Longitudinal characterization of the metabolome of dairy cows transitioning from one lactation to the next: Investigations in blood serum.

The objective of this study was to characterize changes in the serum metabolome and various indicators of oxidative balance in dairy cows starting 2 wk before dry-off and continuing until wk 16 of lactation. Twelve Holstein dairy cows (body weight 745 ± 71 kg, body condition score 3.43 ± 0.66; mean ± SD) were housed in a tiestall barn from 10 wk before to 16 wk after parturition. Cows were dried off 6 wk before the expected calving date (mean dry period length = 42 d). From 8 wk before calving to 16 wk after calving, blood samples were taken weekly to study redox metabolism by determining antioxidant capacity, measured as the ferric-reducing ability of plasma, reactive oxidative metabolites, oxidative stress index, oxidative damage of lipids, measured as thiobarbituric acid reactive substances, and glutathione peroxidase activity. According to these results, dairy cows had the lowest serum antioxidant capacity and greater levels of oxidative stress during the dry-off period and the early postpartum period. For metabolomics, a subset of serum samples including wk -7 (before dry-off), -5 (after dry-off), -1, 1, 5, 10, and 15 relative to calving were used. A targeted metabolomics approach was performed using liquid chromatography and flow injection with electrospray ionization triple quadrupole mass spectrometry using the MxP Quant 500 kit (Biocrates Life Sciences AG). A total of 240 metabolites in serum were used in the final data analysis. Principal component analysis revealed a clear separation by days of sampling, indicating a remarkable shift in metabolic phenotype between the dry period and late and early lactation. Changes in many non-lipid metabolites associated with one-carbon metabolism, the tricarboxylic acid cycle, the urea cycle, and AA catabolism were observed in the study, with changes in AA serum concentrations likely related to factors such as energy and nitrogen balance, digestive efficiency, and changing diets. The study confirmed an extensive remodeling of the serum lipidome in peripartum dairy cows, highlighting the importance of changes in acylcarnitine (acylCN), phosphatidylcholines (PC), and triacylglycerols (TG), as they play a crucial role in lipid metabolism. Results showed that short-chain acylCN increased after dry-off and decreased thereafter, whereas lipid-derived acylCN increased around parturition, suggesting that more fatty acids could enter mitochondria. Phospholipids and sphingolipids in serum showed changes during lactation. In particular, concentrations of sphingomyelins, PC, and lysoPC decreased around calving but increased in mid- and late lactation. In contrast, concentrations of TG remained consistently low after parturition. The serum concentrations of bile acids fluctuated during the dry period and lactation, with glycocholic acid, cholic acid, glycodeoxycholic acid, and taurocholic acid showing the greatest concentrations. These changes are likely due to the interplay of diet, liver function, and the ability of the gut microbiota to convert primary to secondary bile acids. Overall, these descriptive results may aid in hypothesis generation and in the design and interpretation of future metabolite-based studies in dairy cows. Furthermore, they contribute to our understanding of the physiological ranges in serum metabolites relative to the lactation cycle of the dairy cow.

Mammary epithelial cell transcriptome reveals potential roles of lncRNAs in regulating milk synthesis pathways in Jersey and Kashmiri cattle.

BACKGROUND: Long noncoding RNAs (lncRNAs) are now proven as essential regulatory elements, playing diverse roles in many biological processes including mammary gland development. However, little is known about their roles in the bovine lactation process. RESULTS: To identify and characterize the roles of lncRNAs in bovine lactation, high throughput RNA sequencing data from Jersey (high milk yield producer), and Kashmiri cattle (low milk yield producer) were utilized. Transcriptome data from three Kashmiri and three Jersey cattle throughout their lactation stages were utilized for differential expression analysis. At each stage (early, mid and late) three samples were taken from each breed. A total of 45 differentially expressed lncRNAs were identified between the three stages of lactation. The differentially expressed lncRNAs were found co-expressed with genes involved in the milk synthesis processes such as GPAM, LPL, and ABCG2 indicating their potential regulatory effects on milk quality genes. KEGG pathways analysis of potential cis and trans target genes of differentially expressed lncRNAs indicated that 27 and 48 pathways were significantly enriched between the three stages of lactation in Kashmiri and Jersey respectively, including mTOR signaling, PI3K-Akt signaling, and RAP1 signaling pathways. These pathways are known to play key roles in lactation biology and mammary gland development. CONCLUSIONS: Expression profiles of lncRNAs across different lactation stages in Jersey and Kashmiri cattle provide a valuable resource for the study of the regulatory mechanisms involved in the lactation process as well as facilitate understanding of the role of lncRNAs in bovine lactation biology.

Carotenoid profile in breast milk and maternal and cord plasma: a longitudinal study in Southwest China.

Carotenoids are increasingly being implicated to have an important role in brain and eye development. This study aimed to quantify the content and profile of carotenoids in human breast milk, maternal plasma and neonatal umbilical cord plasma in Chengdu, an urban area in Southwest China. In this study, fifty-four healthy mothers were enrolled. Maternal blood, umbilical cord blood, colostrum, transitional milk and mature milk were collected. Concentrations of carotenoids (lutein, zeaxanthin, ß-cryptoxanthin, ß-carotene and lycopene) were analysed by HPLC. We found that carotenoid concentrations decreased from colostrum to mature milk. Hydrocarbon carotenoids with weaker polarity decreased more than the polar carotenoids. Lycopene concentrations dropped by 99 %, ß-carotene by 92 %, ß-cryptoxanthin by 83 %, lutein by 32 % and zeaxanthin by 22 %. Lycopene and ß-carotene accounted for 70 % of the total carotenoids in colostrum, and lutein predominated amongst carotenoids in transitional milk and mature milk (51-55 %). Carotenoid concentrations in maternal plasma were much higher than that in cord plasma. Lutein predominated in cord plasma. The concentrations of all carotenoids in maternal plasma were correlated with those of cord plasma and human milk. These results are consistent with selective transport mechanisms in the mammary gland related to the polarity of carotenoids, and each carotenoid has its own implications, which may have different priorities in the early life development of infants. These findings may help guide dietary recommendations for carotenoid inclusion in infant formulas.

Lactational changes of fatty acids and fat-soluble antioxidants in human milk from healthy Chinese mothers.

Human milk fat is specially tailored to supply the developing infant with adequate and balanced nutrients. The present study aimed to quantify the composition of fatty acids, tocopherols and carotenoids in human milk, with special emphasis on the lactational changes. Colostrum, transitional and mature milk samples were collected longitudinally from the same forty-two healthy, well-nourished Chinese mothers. Fatty acids were quantified by GC with carotenoids (carotenes and xanthophylls) and tocopherols (α-, γ-tocopherol) determined by HPLC. Total fatty acid (TFA) content increased from 15·09 g/l in colostrum to 32·57 g/l in mature milk with the percentages of DHA and arachidonic acid (ARA) decreased. The ratio of n-6:n-3 PUFA and ARA:DHA remained constant during lactation at about 11:1 and 1·3:1, respectively. Both α-tocopherol and γ-tocopherol decreased over lactation with the ratio of α-:γ-tocopherol declined significantly from 7·21:1 to 4·21:1 (P < 0·001). Carotenoids all dropped from colostrum to mature milk as the less polar carotenes dropped by 88·67 %, while xanthophylls only dropped by 35·92 %. Lutein was predominated in both transitional and mature milk carotenoids (51·64-52·49 %), while colostrum carotenoids were mainly composed of lycopene (32·83 %) and ß-carotene (30·78 %). The concentrations of tocopherols and xanthophylls but not carotenes were positively associated with TFA content in milk. These results suggested that colostrum and mature milk contained divergent lipid profiles and selective transfer mechanisms related to polarity might be involved. The present outcomes provide new insights for future breast-feeding studies, which also add in scientific evidences for the design of both initial and follow-on infant formulas.

Fatty acid positional distribution (sn-2 fatty acids) and phospholipid composition in Chinese breast milk from colostrum to mature stage.

This study quantified the fatty acid profile with emphasis on the stereo-specifically numbered (sn) 2 positional distribution in TAG and the composition of main phospholipids at different lactation stages. Colostrum milk (n 70), transitional milk (n 96) and mature milk (n 82) were obtained longitudinally from healthy lactating women in Shanghai. During lactation, total fatty acid content increased, with SFA dominating in fatty acid profile. A high ratio of n-6:n-3 PUFA was observed as 11:1 over lactation due to the abundance of linoleic acid in Chinese human milk. As the main SFA, palmitic acid showed absolute sn-2 selectivity, while oleic acid, linoleic acid and α-linolenic acid, the main unsaturated fatty acids, were primarily esterified at the sn-1 and sn-3 positions. Nervonic acid and C22 PUFA including DHA were more enriched in colostrum with an sn-2 positional preference. A total of three dominant phospholipids (phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM)) were analysed in the collected samples, and each showed a decline in amount over lactation. PC was the dominant compound followed by SM and PE. With prolonged breast-feeding time, percentage of PE in total phospholipids remained constant, but PC decreased, and SM increased. Results from this study indicated a lipid profile different from Western reports and may aid the development of future infant formula more suitable for Chinese babies.

Quantitative proteome analysis of bovine mammary gland reveals protein dynamic changes involved in peak and late lactation stages.

Mammary gland is an important organ for milk synthesis and secretion. It undergoes dramatic physiological changes to adapt the shift from peak to late lactation stage. Protein plays a final very vital role in many life functions, and the protein changes during different lactation stages potentially reflect the biology of lactation and the functions of mammary gland in cows. In current study, we adopted tandem mass tags label-based quantitative analysis technique and to investigate proteome changes occurring in bovine mammary gland from peak to late lactation stages. A total of 3753 proteins from mammary tissues taken at two lactation points from four individual cows by biopsy were quantified, out of which 179 proteins were expressed differentially between two stages. We observed five new DEPs (AACS, DHCR7, GSTM3, SFRP1 and SFRP4) and nine functional well-studies known proteins (PLIN2, LPIN1, PLIN3, GSN, CD74, MMP2, SOD1, SOD3 and GPX3) related to milk performance and mammary morphology. Bioinformatics analyses of the DEPs showed a majority of the up-regulated proteins during late lactation stage were related to apoptosis and immune process, while the downregulated proteins were mainly involved in localization, lipid metabolic and transport process. This suggests that the mammary gland can adapt to different molecular functions according to the biological need of the animal. From the integrated analysis of the differentially expressed proteins with known quantitative trait loci and genome-wide association study data, we identified 95 proteins may potentially affect milking performance. We expect findings in this study could be a valuable resource for future studies investigating the bovine proteome and functional studies.

Characterization and discrimination of donkey milk lipids and volatiles across lactation stages.

The lipid and flavor in milk are key factors that affect its quality, which profiles during donkey lactation are not yet clear. In this study, the lipids and volatile compounds (VOCs) in donkey milk from stages of lactation were analyzed by using LC-MS and GC-IMS. A total of 1774 lipids were identified in donkey milk, spanning over 6 major categories and attributed to 30 subclasses. The 233 differentially expressed lipids were identified between donkey colostrum and mature milk, which participate in 20 metabolic pathways, including glycerophospholipid, linoleic acid, and sphingolipid. Additionally, 35 VOCs in donkey milk were identified, including 28.57% aldehydes, 28.57% ketones, 25.71% esters, and 8.57% alcohols. Of these VOCs, 15 were determined to be characteristic flavors in donkey milk, mainly including methyl 2-methylbutanoate, 2-pentanone, and butyl acetate. 11 significantly different VOCs were found between the groups. Acetone, 2-heptanone, and ethyl acetate-m were considered potential discriminatory markers.

Microbial Quality of Donkey Milk during Lactation Stages.

The microbial community in donkey milk and its impact on the nutritional value of donkey milk are still unclear. We evaluated the effects of different lactation stages on the composition and function of donkey milk microbiota. The milk samples were collected at 1, 30, 60, 90, 120, 150, and 180 days post-delivery. The result showed that the microbial composition and functions in donkey milk were significantly affected by different lactation stages. The dominant bacterial phyla in donkey milk are Proteobacteria (60%) and Firmicutes (22%). Ralstonia (39%), Pseudomonas (4%), and Acinetobacter (2%) were the predominant bacterial genera detected in all milk samples. In the mature milk, the abundance of lactic acid bacteria Streptococcus (7%) was higher. Chloroplast (5%) and Rothia (3%) were more plentiful in milk samples from middle and later lactation stages (90-180 d). Furthermore, the pathogens Escherichia-Shigella and Staphylococcus and thermoduric bacteria Corynebacterium, Arthrobacter, and Microbacterium were also detected. Donkey milk is rich in beneficial bacteria and also poses a potential health risk. The above findings have improved our understanding of the composition and function changes of donkey milk microbiota, which is beneficial for the rational utilization of donkey milk.

Longitudinal changes in choline concentration and associated factors in human breast milk.

BACKGROUND: Human breast milk is the primary source of choline and choline-containing compounds for infants at early stages of life. Choline data across lactation in Chinese human milk were limited. OBJECTIVE: This study aimed to quantify the five choline compounds in Chinese human breast milk and explore associated factors. METHODS: A total of 540 lactating mothers from the MUAI (Maternal Nutrition and Infant Investigation) study were included. The content of water-soluble choline (free choline, phosphocholine, glycerophosphocholine) and lipid-soluble choline (phosphatidylcholine, sphingomyelin) in 892 human milk samples collected from 0 to 400 days postpartum were examined, and associated factors were explored. RESULTS: Choline concentrations in human milk varied from postpartum day 0-400 (92.06 ± 65.22 to 171.01 ± 47.84 mg/L). Water-soluble choline was the major component (88.6%-93.8%) in human milk and ranged from 793.03 (659.22) to 1544.43 (443.32) µmol/L. Its trajectory followed that of total choline, increasing from colostrum to transitional milk and then declining in mature milk. In contrast, lipid-soluble choline accounted for 6.2%-11.4% over lactation and had an opposite trajectory. Choline composition varied by delivery mode and parity history. CONCLUSION: The concentrations of individual choline and choline-containing compounds during lactation in Chinese human breast milk were described for the first time. Our results address gaps in extant Chinese human milk choline data and support tailored dietary reference intakes for Chinese lactating women and infants. Our data describes the level and profile of choline from 0 to 400 days postpartum in Chinese human breast milk. This is the most updated data on choline and also the first report of water-soluble choline as the predominant type in Chinese human milk. Our results compensate for the deficiencies in data on choline in Chinese human milk. CLINICAL TRIAL REGISTRATION: Clinical Trial Registry number: ChiCTR1800015387. Web link to study on registry: https://www.chictr.org.cn/index.aspx.

Human Milk Oligosaccharide Profile across Lactation Stages in Israeli Women-A Prospective Observational Study.

Human milk oligosaccharides (HMOs) stimulate the growth of gut commensals, prevent the adhesion of enteropathogens and modulate host immunity. The major factors influencing variations in the HMO profile are polymorphisms in the secretor (Se) or Lewis (Le) gene, which affect the activity of the enzymes fucoslytransferase 2 and 3 (FUT2 and FUT3) that lead to the formation of four major fucosylated and non-fucosylated oligosaccharides (OS). This pilot study aimed to determine the HMO profile of Israeli breastfeeding mothers of 16 term and 4 preterm infants, from a single tertiary center in the Tel Aviv area. Fifty-two human milk samples were collected from 20 mothers at three-time points: colostrum, transitional milk and mature milk. The concentrations of nine HMOs were assessed using liquid chromatography coupled with mass spectra chromatograms. Fifty-five percent of the mothers were secretors and 45% were non-secretors. Infant sex affected HMO levels depending on the maternal secretor status. Secretor mothers to boys had higher levels of FUT2-dependent OS and higher levels of disialyllacto-N-tetraose in the milk of mothers to girls, whereas non-secretor mothers to girls had higher levels of 3'-sialyllactose. In addition, the season at which the human milk samples were obtained affected the levels of some HMOs, resulting in significantly lower levels in the summer. Our findings provide novel information on the irregularity in the HMO profile among Israeli lactating women and identify several factors contributing to this variability.

Hematology Reference Intervals for Holstein Cows in Southern China: A Study of 786 Subjects.

Hematology RIs help clinicians and researchers determine whether a hematology parameter is abnormal, which plays an important role in animal health surveillance. China is one of the largest dairy producers in the world, with millions of Holstein cows. However, there has been no published data on hematology RIs for dairy cows in China yet. Therefore, the aim of this study is to establish updated and accurate RIs for Holstein cows in southern China. To increase the accuracy of the RIs, we collected blood samples from 786 Holstein cows and analyzed 25 hematologic variables. The RIs for Holstein cows were established using the 95% percentile RIs according to the American Society of Veterinary Clinical Pathology guidelines. The effects of different ages, parities and lactation stages were also checked in this study. The data of 21, 22 and 19 out of 25 hematology parameters were significantly different between different ages, parities and lactation stages, respectively. Furthermore, the hematology RIs of separate subclasses according to different ages, parities and lactation stages were generated. Hematology RIs according to ages and lactation stages, as well as parities and lactation stages, were also assessed. Together, our results confirm that hematology RIs for cows vary by ages, parities and lactation stages. The present study helps to fill the gap in hematology RIs for Holstein cows in southern China, and our data may serve as a very useful tool for monitoring the health and welfare of dairy cattle in China.

Genome-wide identification of long noncoding RNA genes and their potential association with mammary gland development in water buffalo.

OBJECTIVE: Water buffalo, an important domestic animal in tropical and subtropical regions, play an important role in agricultural economy. It is an important source for milk, meat, horns, skin, and draft power, especially its rich milk that is the great source of cream, butter, yogurt, and many cheeses. In recent years, long noncoding RNAs (lncRNAs) have been reported to play pivotal roles in many biological processes. Previous studies for the mammary gland development of water buffalo mainly focus on protein coding genes. However, lncRNAs of water buffalo remain poorly understood, and the regulation relationship between mammary gland development/milk production traits and lncRNA expression is also unclear. METHODS: Here, we sequenced 22 samples of the milk somatic cells from three lactation stages and integrated the current annotation and identified 7,962 lncRNA genes. RESULTS: By comparing the lncRNA genes of the water buffalo in the early, peak, and late different lactation stages, we found that lncRNA gene lnc-bbug14207 displayed significantly different expression between early and late lactation stages. And lnc-bbug14207 may regulate neighboring milk fat globule-EGF factor 8 (MFG-E8) and hyaluronan and proteoglycan link protein 3 (HAPLN3) protein coding genes, which are vital for mammary gland development. CONCLUSION: This study provides the first genome-wide identification of water buffalo lncRNAs and unveils the potential lncRNAs that impact mammary gland development.

Vitamin E and beta-carotene status of dairy cows: a survey of plasma levels and supplementation practices.

Culling rate in dairy cattle has increased considerably, thereby reducing cows longevity and raising sustainability concerns worldwide. In the last decades, feeding systems have changed towards larger inclusion of preserved forages and reduced fresh herbage, which may limit vitamin E and beta-carotene dietary supply to dairy cows. Because of higher oxidative stress, engendered by greater milk production of modern genetics, the requirement for these nutrients is increased. Therefore, this study aimed to assess the current status of vitamin E and beta-carotene of commercial dairy cows. Blood vitamin E and beta-carotene concentrations were measured in 2 467 dairy cows from 127 farms in Belgium, Germany, Iberia and The Netherlands, that were visited once. Five cows were randomly selected per lactation stage per farm: Dry (between 30 and 1 day(s) before calving), Very-early (from calving until 15 days in milk (DIM)), Early (between 16 and 119 DIM), and Mid-late (from 120 DIM onwards). In addition, a survey was conducted to retrieve data on vitamin E and beta-carotene supplementation and feeding practices. Vitamin E and beta-carotene blood concentrations dropped considerably around calving. Among all surveyed cows, more than 75 and 44% were deficient in vitamin E and beta-carotene (i.e., blood concentration below 3.0 and 3.5 mg/l, respectively). Of the Very-early group, more than 97 and 78% of the cows were deficient in vitamin E and beta-carotene, respectively, with respective blood concentrations of 1.15 and 2.71 mg/l, which was significantly lower than the other lactation stages. Vitamin E and beta-carotene blood concentrations, as well as their supplementation levels, significantly varied among countries. Vitamin E and beta-carotene blood concentrations were positively related to the total estimated daily intakes of vitamin E and beta-carotene. Therefore, blood concentrations of vitamin E and beta-carotene depend on their respective level of intake, which is generally below recommendations and varies greatly between countries. Supplementation could contribute to provide cows with adequate amounts of vitamin E and beta-carotene all along the lactation, to ensure their lifetime performance and improve their fertility.

Alteration of the goat milk glycoproteins N/O-glycome at different lactation stages.

Goat milk oligosaccharides represent an unexplored multi-functional ingredient for the dairy industry. Here, we qualitatively and quantitatively compared the N/O-glycome at different lactation stages via online hydrophilic interaction chromatography-tandem mass spectrometry. Complex N-glycans and high mannose N-glycans constituted 82.1% and 17.9% of the glycan pool, respectively. N-glycans with isomers containing non-bisected antenna complex structures accounted for 30.8%. N-glycans modified with Neu5Ac, Neu5Gc and fucosylated were 3.7%, 5.3% and 35.3%. The triantennary trifucosylated complex N-glycan (H5N5F3) was reported for the first time. A comparison between colostrum and mature milk revealed a 1.20-fold decrease in total N-glycans and 1.66-fold decrease in fucosylation with ongoing lactation, echoing the trend in human milk. Similarly, Neu5Ac- and Neu5Gc-modified sialylation decreased by 1.69 and 3.62 times, respectively. In the O-glycome, 46.2% of structures were O-linked core 1, 23.1% were O-linked core 2, 7.7% were O-linked core 3 and core 4. As lactation progressed, overall O-glycans content decreased by 1.26-fold. Unlike human milk, Neu5Ac- and Neu5Gc-modified sialylation increased by 4.4 and 2 times, respectively. These findings will facilitate research on the structure-function relationship of goat milk oligosaccharides and the development of formula food targeting different age groups.

Relations of Ruminal Fermentation Parameters and Microbial Matters to Odd- and Branched-Chain Fatty Acids in Rumen Fluid of Dairy Cows at Different Milk Stages.

The purpose of this research was to evaluate whether relationships exist between odd- and branched-chain fatty acids (OBCFAs) originating from milk fat and the corresponding data of ruminal fermentation parameters, microbial populations, and base contents that were used to mark microbial protein in rumen. Nine lactating Holstein dairy cows with similar body weights and parity were selected in this study, and the samples of rumen and milk were collected at the early, middle, and late stages, respectively. The rumen and milk samples were collected over three consecutive days from each cow, and the ruminal and milk OBCFA profiles, ruminal fermentation parameters, bacterial populations, and base contents were measured. The results showed that the concentrations of OBCFAs, with the exception of C11:0 and C15:0, were significantly different between milk and rumen (p < 0.05). The concentrations of anteiso-fatty acids in milk were higher than those in rumen, and the contents of linear odd-chain fatty acids were higher than those of branched-chain fatty acids in both milk and rumen. Significant relationships that existed between the concentrations of C11:0, iso-C15:0, anteiso-C15:0, C15:0, and anteiso-C17:0 in rumen and milk (p < 0.05). The total OBCFA content in milk was positively related to the acetate molar proportion but negatively correlated with isoacid contents (p < 0.05). The populations of Ruminococcus albus, R. flavefacients, and Eubacterium ruminantium were significantly related to milk C13:0 contents (p < 0.05). The adenine/N ratio was negatively related to milk OBCFA content (p < 0.05) but positively associated with the iso-C15:0/iso-C17:0 ratio (p < 0.05). Milk OBCFAs were significantly correlated with ruminal fermentation parameters, ruminal bacterial populations, and base contents. Milk OBCFAs had the potential to predict microbial nitrogen flow, and the prediction equations for ruminal microbial nitrogen flow were established for OBCFAs in dairy milk.

Milk-derived mammary epithelial cells as non-invasive source to define stage-specific abundance of milk protein and fat synthesis transcripts in native Sahiwal cows and Murrah buffaloes.

The molecular physiology of milk production of two important dairy species; Sahiwal cows (Bos indicus) and Murrah buffaloes (Bubalus bubalis) are not fully understood due to constraints in obtaining mammary tissue samples because of sacred and ethical reasons. The present study suggests the use of milk-derived mammary epithelial cells (MECs) as a non-invasive method to understand molecular aspects of lactation biology in dairy animals. A total of 76 MECs were collected from five different lactation periods viz. colostrum (0-2), early (5-20), peak (30-50), mid (90-140) and late lactation (> 215 days) stages from Sahiwal cows and Murrah buffaloes to study the transcription kinetics of milk protein, fat synthesis, and their regulatory genes. Significant changes were observed in milk composition of both dairy species with lactation stages. High mRNA abundance of all milk protein and fat synthesis genes was observed in MECs of Murrah buffaloes as compared to Sahiwal cows. The mRNA abundance of caseins (CSN1S1, CSN1S2, CSN2, and CSN3) and whey protein (LALBA, LF) were higher in early lactation stage. Similarly, the expression of milk fat synthesis genes (SCD, BTN1A1, ACACA, GPAM, FAPB3, FASN) was also high in early lactation stage. The relative abundance of 4 regulatory genes (JAK2, STAT5, SREBF1 and EIF4BP41) remained high during early lactation indicating their regulatory roles in lactogenesis process. Overall, results suggested a significant effect of lactation stages on milk composition and transcription abundance of milk protein and fat synthesis genes. The present study establishes the fact that milk-derived MECs could be utilized as a valuable source to understand mammary gland functioning of native cows and buffaloes.

Bovine Milk Comparative Proteome Analysis from Early, Mid, and Late Lactation in the Cattle Breed, Malnad Gidda (Bos indicus).

Bovine milk is important for both veterinary medicine and human nutrition. Understanding the bovine milk proteome at different stages of lactation has therefore broad significance for integrative biology and clinical medicine as well. Indeed, different lactation stages have marked influence on the milk yield, milk constituents, and nourishment of the neonates. We performed a comparative proteome analysis of the bovine milk obtained at different stages of lactation from the Indian indigenous cattle Malnad Gidda (Bos indicus), a widely available breed. The milk differential proteome during the lactation stages in B. indicus has not been investigated to date. Using high-resolution mass spectrometry-based quantitative proteomics of the bovine whey proteins at early, mid, and late lactation stages, we identified a total of 564 proteins, out of which 403 proteins were found to be differentially abundant at different lactation stages. As is expected of any body fluid proteome, 51% of the proteins identified in the milk were found to have signal peptides. Gene ontology analyses were carried out to categorize proteins altered across different lactation stages based on biological process and molecular function, which enabled us to correlate their significance in each lactation stage. We also investigated the potential pathways enriched in different lactation stages using bioinformatics pathway analysis tools. To the best of our knowledge, this study represents the first and largest inventory of milk proteins identified to date for an Indian cattle breed. We believe that the current study broadly informs both veterinary omics research and the emerging field of nutriproteomics during lactation stages.

Changes in Caprine Milk Oligosaccharides at Different Lactation Stages Analyzed by High Performance Liquid Chromatography Coupled to Mass Spectrometry.

Changes of the abundance of caprine milk oligosaccharides (CMO) at different lactation stages have been evaluated by hydrophilic interaction liquid chromatography coupled to mass spectrometry (HILIC-Q MS) and nanoflow liquid chromatography-quadrupole-time-of-flight mass spectrometry (nano-LC-Chip-QTOF MS). Eight major oligosaccharides (OS) were quantified at different lactation stages by HILIC-Q MS, while the use of nano-LC-Chip-QToF MS allowed expanding the study to forty-nine different OS by monitoring neutral non- and fucosylated species, as well as acidic species containing not only N-acetyl-neuraminic acid or N-glycolyl-neuraminic acid residues but also the combination of both sialic acids. Overall, the most abundant OS decreased with lactation time, whereas different trends were observed for minor OS. 6'-Sialyl-lactose was the most abundant acidic OS while galactosyl-lactose isomers were identified as the most abundant neutral OS. This is the first time that a comprehensive study regarding the changes of the abundance of CMO, both neutral and acidic, at different lactation stages is carried out.