- and later mid-lactation. Untargeted metabolomics and 16S rRNA sequencing were applied for analyzing milk and rumen metabolites, as well as rumen microbial composition, respectively. The levels of lipid-related metabolites, L-glutamate, glucose-1-phosphate and acetylphosphate in milk exhibited lactation-dependent attenuation. Maltol, N-acetyl-D-glucosamine, and choline, which are associated with milk flavor or coagulation properties, as well as L-valine, lansioside-A, clitocine and ginsenoside-La increased significantly in early mid- and later mid-lactation, especially in later mid-lactation. The obvious increase in rumen microbial diversities (Ace and Shannon indices) were observed in early mid-lactation compared with peak lactation. Twenty-one differential bacterial genera of the rumen were identified, with Succinivibrionaceae_UCG-001, Candidatus Saccharimonas, Fibrobacter, and SP3-e08 being significantly enriched in peak lactation. Rikenellaceae_RC9_gut_group, Eubacterium_ruminantium_group, Lachnospira, Butyrivibrio, Eubacterium_hallii_group, and Schwartzia were most significantly enriched in early mid-lactation. In comparison, only 2 bacteria (unclassified_f__Prevotellaceae and Prevotellaceae_UCG-001) were enriched in later mid-lactation. For rumen metabolites, LPE(16:0), L-glutamate and L-tyrosine had higher levels in peak lactation, whereas PE(17:0/0:0), PE(16:0/0:0), PS(18:1(9Z)/0:0), L-phenylalanine, dulcitol, 2-(methoxymethyl)furan and 3-phenylpropyl acetate showed higher levels in early mid- and later mid-lactation. Multiomics integrated analysis revealed that a greater abundance of Fibrobacter contributed to phospholipid content in milk by increasing ruminal acetate, L-glutamate and LysoPE(16:0). Prevotellaceae_UCG-001 and unclassified_f_Prevotellaceae provide substrates for milk metabolites of the same category by increasing ruminal L-phenylalanine and dulcitol contents. These results demonstrated that milk metabolomic fingerprints and critical functional metabolites during lactation, and the key bacteria in rumen related to them. These findings provide new insights into the development of functional dairy products.

Deciphering the Mechanism by Which Carbon Dioxide Extends the Shelf Life of Raw Milk: A Microbiomics- and Metabolomics-Based Approach

Microbial community succession in raw milk determines its quality and storage period. In this study, carbon dioxide (CO2) at 2000 ppm was used to treat raw milk to investigate the mechanism of extending the shelf life of raw milk by CO2 treatment from the viewpoint of microbial colonies and metabolites. The results showed that the shelf life of CO2-treated raw milk was extended to 16 days at 4 °C, while that of the control raw milk was only 6 days. Microbiomics analysis identified 221 amplicon sequence variants (ASVs) in raw milk, and the alpha diversity of microbial communities increased (p < 0.05) with the extension of storage time. Among them, Pseudomonas, Actinobacteria and Serratia were the major microbial genera responsible for the deterioration of raw milk, with a percentage of 85.7%. A combined metagenomics and metabolomics analysis revealed that microorganisms altered the levels of metabolites, such as pyruvic acid, glutamic acid, 5'-cmp, arginine, 2-propenoic acid and phenylalanine, in the raw milk through metabolic activities, such as ABC transporters, pyrimidine metabolism, arginine and proline metabolism and phenylalanine metabolism, and reduced the shelf life of raw milk. CO2 treatment prolonged the shelf life of raw milk by inhibiting the growth of Gram-negative aerobic bacteria, such as Acinetobacter guillouiae, Pseudomonas fluorescens, Serratia liquefaciens and Pseudomonas simiae.