Linoleic Acid In Milk Research Articles

A New Strain of Saccharomyces cerevisiae in Diets of Lactating Holstein Cows Improved Feed Efficiency and Lactation Performance

Abstract This study compared the effects of feeding a new strain of Saccharomyces cerevisiae HSA2020 with a commercial strain on in vitro rumen fermentation and production performance of dairy cows. Permeate was used as a substrate for the laboratory production of the new strain of S. cerevisiae after the hydrolysis by β-galactosidase (5000 µ/mL at 37°C). Two experiments were conducted: in Experiment 1, the effects of three levels (1, 2 and 3 g/kg dry matter) of S. cerevisiae on in vitro ruminal fermentation kinetics were evaluated. In Experiment 2, for 60 days, sixty multiparous Holstein cows (639±24.8 kg BW, 3±1 parity, 7±1 days in milk, with a previous milk production of 23±2.0 kg/d) during the previous lactation, were randomly assigned to 3 treatments in a completely randomized design. Cows were fed without any additives (control treatment) or supplemented with 2 g/kg feed daily of laboratory produced (PY) or commercial (CY) S. cerevisiae. In Experiment 1, inclusion of PY and CY increased (P<0.05) gas production, propionate, and nutrient disappearance, while decreased (P<0.05) methane production and protozoal count. Moreover, in Experiment 2, PY followed by CY increased (P<0.01) nutrient digestibility, and serum concentrations of total protein, albumin, and glucose (P<0.05). Higher daily milk yield, and milk energy output were observed with PY and CY without affecting concentrations of milk components or milk fatty acid profile. Compared to control, increased feed efficiency was observed with PY and CY. Compared to PY, CY increased serum concentrations of urea-N and decreased triglycerides, while PY decreased serum aspartate transaminase and increased concentration of conjugated linoleic acids in milk. In early lactating cow diets, both strains of S. cerevisiae improved production performance at 2 g/kg, and minimal differences between strains were found.

Associating changes in the bacterial community of rumen and faeces and milk fatty acid profiles in dairy cows fed high-starch or starch and oil-supplemented diets.

The experiment reported in this research paper aimed to evaluate the effects of high-starch or starch and oil-supplemented diets on rumen and faecal bacteria, and explore links between the structure of bacterial communities and milk fatty acid (FA) profiles. We used four Holstein dairy cows in a 4 × 4 Latin square design. Cows were fed a diet rich in cereals (high-starch diet with 23% starch content on dry matter (DM) basis), a diet supplemented with saturated FA from Ca salts of palm oil + 18% DM starch, a diet with high content of monounsaturated FA (from extruded rapeseeds) + 18% DM starch or a diet rich in polyunsaturated FA (from extruded sunflower seeds) + 17% DM starch. At the end of each experimental period, cows were sampled for rumen and faecal contents, which were used for DNA extraction and amplicon sequencing. Partial least squares (PLS) regression analysis highlighted diet-related changes in both rumen and faecal bacterial structures. Sparse PLS discriminant analysis was further employed to identify biologically relevant operational taxonomical units (OTUs) driving these differences. Our results show that Butyrivibrio discriminated the high-starch diet and linked positively with higher concentrations of milk odd- and branched-chain FA. YS2-related OTUs were key taxa distinguishing diets supplemented with Ca salts of palm oil or sunflower seeds and correlated positively with linoleic acid in milk. Similarly, diets modulated faecal bacterial composition. However, correlations between changes in faecal and rumen bacteria were poor. With this work, we demonstrated that high-starch or lipid-supplemented diets affect rumen and faecal bacterial community structure, and these changes could have a knock-on effect on milk FA profiles.

Effects of Heavy Metal Exposure from Leather Processing Plants on Serum Oxidative Stress and the Milk Fatty Acid Composition of Dairy Cows: A Preliminary Study.

Simple SummaryThe leather industry has raised the blood lead and arsenic levels of cows in nearby farms. Significant decreases in serum GST, GPX, and GSH activity were observed in the polluted area. Milk linoleic acid (C18:2n6c) was significantly reduced in the polluted area. Heavy metal exposure through leather industry imposes oxidative stress on cows, leading to modifications in the unsaturated fatty acids of milk.This study investigated whether unsaturated fatty acids in milk and the oxidative status of cows are affected by heavy metal exposure due to leather processing. The blood lead (Pb) concentrations in cows from two farms in the polluted area were 16.27 ± 8.63 μg/L, respectively, which were significantly (p < 0.05) higher than the blood Pb concentrations in cows from an unpolluted farm (6.25 ± 3.04 μg/L). There were significantly (p < 0.05) lower levels of glutathione S-transferase (GST), glutathione peroxidase (GPX), and glutathione (GSH) in the serum of cows from the polluted area compared to the levels in cows from an unpolluted area. The linoleic acid (C18:2n6c) content in milk from the polluted area was 15% lower than in the control area. There was a significant correlation between linoleic acid in milk with the blood Pb and serum GSH levels. Heavy metals can alter fatty acid synthesis through oxidative stress, which may be the mechanism by which heavy metals affect fatty acid synthesis in milk.

The Case for Grazing Dairy Cows

The case for grazing dairy cows at pasture is reviewed in six categories: (i) optimal land use for food production; (ii) soil carbon sequestration; (iii) carbon footprint; (iv) animal health and welfare; (v) effects on human health of milk produced from grazed pasture; and (vi) consumer demand for milk from grazed cows. Land best-suited to grazing is uncultivatable peaty soil receiving relatively low levels of fertilisation. With soil carbon sequestration, carbon footprint is lower for grazing than for other systems of milk production. Some indices of animal health and welfare (e.g., lameness, status of hock integument) are influenced positively by extent of grazing. Benefits to human health may accrue from higher levels of essential amino acids, carotenoids, omega-3 fatty acids and conjugated linoleic acid in milk from cows given pasture compared to diets based on silage and concentrates. Milk producers, processors and supermarkets are responding to consumer demand for milk and milk products from cows given access to pasture during the grazing season. The major constraint to milk production from grazing is energy intake. Research opportunities to address this constraint include application of remote sensing and artificial intelligence to grazing management.

The use of bacterial cultures to increase the content of conjugated linoleic acid in milk and dairy products

The bioactive properties of conjugated linoleic acid (CLA) are associated with human health promotion processes, including anticarcinogenic, antiatherogenic, antiinflammatory and antidiabetic activity, and the ability to reduce body fat. The functional properties of the bioactive component of the fat phase of cow’s milk, called conjugated linoleic acid (CLA), are described in this article. The content of conjugated linoleic acid in raw milk was studied using the capillary gas chromatography (GC) method. The content of CLA in raw milk was evaluated, taking into account the influence of the diet of feeding cows. Many samples of raw milk were studied in summer and winter for this purpose. It was determined that the concentration of conjugated linoleic acid in the fat phase of milk in winter is lower than in summer, when the diet of cows is dominated by green feed. The content of conjugated linoleic acid in the summer period ranged from 122.3 to 372.2 mg/dm 3 , and in winter it ranged from 54.7 to 136.47 mg/dm 3 . Experimental data of the possibility of increasing the content of conjugated linoleic acid in the fat phase of milk by inserting bacterial cultures is also presented. Re sults of the parameters of production conjugated linoleic acid under the influence of Lactobacillus acidophilus and Lactobacillus delbrueckii subsp . bulgaricus were obtained. The use of these bacterial cultures allowed to increase the content of conjugated linoleic acid by 23–36% in the studied samples.

Considerations on goat milk biochemical composition

Abstract The benefits of human consumption of goat's milk are given by the presence in this milk of short-chain fatty acids (approximately 20% are short-chain fatty acids) and medium-chain fatty acids (55%), this milk being easier to digest. An important qualitative indicator of goat's milk with technological, nutritional and dietary impact is the fat content. Our data show that the percentage of milk fat increases immediately after parturition, then decreases for most of the lactation. This is due to two factors: a diluting effect, by increasing the volume of milk to the maximum level of lactation and a decreasing effect of lipid mobilization, which leads to a decrease in the plasma level of unesterified fatty acids (especially C18:0 and C18:1), with a role in lipid synthesis in the mammary gland. From the third month of lactation, the average daily amount of milking milk undergoes only slight variations. Also, the fat and protein percentage remain relatively constant during June-August. In summer there was an increase in the levels of monounsaturated, polyunsaturated fatty acids and of conjugated linoleic acids in milk, compared to spring. Our results indicate that multiparous Carpathian breed females, whose food comes mostly from grazing, produce milk during the summer with a ratio between omega-6 and omega-3 below 4.

Milk production, nitrogen utilization, and methane emissions of dairy cows grazing grass, forb, and legume-based pastures.

Achieving high animal productivity without degrading the environment is the primary target in pasture-based dairy farming. This study investigated the effects of changing the forage base in spring from grass-clover pastures to forb or legume-based pastures on milk yield, N utilization, and methane emissions of Jersey cows in Western Oregon. Twenty-seven mid-lactation dairy cows were randomly assigned to one of three pasture treatments: grass-clover-based pasture composed of festulolium, tall fescue, orchardgrass, and white clover (Grass); forb-based pasture composed of chicory, plantain, and white clover (Forb); and legume-based pasture composed of red clover, bird's-foot trefoil, berseem clover, and balansa clover (Legume). Pastures were arranged in a randomized complete block design with three replicates (i.e., blocks) with each replicate grazed by a group of three cows. Production and nutritive quality of the forages, animal performance, milk components, nitrogen partitioning, and methane emissions were measured. Feed quality and dry matter intake (DMI) of cows were greater (P ≤ 0.05) for Legume and Forb vs. Grass, with consequent greater milk and milk solids yields (P < 0.01). Cows grazing Forb also had more (P < 0.01) lactose and linoleic acid in milk compared with cows grazing the other pastures, and less (P = 0.04) somatic cell counts compared with Grass. Cows grazing Forb had substantially less (P < 0.01) N in urine, milk, and blood compared with cows grazing the other pastures, with not only a greater (P < 0.01) efficiency of N utilization for milk synthesis calculated using milk urea nitrogen but also a larger (P < 0.01) fecal N content, indicating a shift of N from urine to feces. Both Forb and Legume had a diuretic effect on cows, as indicated by the lower (P < 0.01) creatinine concentration in urine compared with Grass. Methane emissions tended to be less (P = 0.07) in cows grazed on Forb vs. the other pastures. The results indicate that Forb pasture can support animal performance, milk quality, and health comparable to Legume pasture; however, Forb pasture provides the additional benefit of reduced environmental impact of pasture-based dairy production.

Milk fatty acid composition reflects metabolic adaptation of early lactation cows fed hay rich in water-soluble carbohydrates with or without concentrates

We hypothesized that alterations in metabolic status systematically affect the milk fatty acid (FA) composition and thus milk FA can reveal the metabolic status of dairy cows. We, therefore, investigated changes in the milk FA profile of 24 Simmental cows fed high-quality ryegrass hay (HQ hay) rich in water-soluble carbohydrates (WSC) in the diet, which was shown to affect energy partitioning towards either milk production or body reserve retention, and consequently the metabolic status depending on the dietary proportion of concentrates supplied. The test diets (per kg dry matter (DM)) were CON (600 g fiber-rich hay + 400 g concentrate), 60HQ (600 g HQ hay + 400 g concentrate), 75HQ (750 g HQ hay + 250 g concentrate), and 100HQ (100 g HQ hay). As opposed to the fiber-rich hay, the HQ hay was richer in crude protein (CP; 223 vs. 65 g/kg CP in DM), WSC (198 vs. 110 g/kg WSC in DM) and 18:3 n-3 (560 vs. 316 g/kg FA). The feeding trial was performed from 10 d before calving until 28 d thereafter and milk samples were collected on 7, 14, 21 and 28 d after calving for the FA analysis. Linear and non-linear regression analyses of milk FA and serum metabolites (NEFA and BHB) concentrations were performed. Energy secreted with the milk relative to the intake was highest in cows fed CON and 100HQ and lowest in the 75HQ cows. Both energy-deficient groups (CON and 100HQ) showed elevated levels of milk 18:1 n-9 at the expense of some mammary de novo FA compared to the other two groups (P < 0.05). Cows fed 60HQ secreted greater amounts (g/d) of the de novo FA compared to 75HQ and CON (P < 0.05). The HQ hay promoted the level of conjugated linoleic acids in milk regardless of the inclusion level, and, when used at 75 % or more in the diet, also promoted the level of 18:3 n-3 (P < 0.001) due to increased 18:3 n-3 intake with the hay. The modeled data using the ratios of 15:0 to 18:1 n-9, 14:0 to 18:1 n-9 and the sum of de novo FA to 18:1 n-9 were consistently associated with serum concentrations of NEFA and BHB with a ratio below 0.02, 0.2 and 0.4 indicating excessive mobilization and greater risk of metabolic disturbances. The relationships between the FA ratios and BHB were confirmed with a meta-analysis using means of published studies. In summary, milk FA reflect the metabolic status of early lactation dairy cows. Feeding HQ hay generally promotes health beneficial C18 FA in milk.

The relationship between plasma \u03b2-hydroxybutyric acid and conjugated linoleic acid in milk as a biomarker for early diagnosis of ketosis in postpartum Polish Holstein-Friesian cows

BackgroundThe aim of this study was to investigate the association between plasma β-hydroxybutyric acid (BHBA) and conjugated linoleic acid in postpartum Polish Holstein-Friesian (PHF) cows. The experiment was carried out at an experimental dairy farm, where a herd of approximately 350 cows was kept. Samples were taken at six time points: between days 5–7, 8–14, 15–21, 22–28, 29–35, and 36–42, resulting in 510 samples of both milk and blood. The cows involved in the experiment were divided into two groups – ketotic and healthy – by taking into account general health symptoms, blood serum BHBA, and non-esterified fatty acids (NEFA) concentration at 5–7 days postpartum.ResultsIn the first week of lactation, at 5–7 day in milk (DIM), the study showed a 53% lower level of C18:2 cis-9 trans-11 (CLA9) and an 80% lower level of C18:2 trans-10 cis-12 (CLA10) in cows with diagnosed ketosis compared to healthy cows. In the second week of lactation (8–14 DIM), a 34% lower level of CLA9 and a 54% lower level of CLA10 was found in the group of cows with BHBA levels > 1.2 mmol/L. Additionally, Pearson correlation analysis showed significant negative correlation between BHBA x CLA9 and BHBA x CLA10 in the first week of lactation: − 0.732and − 0.821, respectively.ConclusionThe study shows that that both CLA9 and CLA10 can be used as markers for the early diagnosis of elevated blood levels of BHBA in postpartum Polish Holstein-Friesian cows.

The Effect of Maternal Obesity on Breast Milk Fatty Acids and Its Association with Infant Growth and Cognition—The PREOBE Follow-Up

This study analyzed how maternal obesity affected fatty acids (FAs) in breast milk and their association with infant growth and cognition to raise awareness about the programming effect of maternal health and to promote a healthy prenatal weight. Mother–child pairs (n = 78) were grouped per maternal pre-pregnancy body mass index (BMI): normal-weight (BMI = 18.5–24.99), overweight (BMI = 25–29.99) and obese (BMI > 30). Colostrum and mature milk FAs were determined. Infant anthropometry at 6, 18 and 36 months of age and cognition at 18 were analyzed. Mature milk exhibited lower arachidonic acid (AA) and docosahexaenoic acid (DHA), among others, than colostrum. Breast milk of non-normal weight mothers presented increased saturated FAs and n6:n3 ratio and decreased α-linolenic acid (ALA), DHA and monounsaturated FAs. Infant BMI-for-age at 6 months of age was inversely associated with colostrum n6 (e.g., AA) and n3 (e.g., DHA) FAs and positively associated with n6:n3 ratio. Depending on the maternal weight, infant cognition was positively influenced by breast milk linoleic acid, n6 PUFAs, ALA, DHA and n3 LC-PUFAs, and negatively affected by n6:n3 ratio. In conclusion, this study shows that maternal pre-pregnancy BMI can influence breast milk FAs and infant growth and cognition, endorsing the importance of a healthy weight in future generations.

Identification of Conjugated Linoleic Acid in Milk Fermented by Probiotics Originating in the Gastrointestinal Tract

One of the benefits of probiotics is their ability to synthesize conjugated linoleic acid (CLA) as a functional bioactive compound. The objective of this study is to identify CLA synthesized in milk fermented with the probiotic Lactobacillus casei strain AP and Lactobacillus casei strain AG as starter cultures. Fermented milk products were analyzed using gas chromatography-mass spectrometry (GC-MS) to characterize the CLA formed. The result of GC-MS in milk fermented using Lactobacillus casei strain AG was detection of a CLA compound with a retention time of 41.467, whereas in milk fermented using Lactobacillus casei strain AP, linoleic acid, but not CLA, was detected.

The Effects of Pasteurization Types on the Content and Isomerization of Conjugated Linoleic Acid in Milk

The world is currently facing an epidemic of giant proportions – diet‐induced obesity (DIO) and associated co‐morbidities (type 2 diabetes, hypertension, certain cancers, etc.). While diet and exercise are the gold standards for treatment and prevention of DIO, isomers of conjugated linoleic acid (CLA) (cis‐9/trans‐11 and trans‐10/cis‐12) have been shown to reduce body fat mass and increase lean tissue mass, and more importantly, aid in the treatment of a host of co‐morbidities. Apart from supplementation, meat and dairy products from ruminants (cows, sheep, and goats) are the major source of CLA for humans. However, CLA composition ranges greatly in these products as processing i.e. cooking, pasteurization, etc. alters the content of CLA as well the isomers themselves. As the extend of these changes are unknown, the effects of time and temperature on CLA isomerization in milk through varying pasteurization types was investigated. First, raw milk samples were obtained from a local farm, and subjected to three different types of pasteurization – vat, ultra, and high temperature, short time pasteurization. Results show that the ultra‐high temperature pasteurized sample had more trans/trans isomerization than the raw sample, while the other samples were comparable to the raw. Therefore, as temperature increased, the extent of CLA isomerization also increased. Further experiments using thermochemistry and kinetics should be conducted to identify the times and temperatures at which each isomer is converted or formed. This knowledge could then be used to produce more beneficial CLA within a given sample and to decrease the undesired trans/trans CLA.Support or Funding InformationSupport for this work was provided by the Department of Chemistry, Maryville College.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of berry seed residues on ruminal fermentation, methane concentration, milk production, and fatty acid proportions in the rumen and milk of dairy cows

Strawberry (SB), black currant (BC), and raspberry seed (RB) residues were used in 3 experiments to study their effects on ruminal fermentation, methane concentration, and fatty acid (FA) proportions in the ruminal fluid and milk of dairy cows. Initially, a batch fermentation in vitro study (experiment 1) was performed to investigate the effects of the 3 berry residues on basic ruminal fermentation parameters. Total volatile fatty acid concentrations, including acetate, propionate, and butyrate, increased in the BC group compared with other treatments. Based on the preliminary in vitro results, 2 consecutive in vivo experiments were conducted using 4 Polish Holstein-Friesian cows fitted with rumen cannulas (experiment 2) and 30 lactating Polish Holstein-Friesian dairy cows (experiment 3) in a replicated 2 × 2 crossover design. Cows in both experiments received a partial mixed ration (PMR) in 2 variants: (1) a control diet of PMR + 2 kg of concentrate (control); (2) PMR + 2 kg of BC seed residues (BC). The BC diet did not mitigate ruminal methane production. Ruminal fermentation (experiment 2) was not affected by the BC diet; however, the concentrations of C18:1 trans-11 and C18:2 cis-9,trans-11 increased significantly by 91 and 131%, respectively. Likewise, concentrations of total trans C18:1 and total monounsaturated FA in ruminal fluid were increased significantly by BC seed residues. In experiment 3, BC significantly increased milk fat C18:1 trans-11, C18:2 cis-9,trans-11, n-3, n-6, and polyunsaturated FA concentrations without affecting milk production performance. In conclusion, the amount (2 kg/d) of BC used in this study did not adversely affect ruminal fermentation or milk production and composition. However, using BC increased proportions of unsaturated FA and conjugated linoleic acid in milk. Although dietary BC did not exert a strong methane inhibition effect, it could represent an inexpensive alternative concentrate to improve beneficial FA in milk without negative effects on rumen fermentation and production parameters in dairy cows. Incorporation of berry seed residues in diets would be profitable economically and nutritionally for dairy cattle production.

Screening of Lactobacillus strains for their ability to produce conjugated linoleic acid in milk and to adhere to the intestinal tract

Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44±0.78 to 50.9±0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB.

Combined Effect of Pressure-Assisted Thermal Processing and Antioxidants on the Retention of Conjugated Linoleic Acid in Milk.

The effect of pressure-assisted thermal processing (PATP) in combination with seven synthetic antioxidants was evaluated on the retention of conjugated linoleic acid (CLA) in enriched milk. Milk rich in CLA was first saturated with oxygen, followed by the addition of either catechin, cysteine, ascorbic acid, tannic acid, gallic acid, caffeic acid or p-coumaric acid (500 mg kg−1 untreated milk). Samples were treated at 600 MPa and 120 °C up to 15 min of holding time. During PATP, CLA not only oxidized at a slower rate, but also less oxygen was consumed compared to the control (0.1 MPa and 120 °C). In addition, phenolic antioxidants were able to quench dissolved oxygen in samples treated with PATP. For those samples added with gallic acid and catechin, 85% and 75% of the CLA was retained after 15 min of holding time at 600 MPa and 120 °C, respectively. The retention of CLA was enhanced by the application of PATP in combination with gallic acid.

High-pressure and temperature effects on the inactivation of Bacillus amyloliquefaciens, alkaline phosphatase and storage stability of conjugated linoleic acid in milk

Milk rich in conjugated linoleic acid (CLA, 42 ± 3 mg g− 1 fat) was used to evaluate the impact of high-pressure sterilization (HPS). The pressure, temperature and time needed to reduce 7-log of Bacillus amyloliquefaciens endospores were determined in the presence of nisin (4–64 mg L− 1). In addition, the inactivation of alkaline phosphatase was evaluated. After HPS treatment, the remaining CLA and formation of hydroperoxides were monitored during storage up to 60 d at 25 °C. The addition of nisin (≥ 16 mg L− 1) to milk significantly enhanced the inactivation of B. amyloliquefaciens (7-log reduction) after treatment at 600 MPa, 120 °C and 5 min of holding time. These conditions were selected to evaluate the impact of HPS on the CLA retention and hydroperoxides formation. Milk with the addition of nisin and treated with HPS delivered higher retention of CLA and a lower concentration of hydroperoxides compared with the UHT equivalent process (125 °C/15 s and 135 °C/10 s).

Effect of feeding buckwheat and chicory silages on fatty acid profile and cheese-making properties of milk from dairy cows.

Fresh buckwheat (Fagopyrum esculentum) and chicory (Cichorium intybus) had been shown to have the potential to improve certain milk quality traits when fed as forages to dairy cows. However, the process of ensiling might alter these properties. In the present study, two silages, prepared from mixtures of buckwheat or chicory and ryegrass, were compared with pure ryegrass silage (Lolium multiflorum) by feeding to 3 × 6 late-lactating cows. The dietary dry matter proportions realised for buckwheat and chicory were 0.46 and 0.34 accounting also for 2 kg/d of concentrate. Data and samples were collected from days 10 to 15 of treatment feeding. Buckwheat silage was richest in condensed tannins. Proportions of polyunsaturated fatty acids (PUFA) and α-linoleic acid in total fatty acids (FA) were highest in the ryegrass silage. Feed intake, milk yield and milk gross composition did not differ among the groups. Feeding buckwheat resulted in the highest milk fat concentrations (g/kg) of linoleic acid (15.7) and total PUFA (40.5; both P < 0.05 compared with ryegrass). The concentration of α-linolenic acid in milk fat was similar across treatments, but its apparent recovery in milk relative to the amounts ingested was highest with buckwheat. The same was true for the occurrence of FA biohydrogenation products in milk relative to α-linolenic acid intake. Recovery of dietary linoleic acid in milk remained unaffected. Feeding buckwheat silage shortened rennet coagulation time by 26% and tended (P < 0.1) to increase curd firmness by 29%. In conclusion, particularly buckwheat silage seems to have a certain potential to modify the transfer of FA from feed to milk and to contribute to improved cheese-making properties.

Relationship between maternal diet, plasma lipids and human milk cholesterol and fatty acids

Human milk cholesterol and fatty acids (FA) are important for infant development. Few studies have examined the relationship between maternal diet or plasma lipids on human milk composition. From 120 longitudinally‐studied breastfeeding mother‐infant pairs, mothers with the 15 highest (HC) and 15 lowest (LC) dietary cholesterol were analyzed. Maternal diet (4–13 weeks postpartum) was assessed, and plasma and milk were collected at 4 weeks postpartum. Demographics and anthropometrics were similar between LC and HC, but HC had higher intake of kcal and macronutrients, except carbohydrate. Plasma and milk total cholesterol did not differ by group. LC had lower milk palmitic acid (median 19.1 %wt/wt vs. 21.1, p=0.03), higher milk linoleic acid (20.5 vs 17.9, p=0.003) and marginally higher plasma linoleic acid (42.8 vs 40.4, p=0.06). In HC, milk oleic and stearic acids were correlated with kcal (Spearman rho=0.45 and 0.43, respectively). In LC, plasma and milk FAs were significantly correlated with each other. These data suggest that milk FA, but not total cholesterol, may be partially influenced by maternal diet and plasma FA. This work was funded by the CCHMC CTRC and Mead Johnson Nutrition, Inc.

Effect of supplementation of soy sauce oil and Ca salts of fatty acids on rumen fermentation, milk production and conjugated linoleic acid in milk of dairy cows

Eight cows were used to evaluate the effects of supplementation of soy sauce oil (SO) or Ca salts of fatty acids (FA) on rumen fermentation and milk production. The control diet (CO) consisted mainly of hay, corn silage and a concentrate. In the experimental diets, 400 g/day per cow of SO or FA (soybean oil and rapeseed oil) was supplemented to the CO diet. Experimental period for the three treatments was 14 days, and milk samples were taken during the last 2 days and rumen sample was taken on the last day. Dry matter intake was not affected by the treatments. The number of rumen protozoa at 0 h increased by SO and FA diets. Total volatile fatty acids at 2 h after feeding of SO diet was decreased compared to CO. The milk composition yield did not differ among treatments, although the percentages of fat and protein were decreased by SO and FA diets. The proportions of C8-C16 fatty acids in milk fat decreased, and those of C18 increased by SO and FA diets. The proportion of cis-9, trans-11 conjugated linoleic acid in milk fat by SO and FA diets increased by 120% and 135%, respectively. In spite of the slight suppression of rumen fermentation by SO diet, negative effects on feed intake and milk production were not detected.

Feeding transition cows with oilseeds: Effects on fatty acid composition of adipose tissue, colostrum and milk

The present investigation was aimed to test whether α-linolenic acid (ALA) concentrations in the adipose tissue can be increased by linseed feeding of dry cows and whether ALA is preferentially mobilized during the catabolic phase after parturition. The second objective was the determination of the influence of mobilization on fatty acid composition of colostrum and mature milk. For this purpose, four groups of six cows were fed diets supplemented either with crushed linseed (rich in ALA; two groups) or sunflower seed (rich in linoleic acid (LA)) or a 1:1 mixture of both for 6 weeks. This supplementation was either kept post partum or switched shortly before calving from linseed or the mixture to sunflower seed. The post partum experimental period lasted for another 40 d. Samples of blood were obtained in weeks − 6, − 2, 3 and 6 pre/post calving, those of backfat adipose tissue in weeks − 2 and 6 pre/post calving (by biopsy) and milk samples on days 1, 2, 10, 20, 30 and 40 of lactation. Clear changes over time occurred in blood plasma metabolites and hormones as well as in body weight, body condition scores and backfat thickness, especially during the transition before and after calving. Milk yield and composition showed the typical time trends as well. Proportions of long-chain polyunsaturated fatty acids in the colostrum compared to the mature milk were clearly higher. This appeared similarly in all groups and was not influenced by the oilseed treatment. Compared with the physiological time effects, the effects of the oilseed treatments were weak. It was possible to load the adipose backfat tissue with ALA by supplementing linseed in the dry period, but the magnitude of this increase was small. Milk fat profile was not affected accordingly, although the changes found in adipose tissue post partum suggested the preferential mobilization of ALA during early lactation. Supplementing sunflower seed instead of linseed in the dry period did not elevate LA proportion in adipose tissue nor affected linoleic acid in milk. By contrast, direct transfer of LA, and especially of ALA, from feed to milk happened when sunflower seed or linseed was fed in the lactation period of the experiment. Overall this suggests that strategies aiming at changing n−3 fatty acid concentrations in milk fat composition by loading the adipose tissue of dry cows with ALA are not effective.