Milk Fat Content Research Articles

Breast size in lactating women and the content of macronutrients in human milk.

Although the primary function of a woman's breast is milk synthesis, only a few studies have evaluated the relationship between breast size and human milk composition, showing equivocal results. This study aims to test if breast size during fully established lactation is related to energy density and content of macronutrients in human milk. Mothers of healthy, born-on-term infants at stage III of lactogenesis (N = 137) provided breast milk samples. Milk composition was analyzed using midinfrared transmission spectroscopy. The breast size index was calculated by dividing the breast by the circumference below the breast. Stepwise forward linear regression showed a negative association between breast size index and lactose concentration in breast milk (β = -.242, p = .003). The final model, which includes breast size index, feeding frequency, and maternal energy intake together explained around 13% of the variance in breast milk lactose content (R2 adj = .126, p < .001). No statistically significant relationship was found between breast size index and milk's energy density, protein, and fat content. This is the first study that shows a negative relationship between breast size during fully established lactation and lactose concentration in milk in a large sample size. No relationship between other macronutrients and breast size indicates that large breast size is not necessary for adequate milk production; however, it may contribute to an altered lactose concentration.

Comparison of miR-106b, miR-191, and miR-30d expression dynamics in milk with regard to its composition in Holstein and Ayrshire cows.

Milk composition varies considerably and depends on paratypical, genetic, and epigenetic factors. MiRNAs belong to the class of small non-coding RNAs; they are one of the key tools of epigenetic control because of their ability to regulate gene expression at the post-transcriptional level. We compared the relative expression levels of miR-106b, miR-191, and miR-30d in milk to demonstrate the relationship between the content of these miRNAs with protein and fat components of milk in Holstein and Ayrshire cattle. Milk fat, protein, and casein contents were determined in the obtained samples, as well as the content of the main fatty acids (g/100 g milk), including: saturated acids, such as myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids; monounsaturated acids, including oleic (C18:1) acid; as well as long-, medium- and short-chain, polyunsaturated, and trans fatty acids. Real-time stem-loop one-tube reverse transcription polymerase chain reaction with TaqMan probes was used to measure the miRNA expression levels. The miRNA expression levels in milk samples were found to be decreased in the first two months in Holstein breed, and in the first four months in Ayrshire breed. Correlation analysis did not reveal any dependence between changes in the expression level of miRNA and milk fat content, but showed a multidirectional relationship with individual milk fatty acids. Positive associations between the expression levels of miR-106b and miR-30d and protein and casein content were found in the Ayrshire breed. Receiver operating characteristic curve analysis showed that miR-106b and miR-30d expression levels can cause changes in fatty acid and protein composition of milk in Ayrshire cows, whereas miR-106b expression level determines the fatty acid composition in Holsteins. The data obtained in this study showed that miR-106b, miR-191, and miR-30d expression levels in milk samples have peculiarities associated with breed affiliation and the lactation period.

Changes in milking time modify behavior of grazing dairy cows

Milking often coincides with the main grazing periods of dairy cows, at dawn and evening, and thus, it might impair grazing behavior and pasture intake. This study aimed to evaluate the effects of changing the morning and evening milking time on the ingestive behavior of lactating dairy cows. Eighteen multiparous Holstein and Jersey cows were evaluated at conventional (7 am and 5 pm) and at alternative milking time (8 am and 4 pm) in a switch-over design. Milk yield and composition, and ingestive behavior were recorded during before (BC; days 1–7 of the trial) and after the change (AC; days 21–35 of the trial) in the milking schedule. Behavior activities consisted of diurnal ingestive behavior (time spent grazing, ruminating, idling and eating the supplement), position (standing up or lying down) and time in shade or in the outdoor areas and were registered from 6:30 am to 6:30 pm. Data were submitted to analysis of variance, considering effect of milking time change and days as repeated measurements. Diurnal and per shift (morning, afternoon) means of behavioral activities were compared between before and after milking time changed. Changes in milking time did not affect (P > 0.05) body weight (BC = 647 vs. AC = 653 kg) and milk yield (BC = 24.6 vs. AC = 25.0 kg), but increased (P < 0.05) the concentration of milk fat (BC = 4.19 vs. AC = 4.77 g/100 g), total solids (BC = 12.97 vs. AC = 13.63 g/100 g) and milk ureic nitrogen contents (BC = 11.93 vs. AC = 15.35 mg/dL), as well increased diurnal time spent grazing (BC = 125.3 vs. AC = 183.9 min; P < 0.05). After milking time changed, time eating the supplement decreased (BC = 181.9 vs. AC = 152.8 min; P < 0.05), while rumination time decreased (P < 0.05) at day 1 and increased at day 2, with idling time showing the inverse pattern. Cows spent more time (P < 0.05) lying down (BC = 45.6 vs. AC = 162.8 min) and at outdoors (BC = 331.7 vs. AC = 421.1 min) after change in milking time. Changes in milking time, avoiding coincidence of milking with main grazing periods, favored late afternoon grazing and reduced time spent feeding supplement without changes in milk yield.

Anaerobic flora, Selenomonas ruminis sp. nov., and the bacteriocinogenic Ligilactobacillus salivarius strain MP3 from crossbred-lactating goats

This study aimed to examine the distribution of anaerobic bacteria in the rumen fluid of Thai crossbred goats and to screen potential probiotic strains capable of producing antimicrobial compounds and inhibiting bacteria that cause milk fat depression. Thirty-four strains of bacteria from the rumen fluid were divided into 13 groups within 12 genera based on 16S rRNA gene sequences. The RF1-5 and RF5-12 were identified as Streptococcus luteliensis and Bacillus licheniformis, respectively, and demonstrated non-ropy exopolysaccharide. Furthermore, mPRGC5T was closely related to Selenomonas caprae JCM 33725 T (97.8% similarity) based on 16S rRNA gene sequences. It exhibited low average nucleotide identity, digital DNA–DNA hybridization, and average amino acid identity values with related type strains ranging from 84.9 to 86.0%, 21.3 to 21.8%, and 73.8 to 76.1%, respectively. The genotypic and phenotypic characteristics of mPRGC5T strongly support this strain as a new species of the genus Selenomonas for which the name Selenomonas ruminis mPRGC5T was proposed. The type strain is mPRGC5T (= JCM 33724 T = KCTC 25177 T). Ligilactobacillus salivarius MP3 showed antibacterial activity against Cutibacterium acnes subsp. acnes DSM 1897 T and Kocuria rhizophila MIII. The enterolysin A cluster gene was identified in its genome. The auto-aggregation of L. salivarius MP3 was 93.6 ± 0.2%. Additionally, co-aggregation of L. salivarius MP3 with C. acnes DSM 1897 T and K. rhizophila MIII had 92.2 ± 3.4% and 87.3 ± 4.5%, respectively. The adhesion capacity of strain MP3 was 76.11 ± 2.2%. Probiogenomic analysis revealed that L. salivarius MP3 was nonhazardous to animal supplementation and included acid- and bile-tolerant ability. However, strain MP3 contained three antibiotic resistance genes. Thus, the supplementation of L. salivarius MP3 could increase the milk fat content by suppressing C. acnes DSM 1897 T with antibiotic resistance gene horizontal transfer awareness.

Feeding live or inactive yeast to primiparous Jersey cows: nutrient digestibility, rumen fermentation, and milk fatty acid profile

ABSTRACT The aim of this study was to evaluate the effects of live yeast (LY) or inactive yeast (IY) on intake and apparent total-tract digestibility of nutrients, ruminal fermentation, milk yield and composition, milk fatty acid profile, N utilisation, and microbial protein synthesis of primiparous Jersey cows. Twelve primiparous Jersey cows were employed, with an average body weight of 403 kg, a lactation period of 100 days, and average daily milk output of 14.7 kg. The experimental diets were: 1 – CON (no additives); 2 – LY (inclusion of 40 g/day of live yeast); 3 – IY (inclusion of 40 g/day of inactivated yeast wall). Cows fed LY exhibited the greatest DM intake. Cows’ intake IY had the greatest digestibility of DM, OM, and NDF. Feeding IY reduced ruminal concentrations of acetate, isobutyrate, and branched-chain fatty acids. Cows fed either LY or IY increased the production of milk and FCM. Cows under the LY treatment had greater milk fat content. Cows fed LY had the greatest N intake. Yeast treatments also increased the absorbable purine estimation. Supplementing primiparous dairy cows with yeast products, especially live yeast, improved dry matter intake by positively influencing digestibility, particularly for starch and NDF.

Efficiency of the use of bulls of the Russian and imported selection of the breeding stock of the Red Steppe and Black-and-White breeds at the farms of the Omsk region

The possibilities of increasing the genetic potential of the breeding stock of dairy cattle by using the seed of stud bulls belonging to Russian organizations for artificial insemination of farm animals and the imported ones have been studied. The use of the Holstein breed bulls' seed of the Russian and imported selection on the breeding stock of the Red Steppe and Black-and-White breeds in the conditions of the Omsk region farms has been analyzed. The obtained results of researches have revealed the improving ability of stud bulls of the Russian selection, used on the breeding stock of the Red Steppe breed, on the main productive indices of the first and the highest lactation. The milk yield of the first heifers by 150 kg, or 2.4%, exceeded the productivity level of the imported root counterparts, the excess in fat and protein amounted to 0.1 and 0.08%, respectively. The coefficient of stability of lactation activity in this group of animals was maximum among the whole livestock – 92%. The superiority of imported rootstock animals on the main productive indicators has been identified on the breeding stock of the Black-and-White breed: milk yield (+769 kg), fat and protein content (+0.04 and +0.13%, respectively), milk fat and protein yield (+13 and +17%). Also, in the process of research the improving influence of the genetic potential of stud bulls of the imported selection on the whole breeding stock of the Red Steppe breed and on the breeding stock of the Black-and-White breed with the level of productivity of 8000 kg has been determined. The improving effect on the milk yield of the bulls of the Russian selection when they are selected to the breeding stock with the level of productivity up to 7000 kg has been found.

Zirconium-rich magnetic polyoxometalate-based metal–organic framework: Tailored for phosphopeptide analysis from lung cancer A549 cells

Polyoxometalate-based metal–organic frameworks (POMOFs) have become a promising affinity material for separation and enrichment. The analysis of protein phosphorylation represents a challenge for the development of efficient enrichment materials. Here, a novel zirconium-rich magnetic POMOF was successfully designed and prepared for the enrichment of phosphopeptides. The binding affinity of the nanomaterial partly came from Fe–O clusters in the MOF. The Lewis acid–base interactions between V–O clusters and zirconium ions in V10O28-Zr4+ and phosphate groups in phosphopeptides further strengthened the enrichment ability. The zirconium-rich magnetic POMOF was employed to capture phosphopeptides from non-fat milk, human saliva, and serum. Additionally, 748 unique phosphopeptide peaks were detected from the tryptic digests of lung cancer A549 cell proteins with a high specificity (86.9 %). POMOFs will become an active competitor for the design of protein affinity materials and will provide a new approach for phosphopeptide analysis.

Молокосодержащее мороженое с усовершенствованным белково-углеводным и минеральным составом

Milk-containing ice-cream is low in fat and non-fat milk solids. To maintain the conventional sensory and technological properties, dry substances have to be restored, including dry milk solids. This article introduces a new formulation of milk-containing ice-cream with an improved protein-carbohydrate and mineral content and the conventional sensory profile. Whey protein concentrates and dry cheese whey served as substitute components. The research involved physical, chemical, microstructural, and thermostatic methods. In the experimental product, 2 % whey protein concentrate and 4 % dry cheese whey brought dry milk solids up to 38 %, which was similar to the control milk ice-cream sample. The dispersion of ice crystals and the thermal and shape stability were also similar to the traditional ice-cream. However, the dynamic viscosity and the temperature of freezer discharge of the experimental mix exceeded those of the control sample by 1.5 times and 0.6 °C, respectively, while the aerating ability and the air-phase dispersion were lower. Whey protein concentrates and dry cheese improved the protein-carbohydrate and mineral composition of the milk-containing ice-cream, as well as made it possible to approximate it to the traditional sensory parameters. A further study is necessary to select flavors that could improve the sensory profile of the milk-containing ice-cream product.

Combining transmission speckle photography and convolutional neural network for determination of fat content in cow milk: an exercise in classification of parameters of a complex suspension

Combining transmission speckle photography and convolutional neural network for determination of fat content in cow milk: an exercise in classification of parameters of a complex suspension

Physical and chemical properties, hygienic quality and fatty acid profile in milk of lactating Lacaune dairy sheep

Abstract. In recent years, there has been globally increasing interest in dairy sheep breeding, including Lacaune sheep, which is supported by a high demand for sheep's milk on the market. This paper elaborates on the influence of a sheep's lactation stage on the physical and chemical properties, hygienic quality and content of fatty acids in milk produced by Lacaune sheep kept in intensive breeding. The research was conducted on 30 Lacaune sheep, which were tested in the early (60th day), middle (120th day) and late (180th day) stages of lactation. Density, freezing point and titration acidity were determined by applying the infrared spectrometry method, and indicators of the hygienic quality of milk, such as somatic cell count (SCC), were determined by the fluoro-opto-electronic method, and the total count of aerobic mesophilic bacteria (CFU) was determined by the flow cytometry method. The fatty acid profile of feed and milk was obtained by gas–liquid chromatography. Depending on the stage of lactation, results referring to the chemical composition of Lacaune sheep's milk showed a significant increase in the content of fat, protein, total dry matter and casein together with a significant decrease in the content of lactose in the late stage of lactation. There was also a significant increase confirmed for the concentration of urea and the freezing point in milk along with the lactation progress. Depending on the stage of lactation, milk yield in Lacaune sheep significantly decreased as lactation progressed. Analysis of the fatty acid composition in milk of Lacaune sheep proved a significant decrease in the concentrations of C4 : 0, C6 : 0, C11 : 0, C12 : 0, C13 : 0, C15 : 0, C17 : 1, C18 : 2n6 and C18 : 3n6 as well as the n6 concentrations and the n6 / n3 ratio. The opposite trend was observed for concentrations of C10 : 0, C14 : 1, C16 : 0, C16 : 1, C18 : 0, C20 : 2, C18 : 3n3, C20 : 3n6, C20 : 5n3 and C22 : 6n3 as well as for the n3 concentrations. When compared to the early lactation stage, the C18 : 3n6 and n6 concentrations were significantly lower in the late lactation stage, while the C20 : 2 and C20 : 5n3 concentrations were significantly lower in the middle lactation stage when compared to the late lactation stage. There were many significant positive and negative correlations determined between the researched properties of milk. The research results obtained with Lacaune sheep's milk can be compared to the results of other studies, except for the lower content of milk fat. This confirms the good adaptability of Lacaune sheep to different breeding conditions and the necessity to provide sheep with quality pastures for grazing.

Farm-level nutritional factors associated with milk production and milking behavior on Canadian farms with automated milking systems

The objective of this study was to describe nutritional strategies utilized on Canadian dairy farms with automated milking systems (AMS), both at the feed bunk and the concentrate offered at the AMS, as well as to determine what dietary components and nutrients, as formulated, were associated with milk production and milking behaviors on those farms. Formulated diets, including ingredients and nutrient content, and AMS data were collected from April 1, 2019, until September 30, 2020, on 160 AMS farms (Eastern Canada [East] = 8, Ontario [ON] = 76, Quebec [QC] = 22, and Western Canada [West] = 54). Both partial mixed ration (PMR) and AMS concentrate samples were collected from May 1 to September 30, 2019, on 169 farms (East = 12, ON = 63, QC = 42, West = 52). AMS milking data were collected for 154 herds. For each farm (n = 160), milk recording data were collected and summarized by farm to calculate average milk yield and components. Multivariable regression models were used to associate herd-level formulated nutrient composition and feeding management practices with milk production and milking behavior. Milk yield (37.0 ± 0.3 kg/d) was positively associated with the PMR ether extract (EE) concentration (PMR % EE; +0.97 kg/d per percentage point (p.p.) increase) and with farms that fed barley silage as their major forage source on farm (n = 16; +2.18 kg/d) compared with haylage (n = 42), while farms that fed corn silage (n = 96; +1.23 kg/d) tended to produce more milk than farms that fed haylage. Greater milk fat content (4.09 ± 0.28%) was associated with greater PMR-to-AMS concentrate ratio (+0.02 p.p. per unit increase) and total diet net energy for lactation (+0.046 p.p. per 0.1 Mcal/kg increase), but lesser % non-fiber carbohydrates (NFC) of the PMR (-0.016 p.p. per p.p. increase of % NFC). Milk protein content (3.38 ± 0.14%) was positively associated with forage % of the PMR (+0.003 p.p. per p.p. increase of % forage) and total diet % starch (+0.009 p.p. per p.p. increase of % starch), but negatively associated with farms feeding corn silage (-0.1 p.p. compared with haylage) as their major forage. Greater milking frequency (2.77 ± 0.40 milkings/d) was observed on farms with free-flow cow traffic systems (+0.62 milkings/d) and positively associated with feed push-up frequency (+0.013 milkings/d per additional feed push-up), while being negatively associated with PMR NFC content and % forage of the total ration (-0.017 milkings/d per p.p. increase of % forage). Lastly, greater milking refusal frequency (1.49 ± 0.82 refusals/d) was observed on farms with free-flow cow traffic systems (+0.84 refusals/d) and farms feeding barley silage (+0.58 refusals/d) than guided flow and farms feeding either corn silage or haylage, respectively. These data give insight into the ingredients, nutrient formulations and type of diets fed on AMS dairy farms across Canada and the association of those factors with milk production and milking behaviors.

Rumen degradable protein levels on fatty acid profile of rumen bacteria and milk fat of dairy cows supplemented with calcium salts of fatty acids.

This study aimed to evaluate the effects of calcium salts of fatty acids (CSFA) from soybean oil in diets with different levels of rumen degradable protein (RDP) on bio-hydrogenation extent, and fatty acid (FA) profile intake, omasal digesta, rumen bacteria, and milk fat. Eight Holstein lactating cows were used in a replicated 4 × 4 Latin square design. Treatments were arranged in a 2 × 2 factorial design with two CSFA levels (0 or 33.2g/kg DM of CSFA) and two RDP levels (98.0 or 110 g/kg DM). There was RDP and CSFA interaction effect on the omasal flow of total FA and some specific FA. Only in -CSFA diets, the higher RDP level increased omasal flow of total FA. Dietary RDP levels did not affect the FA profile of bacteria and milk fat. Feeding CSFA reduced or tended to reduce the bacterial proportion of C15:0, C16:0, C16:1, C17:0, and C18:0 FA and decreased the concentrations of short- and medium-chain FA (<18C) and increased the concentrations of unsaturated and long-chain FA (≥18C) in milk fat. Feeding CSFA of soybean oil increases the intake and omasal flow of FA and augments unsaturated FA content in bacteria pellets and milk fat.

Relationship among thermal environment, stage of lactation, body characteristics, yield and milk constituents of dairy Gyr cows managed on pasture.

Our aims were to evaluate changes in body characteristics, milk yield and milk constituents as well as to determine the relationship between the thermal environment and production characteristics during the first lactation of dairy Gyr cows managed on pasture. Between 2013 and 2015, forty-five primiparous dairy Gyr cows were evaluated from prepartum to 10 months of lactation in Southeast of Brazil. Body weight, body condition score (BCS), subcutaneous fat thickness (SFT), milk yield (305 d), and milk constituents were collected monthly and progesterone was collected weekly. Additionally, we determined the temperature humidity index (THI) based on microclimate data. Overall, the cows lost body weight until six months of lactation and there was a progressive decrease in BCS, SFT, milk yield and milk lactose as the months in lactation progressed. In contrast, there was an increase in milk fat, milk protein and milk solids. The thermal environment did not pose a consistent heat challenge, nevertheless, we found a positive correlation between the average THI two days before milk collection with milk yield, fat and lactose contents, but in contrast a negative correlation was found with total solids and protein. In conclusion, the THI and months of lactation affected the yield and constituents of milk. However, more studies are necessary to understand the impacts of body characteristics and thermal environment on yield and milk constituents throughout the productive life of Gyr dairy cows.

Current state and ways to increase the dairy productivity of camels in the south-western region of the Republic of Kazakhstan

Abstract Increasing the dairy productivity of camels is an urgent task for many countries where these animals are of great importance as a source of dairy and meat. The purpose of the study was to evaluate and select heavy milk-producing camels for breeding by genotyping, studying the genealogical structure, and selecting related groups with high productivity. To achieve this goal, the number of camel herds in the south-western region of Kazakhstan was monitored during 2020–2022 to study their external characteristics, live weight dynamics, and milk productivity. As a result, it was found that in female camels for 12 months of lactation, the average daily milk yields of the Arvana breed were 7.4 kg, with milk yield for lactation of 2682.8 kg of milk, and in the Bactrian breed with average daily milk yields of 5.8 kg of milk, milk yield for lactation was 1186.3 kg. It was also revealed that the herds of Arvana camels have 15 breeders, and the herds of Bactrian camels have 14 breeders, which are characterised by a sufficient number of offspring for selection and breeding to improve the productive qualities of animals. In addition, it was found that in the herds of Arvana camels, the descendants of the breeders of “Tekele-lek”, “Kara-lek”, “Zhana-lek”, “Mayakum-lek”, “Yrys-lek” and “Shilikti-lek”, and in the herds of Bactrian camels, “Bal-bura”, “Kulsary-bura”, “Zhas-bura”, “Taushyk-II-bura”, “Sakon-bura”, “Konai-bura”, and “Kulandy-bura” noted high milk productivity. It was found that in the milk of camels of the Arvana breed, the content of nonfat milk solids was 8.3%, the density was 27.66 g/cm 3 , the acidity was 19 0 T, in the milk of the Bactrian breed, these indicators were, respectively: 8.23%, 27.81 g/cm, 3 and 19 0 T. The results obtained are of great practical importance, as they can be applied to create new methods and technologies for managing camel herds that will help increase their dairy productivity.

Changes in the Concentration of fat, Protein and Carbohydrates During the Excretion of Milk by Vacuum Breast Pump and Breast Pump with Compression

Background: The purpose of the work is to investigate the contents of the main nutrients of milk (fat, protein, lactose), as well as the energy value of milk in the process of expression milk using an vacuum electric breast pump and vacuum electric breast pump with compression pulses simultaneously. Method: Surveys were conducted on 9 women 5-8 weeks of lactation. The analysis was carried out in 10 ml samples of milk, which were continuously expression with breast pump «Laktopuls»: only with vacuum stimuli, and simultaneously with vacuum and compression stimuli. The sampling continuity was ensured by a specially developed procedure. Milk analysis in the samples was performed 1-1.5 hours after gland expression on a Miris AB Uppsala, Sweden, human milk analyzer. Finding: The largest changes in milk samples were observed in fat concentration. The fat content in milk increased in each subsequent sample and in the latter samples could exceed its content in the initial samples by 3-4 times. The total amount of fat was about 25% more when milk ejected by breast pump with vacuum and compression stimuli than with vacuum stimulus only. When determining the protein concentration in milk samples, an increase in its concentration was also found during milk ejection, but on 10-20%. In contrast to the dynamics of fat and protein concentrations, the carbohydrate concentration did not change in all women during the milk ejection. Conclusion: A method has been developed that allows analyzing milk nutrients during the continuous removal of milk from the gland. Surveys have shown that ejection of milk with breast pump with vacuum and compression stimuli, increases the amount of fat and protein in breast milk.

Use of sugarcane crop residue silage with different levels of inclusion in dual-purpose cow diets

In the sugar cane production chain, different byproducts are generated that can be used in animal feed. Their conservation in the form of silage is an important contribution towards improving animal production in tropical regions. The objective was to evaluate the inclusion of different levels of silage from sugarcane crop residues in the diet of dairy cows in a family farming system. Nine lactating cows were used in a 3x3 Latin square design in triplicate and means were compared using the Tukey test. The treatment sequences were randomly assigned with periods of 14 days. Three treatments were formulated that included feed of mixed native grasses, supplemented with sugarcane top silage with different inclusion levels (2 kg/DM for T1, 4 kg/DM for T2 and 6 kg/DM for T3), along with commercial concentrate and corn silage. Milk production, its chemical composition, and the efficiency of feed utilization were evaluated. The average milk production, fat content and crude protein were, respectively, 9.38kg/cow/day, 32.6 and 340.0 g/cow/day. No differences were detected (P&gt;0.05) for any of the variables evaluated, but the inclusion of 6 kg of sugarcane residues silage improved the animals' feed efficiency. Therefore, sugarcane top silage is a viable alternative for feeding ruminants.

High-Fat, High-Calorie Breast Milk in Women with Overweight or Obesity and Its Association with Maternal Serum Insulin Concentration and Triglycerides Levels.

The childhood obesity epidemic continues to be a challenge. Maternal obesity and excessive infant weight gain are strong predictors of childhood obesity, which itself is a major risk factor for adult obesity. The primary source of nutrition during early life is breast milk, and its composition is impacted by maternal habitus and diet. We thus studied the relationship between maternal BMI, serum lipids and insulin, and breast milk fat and calorie content from foremilk to hindmilk. Women who were exclusively breastfeeding at 7-8 weeks postpartum were BMI classified as Normal (18.5-24.9, n = 9) and women with Overweight/Obese (OW/OB ≥ 25, n = 13). Maternal blood and continuous breast milk samples obtained from foremilk to hindmilk were analyzed, and infant milk intake was assessed. Women with OW/OB had significantly higher milk fat and calorie content in the first foremilk and last hindmilk sample as compared to Normal BMI women. Amongst all women, maternal serum triglycerides, insulin, and HOMA were significantly correlated with foremilk triglyceride concentration, suggesting that maternal serum triglyceride and insulin action contribute to human milk fat content. As the milk fat content of OW/OB women has caloric implications for infant growth and childhood obesity, these results suggest the potential for modulating milk fat content by a reduction in maternal serum lipids or insulin.

Enhancing milk quality and modulating rectal microbiota of dairy goats in starch-rich diet: the role of bile acid supplementation.

Diets rich in starch have been shown to increase a risk of reducing milk fat content in dairy goats. While bile acids (BAs) have been used as a lipid emulsifier in monogastric and aquatic animals, their effect on ruminants is not well understood. This study aimed to investigate the impact of BAs supplementation on various aspects of dairy goat physiology, including milk composition, rumen fermentation, gut microbiota, and BA metabolism. We randomly divided eighteen healthy primiparity lactating dairy goats (days in milk = 100 ± 6 d) into two groups and supplemented them with 0 or 4g/d of BAs undergoing 5weeks of feeding on a starch-rich diet. The results showed that BAs supplementation positively influenced milk yield and improved the quality of fatty acids in goat milk. BAs supplementation led to a reduction in saturated fatty acids (C16:0) and an increase in monounsaturated fatty acids (cis-9 C18:1), resulting in a healthier milk fatty acid profile. We observed a significant increase in plasma total bile acid concentration while the proportion of rumen short-chain fatty acids was not affected. Furthermore, BAs supplementation induced significant changes in the composition of the gut microbiota, favoring the enrichment of specific bacterial groups and altering the balance of microbial populations. Correlation analysis revealed associations between specific bacterial groups (Bacillus and ChristensenellaceaeR-7group) and BA types, suggesting a role for the gut microbiota in BA metabolism. Functional prediction analysis revealed notable changes in pathways associated with lipid metabolism, suggesting that BAs supplementation has the potential to modulate lipid-related processes. These findings highlight the potential benefits of BAs supplementation in enhancing milk production, improving milk quality, and influencing metabolic pathways in dairy goats. Further research is warranted to elucidate the underlying mechanisms and explore the broader implications of these findings.

CGA alleviates LPS-induced inflammation and milk fat reduction in BMECs through the NF-κB signaling pathway

Mastitis is an easy clinical disease in dairy cows, which seriously affects the milk yield and quality of dairy cows. Chlorogenic acid (CGA), a polyphenolic substance, is abundant in Eucommia ulmoides leaves and has anti-inflammatory and anti-oxidative stress effects. Here, we explore whether CGA attenuated lipopolysaccharide (LPS)-induced inflammation and decreased milk fat in bovine mammary epithelial cells (BMECs). 10 μg/mL LPS was used to induce mastitis in BMECs. QRT-PCR, Western blotting, oil red O staining, and triglyceride (TG) assay were used to examine the effects of CGA on BMECs, including inflammatory response, oxidative stress response, and milk fat synthesis. The results showed that CGA repaired LPS-induced inflammation in BMECs. The expression of IL-6, IL-8, TNF-α, IL-1β, and iNOS was decreased, and the expression levels of CHOP, XCT, NRF2, and HO-1 were increased, which reduced the oxidative stress level of cells and alleviated the reduction of milk fat synthesis. In addition, the regulation of P65 phosphorylation by CGA suggests that CGA may exert its anti-inflammatory and anti-oxidative effects through the NF-κB signaling pathway. Our study showed that CGA attenuated LPS-induced inflammation and oxidative stress, and restored the decrease in milk fat content in BMECs by regulating the NF-κB signaling pathway.

The serine protease 2 gene regulates lipid metabolism through the LEP/ampkα1/SREBP1 pathway in bovine mammary epithelial cells

Molecular breeding has brought about significant transformations in the milk market and production system during the twenty-first century. The primary economic characteristic of dairy production pertains to milk fat content. Our previous transcriptome analyses revealed that serine protease 2 (PRSS2) is a candidate gene that could impact milk fat synthesis in bovine mammary epithelial cells (BMECs) of Chinese Holstein dairy cows. To elucidate the function of the PRSS2 gene in milk fat synthesis, we constructed vectors for PRSS2 overexpression and interference and assessed intracellular triglycerides (TGs), cholesterol (CHOL), and nonesterified fatty acid (NEFA) contents in BMECs. Fatty acid varieties and components were also quantified using gas chromatography‒mass spectrometry (GC‒MS) technology. The regulatory pathway mediated by PRSS2 was validated through qPCR, ELISA, and WB techniques. Based on our research findings, PRSS2 emerges as a pivotal gene that regulates the expression of associated genes, thereby making a substantial contribution to lipid metabolism via the leptin (LEP)/Adenylate-activated protein kinase, alpha 1 catalytic subunit (AMPKα1)/sterol regulatory element binding protein 1(SREBP1) pathway by inhibiting TGs and CHOL accumulation while potentially promoting NEFA synthesis in BMECs. Furthermore, the PRSS2 gene enhances intracellular medium- and long-chain fatty acid metabolism by modulating genes related to the LEP/AMPKα1/SREBP1 pathway, leading to increased contents of unsaturated fatty acids C17:1N7 and C22:4N6. This study provides a robust theoretical framework for further investigation into the underlying molecular mechanisms through which PRSS2 influences lipid metabolism in dairy cows.