Exploring the health benefits and functional properties of goat milk proteins

Transcriptome analysis of mammary epithelial cell between Sewa sheep and East FriEsian sheep from different localities

Mammary epithelial cells, the only milk-producing cell type in the mammary gland, undergo dynamic proliferation and differentiation during pregnancy, culminating in lactation postpartum. The East FriEsian sheep ranks among the world's most prolific dairy breeds, while the Sewa sheep, a unique dual-purpose breed autochthonous to the Qinghai-Tibet Plateau, exhibits significantly lower milk production. Employing tissue culture methods, we successfully established mammary epithelial cell lines from both breeds. Morphological assessment of mammary epithelial cells and immunofluorescence identification of Cytokeratin 7 and Cytokeratin 8 confirmed the epithelial identity of the isolated cells. Subsequent RNA-seq analysis of these in vitro epithelial cell lines revealed 1813 differentially expressed genes (DEGs). Among these, 1108 were significantly up-regulated and 705 were down-regulated in Sewa epithelial sheep cells compared to East FriEsian epithelial cells. KEGG enrichment analysis identified cellular processes, environmental information processing, human diseases, metabolism, and organismal systems as the primary functional categories associated with DEGs. Gene ontology (GO) terms annotation, categorized into molecular function, biological processes, and cellular component, yielded "binding and catalytic activity," "molecular function regulator activity," and "cellular process," "biological regulation," and "regulation of biological process" as the top three terms within each domain, respectively. Clusters of Orthologous Groups of proteins (KOG) classification further revealed that "signal transduction mechanisms" accounted for the largest proportion of DEGs among all KOG categories. Finally, based on these analyses, ATF3 and MPP7 were identified as promising candidate genes for regulating lactation.

Unveiling Novel Mechanism of CIDEB in Fatty Acid Synthesis Through ChIP-Seq and Functional Analysis in Dairy Goat

Goat milk is abundant in nutrients, particularly in milk fats, which confer health benefits to humans. Exploring the regulatory mechanism of fatty acid synthesis is highly important to understand milk composition manipulation. In this study, we used chromatin immunoprecipitation sequencing (ChIP-seq) on goat mammary glands at different lactation stages which revealed a novel lactation regulatory factor: cell death-inducing DFFA-like effector B (CIDEB). RT-qPCR results revealed that CIDEB was significantly upregulated during lactation in dairy goats. CIDEB overexpression significantly increased the expression levels of genes involved in fatty acid synthesis (ACACA, SCD1, p < 0.05; ELOVL6, p < 0.01), lipid droplet formation (XDH, p < 0.05), and triacylglycerol (TAG) synthesis (DGAT1, p < 0.05; GPAM, p < 0.01) in goat mammary epithelial cells (GMECs). The contents of lipid droplets, TAG, and cholesterol were increased (p < 0.05) in CIDEB-overexpressing GMECs, and knockdown of CIDEB led to the opposite results. In addition, CIDEB knockdown significantly decreased the proportion of C16:0 and total C18:2. Luciferase reporter assays indicated that X-box binding protein 1 (XBP1) promoted CIDEB transcription via XBP1 binding sites located in the CIDEB promoter. Furthermore, CIDEB knockdown attenuated the stimulatory effect of XBP1 on lipid droplet accumulation. Collectively, these findings elucidate the critical regulatory roles of CIDEB in milk fat synthesis, thus providing new insights into improving the quality of goat milk.

Cross-Over Application of Algerian Dairy Lactic Acid Bacteria for the Design of Plant-Based Products: Characterization of Weissella cibaria and Lactiplantibacillus plantarum for the Formulation of Quinoa-Based Beverage

The food industry constantly seeks new starter cultures with superior characteristics to enhance the sensory and overall quality of final products. Starting from a collection of Algerian dairy (goat and camel) lactic acid bacteria, this work focused on the exploration of the technological and probiotic potential of Weissella cibaria (VR81 and LVT1) and Lactiplantibacillus plantarum R12 strains isolated from raw camel milk and fermented milk, respectively. These bioactive strains were selected for their high performance among ten other LAB strains and were used as starter cultures to develop a novel and nutritionally enhanced dairy-like plant-based yogurt using quinoa (Chenopodium quinoa Willd) as a raw matrix. The strains were evaluated for their antagonistic effects against Listeria innocua, Listeria ivanovii, Staphylococcus aureus, Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa, resilience to acidic and osmotic challenges, and tolerance to gastrointestinal mimicking conditions (i.e., pepsin and bile salt). Their aggregation and adhesion profiles were also analyzed. Furthermore, L. plantarum and W. cibaria were tested in single and co-culture for the fermentation and biocontrol of quinoa. The strains exhibited probiotic properties, including a high potential for biocontrol applications, specifically against L. innocua and P. aeruginosa (20 mm diameter zone with the neutralized cell-free supernatant), which disappeared after protease treatment, suggesting that bioactive peptides might be responsible for the observed antimicrobial effect. Additionally, they demonstrated resilience to acidic (pH 2) and osmotic challenges (1M sucrose), tolerance to gastro-intestinal conditions, as well as good aggregation and adhesion profile. Furthermore, the strains were able to produce metabolites of interest, such as exopolysaccharide (yielding up to 4.7 mg/mL) and riboflavin, reaching considerable production levels of 2.5 mg/L upon roseoflavin selection. The application of W. cibaria and L. plantarum as primary starters (both in single and co-culture) for fermenting quinoa resulted in effective acidification of the matrix (ΔpH of 2.03 units) and high-quality beverage production. in vivo challenge tests against L. innocua showed the complete inhibition of this pathogen when L. plantarum was included in the starter, either alone or in combination with W. cibaria. Both species also inhibited Staphylococcus and filamentous fungi. Moreover, the co-culture of mutant strains of L. plantarum R12d and W. cibaria VR81d produced riboflavin levels of 175.41 µg/100 g in fermented quinoa, underscoring their potential as starters for the fermentation, biopreservation, and biofortification of quinoa while also displaying promising probiotic characteristics.

Chromosome-level dairy goat genome reveals the regulatory landscape of lactation

Goat milk is rich in various nutrients that are beneficial for human health. However, the genomic evolution and genetic basis underlying the nutritional value and unique flavor formation in dairy goats remain poorly understood. In the present study, we generate a chromosome-level genome assembly for dairy goats comprising 2.63 Gb with a contig N50 of 43 Mb and a scaffold N50 of 101 Mb. Genome quality comparisons revealed that the dairy goat genome has higher integrity and continuity than the published goat and sheep genomes. The identification of genes under positive selection in dairy goats highlights potential candidates to explain their high milk production. Comparative genomic analysis elucidates the adaptive evolutionary mechanisms of dairy goats such as strong disease resistance, broad adaptability, and unique milk flavor. Moreover, we demonstrate the conservation of the lactation gene network and identify new potential regulators associated with lipid metabolism. Additionally, we establish the regulatory landscape of lactation for the first time in dairy goats, revealing its unique gene regulatory characteristics. Hence, our study not only provides the first chromosome-level reference genome for dairy goat, but also offers potential research directions for dairy production and genetic improvement.

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.

Impacts of people at-risk of either cow milk allergies or lactose intolerance on their daily calcium intake and bone mineral density

Background

People who are at risk of either cow milk allergies or lactose intolerance may need to avoid consuming milk and milk products, which are well-known abundant sources of calcium (Ca). This limitation in calcium intake could affect bone health. Currently, there is limited knowledge on the impact of avoiding the consumption of milk and milk products on the daily Ca intake and bone mineral density (BMD) of people at risk of cow milk allergies. This study aimed to investigate the differences between the amount of Ca intake and BMD values between people who are at risk of cow milk allergies and those who are not.

Methods

A total of 80 participants were recruited, and further divided into two groups, the at-risk cow milk allergies (AR) group (n = 40) and the normal (NOR) group, using the cow milk allergies and lactose intolerance screening questionnaire. The anthropometric assessment, body composition analyses, 3-day dietary record, and bone mass density (wrist and ankle bones) measurement of all participants were collected using the dual x-ray absorptiometry (DEXA) technique to compare the differences of variables between the two groups.

Results

The participants in the AR group presented a significantly lower amount of Ca intake (317 mg/day) than those in the NOR group (623 mg/day) (p < 0.05). The bone mineral density (BMD) parameters indicated that the NOR group presented significantly higher T-scores and BMD values of the wrist (T-score = -0.27 and BMD = 0.57 g/cm2) and ankle (T-score = -0.01 and BMD = 0.59 g/cm2) bones when compared with the AR group (T-score = -1.96 and BMD = 0.48 g/cm2 for the wrist bone, and T-score = -1.18 and BMD = 0.47 g/cm2 for the ankle bone) (p < 0.05). In addition, the results indicated significantly positive correlations between the amount of Ca intake and the T-scores and BMD values of both the wrist and ankle bones among all participants (p < 0.05).

Conclusion

In this responding sample, participants at risk of cow milk allergies experienced a significantly negative impact on the amount of Ca intake and BMD values. Professionals in nutrition and dietetics should provide nutrition education and strategies that can enhance the Ca intake among this population to help them meet the daily Ca intake recommendation, ultimately leading to better bone health.

Unveiling the Potential of Lactic Acid Bacteria from Serbian Goat Cheese

This study aimed to unleash the potential of indigenous lactic acid bacteria (LAB) originating from traditionally made Serbian goat cheese. Following the isolation and identification of the LAB, the safety aspects of the isolates were evaluated through tests for hemolytic activity and antibiotic sensitivity. The selected isolates were then tested for various technological properties, including growth in methylene blue, proteolytic activity, acidification, curd formation ability in both pure and enriched goat milk, diacetyl production, antagonistic potential against other LAB, and biofilm formation ability. The results indicated that Lactococcus spp., Lacticaseibacillus spp., and Lactiplantibacillus spp. did not exhibit α or β hemolysis, while enterococci displayed α hemolysis. A higher number of isolates demonstrated sensitivity to ampicillin, tetracycline, and streptomycin, while sensitivity to gentamicin and vancomycin was strain-dependent. Based on the evaluation of technological properties, Lacticaseibacillus paracasei M-1 and Lactiplantibacillus plantarum C7-7, C7-8, and C14-5 showed promising characteristics. Additionally, Lactococcus lactis subsp. lactis strains C0-14 and C21-8 emerged as promising candidates with notable technological properties. Notably, certain indigenous strains LAB exhibit promising technological properties and safety profiles. These characteristics make them suitable candidates for use as starter or adjunct cultures in goat's milk cheese production, potentially enhancing the quality and safety of the cheese as well as hygiene practices among small-scale dairy producers.

Goat milk exosomal microRNAs alleviate LPS-induced intestinal inflammation in mice

Intestinal inflammation is a common digestive system disease. Milk-derived exosomes can participate in intercellular communication and transport a variety of bioactive components, and the microRNAs (miRNAs) they carry play important roles in a variety of biological processes in the body. At present, the preventive effect and mechanism of action of goat milk exosomes and their derived miRNAs on intestinal inflammation are still unclear. In this study, the protective effect of goat milk exosomes on LPS-induced intestinal inflammation was investigated using mouse intestinal inflammation model and IEC-6 cell inflammation model. Small RNA sequencing was used to analyze the miRNA expression profile of goat milk exosomes. In this study, C-Exo and M-Exo alleviated intestinal inflammation by reducing the LPS-induced release of proinflammatory cytokines, inhibiting the increase in the NLRP3 protein and the activation of the TLR4/NFκB signaling pathway. C-Exo has a more significant inhibitory effect on them, and better therapeutic efficacy than M-Exo. Notably, the target genes of miRNAs in C-Exo and M-Exo were significantly enriched in immune-related pathways. Furthermore, their derived miR-26a-5p and miR-30a-5p were found to ameliorate the IEC-6 inflammatory response. These findings suggest that miRNAs in goat milk exosomes have the potential to attenuate LPS-induced intestinal inflammation.

Total Replacement of Soybean Meal with Sundried Soymilk Residue in the Total Mixed Ration has a Negative Impact on Intake, Digestibility, and Milk Production in Dairy Goats

This study aimed to evaluate whether total replacement of soybean meal (SBM) with sundried soymilk residue (SSR) in a total mixed ration (TMR) affects intake, digestibility, milk production, and blood metabolites in dairy goats. A total of 12 healthy Saanen dairy goats (40.12 ± 5.80 kg of BW) in midlactation (31.23 ± 10.12 days) were used in a randomized complete design (n = 4 goats/group). Dietary treatments were based on a TMR as follows: control TMR without SSR (CON) or SBM-based TMR with 50% or 100% of SSR replacing SBM (SSR-50 and SSR-100, respectively). All goats had ad libitum access to feed and clean water throughout the experiment. The dry matter (DM) intake decreased (p < 0.05) with the increasing replacement ratio of SBM and was lowest in the SSR-100 group. Similarly, organic matter (OM) digestibility was lowest (p < 0.05) in the SSR-100 group. However, the digestibility of DM, CP, NDF, and ADF did not change (p > 0.05) by dietary treatments. Compared with CON, the milk yield decreased significantly (p < 0.05) with increasing replacement ratio of SBM. In contrast, milk composition such as total solids, solids-not-fat, milk fat, lactose, protein, and pH were not influenced (p > 0.05) by feeding dietary SSR. Compared with other treatments, blood glucose concentration was lower (p < 0.05) in the SSR-100 group. In contrast, packed cell volume, glucose, and plasma urea nitrogen concentrations did not differ (p > 0.05). The results indicated that SSR could replace SBM in a TMR at less than 50%. Thus, the present study provides support for further investigation to enhance the utilization of soybean waste as an alternative protein source in the TMR for dairy goats and potentially other ruminants.

Microproteomic-Based Analysis of the Goat Milk Protein Synthesis Network and Casein Production Evaluation

Goat milk has been consumed by humans since ancient times and is highly nutritious. Its quality is mainly determined by its casein content. Milk protein synthesis is controlled by a complex network with many signal pathways. Therefore, the aim of our study is to clearly depict the signal pathways involved in milk protein synthesis in goat mammary epithelial cells (GMECs) using state-of-the-art microproteomic techniques and to identify the key genes involved in the signal pathway. The microproteomic analysis identified more than 2253 proteins, with 323 pathways annotated from the identified proteins. Knockdown of IRS1 expression significantly influenced goat casein composition (α, β, and κ); therefore, this study also examined the insulin receptor substrate 1 (IRS1) gene more closely. A total of 12 differential expression proteins (DEPs) were characterized as upregulated or downregulated in the IRS1-silenced sample compared to the negative control. The enrichment and signal pathways of these DEPs in GMECs were identified using GO annotation and KEGG, as well as KOG analysis. Our findings expand our understanding of the functional genes involved in milk protein synthesis in goats, paving the way for new approaches for modifying casein content for the dairy goat industry and milk product development.