Short-chain Fatty Acids In Milk Research Articles

A new isopropyl esterification method for quantitative profiling of short-chain fatty acids in human and cow milk by gas chromatograph-mass spectrometer

Short-chain fatty acids (SCFAs) content in milk may have been underestimated due to the neglect of the esterified SCFAs content and the lack of an accurate detection method, especially for C1:0, C2:0, and C3:0 SCFAs. In this study, an accurate gas chromatography-mass spectrometry profiling method was established for 10 SCFAs. A 2-step esterification, including alkaline saponification (60°C for 30 min) and acid-catalyzed esterification (80°C for 150 min) in water/isopropyl/hexane (1:2:1, volume ratio), was found to be the most suitable for the quantification of esterified and nonesterified SCFAs analysis. The validation results demonstrate satisfactory linearity, sensitivity, matrix effects, precision, and accuracy. The recoveries of nonesterified and esterified SCFAs ranged from 82.78% to 112.49%, respectively. Human milk is distinguished from cow milk by its higher C1:0 and C2:0 content and lower C4:0 and C6:0 content. This method successfully accomplished qualitative and quantitative estimation of all 10 SCFAs in milk, including both nonesterified and esterified SCFAs. Furthermore, whether our method is applicable for the determination of SCFAs in serum, rumen fluid, and feces remains to be explored.

The effect of feeding whole-crop barley or black oat silage in the fatty acid content of milk from cows in small-scale dairy systems in the highlands of Mexico.

Diets have an important effect on the fatty acid (FA) content in milk from dairy cows so that feeding strategies may modify the FA profile. There is little information on the fatty acid contents of whole-crop barley (BLY) and black oat (BKO) silages and on milk from cows fed these silages that are an alternative forage for small-scale dairy systems (SSDS). Given the growing interest in foods with favourable health attributes, the objective was to identify the FA content of milk from dairy cows fed whole-crop BLY and BKO silages in small-scale systems. Three inclusion levels of BLY and BKO silage were assessed in nine lactating cows at pasture for 8h/day and supplemented with 4.6kg/DM/cow/day commercial concentrate. Treatments were BLY: 10kg DM/cow/day BLY silage; BKO: 10kg DM/cow/d BKO silage; and BLY/BKO: 5kg BLY and 5kg DM/cow/d BKO silages (50:50). A 3 × 3 Latin square design repeated three times with nine cows and 14-day periods was utilised. Variables evaluated were the content of fatty acids present in feeds and milk. Contents of linoleic (C18:2n-6) and linolenic (C18:3n-3) acids, as precursors of polyunsaturated fatty acids, were 46 in BLY and 50 BKO g/100g, lower than for multispecies pasture (61g/100g). There were statistical differences in the content of short-chain fatty acids in milk (P < 0.05), being lower for BLY (18.9g/100g) compared with BKO (20.4g/100g) and BLY/BKO (20.6g/100g), the saturated fatty acids and linoleic acid (C18:2n-6c) were higher in BLY/BKO in relation to BLY and BKO. Content of health-promoting polyunsaturated fatty acids in milk was higher in BLY/BKO (P < 0.05). There were no differences (P < 0.05) in the atherogenic index, with values within reports. Small-grain cereal forages may produce milk with a favourable fatty acid content for human health.

Dose-response effect of 3-nitrooxypropanol on enteric methane emissions in dairy cows

This experiment was designed to test the effect of inclusion rate of 3-nitrooxypropanol (3-NOP), a methane inhibitor, on enteric methane emissions in dairy cows. The study was conducted with 49 multiparous Holstein cows in a randomized complete block design in 2 phases; phase 1 was with 28 cows, and phase 2 with 21 cows. Cows were fed a basal total mixed ration ad libitum and were blocked based on days in milk, milk yield, and enteric methane emissions during a 14-d covariate period. Treatments were control (no 3-NOP) and 40, 60, 80, 100, 150, and 200 mg of 3-NOP/kg of feed dry matter. Following a 14-d adaptation period, enteric gaseous emissions (methane, carbon dioxide, and hydrogen) were measured using the GreenFeed system (C-Lock Inc., Rapid City, SD) over a 3-d period. Compared with the control, inclusion rate of 3-NOP quadratically decreased daily enteric methane emissions from 22 to 40%. Maximum mitigation effect was achieved with the 3 highest 3-NOP doses (with no statistical difference among 100, 150, and 200 mg/kg). The decrease in methane emission yield and emission intensity ranged from 16 to 36% and from 25 to 45%, respectively. Emissions of hydrogen quadratically increased 6- to 10-fold, compared with the control; the maximum increase was with 150 mg/kg 3-NOP. Treatment did not affect daily emissions of carbon dioxide, but a linear increase in carbon dioxide emission yield was observed with increasing 3-NOP doses. Dry matter intake and milk yield of the cows was not affected by 3-NOP. Milk fat concentration and yield were increased by 3-NOP due to increased concentration of de novo synthetized short-chain fatty acids in milk. Inclusion of 3-NOP also tended to increase milk urea nitrogen but had no other effects on milk components. In this short-term experiment, 3-NOP decreased enteric methane emissions without affecting dry matter intake or milk yield and increased milk fat in dairy cows. Maximum mitigation effect was achieved at 100 to 200 mg/kg of feed dry matter.

Effects of 3-nitrooxypropanol on rumen fermentation, lactational performance, and resumption of ovarian cyclicity in dairy cows

This study examined the effect of 3-nitrooxypropanol (3-NOP), a substance under investigation, on enteric methane (CH4) emission, rumen fermentation, lactational performance, sensory properties of milk, and the resumption of ovarian cyclicity in early-lactation dairy cows. Fifty-six multi- and primiparous Holstein cows, including 8 that were rumen cannulated, were used in a 15-wk randomized complete block design experiment. Cows were blocked based on parity and previous lactation milk yield (MY) or predicted MY, and within each block were randomly assigned to one of 2 treatments: (1) control (CON), administered no 3-NOP, or (2) 3-NOP applied at 60 mg/kg of feed dry matter (3-NOP). Enteric CH4 emission was measured during experimental wk 2, 6, 9, and 15, using the GreenFeed system. Dry matter intake (DMI) and MY data were collected daily throughout the experiment, and milk composition samples were collected 7 times during the experiment. Milk samples were collected from 14 to 60 (±2) d after calving, 3 d per week, and assayed for progesterone concentration to determine resumption of ovarian activity. Compared with CON, 3-NOP decreased daily CH4 emission by 26%, CH4 yield (CH4 per kg of DMI) by 21%, and CH4 emission intensity [CH4 per kg of MY or energy-corrected milk (ECM)] by 25%. Enteric emission of carbon dioxide was decreased by 5%, and hydrogen emission was increased 48-fold by 3-NOP. Inclusion of 3-NOP decreased concentration of total volatile fatty acids (by 9.3%) and acetate but increased butyrate molar proportion, ethanol, and formate concentrations in ruminal fluid. Dry matter intake was lower for 3-NOP compared with CON, but DMI expressed as a percentage of body weight was not different between treatments. Treatment had no effect on milk and ECM, body weight change, or body condition score. Milk composition and milk fat and protein yields were not affected by treatment, except that concentrations of short-chain fatty acids in milk were increased by 3-NOP. Nutrient digestibility and blood metabolites and hormones were not affected by 3-NOP, except that insulin was decreased by 3-NOP. There was no effect of 3-NOP on postpartum resumption of ovarian activity, including days to first and second luteal phases, length of first and second luteal phases, and interval from first to second luteal phase. Sensory properties of milk from cows fed 3-NOP and cheese made from that milk were not affected by treatment. In this experiment, 3-NOP decreased daily enteric CH4 emission, emission yield, and emission intensity, improved feed efficiency, and did not affect lactational performance or onset of ovarian activity in early-lactation dairy cows.

Effects of recombinant bovine somatotropin administration to lactating goats

Eight multiparus lactating goats, matched for parity and days in milk were used to evaluate the effects of recombinant bovine somatotropin (rbST) administration on milk yield and composition, as well as on certain metabolic parameters. The experiment was a switch-back design, with three periods lasting 28 days each. Animals were divided into two groups ( n = 4) and treatments consisted of subcutaneous injection of 160 mg rbST at 14-day intervals. Controls remained uninjected. Supplementation with rbST increased milk yield significantly over the entire experimental period (1506 ± 80.8 vs. 1337 ± 81.8 ml/day, p < 0.05). Percentage of fat in milk was greater for goats treated with rbST than controls, (3.26 ± 0.09% vs. 2.9 ± 0.08%, p < 0.05), while protein percentage did not differ ( p > 0.05) between treated and control animals. Lactose content also increased after rbST administration (3.88 ± 0.06% vs. 3.55 ± 0.06%, p < 0.01). Plasma NEFA and β-hydroxybutyrate levels were not affected by treatment. Short-chain fatty acids in milk were similar in both groups. In conclusion, rbST administration increased milk yield and the percentage of fat and lactose in milk, while no effect was recorded in milk protein content.

Comparison of Growth Hormone-Releasing Factor and Somatotropin: Lipid and Glucose Metabolism in Dairy Cows

Lactating, primiparous Holstein cows were continuously infused for 63 d with either recombinant growth hormone-releasing factor or recombinant bST or were not infused (control). The releasing factor and bST treatments reduced fat synthesis from acetate and lipoprotein lipase activity in omental adipose tissue. Also, both treatments increased hormone-sensitive lipase activity per gram of adipose tissue and reduced fatty acid esterification per milligram of protein in adipose tissue. Protein concentration in adipose tissue with both treatments was greater than that of the control, although the protein concentration was less in adipose tissue from cows treated with the releasing factor than from those treated with bST. In mammary tissue, releasing factor increased fat synthesis from acetate more than did bST treatment, but percentages of fat or short-chain fatty acids in milk were not different between treatments, nor were differences significant between treatments and control for fatty acid esterification or lipoprotein lipase activity in mammary tissue or gluconeogenesis and fatty acid esterification in liver. We conclude that protein concentration was lower in omental adipose tissue of cows treated with releasing factor than that in tissue of cows treated with bST, although both treatments similarly suppressed synthesis of fat from acetate and activity of lipoprotein lipase.

Flow injection analysis of short-chain fatty acids in milk based on a microbial electrode

A flow injection analysis system for the determination of short-chain fatty acids was developed incorporating a microbial electrode based on an oxygen electrode and Arthrobacter nicotiana immobilized behind a dialysis membrane. The system showed a high selectivity for short-chain fatty acids (C 4:0 -C 12:0 ), and the system response was linearly related to the concentration of butyric acid over the range 0.11-1.7 mM. The sampling freguency was approximately 20 samples/h at a carrier flow rate of 1.0 mL/min

Effect of a Protected Fat Product on Productivity of Lactating Holstein and Jersey Cows

Diets supplemented with Ca salts of fatty acids were fed to Holstein and Jersey cows to determine the effects on production and metabolic measures. Cows averaged 95 d in milk at the start of the study. A total mixed ration (concentrate, corn silage, and alfalfa silage) was offered. Holsteins and Jerseys consumed approximately .45 and .35kg/d Ca salts of fatty acids, respectively. Milk production was not changed by fat supplementation, but FCM increased from 25.9 to 27.1kg, milk fat percentage increased 5.5%, and milk protein declined 3.2% for cows receiving Ca salts of fatty acids. No breed by treatment interaction was significant. Group DM intake was similar among treatments, and calculated net energy intake exceeded net energy needs for maintenance and milk production. Body weight changes were similar among treatments. Apparent digestibility of dietary DM, fiber, and fatty acids was not altered by treatment. Serum C16:0 fatty acids increased, milk short-chain fatty acids (C4:0 to C14:0) decreased, and milk long-chain fatty acids (C16:0 to C18:3) increased when fat was added to the diet. Calcium salts of fatty acids improved FCM yield of lactating cows, primarily through increased milk fat percentages. No change occurred in apparent digestibility of the diet. In most cases, breed responses to treatment were similar.