Milk Microbiota Composition Research Articles

Fatty acid profile driven by maternal diet is associated with the composition of human milk microbiota

Fatty acid profile driven by maternal diet is associated with the composition of human milk microbiota

Composition of Human Breast Milk Microbiota and Its Role in Children's Health.

Human milk contains a number of nutritional and bioactive molecules including microorganisms that constitute the so-called “Human Milk Microbiota (HMM)”. Recent studies have shown that not only bacterial but also viral, fungal, and archaeal components are present in the HMM. Previous research has established, a “core” microbiome, consisting of Firmicutes (i.e., Streptococcus, Staphylococcus), Proteobacteria (i.e., Serratia, Pseudomonas, Ralstonia, Sphingomonas, Bradyrhizobium), and Actinobacteria (i.e., Propionibacterium, Corynebacterium). This review aims to summarize the main characteristics of HMM and the role it plays in shaping a child’s health. We reviewed the most recent literature on the topic (2019-2021), using the PubMed database. The main sources of HMM origin were identified as the retrograde flow and the entero-mammary pathway. Several factors can influence its composition, such as maternal body mass index and diet, use of antibiotics, time and type of delivery, and mode of breastfeeding. The COVID-19 pandemic, by altering the mother-infant dyad and modifying many of our previous habits, has emerged as a new risk factor for the modification of HMM.HMM is an important contributor to gastrointestinal colonization in children and therefore, it is fundamental to avoid any form of perturbation in the HMM that can alter the microbial equilibrium, especially in the first 100 days of life. Microbial dysbiosis can be a trigger point for the development of necrotizing enterocolitis, especially in preterm infants, and for onset of chronic diseases, such as asthma and obesity, later in life.

Oligosaccharides and Microbiota in Human Milk Are Interrelated at 3 Months Postpartum in a Cohort of Women with a High Prevalence of Gestational Impaired Glucose Tolerance

BackgroundHuman milk is a rich source of human milk oligosaccharides (HMOs) and bacteria. It is unclear how these components interact within the breast microenvironment. ObjectivesThe objectives were first, to investigate the association between maternal characteristics and HMOs, and second, to assess the association between HMOs and microbial community composition and predicted function in milk from women with high rates of gestational glucose intolerance. MethodsThis was an exploratory analysis of a previously completed prospective cohort study (NCT01405547) where milk samples (n = 107) were collected at 3 mo postpartum. Milk microbiota composition was analyzed by V4-16S ribosomal RNA gene sequencing and HMOs by rapid high-throughput HPLC. Data were stratified and analyzed by maternal secretor status phenotype and associations between HMOs and microbiota were determined using linear regression models (ɑ-diversity), Adonis (B-diversity), Poisson regression models (differential abundance), and general linear models (predicted microbial function). ResultsPrepregnancy BMI, race, and frequency of direct breastfeeding, but not gestational glucose intolerance, were found to be significantly associated with a number of HMOs among secretors and non-secretors. Fucosyllacto-N-hexaose was negatively associated with microbial richness (Chao1) among secretors [B-estimate (SE): −9.3 × 102 (3.4 × 102); P= 0.0082] and difucosyllacto-N-hexaose was negatively associated with microbiota diversity (Shannon index) [−1.7 (0.78); P= 0.029] among secretors. Lacto-N-neotetraose (LNnT) was associated with both microbial B-diversity (weighted UniFrac R2= 0.040, P= 0.036) and KEGG ortholog B-diversity (Bray-Curtis R2= 0.039, P= 0.043) in secretors. Additionally, difucosyllactose in secretors and disialyllacto-N-hexaose and LNnT in non-secretors were associated with enrichment of predicted microbial genes encoding for metabolism- and infection-related pathways (P-false discovery rate < 0.1). ConclusionsHMOs are associated with the microbial composition and predicted microbial functions in human milk at 3 mo postpartum. Further research is needed to investigate the role these relations play in maternal and infant health.

Factors influencing the microbial composition of human milk

Aside from nutritional components, human milk is rich in microorganisms. Through breastfeeding these microorganisms are introduced to the infant gut where they may transiently or persistently colonize it. Therefore, the human milk microbiota may be an important factor which shapes the infant gut microbiota further influencing infant health and disease. In the current review we aim to give a brief updated insight into the putative origin of the human milk microbiota, its constituents and the possible factors that shape it. Understanding the factors that determine the human milk microbiota composition and function will aid developing optimal postnatal feeding and intervention strategies to reduce the risk of communicable and noncommunicable diseases.

PacBio sequencing revealed variation in the microbiota diversity, species richness and composition between milk collected from healthy and mastitis cows.

Mastitis is the economically most important disease of dairy cows. This study used PacBio single-molecule real-time sequencing technology to sequence the full-length 16S rRNAs from 27 milk samples (18 from mastitis and nine from healthy cows; the cows were at different stages of lactation). We observed that healthy or late stage milk microbiota had significantly higher microbial diversity and richness. The community composition of the microbiota of different groups also varied greatly. The healthy cow milk microbiota was predominantly comprised of Lactococcus lactis, Acinetobacter johnsonii, and Bacteroides dorei, while the milk from mastitis cows was predominantly comprised of Bacillus cereus. The prevalence of L. lactis and B. cereus in the milk samples was confirmed by digital droplets PCR. Differences in the milk microbiota diversity and composition could suggest an important role for some these microbes in protecting the host from mastitis while others associated with mastitis. The results of our research serve as useful references for designing strategies to prevent and treat mastitis.

Maternal Prenatal Supplement Intake, but Not Dietary Patterns, Is Associated With Human Milk Microbiota Composition in the CHILD Cohort Study

ObjectivesThe human milk microbiome plays an important role in child health and is affected by several factors. We aim to examine whether prenatal diet and supplement intake are associated with human milk microbiota composition. MethodsAmong the CHILD Cohort Study members, 771 mothers provided data on diet and supplement intake during pregnancy and a milk sample between 2–6 months postpartum. Maternal diet was assessed using a food frequency questionnaire adapted from the Fred Hutchinson Cancer Center. Three dietary patterns were derived using principal component analysis: plant-based, Western, and balanced. The milk microbiome was analyzed using 16S rRNA gene sequencing. Associations between maternal intake and microbial diversity (Shannon index) and genera relative abundances were examined in R using the Wilcoxon signed-rank test adjusted for multiple comparisons. ResultsMaternal supplement intake, but not dietary patterns, was associated with human milk microbiota composition. Approximately 88% of the mothers took prenatal multivitamins. Mothers who took fish oil (18%) or folate supplements (17%) during pregnancy had lower microbial diversity than those who did not (mean ± SD: 1.61 ± 0.64 v. 1.79 ± 0.66 for fish oil [p = 0.01] and 1.64 ± 0.64 v. 1.78 ± 0.67 for folate [P = 0.02]). Mothers who took vitamin C supplements (4%), compared to those who did not, had higher microbial diversity (1.99 ± 0.59 v. 1.72 ± 0.65 [P = 0.03]) and higher relative abundance of Veillonella but lower abundances of Finegoldia and Stenotrophomonas (pfdr < 0.05). Compared to the respective supplement non-takers, mothers who took vitamin D supplements (23%) had lower abundance of unclassified Comamonadaceae (pfdr < 0.05), while mothers who took Ca-containing antacids (11%) had higher abundances of Streptococcus, unclassified Gemellaceae, and Rothia but lower abundances of unclassified Comamonadaceae and unclassified Enterobacteriaceae (pfdr < 0.05). ConclusionsHuman milk microbiota composition differed among mothers who took specific prenatal supplements. Further analysis is needed to explore additional associations while accounting for covariates that impact the human milk microbiome. Funding SourcesCIHR and AllerGen NCE funded the CHILD Cohort Study. The Canadian Lung Association and Canadian Respiratory Research Network funded the milk microbiome sequencing.

Temporal and geographical comparison of bulk tank milk and water microbiota composition in Brazilian dairy farms

This study investigated the relationship between the bacterial communities of bulk tank milk (BTM) and water used in Brazilian dairy farms. We also explored the association between BTM microbiota and its quality parameters (i.e., somatic cell count [SCC] and total bacteria count [TBC]). Water and BTM samples were collected twice for high throughput metataxonomic characterization. Milk samples were collected for SCCs, TBCs, and antimicrobial residue analysis. Water samples were submitted for physico-chemical and microbiological analyses. Overall, the BTM bacterial community was not influenced by the water microbiota. Furthermore, a higher number of Bacillus spp. and a tendency toward a higher number of Lactococcus spp. was associated with a higher TBC, and consequently could be used as an indicator of milk quality. A higher number of Streptococcus spp. and a tendency toward a higher number of Staphylococcus spp. were associated with a higher SCC. Apart from a variation on the content of the Bacillus taxa, no effect of sampling time on BTM bacterial community was observed. Finally, a negative correlation between the number of different species (richness) on BTM and SCC was found.

Longitudinal Study of the Bulk Tank Milk Microbiota Reveals Major Temporal Shifts in Composition.

Introduction of microbial contaminations in the dairy value chain starts at the farm level and the initial microbial composition may severely affect the production of high-quality dairy products. Therefore, understanding the farm-to-farm variation and longitudinal shifts in the composition of the bulk tank milk microbiota is fundamental to increase the quality and reduce the spoilage and waste of milk and dairy products. In this study, we performed a double experiment to study long- and short-term longitudinal shifts in microbial composition using 16S rRNA gene amplicon sequencing. We analyzed milk from 37 farms, that had also been investigated two years earlier, to understand the stability and overall microbial changes over a longer time span. In addition, we sampled bulk tank milk from five farms every 1–2 weeks for up to 7 months to observe short-term changes in microbial composition. We demonstrated that a persistent and farm-specific microbiota is found in bulk tank milk and that changes in composition within the same farm are mostly driven by bacterial genera associated with mastitis (e.g., Staphylococcus and Streptococcus). On a long-term, we detected that major shift in milk microbiota were not correlated with farm settings, such as milking system, number of cows and quality of the milk but other factors, such as weather and feeding, may have had a greater impact on the main shifts in composition of the bulk tank milk microbiota. Our results provide new information regarding the ecology of raw milk microbiota at the farm level.

Microbiota Assessments for the Identification and Confirmation of Slit Defect-Causing Bacteria in Milk and Cheddar Cheese.

Validated methods are needed to detect spoilage microbes present in low numbers in foods and ingredients prior to defect onset. We applied propidium monoazide combined with 16S rRNA gene sequencing, qPCR, isolate identification, and pilot-scale cheese making to identify the microorganisms that cause slit defects in industrially produced Cheddar cheese. To investigate milk as the source of spoilage microbes, bacterial composition in milk was measured immediately before and after high-temperature, short-time (HTST) pasteurization over 10-h periods on 10 days and in the resulting cheese blocks. Besides HTST pasteurization-induced changes to milk microbiota composition, a significant increase in numbers of viable bacteria was observed over the 10-h run times of the pasteurizer, including 68-fold-higher numbers of the genus Thermus However, Thermus was not associated with slit development. Milk used to make cheese which developed slits instead contained a lower number of total bacteria, higher alpha diversity, and higher proportions of Lactobacillus, Bacillus, Brevibacillus, and Clostridium Only Lactobacillus proportions were significantly increased during cheese aging, and Limosilactobacillus (Lactobacillus) fermentum, in particular, was enriched in slit-containing cheeses and the pre- and post-HTST-pasteurization milk used to make them. Pilot-scale cheeses developed slits when inoculated with strains of L. fermentum, other heterofermentative lactic acid bacteria, or uncultured bacterial consortia from slit-associated pasteurized milk, thereby confirming that low-abundance taxa in milk can negatively affect cheese quality. The likelihood that certain microorganisms in milk cause slit defects can be predicted based on comparisons of the bacteria present in the milk used for cheese manufacture.IMPORTANCE Food production involves numerous control points for microorganisms to ensure quality and safety. These control points (e.g., pasteurization) are difficult to develop for fermented foods wherein some microbial contaminants are also expected to provide positive contributions to the final product and spoilage microbes may constitute only a small proportion of all microorganisms present. We showed that microbial composition assessments with 16S rRNA marker gene DNA sequencing are sufficiently robust to detect very-low-abundance bacterial taxa responsible for a major but sporadic Cheddar cheese spoilage defect. Bacterial composition in the (pasteurized) milk and cheese was associated with slit defect development. The application of Koch's postulates showed that individual bacterial isolates as well as uncultured bacterial consortia were sufficient to cause slits, even when present in very low numbers. This approach may be useful for detection and control of low-abundance spoilage microorganisms present in other foods.

Maternal Diet Shapes the Breast Milk Microbiota Composition and Diversity: Impact of Mode of Delivery and Antibiotic Exposure

ABSTRACTBackgroundBreast milk is a complex biofluid that provides nutrients and bioactive agents, including bacteria, for the development of the infant gut microbiota. However, the impact of maternal diet and other factors, such as mode of delivery and antibiotic exposure, on the breast milk microbiota has yet to be understood.ObjectivesThis study aimed to examine the association between maternal diet and breast milk microbiota and to ascertain the potential role of mode of delivery and antibiotic exposure.MethodsIn a cross-sectional study of the MAMI cohort, breast milk microbiota profiling was assessed in 120 samples from healthy mothers by 16S rRNA gene sequencing. Maternal dietary information was recorded through an FFQ, and clinical characteristics, including mode of delivery, antibiotic exposure, and exclusive breastfeeding, were collected.ResultsMaternal diet was grouped into 2 clusters: Cluster I (high intake of plant protein, fiber, and carbohydrates), and Cluster II (high intake of animal protein and lipids). Breast milk microbiota was shaped by maternal dietary clusters. Staphylococcus and Bifidobacterium were associated with carbohydrate intake whereas the Streptococcus genus was associated with intakes of the n–3 PUFAs [EPA and docosapentaenoic acid (22:5ω-3)]. Mode of delivery and antibiotic exposure influenced breast milk microbiota in a diet cluster–dependent manner. Differences between/among the maternal dietary clusters were found in the milk microbiota of the cesarean-section (C-section)/antibiotic group, whereas no differences were observed in vaginal births. Lower abundances of Lactobacillus, Bacteroides, and Sediminibacterium genera were observed in Cluster II/C-section/antibiotic exposure compared with the other groups.ConclusionsMaternal diet shapes the composition and diversity of breast milk microbiota, with the most important contributions coming from dietary fiber and both plant and animal protein intakes. The relation between the maternal diet and the milk microbiota needs further research because it has a key impact on infant microbiota development and contributes to infant health outcomes in the short and long term.This trial was registered at clinicaltrials.gov as NCT03552939.

Capturing the diversity of the human milk microbiota through culture-enriched molecular profiling: a feasibility study.

Previous human milk studies have confirmed the existence of a highly diverse bacterial community using culture-independent and targeted culture-dependent techniques. However, culture-enriched molecular profiling of milk microbiota has not been done. Additionally, the impact of storage conditions and milk fractionation on microbiota composition is not understood. In this feasibility study, we optimized and applied culture-enriched molecular profiling to study culturable milk microbiota in eight milk samples collected from mothers of infants admitted to a neonatal intensive care unit. Fresh samples were immediately plated or stored at -80°C for 2 weeks (short-term frozen). Long-term samples were stored at -20°C for >6 months. Samples were cultured using 10 different culture media and incubated both aerobically and anaerobically. We successfully isolated major milk bacteria, including Streptococcus, Staphylococcus and Bifidobacterium, from fresh milk samples, but were unable to culture any bacteria from the long-term frozen samples. Short-term freezing shifted the composition of viable milk bacteria from the original composition in fresh samples. Nevertheless, the inter-individual variability of milk microbiota composition was observed even after short-term storage. There was no major difference in the overall milk microbiota composition between milk fractions in this feasibility study. This is among the first studies on culture-enriched molecular profiling of the milk microbiota demonstrating the effect of storage and fractionation on milk microbiota composition.

Compositional and Functional Comparisons of the Microbiota in the Colostrum and Mature Milk of Dairy Goats.

Simple SummaryOur findings revealed significant influences of lactation stage on goat milk microbial and functional composition both in colostrum and mature milk. Microbial communities which were found in colostrum and mature milk could potentially establish goat kids’ gut microbiota and have an influence on the development of microbial components that provide potential health promotion effects in goats.Goat milk is essential for the initial development of kids by providing a great source of commensal bacteria. In this study, we analyzed the microbiota of the milk of 30 healthy Saanen dairy goats. The 30 samples comprised 15 colostrum and 15 mature milk samples, collected from three different farms of Shaanxi Province. Colostrum samples were collected daily for five days post-delivery and mature milk was collected on the 7th, 10th, 20th, 30th, and 40th days. The result showed that microbial alpha diversity was higher in the mature milk compared with that in the colostrum. Linear discriminant analysis effect size (LEfSe) was performed to detect differentially abundant taxa in colostrum and goat milk. According to taxonomy results, Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were the predominant bacteria phyla in both colostrum and mature milk. In addition, lactation stage noticeably influenced the composition of milk microbiota. Specifically, Novosphingobium, Brachybacterium, Psychrobacter, Lactobacillus, Yersinia, Roseateles, Rothia, Sanguibacter, Cloacibacterium, Variovorax, Sphingobacterium, and Coxiella were enriched in the colostrum, while Georgenia, Peptostreptococcus, Bacteroidales, Yaniella, Planomicrobium, Cloacibacterium, Azospirillum, Turicibacter, Cupriavidus, Herbaspirillum, Rhodobacteraceae, and Aeromonadales were the dominant genera in the mature milk. The enriched metabolic functions of the goat milk microbiota were predicted by PICRUSt and classified by KEGG pathway. Moreover, the abundances of environmental information processing, cellular processes pathway, genetic information processing pathway, organismal systems pathway, and metabolism pathway were significantly different between microbiota of colostrum and mature milk. Altogether, our study disclosed the significant difference between the microbial communities of colostrum and mature milk and provided grounds for further research in dairy microbiology.

A Randomized Controlled Trial of Teat-Sealant and Antibiotic Dry-Cow Treatments for Mastitis Prevention Shows Similar Effect on the Healthy Milk Microbiome.

Lactating cows are routinely treated at dry-off with antibiotic infusions in each quarter for the cure and prevention of pathogenic intramammary infection, which remains the most common disease in dairy herds. This approach is known as blanket dry-cow therapy, usually effective for the prevention and cure of infections, but has been shown to potentially contribute to the emergence and spreading of antibiotic resistant bacterial strains. Exploring the use of non-antibiotic treatments coupled with selective dry-cow therapy is necessary to reduce the risk of antibiotic resistance and potential interference with milk microbiome balance. The impact of selective dry-cow therapy on the physiological milk microbiome needs to be carefully evaluated. In this small-scale trial, five healthy (no mastits, SCC <200,000 cells mL−1) second-parity cows from dry-off to 5 days after calving were sampled. For every cow, each quarter received a different treatment: (i) bismuth salnitrate (internal teat sealant, OrbSeal®, Zoetis, Italy), front right quarter; (ii) cephalonium dihydrate (Cepravin®, MSD, Italy), rear right quarter; (iii) benzathine cloxacillin (Cloxalene dry, Ati, Italy), rear left quarter. No treatment was applied to the remaining quarter (front left) which served as experimental control. For 16S rRNA gene sequencing, bacterial DNA was extracted from 5 ml of milk samples, amplified using the primers for the V3–V4 hypervariable regions and sequenced in one MiSeq (Illumina) run with 2 × 250-base paired-end reads. Bacteriological results confirmed that the quarters were all healthy. The phyla Proteobacteria, Firmicutes, and Actinobacteria were the most abundant for all treatments and controls at all three timepoints, accounting for over 80% of the entire milk microbiota composition. No significant differences were found between treatments and controls in terms of the major alpha and beta diversity indexes, revealing that antibiotic, and non-antibiotic treatments for selective dry-cow therapy did not alter significantly the milk microbiome of dairy cows. The milk microbiota composition showed a clear evolution over the lactation cycle, and the overall changes in the milk microbiota diversity over the lactation cycle were mainly independent of treatments.

The Milk Microbiota of the Spanish Churra Sheep Breed: New Insights into the Complexity of the Milk Microbiome of Dairy Species.

Simple SummaryIn the last decade, the number of studies focused on the study of the microbiota of different tissues, organs, or physiological fluids has considerably increased. The milk of dairy species is an important and continuous source of commensal, mutualistic and potentially probiotic bacteria. Second-generation sequencing technologies have been applied to characterise the milk microbiota of dairy cows, whereas the study of the sheep milk microbiota is scarce. In the present study, we aimed to explore the bacterial diversity and composition of milk samples from the Churra sheep breed, a rustic autochthonous breed from the region of Castilla y León (Spain). Moreover, this study tries to clarify the complex bacterial composition of sheep milk comparing the results presented here with previous research on the milk microbiota of the Assaf sheep breed. This assessment has shown that the milk microbiota of ewes from one flock of the Assaf breed is more diverse than the milk microbiota reported here for two different flocks of Churra sheep. The study also provides a step into a better understanding of the link between the bacterial milk composition in these two sheep breeds and somatic cell count, an indicator trait of subclinical mastitis resistance in dairy sheep.Milk from healthy animals has classically been considered a sterile fluid. With the development of massively parallel sequencing and its application to the study of the microbiome of different body fluids, milk microbiota has been documented in several animal species. In this study, the main objective of this work was to access bacterial profiles of healthy milk samples using the next-generation sequencing of amplicons from the 16S rRNA gene to characterise the milk microbiome of the Churra breed. A total of 212 samples were collected from two Churra dairy farms with a different management system. The core milk microbiota in Churra ewes includes lesser genera (only two taxa: Staphylococcus and Escherichia/Shigella) than studies reported in other dairy species or even in a previous study in Assaf sheep milk. We found that diversity values in the two flocks of Churra breed were lower than the diversity of the milk microbiota in Assaf. The non-metric multidimensional scaling (NMDS) ordination using Bray-Curtis distance separates samples based on their microbiota composition. The information reported here might be used to understand the complex issue of milk microbiota composition.

Raw milk and fecal microbiota of commercial Alpine dairy cows varies with herd, fat content and diet.

The factors that influence the diversity and composition of raw milk and fecal microbiota in healthy commercial dairy herds are not fully understood, partially because the majority of metataxonomic studies involve experimental farms and/or single factors. We analyzed the raw milk and fecal microbiota of 100 healthy cows from 10 commercial alpine farms from the Province of Trento, Italy, using metataxonomics and applied statistical modelling to investigate which extrinsic and intrinsic parameters (e.g. herd, diet and milk characteristics) correlated with microbiota richness and composition in these relatively small traditional farms. We confirmed that Firmicutes, Ruminococcaceae and Lachnospiraceae families dominated the fecal and milk samples of these dairy cows, but in addition, we found an association between the number of observed OTUs and Shannon entropy on each farm that indicates higher microbiota richness is associated with increased microbiota stability. Modelling showed that herd was the most significant factor affecting the variation in both milk and fecal microbiota composition. Furthermore, the most important predictors explaining the variation of microbiota richness were milk characteristics (i.e. percentage fat) and diet for milk and fecal samples, respectively. We discuss how high intra-herd variation could affect the development of treatments based on microbiota manipulation.

The Composition and Function of Pigeon Milk Microbiota Transmitted From Parent Pigeons to Squabs.

Mammalian neonates obtain antibodies, nutrients, and microbiota from breast milk that help them resist the complex growth environment. Similar to mammals’ lactation behavior for their offspring, parent pigeons regurgitate pigeon milk (PM) from their crops to feed the squabs. Whether pigeon milk is as valuable as mammalian milk is not clear, especially in terms of microbiota. This study adopted 16S rRNA gene sequencing to investigate the microbial composition and function in pigeon milk. We found abundant microbiota in pigeon milk. The dominant genera in parent pigeons’ milk were Lactobacillus, Enterococcus, Veillonella, and Bifidobacterium. An analysis of squab milk (SM) showed that Lactobacillus also accounted for a considerable proportion, followed by Bifidobacterium. Most of the squab milk microbial genera were also detected in parent pigeons. Microbial functional analysis showed that the squab milk microbes were more involved in the pathways of carbohydrate metabolism, amino acid metabolism, and energy metabolism. These findings indicated that microbiota play an important role in squabs and can be transmitted from parent pigeons to squabs by pigeon milk. The presence of plentiful probiotics in squabs also suggests that adding probiotics in artificial pigeon milk may promote the growth and development of squabs and improve the production performance of pigeons.

Microbiota of bovine milk, teat skin, and teat canal: Similarity and variation due to sampling technique and milk fraction

The aim of this study was to evaluate the effect of sampling technique and milk fraction on bovine milk microbiota data and to compare the microbiota in milk to microbiota on the teat end and in the teat canal. Representative milk samples are highly important for assessment of bacteriological findings and microbiota in milk. Samples were obtained from 5 healthy lactating dairy cows at udder quarter level during 1 milking. Swab samples from the teat end and teat canal, and milk samples collected using different techniques and in different milk fractions were included. Milk was collected by hand stripping and through a teat canal cannula before and after machine milking, through a trans-teat wall needle aspirate after milking, and from udder quarter composite milk. The microbiota of the samples was analyzed with sequencing of the V1-V3 region of the 16S rRNA gene. In addition, somatic cell counts and bacterial cultivability were analyzed in the milk samples. Microbiota data were analyzed using multivariate methods, and differences between samples were tested using analysis of similarity (ANOSIM). Differences between samples were further explored via individual studies of the 10 most abundant genera. The microbiota on the teat end, in the teat canal, and in udder quarter composite milk, collected using a milking machine, differed in composition from the microbiota in milk collected directly from the udder quarter. No differences in milk microbiota composition were detected between hand-stripped milk samples, milk samples taken through a teat canal cannula, or milk samples taken as a trans-teat wall needle aspirate before or after milking. We conclude that for aseptic milk samples collected directly from the lactating udder quarter, sampling technique or milk fraction has minor effect on the microbiota composition.

Lactobacillus fermentum CECT5716 supplementation in rats during pregnancy and lactation affects mammary milk composition

Lactobacillus fermentum CECT5716 has shown immunomodulatory action and reduction of infections; therefore, it is suggested to be appropriate for use in early life. The present study aimed to assess the effects of the supplementation of L. fermentum CECT5716 in rats during gestation and lactation periods on the composition of some mammary milk components such as microbiota, fatty acid (FA) profile, and immunoglobulins. Wistar rats were supplemented by oral gavage with 1010 cfu/d of Lactobacillus fermentum CECT5716 (n = 6) or vehicle (n = 6) for 5 wk, comprising the 3 wk of gestation and the first 2 wk of lactation. At the end of the intervention, milk, mammary glands, and cecal contents were obtained for the tracking of the probiotic strain by nested PCR-quantitative PCR. Additionally, milk samples were used for the analysis of microbiota by 16S rRNA sequencing, FA by gas chromatography-flame ionization detector, and immunoglobulin by Luminex (Luminex Corporation, Austin, TX). Although L. fermentum CECT5716 administration did not modify the overall composition of milk microbiota, the strain was detected in 50% of the milk samples of rats supplemented with the probiotic. Moreover, probiotic administration induced beneficial changes in the FA composition of milk by increasing total PUFA, including linoleic and α-linolenic acids, and decreasing the proportion of palmitic acid. Finally, the milk of the rats treated with the probiotic showed a 2-fold increase of IgA levels. The supplementation with L. fermentum CECT5716 during pregnancy and lactation periods improved the milk composition of FA and immunoglobulins. These effects were not linked to the presence of the strain in milk, thus suggesting that the mechanism is connected to intestinal compartment. These findings provide novel insight into a potential new approach for infants to benefit from better nutrition, development of a healthy immune system and microbiota, and protection from gastrointestinal infections.

Impact of yeast and lactic acid bacteria on mastitis and milk microbiota composition of dairy cows

This experiment was conducted to evaluate the impact of yeast and lactic acid bacteria (LAB) on mastitis and milk microbiota composition of dairy cows. Thirty lactating Holstein cows with similar parity, days in milk were randomly assigned to five treatments, including: (1) Health cows with milk SCC < 500,000 cells/mL, no clinical signs of mastitis were found, fed basal total mixed ration (TMR) without supplementation (H); (2) Mastitis cows with milk SCC > 500,000 cells/mL, fed basal TMR without supplementation (M); (3) Mastitis cows fed basal TMR supplemented with 8 g day−1 yeast (M + Y); (4) Mastitis cows fed basal TMR supplemented with 8 g day−1 LAB (M + L); (5) Mastitis cows (milk SCC > 500,000 cells/mL) fed basal TMR supplemented with 4 g day−1 yeast and 4 g day−1 LAB (M + Y + L). Blood and milk sample were collected at day 0, day 20 and day 40. The results showed efficacy of probiotic: On day 20 and day 40, milk SCC in H, M + Y, M + L, M + Y + L was significantly lower than that of M (P < 0.05). Milk concentration of TNF-α, IL-6 and IL-1β in M + Y + L were significantly reduced compared with that of M on day 40 (P < 0.05). Milk Myeloperoxidase (MPO) and N-Acetyl-β-d-Glucosaminidase (NAG) activity of M + Y, M + L, M + L + Y were lower than that of M on day 40 (P < 0.05). At genus level, Staphylococcus, Chryseobacterium and Lactococcus were dominant. Supplementation of LAB decreased abundance of Enterococcus and Streptococcus, identified as mastitis-causing pathogen. The results suggested the potential of LAB to prevent mastitis by relieving mammary gland inflammation and regulating milk microorganisms.

Is there a connection between fecal and milk microbiota composition and function and perinatal depression? Rationale for future studies

Introduction: Coping with perinatal depression in healthcare systems worldwide has been so far more or less insufficient and there is a huge need of implementing new prevention and treatment options. Methods: Literature review has been done to assess state of current knowledge on microbiome changes in perinatal period and form potential clinical implementation of these information. Results: Intestinal microbiota can influence central nervous system functions and this relation seems bidirectional. The diversity of gut microbiota has emerged to play a significant role in the occurrence of mood and anxiety disorders, but this relationship is poorly understood in perinatal period. Studies have shown a reduced phylogenetic diversity and species richness of gut microbiota in depressed pregnant women, and a significant association between antibiotic exposure during the peripartum period and development of depressive symptoms. Even though breast milk is the fundamental source of microbes colonizing the infant’s gut, there is very little known about possible human milk microbiota changes in depressed women. Our microbiome may be modulated by numerous circumstances, especially diet but no current microbiome-specific dietary recommendations exist. Conclusions: Future research in the relationship between the gut microbiota, diet and PND holds tremendous potential to be integrated in clinical practice. The impact of breast milk microbiota on infant development and health could have important implications for early-life prevention of chronic conditions. Given that bacterial functions are conserved across taxonomic groups, incorporating microbial function biomarkers may be more productive than a purely taxonomic approach to understanding the microbiome in diseases. Keywords: Perinatal depression; Microbiota; Diet; Pregnancy; Breastfeeding