Quality Of Milk Fat Research Articles

Trans-10 shifted ruminal biohydrogenation and its implications for ruminant milk and meat fat content and quality

Feeding high-grain diets is a common practice in intensive ruminant production systems to meet animal energy requirements and maximize feed efficiency. One of the consequences of these diets is trans (t)10 shifted ruminal biohydrogenation, which includes increased formation of t10-18:1 and t10,cis (c)12-conjugated linoleic acid (t10,c12-CLA) at the expense of t11-18:1 and c9,t11-CLA. In dairy cows, the t10 shift has been associated with milk fat depression. In beef cattle, the t10 shift has not been associated with negative effects on animal performance or marbling fat deposition, however, it may negatively impact meat fat eating quality by decreasing its cis monounsaturated fatty acid to saturated fatty acid ratio. Finally, the t10 shift increases t10-18:1 accumulation in ruminant-derived foods (dairy, beef and lamb) which at high enough levels may compromise the nutritional quality of these foods. The present review will cover our current understanding of the rumen microbes involved in the t10 shift and its implications for milk fat synthesis and beef fat quality.

Effects of lysine and threonine on milk yield, amino acid metabolism, and fecal microbiota of Yili lactating mares.

The nutritional benefits of mare milk are attracting increasing consumer interest. Limited availability due to low yield poses a challenge for widespread adoption. Although lysine and threonine are often used to enhance protein synthesis and muscle mass in horses, their impact on mare milk yield and nutrient composition remains underexplored. This study investigated the effects of lysine and threonine supplementation on 24 healthy Yili mares, mares at day 30 of lactation, over a 120-day period. The mares were divided into control and three experimental groups (six mares each) under pure grazing conditions. The control group received no amino acid supplementation, while experimental groups received varying daily doses of lysine and threonine: Group I (40 g lysine + 20 g threonine), Group II (60 g lysine + 40 g threonine), and Group III (80 g lysine + 60 g threonine). Supplementation in Group II notably increased milk yield, while Groups I and II showed higher milk fat percentages, and all experimental groups exhibited improved milk protein percentages. Additionally, blood levels of total protein, albumin, triglycerides, and glucose were reduced. Detailed analyses from Group II at peak lactation (day 60) included targeted metabolomics and microbial sequencing of milk, blood, and fecal samples. Amino acid metabolomics assessed amino acid content in mare milk and serum, while 16S rRNA gene sequencing evaluated rectal microbial composition. The results indicated that lysine and threonine supplementation significantly increased levels of threonine and creatine in the blood, and lysine, threonine, glutamine, and alanine in mare milk. Microbial analysis revealed a higher prevalence of certain bacterial families and genera, including Prevotellaceae, p_251_o5, and Rikenellaceae at the family level, and unclassified_p_251_o5, Prevotellaceae_UCG_001, and Rikenellaceae_RC9_gut_group at the genus level. Multi-omics analysis showed positive correlations between specific fecal genera and amino acids in mare milk. For instance, Prevotellaceae_UCG_003, unclassified Bacteroidetes_BS11_gut_group, and Corynebacterium were positively correlated with lysine, while unclassified Prevotellaceae was positively correlated with alanine and threonine, and Unclassified_Bacteroidales_BS11_gut_group was positively correlated with glutamine. In summary, lysine and threonine supplementation in grazing lactating mares enhanced milk production and improved milk protein and fat quality. It is recommended that herders, veterinarians, and technicians consider amino acid content in the diet of lactating mares. The optimal supplementation levels under grazing conditions for Yili horses were determined to be 60 g lysine and 40 g threonine per day. Future research should explore the molecular mechanisms by which these amino acids influence milk protein and lipid synthesis in mare mammary epithelial cells.

The Effects of Flax and Mustard Seed Inclusion in Dairy Goats’ Diet on Milk Nutritional Quality

Our study evaluated the impact of incorporating flax seeds or a flax and mustard seeds’ mixture into goats’ diets to enhance milk polyunsaturated fatty acids (PUFAs). The incorporation of mustard seeds also aimed to slow the lipid oxidation process. A three-week feeding trial was conducted on 18 lactating goats, randomly distributed in three groups: control (C), FS (replacing 12% of the oil source with flax seeds), and FMS (replacing a quarter of flax seeds with mustard seeds). Flax seed inclusion improved the quality of milk fat by reducing saturated fatty acid concentration (p = 0.004) and increasing PUFA levels (p = 0.001). Both experimental groups significantly lowered the omega 6/omega 3 fatty acid ratio (p < 0.001). The FMS group showed a significantly higher total vitamin E concentration (p = 0.007). The fat oxidation parameters revealed that after 24 h of storage at room temperature, the p-anisidine value increased for the FS group compared to the C group, while the FSM group showed no significant difference, suggesting that the combined inclusion of flax and mustard seeds may prolong milk storage time by mitigating secondary oxidation products. This highlights the potential benefits of incorporating the studied seeds into goats’ diets for improving milk quality and extending its shelf life.

Streptococcus thermophilus JM905-Strain Carbon Source Utilization and Its Fermented Milk Metabolic Profile at Different Fermentation Stages.

The metabolic utilization of different carbon sources by Streptococcus thermophilus JM905(S. thermophilus JM905) was determined using a high-throughput microbial phenotyping system, and changes in fermentation characteristics of S. thermophilus JM905 fermented milk were investigated at different fermentation periods, with changes in pH, water-holding capacity, viscosity, nuisance odor, and viable bacteria count being used to define the fermentation characteristics of the strain. Changes in the key metabolites, 2-hydroxybutyric acid, folic acid, L-lactic acid, D-glycerol-D-galactose-heptanol, (R)-leucine, L-aspartic acid, L-proline, D-arginine, L-isoleucine, hydra starch, L-lysine, L-tryptophan, and D-galactose, were clarified. Correspondingly, the fermented milk protein, amino acid, and fermented milk fat quality nutrient contents were determined to be 3.78 ± 0.054 g per 100 g, 3.405 ± 0.0234 g per 100 mL, and 0.161 ± 0.0030 g per 100 g, respectively. This study addressed strain carbon source utilization, changes in fermentation characteristics and metabolites during fermentation, with the aim of investigating the link between fermentation characteristics and metabolite quality components of Streptococcus thermophilus JM905 and its fermented milk with fermentation potential and to provide a useful reference for the screening of superior fermentation strains.

Effects of dietary fat modulation on milk fat quality and gene expression of goats

This study was aimed at investigating the effect of dietary fat modulation via oil blend supplement (linseed oil 1.5/3.0%, sunflower oil 1.5/3.0%, 20 g FineX™NV1810) on the milk production, quality, fatty acid profile and gene (PPAR-α, SCD, ACAC, HMG-CoA synthase) expression of lactating Barbari goats. Eighteen goats were equally divided into three groups, where group A was given a basal diet, while group B and group C were offered two levels of oil blend in addition to the basal diet for 90 days. Oil blend supplementation significantly (P < 0.05) affected milk production, pH, titratable acidity, ash, milk solid-not-fat, and total soluble solids. Further, it significantly (P < 0.05) increased C4:0 C16:1, C18:0, C18:1n–9, C18:2n–6, C18:3n–3, MUFA, PUFA, and P/S ratio, while reduced the fatty acids C8:0 to C16:0, n–6/n–3 ratio, and SFA of milk fat. There was a positive effect (P < 0.05) of the oil blend supplement on the health and metabolic indices of milk fat. The oil supplementation levels and trial period affected the expression of the studied genes.

The effect of 2-day heat stress on the lipid composition of bovine milk and serum

Milk and serum were collected from dairy cows before and during a 2-day heat challenge. The concentrations of free short-chain fatty acids (SCFAs), the fatty acid (FA) profile, and the abundance of the major species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and sphingomyelin (SM) were measured, and samples collected during heat exposure were compared with those collected prior to heat exposure. It was found that a 2-day heat challenge did not alter the global FA composition of milk fat nor the content of the major phospholipids. Although the concentration of SCFAs C3 and C4 and some lysophosphatidylcholine (LPC) species in milk was found to be associated with the forage type, neither of these lipid molecules can be used as an indicator of acute heat stress. While it is a positive finding that short-term heat stress has no detrimental effect on the FA composition or the nutritive quality of milk fat, this study highlights the complexity of validating a milk lipid biomarker for heat stress in dairy cows.

Comprehensive Investigation of Humic-Mineral Substances from Oxyhumolite: Effects on Fatty Acid Composition and Health Lipid Indices in Milk and Cheese from Holstein-Friesian Cows

The objective of this study was to determine the effect of the oxyhumolite supplementation in the feed of cows on the profile and the nutritional indices of fatty acids (FA) in milk and cheese. To the diet of 30 cows, a 100 g/per cow/per day humic-mineral supplement with 65% humic acids was included. Milk was sampled three times: control (0 day, before the dietary modification) and on days 30 and 60 after the introduction of the supplement. For chemical analyses, samples from each cow and for cheese manufacture samples of bulk milk were taken. Fat content in the milk and the cheese, and partial sums of fatty acids profile, nutritional fatty acid ratios and indices were determined. The indicated changes in milk fat quality are difficult to unequivocally assess from a dietary point of view. Negative changes were found in the increase in the proportion of hypercholesterolemic acids (HSFA), atherogenic (AI) and thrombogenic (TI) indices, and a decrease in the hypocholesterolemic/hypercholesterolemic (h/H) ratio, the proportion of desired (DFA) and monounsaturated (MUFA) FA over time of supplementation. Positive changes were also found: the increase in polyunsaturated (PUFA), branched-chain (BCFA), short- and medium-chain (SCSFA) and long-chain (LCSFA) FA percentages, and also content was reported. The cheese (30 and 60 d) showed an increase in the content (mg/100 g) of SFA (including SCFA and LCSFA), OCFA (odd-chain FA), BCFA, MUFA, and DFA. Adverse changes were observed with an increase in PUFA n6, the n6/n3 ratio, and HSFA and TI. No significant differences were found for the AI index. The preliminary results obtained are promising, although further research is needed.

Effect of Sunflower Oil Supplementation on Milk Production, Composition, Fatty Acid Profile and Blood Metabolites of Mehsana Buffaloes

Background: In early post-partum buffaloes, feed intake is generally insufficient to meet the energy demand for milk production; as a consequence, body reserves are mobilized which can result in metabolic disorders and poor production performance. In order to enhance energy intake and reduce the detrimental effects of a negative energy balance, buffalo diets may be supplemented with lipids/vegetable oil. Some reported benefits of vegetable oil supplementation include increased energy concentration in the diet, reduced supply of rapidly fermentable carbohydrates, and better productive performance. Sunflower (Helianthus annuus L.) is an important oilseed crop in India. Sunflower seed contains about 48-53 percent of edible oil. Recent studies demonstrated that sunflower oil supplementation improved the milk production and nutritional quality of milk fat which is beneficial to human health. Therefore, the present study was undertaken to investigate the effect of sunflower (Helianthus annuus L.) oil supplementation on production performance of lactating Mehsana buffalo. Methods: Three experimental groups were as, CON: fed on basal diet (Control), SO125: fed basal diet supplemented with 125 ml of sunflower oil/animal/day and SO250: fed basal diet supplemented with 250 ml of sunflower oil/animal/day for a period of 90 days. Result: There was no difference (P greater than 0.05) in DM intake of lactating buffaloes among the dietary treatments. Dietary inclusion of sunflower oils improved milk yield by 17.9 to 20.7%, 6% FCM yield by 16.4 to 22.9% and ECM yield by 16.0 to 23.0% in SO125 and SO250 groups, respectively as compared to the CON. There were no differences (P greater than 0.05) in milk composition and yields of milk components. The milk fatty acid percentages of C20:0 and C24:0 were significantly decreased due feeding of sunflower oil as compared to the CON. Feeding of sunflower oil did not influence milk fat short chain, medium chain, saturated, unsaturated and polyunsaturated fatty acids in lactating Mehsana buffaloes. The serum concentrations of glucose, total proteins, albumin, urea, creatinine, triglycerides, ALT and AST were not affected (P greater than 0.05) by supplementation of sunflower oil, however, serum cholesterol concentration was significantly (P less than 0.01) increased in SO125 and SO250 groups as compared to the CON group.

Effect of rice bran crude lecithin blended diet on rumen ecology, metabolic profile, and milk fat indices affecting human health

AbstractTwo experiments are conducted to find out the effect of rice bran crude lecithin on rumen ecology, milk fat quality, metabolic indices, and leptin (LEP) gene expression. In first experiment, 12 crossbred calves are randomly divided into two groups, that is, RBCL‐0 and RBCL‐6, and they are fed wheat straw based diet with concentrate mixture containing 0% RBCL (CM1) and 6% RBCL (CM2), respectively, for 120 d for rumen fermentation study. Ruminal ammonia‐N and short chain fatty acids and rumen microbes are nonsignificantly affected in RBCL calves. In second experiment, 12 lactating cows are randomly divided into RBCL‐0 and RBCL‐6 groups and fed CM1 and CM2 concentrate along with napier grass as roughage. In milk fatty acid profile, C16:1 fatty acid is significantly lower whilecis‐C18:1 is significantly higher in the RBCL supplemented cows. The atherogenic index and thrombogenic index are 16 and 19% lower while health promoting index, polyunsaturated saturated fatty acids, and hypocholesterolaemic/hypercholesterolaemic are 16, 10, and 16, respectively, higher in RBCL‐6 cows. The mean nonesterified fatty acid and β‐hydroxy butyric acid value is lower while LEP gene expression is higher in RBCL supplemented cows than control cows. The milk income is higher in RBCL cows. Finally, it can be concluded that RBCL at 6% in concentrate mixture of dairy ration do not adversely affect the rumen ecology. Although RBCL has capacity to enhance health properties of milk fat along with profitability, still more studies are warranted.Practical applications: Cow milk has always been an important component of the human diet in the world. The milk composition, especially fat, is directly influenced by feeding regime in dairy animals. In the milk fat, the unsaturated fatty acids (mainly polyunsaturated fatty acids) help in improving the health condition of consumers along with the keeping quality of milk. In this series, rice bran crude lecithin was used in the dairy ration and found that it altered certain metabolic parameters and gene expression, which may be beneficial for animal health without altering rumen fermentation. Although RBCL substantially modify the milk fatty acid profile and improves the fat indices which will enhance the human health by protecting them from cardiovascular diseases.

Effects of BLG polymorphism and dietary supplementation with carob pulp on ewe milk traits and fatty acid composition

The current study examined the effect on milk traits and composition of the replacement of barley grain with carob pulp as a supplement for grazing ewes with different genotypes at the β-lactoglobulin (BLG) locus. Forty-six Valle del Belìce lactating ewes were chosen for the feeding trial and split into control and carob groups based on the BLG p.Tyr38His polymorphism. The carob group received a supplement of 250 g/d of carob pulp, whereas the control group received 250 g/g of a barley whole grain-based concentrate. There were no milk yield or gross composition variations related to the BLG genotype. Nevertheless, milk fatty acid composition was influenced by the BLG polymorphism. Compared to the AB genotype, milk from BB sheep had higher concentrations of linoleic, linolenic acids, and total polyunsaturated fatty acids. The addition of carob pulp did not significantly modify fat and protein-corrected milk, whereas reduced protein and urea concentration, increased the fat content but worsened the milk quality in terms of fatty acid composition, increasing saturated and medium chain fatty acids. The genotype × feed interaction had no appreciable effect on milk composition or quality. HIGHLIGHTS Diet, genotype, and their interaction affect the milk traits and quality. Carob pulp reduced protein, urea and worsened fat quality. The genotype positively influenced the milk fat quality.

Nutritional Quality of Milk Fat from Cows Fed Full-Fat Corn Germ in Diets Containing Cactus Opuntia and Sugarcane Bagasse as Forage Sources

We evaluated the performance, milk composition, and milk fatty acid profile of cows fed diets composed of cactus cladodes (Opuntia stricta [Haw.] Haw), sugarcane bagasse and increasing levels of full-fat corn germ (FFCG). We hypothesized that ground corn can be effectively replaced by FFCG when cactus cladodes and sugarcane bagasse are used as forage sources. The cows were randomly distributed into two 5 × 5 Latin Squares and fed five diets in which ground corn was progressively replaced with full-fat corn germ (FFCG; 0%, 25%, 50%, 75%, or 100% of substitution). Adding FFCG to the diet increased milk production and milk fat content and reduced milk protein content. Overall, FFCG reduced the proportion of saturated FAs and increased mono- and polyunsaturated FAs in milk, including CLA isomers. In addition, activity indices of stearoyl-CoA desaturase were reduced by increasing levels of FFCG. We conclude that the substitution of corn for FFCG in diets based on cactus cladodes and sugarcane bagasse positively modifies the FA profile of milk and could add commercial value to milk products (e.g., CLA-enriched milk). In addition, the milk fat response indicates that the basal diet was favorable to the rumen environment, preventing the trans-10 shift commonly associated with milk fat depression.

Composição em ácidos graxos no leite de vacas e ovelhas suplementadas com extrato tanífero de acácia negra

ABSTRACT: This study evaluated the effects of Acacia mearnsii tannin extract on milk fatty acid profile of dairy ewes and cows. In experiment 1, twenty-four Lacaune ewes received one of the following dietary treatments: control (no tannin extract added to the diet), T30 (30 g tannin extract/kg concentrate), and T40 (40 g extract/kg concentrate). In experiment 2, thirty Jersey cows received either a control diet (no tannin extract added to the diet) or the same diet containing 40 g tannin extract/kg concentrate (T40). Dry matter intake, milk production and milk solids content of ewes and cows were unaffected by tannin supplementation. The cis-9, trans-11 conjugated linoleic acid (CLA) content increased linearly by 21% in milk fat from ewes fed tannin extract, while the C18:2 n-6 (linoleic acid) content tended (P = 0.051) to increase by 13% in cows fed TE. The supplementation with black wattle tannin extract improves the nutritional quality of milk fat of ewes and cows to a small extent, with no adverse effects on performance or gross milk composition.

Gas chromatographic determination of fatty acid composition in breast milk of mothers with different health conditions

AbstractHuman milk (HM) of healthy, well-nourished, lactating mothers is a unique and ideal source of nutritive factors, like hormones, cytokines, chemokines, growth factors that ensures the proper growth and development of infants. Among the main components of HM, fat is an important energy source and a regulatory factor. The quality of milk fat depends on its fatty acid (FA) composition. Gas chromatography coupled with flame ionisation detection is one of the most common methods for analysis of the FA profile of HM. The aim of this study was to evaluate the FA composition of HM, collected from mothers with different health conditions (normal Body Mass Index (nBMI); overweight and obese) using GC-FID method. The results showed that saturated FAs were present in the highest amount in the HM samples, of which palmitic acid was the main representative. The major monounsaturated FA was oleic acid, while linoleic acid was the most abundant of the polyunsaturated FAs (PUFA). Overweight and obese women have lower levels of PUFA in their breast milk. The data were subjected to principal component and quadratic discriminant analysis (QDA). QDA classified nBMI and overweight and obese mother milk samples with 88.24% accuracy. Significant differences were found between normal and overweight and obese HM samples in case of C10:0 and C18:3 FAs. Higher maternal BMI was associated with a higher n-6/n-3 PUFA ratio.

Quality of milk fat obtained from cows and buffaloes fed a diet supplemented with flaxseed or soybean oils

The experiment was carried out to evaluate the quality of anhydrous milk fat (AMF) of cows and buffaloes supplemented with flaxseed oil (FO), soybean oil (SO), or their mixture (FSO). Lactating crossbred cows and buffaloes were fed with control diet or with one of three supplements: 2% FO, 2% SO, and 2% FSO according to a double 4 x 4 Latin Square Design. The diets with FO, SO, or FSO reduced saturated FA, mainly C4:0, C14:0 and C16:0, while increased the unsaturated FA C18:1 and C18:2 in milk from cows and buffaloes. Cholesterol content decreased in cow's AMF while increased in buffalo's AMF when a diet supplemented with FO, SO, or FSO. The diet with SO or FSO increased the content of vitamin E in AMF obtained from cows (25.06 and 17.89 mg 100 g-1) and buffaloes (28.48 and 30.32 mg 100 g-1) compared with the control diet (11.02 and 15.68 mg 100 g-1), respectively, which correlated positively with scavenging activity for DPPH• (r2 = 0.66) and ABTS• (r2 = 0.67) radicals. Solid fat content (SFC) was high for cow’s AMF, with 58.12-60.37% at 5°C compared to that of buffalo's AMF, with 52.37-56.98%, but was low for cow's AMF at &gt;15°C. Finally, supplementing a diet with vegetable oils, particularly SO, improves the quality of AMF; increases USFA/SFA ratio, vitamin E content, and antioxidant activities

Energy utilization and milk fat responses to rapeseed oil when fed to lactating dairy cows receiving different dietary forage to concentrate ratio

We evaluated energy and N utilization, performance, and milk fatty acid (FA) profile using grass silage-based diets when rapeseed oil (RO) was included in high- or low-forage diets. Four multiparous Nordic Red cows averaging 101 ± 16 days in milk at the beginning of the study were randomly assigned to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Each 21-d period consisted of a 14-d diet adaptation period and 7-d collection period. Cows were fed the following diets comprised total mixed rations based on grass silage with forage to concentrate (FC) ratio of 35:65 and 65:35 containing 0 or 50 g/kg of RO. Significant FC × RO interactions were observed for milk yield, milk protein and lactose yields, milk fat concentration, and milk proportions of trans-11 18:1, trans-10 18:1, trans-10, cis-12 18:2, and saturated FA. Feeding low-forage diet was effective in increasing milk yield compared with the high-forage diet, and the RO supplementation increased it further (P ≤ 0.01). A similar pattern was observed for the yields of milk protein and lactose. Supplementing the low-forage diet with RO reduced milk fat concentration by 19% relative to other diets without affecting milk fat yield. The proportion of N intake lost as urine decreased (P ≤ 0.05) with the RO supplementation of low-forage diet without affecting energy and N balances. Nutrient intakes were greater (P ≤ 0.01) in cows fed low-forage diet, whereas RO decreased (P < 0.05) protein, starch, and fiber intakes. Methane production, expressed as a proportion of energy intake, decreased with low-forage compared with high-forage diets and this variable declined similarly by RO supplementation of both diets (P < 0.01). The milk proportions of trans-10 18:1 and trans-10, cis-12 CLA increased (P ≤ 0.01) by RO supplementation of the low-forage but not high-forage diet. However, RO supplementation of both high- and low-forage diets increased (P < 0.01) total trans FA and decreased saturated FA proportions, even though the changes were more profound in low-forage diet (P ≤ 0.01). In addition, RO increased (P < 0.01) cis monounsaturated FA in milk for both high- and low-forage diets. Overall, the low-forage diets had lower methane emissions and RO increased partitioning of N towards milk secretion (P ≤ 0.01) without influencing energy or N balances. According to the results, RO supplementation did not compromise intake of nutrients with low-forage diets containing 150 g/kg starch, and oil could be preferentially used to improve milk production and milk fat quality accompanied by a reduction in methane energy loss.

Triacylglycerol composition and thermodynamic profiles of fractions from dry fractionation of anhydrous milk fat

This research provided a more in-depth look at the physiochemical properties of milk fat. The milk fat was fractionated between 30 and 15 °C into eight fractions with different melting points, the cooling step were successively 30, 25, 20 and 15 ℃. Physiochemical properties of different fractions, which include fatty acids, triacylglycerols, thermodynamics, and crystallization behavior, also were analyzed by using GC, UPLC-ESI MS, DSC and XRD. The results showed that the melting point of 30 S could reach 38.2 ℃ compared with the native milk fat (31 ℃) after fractionation. As the fractionation temperature decreased, the content of long-chain saturated fatty acids decreased. However, the content of short and medium-chain saturated fatty acids and unsaturated fatty acids showed an increasing trend, and the corresponding saturated triacylglycerols were also reduced. Besides, the high melting point fractions were mixed dominantly by β' crystal form at room temperature. The crystallization or melting temperature was relatively high, and the latent heat of phase change also was large. Therefore, these results demonstrated that the milk fat quality could be improved by dry fractionation and its application was expanded in production.

Milk Fatty Acid Profile of Holstein Cows When Changed from a Mixed System to a Confinement System or Mixed System with Overnight Grazing.

This study is aimed at comparing the milk fatty acid profile (FAP) of cows that changed from a mixed system (MS) of double grazing plus total mixed ration (TMR) to a total confinement system (TCS, 100% TMR) with cows that changed to another MS with one overnight grazing plus TMR and compare with cows that were kept unchanged in TCS. The diet change was made in the second month of lactation. The milk samples were collected at one (M1-spring) and three months of lactation (M3-summer). Three treatments are as follows (each n = 10): confined cows fed with TMR throughout the period (GTMR), cows that changed from MS with double grazing plus TMR in M1 to TCS in M3 (GCHD), and cows that changed from a MS with double grazing plus TMR in M1 to a MS with overnight grazing plus TMR in M3 (GTMR+P). Unlike GTMR+P, GCHD improved milk production after change (increased 14% from M1 to M3), but milk FAP was impaired. In M3, conjugated linoleic acid (C18 : 2-CLA) in GTMR and GCHD was lower than GTMR+P (p < 0.05), and linolenic (C18 : 3-n-3) was lower in GCHD than GTMR+P. Maintaining grazing in summer overnight sustained milk fat quality, evidenced by higher C18 : 3 (n-3); C18 : 2 (CLA); and n-6/n-3 ratio than cows that changed to TCS.

Transcriptional profiling of buffalo mammary gland with different milk fat contents.

Milk fat is the most important energy substance in milk and contributes to its quality and health benefits. Water buffalo milk is well known for its high milk quality with higher fat contents compared with cattle milk. Dehong buffalo is a unique local swamp breed in Yunnan Province with higher milk fat and excellent milk quality which provides a good model for the investigation of the molecular mechanisms of milk fat deposition. In this study, we used RNA-seq to obtain mammary tissue transcriptomics of buffalo with different milk fat phenotypes including high(H), medium (M)and low (L) fat content groups. Comparative analyses of buffalo among three groups yielded differentially expressed genes (DEGs). Analyzing the number of different genes among H_VS_L, H_VS_M, and M_VS_L showed the same expression pattern between H_VS_M. The increasing expression levels of genes including CSN1S1, BTN1A1, LALBA, ALDH1L2, SCD and MUC15, and down-regulated expression levels of genes containing CCL2, CRABP2, ADTRP, CLU and C4A in H_VS_L and M_VS_L were found. GO and KEGG enriched pathways revealed these DEGs involved in milk protein and fat as well as immune response. The findings would enhance the understanding of the interplay between the milk composition and immune response, which suggests that the immune capacity should be considered when we tried to improve the milk quality.

55 Sow Milk Lipidome Study Reveals Changes in Fatty Acyl Residues in Triglycerides and Phosphatidylglycerol, but Not in Plasma Membrane Phospholipids Across Lactation

Abstract Sow milk fat content is crucial to neonatal survival, as it is utilized for thermogenesis and nutrition. However, fat is the most variable component of milk in concentration and lipid species. Characterizing lipid changes across the course of a sow’s lactation may help identify molecules or systems to target to help enhance milk fat quality and quantity for neonatal survival and growth. Percent fat variation is greatest in colostrum, the first milk. Little is known regarding colostrum synthesis, other than it accumulates in the gland beginning in mid-late pregnancy, which is prior to the initiation of fatty acid synthesis in lactocytes. The objective of this study was to characterize changes in lipid composition of milk across the course of lactation and determine if there was a relationship between fat percent and lipid species in colostrum and mature milk. Milk was collected from 9 multiparous sows on days 0, 3, 7, and 14 relative to birth. Percent fat was determined by creamatocrit, and found to be different (p&amp;lt; 0.05) between day 0 (12.36 ± 5.90%) and day 3 (16.22 ± 3.65%) but not between day 7 (13.13 ± 2.19%) and 14 (12.13 ± 2.45%). Fat was extracted from milk using the Bligh-Dyer method and profiled using multiple reaction monitoring. Amounts of lipid species were calculated relative to standards and data analysis was performed using Metaboanalyst 4.0. Principle component analysis revealed lactation day had a significant effect on distribution of fats. Triacylglycerides (TAG), phosphatidylglycerol (PG), and plasma membrane lipids were modified from colostrum to mature milk, with a significant increase in PGs and TAGs across the course of lactation. Correlation analysis of percent fat with lipid concentration indicated strong relationships (P &amp;lt; 0.05; |r| &amp;gt;0.80) with eight lipids. No differences are found in the abundance of plasma membrane phospholipids, sphingomyelin, or cholesterol esters across lactation days.

LC-MS/MS Based Metabolomics Reveal Candidate Biomarkers and Metabolic Changes in Different Buffalo Species.

Simple SummaryMilk and dairy products have become the most common and an essential nutrition in human life, while dairy products with high nutritional value are attracting more and more attention. Buffalo milk contains higher protein, fat, lactose, and total solid contents and has been considered as the source of superior dairy products, such as mozzarella cheese, butter, ice cream, and yoghurt. Moreover, buffalo milk contains more unsaturated fatty acids (UFAs) which are important for human health owing to their desirable physiological effects. However, the composition of milk seems to vary among different buffalo species and inadequate information is available about the underlying mechanism. Therefore, exploring the biomarkers of superior buffalo milk is crucial for the process of dairy products and buffalo breeding. In the present study, diverse significantly different metabolites were identified among the Mediterranean, Murrah, and crossbred buffalo, and the different metabolites were mainly enriched in fat synthesis related pathways which affected the end fat content in the milk. Moreover, these specific metabolites can be used as candidate biomarkers in the identification of milk quality and molecular breeding of high milk fat buffalo.Consumers have shown more and more interest in high-quality and healthy dairy products and buffalo milk is commercially more viable than other milks in producing superior dairy products due to its higher contents of fat, crude protein, and total solids. Metabolomics is one of the most powerful strategies in molecular mechanism research however, little study has been focused on the milk metabolites in different buffalo species. Therefore, the aim of this study was to explore the underlying molecular mechanism of the fatty synthesis and candidate biomarkers by analyzing the metabolomic profiles. Milk of three groups of buffaloes, including 10 Mediterranean, 12 Murrah, and 10 crossbred buffaloes (Murrah × local swamp buffalo), were collected and UPLC-Q-Orbitrap HRMS was used to obtain the metabolomic profiles. Results showed that milk fatty acid in Mediterranean buffalo was significantly higher than Murrah buffalo and crossbred buffalo. A total of 1837/726 metabolites was identified in both positive and negative electrospray ionization (ESI±) mode, including 19 significantly different metabolites between Mediterranean and Murrah buffalo, and 18 different metabolites between Mediterranean and crossbred buffalo. We found 11 of the different metabolites were both significantly different between Mediterranean vs. Murrah group and Mediterranean vs crossbred group, indicating that they can be used as candidate biomarkers of Mediterranean buffalo milk. Further analysis found that the different metabolites were mainly enriched in fat synthesis related pathways such as fatty acid biosynthesis, unsaturated fatty acid biosynthesis, and linoleic acid metabolism, indicating that the priority of different pathways affected the milk fat content in different buffalo species. These specific metabolites may be used as biomarkers in the identification of milk quality and molecular breeding of high milk fat buffalo.