牦牛骨脂质组成及其理化性质分析

为提高牦牛骨的利用率,实现高值化利用,本文采用GC-MS和IUPAC法测定了牦牛骨脂质组成和理化指标,并进行分析。脂质组学分析共检出20种脂肪酸,其中SFA（饱和脂肪酸）含量占脂肪酸总量的41.75%,FA n:1（单不饱和脂肪酸）为53.01%,PUFA（多不饱和脂肪酸）1.46%,其他为3.79%。在负离子模式下共检测出4种脂质:Car（乙酰左旋肉碱）、SM（鞘磷脂）、PC（磷脂酰胆碱）和TAG（三脂酰甘油及中性脂肪）,含量依次是PC>SM>TAG>Car。理化指标结果表明:牦牛腿骨脂质的脂肪酸稳定性较好且饱和脂肪酸较多。从牦牛腿骨中检出了两种物质:α-三烯酚和γ-三烯酚。油脂的氧化稳定性显示,牦牛骨油脂的诱导时间为5.56 h,牦牛骨的油脂氧化稳定性比较高,具有较强的抗氧化效果。脂肪酸与骨健康密不可分,而牦牛骨脂质脂肪酸含量丰富,因此,牦牛骨可以作为维护骨健康的潜在的营养剂。     

Functions of Different Yak Bone Peptides

Nine kinds of oligopeptide were obtained from the yak bone-marrow protein via the hydrolysis of some single or mixed proteases, and the functions of various yak bone peptides were compared. The results indicated that the peptide from yak bone hydrolyzed by Alcalase plus Flavourzyme at 50°C for 4 h showed the strongest antioxidant activity in a H₂O₂ system and chelating activity to Cu²⁺; Yak bone peptide derived from the hydrolysis by papain PSM500 plus Peptidase R presented the most efficient radical-scavenging activity to 2,2-diphenyl-1-picrylhydrazyl free radicals; Yak bone peptide hydrolyzed by Protamex single had the best calcium binding activity and the peptide from the hydrolysis of yak bone by trypsin displayed the most ideal chelating activity on iron (II). Taken together, yak bone peptide hydrolyzed by Alcalase plus Flavourzyme at 50°C for 4 h had the best integration function. Therefore, it might be useful for the application in functional foods.     

A Simple and Sensitive Nanocatalytic Fluorescence Method for the Determination of Folic Acid in Foods Using Fe3O4 Nanoparticle-K2S2O8 System

In pH 2.72 HCl-NaAc buffer solution at room temperature and in the presence of a nanocatalyst of Fe₃O₄ nanoparticles, potassium persulfate rapidly oxidized folic acid (FA) to form a product with strong fluorescence at 446 nm. The analytical conditions were considered, and a simple, rapid, and accurate fluorescence method was proposed for the determination of 0.007–8.0 mg/L FA, with a detection limit of 2.0 ng/mL FA. This method was applied to the analysis of FA in a real sample with satisfactory results that agree with the HPLC results.     

Effects of diet on casein and fatty acid profiles of milk from goats differing in genotype for αS1-casein synthesis

This study investigated the interactions between nutrition and the genotype at α_S1-CN loci (CSN1S1) in goats, evaluating the impact of fresh forage-based diets and an energy supplement on the casein and fatty acid (FA) profiles of milk from Girgentana goats. Twelve goats were selected for having the same genotype at the α_S2-CN, β-CN, and κ-CN loci and differing in the CSN1S1 genotype: homozygous for strong alleles (AA) or heterozygous for strong and weak alleles (AF). Goats of each genotype were divided into three groups and, according to a 3 × 3 Latin square design, fed ad libitum three diets: sulla fresh forage (SFF), SFF plus 800 g/day of barley (SFB), and mixed hay plus 800 g/day of barley (MHB). The SFB diet led to higher-energy intake and milk yield. The energy-supplemented diets (SFB, MHB) reduced milk fat and urea and increased coagulation time. The fresh forage diets (SFF, SFB) increased dry matter (DM) and crude protein (CP) intake and milk β-CN. Diet had a more pronounced effect than CSN1S1 genotype on milk FA profile, which was healthier from goats fed the SFF diet, due to the higher content of rumenic acid, polyunsaturated, and omega-3 FAs. The AA milk had longer coagulation time and higher curd firmness, higher short- and medium-chain FAs (SMFA), and lower oleic acid than AF milk. Significant diet by genotype interactions indicated the higher milk yield of AA goats than AF goats with the higher-energy SFB diet and the lower synthesis of SMFA in AF than in AA goats with the SFF diet.     

Comparison of fruit characteristics,oil properties and fatty acid composition of local Syrian Kaissy cv olive (<Emphasis Type="Italic">Olea europaea</Emphasis>)

Characterization of Syrian (Kaissy cultivar) olive fruits and evaluation of physic-chemical properties of oils were carried out during 3 years of production. The mean values of data for both measured and calculated variables of fruits were: grain length (21.89 mm), grain width (17.92 mm), length/width (1.22), weight of grain (3.79 g), weight of pulp (flesh) (3.19 g), weight of pit (0.60 g), pulp/pit ratio (5.35), crude oil (17.13%), water content (moisture) (51.34%). The 3 year average values of chemical properties of Syrian Kaissy cultivar olive oils (SKOO) including acid value, peroxide vale, Thiobarbituric acid value, iodine value(IV), saponification value, and phenolic content were 0.58%, 4.33 mEq O₂ kg^??1, 0.028 mg MDA kg^??1 oil, 90.77 g I₂, 100 g^??1, 194.91 mg KOH g^??1, and 218.08 g gallic acid kg^??1, respectively. Pefractive index (RI), and viscosity were 1.4666 nD at 25?°C and 139.56 mPa.s, respectively. However, the 2 years average values of Hunter’s color parameters of SKOO were; the lightness (L*= 66.91), redness (a* = 18.80), yellowness (b* = 29.08) and the color differences (?E?=?65.49). FA analysis of the SKOO used showed a high content of monounsaturated fatty acids (oleic acid 70.82% and palmitic acid 1.01%) and low polyunsaturated fatty acids (Linoleic acid 10.72% and Linolenic 0.82%) and saturated fatty acids (Palmitic 14.10% and stearic 2.57%). Results for 3 years production of Syrian Kaissy cultivar olive fruit and oil are discussed in detail.     

Effect of incremental amounts of camelina oil on milk fatty acid composition in lactating cows fed diets based on a mixture of grass and red clover silage and concentrates containing camelina expeller

Camelina is an ancient oilseed crop that produces an oil rich in cis-9,cis-12 18:2 (linoleic acid, LA) and cis-9,cis-12,cis-15 18:3 (α-linolenic acid, ALA); however, reports on the use of camelina oil (CO) for ruminants are limited. The present study investigated the effects of incremental CO supplementation on animal performance, milk fatty acid (FA) composition, and milk sensory quality. Eight Finnish Ayrshire cows (91 d in milk) were used in replicated 4 × 4 Latin squares with 21-d periods. Treatments comprised 4 concentrates (12 kg/d on an air-dry basis) based on cereals and camelina expeller containing 0 (control), 2, 4, or 6% CO on an air-dry basis. Cows were offered a mixture of grass and red clover silage (RCS; 1:1 on a dry matter basis) ad libitum. Incremental CO supplementation linearly decreased silage and total dry matter intake, and linearly increased LA, ALA, and total FA intake. Treatments had no effect on whole-tract apparent organic matter or fiber digestibility and did not have a major influence on rumen fermentation. Supplements of CO quadratically decreased daily milk and lactose yields and linearly decreased milk protein yield and milk taste panel score from 4.2 to 3.6 [on a scale of 1 (poor) to 5 (excellent)], without altering milk fat yield. Inclusion of CO linearly decreased the proportions of saturated FA synthesized de novo (4:0 to 16:0), without altering milk fat 18:0, cis-9 18:1, LA, and ALA concentrations. Milk fat 18:0 was low (<5 g/100 g of FA) across all treatments. Increases in CO linearly decreased the proportions of total saturates from 58 to 45 g/100 g of FA and linearly enriched trans-11 18:1, cis-9,trans-11 18:2, and trans-11,cis-15 18:2 from 5.2, 2.6, and 1.7 to 11, 4.3, and 5.8 g/100 g of FA, respectively. Furthermore, CO quadratically decreased milk fat trans-10 18:1 and linearly decreased trans-10,cis-12 18:2 concentration. Overall, milk FA composition on all treatments suggested that one or more components in camelina seeds may inhibit the complete reduction of 18-carbon unsaturates in the rumen. In conclusion, CO decreased the secretion of saturated FA in milk and increased those of the trans-11 biohydrogenation pathway or their desaturation products. Despite increasing the intake of 18-carbon unsaturated FA, CO had no effect on the secretions of 18:0, cis-9 18:1, LA, or ALA in milk. Concentrates containing camelina expeller and 2% CO could be used for the commercial production of low-saturated milk from grass- and RCS-based diets without major adverse effects on animal performance.     

Influence of sulphur application on protein quality, fatty acid composition and nitrogen fixation of white lupin (Lupinus albus L.)

White lupin (Lupinus albus L.) is an important source of plant protein for both humans and livestock, due to high protein content, low alkaloids level, high level of unsaturated fatty acids, price and market availability in many countries. In this paper is reported the effect of S fertilization on white N fixation capability of lupin, grain yield and chemical characteristics in terms of protein fractions, fatty acid and mineral composition. Randomized complete block design with three replicates was used, and three S applications (0, 30 and 60 kg ha^?1, respectively) for white lupin were used. The S fertilization was split into two: 50 % before sowing and 50 % in the early of March as K₂SO₄. At the same time, both the legume and oat crops were fertilized uniformly with solution of 10 kg N ha^{?1 15}N NH₄ ¹⁵NO₃ (10 % ¹⁵N atomic excess). Data indicated that under Mediterranean environment on sub-alkaline soil, white lupin produces low grain and protein; however, S application increased plant yield and N fixation. In conclusion, it seems that S fertilization to white lupin should be recommended to soils with sub-optimal S levels to obtain maximum seed and protein yields. Moreover, S fertilization enhanced the protein quality increasing its degradable fraction, and improved the lupin oil quality through the increase in oleic and linolenic acids and the remarkable decrease in erucic acid.     

Fatty Acids of Neutral and Phospholipids, Rancidity Scores and TBA Values as Influenced by Packaging and Storage

The fatty acid (FA) of neutral lipids (NL) and phospholipids (PL) and this composition's relationship to rancidity score and TBA values of cooked beef patties, during frozen storage at times up to 4½ months under vacuum and nonpackaged conditions were studied. The predominant FA in the NL was C_18:1 (46.0%), followed by C_16:0 at 29.2%. However, the PL fraction gave a more balanced distribution of FA. In the neutral lipid fractions, reduction in the C_16:1 and C_18:2 fatty acids made significant contributions to increased rancidity scores and TBA values but in the phospholipid fraction, changes in the C_18:3 and C_20:4 were of greatest importance. After 3 months of frozen storage a regression model containing the neutral lipid fatty acids C_18:1 and C_18:2 and the phospholipid fatty acids C_18:3 and C_20:4 accounted for 88% and 85% of the variation in rancidity score and TBA value.     

Fatty acid profile of yak milk from the Qinghai-Tibetan Plateau in different seasons and for different parities

Yaks are the most important grazing livestock for milk production on the Qinghai-Tibetan plateau because these animals are adapted to the high elevations and extremes of cold and can graze throughout the year. In the present study, 30 yaks were selected and the fatty acid (FA) profile of yak milk at different seasons and parities was investigated using gas chromatography. The concentrations of cis-9 C18:1, cis-11 C18:1, cis-9,trans-11 C18:2, and C18:3 n-3 in yak milk were higher in summer (25.26, 1.50, 1.46, and 0.33 g/100 g of total FA, respectively) than in winter (22.17, 0.77, 1.27, and 0.28 g/100 g of total FA, respectively). The contents of monounsaturated and polyunsaturated FA in milk fat of multiparous (parities 2 to 5) yaks (31.61 and 4.20 g/100 g of total FA, respectively) were higher than those in primiparous yaks (29.61 and 3.80 g/100 g of total FA, respectively). These results suggest (1) that the potential exists to improve the FA composition of yak milk by developing local supplement resources during the winter and (2) that multiparous yaks have a more favorable FA profile than primiparous yaks.     

Ferulic Acid Dehydrodimers in the Cell Walls of Beta vulgaris and their Possible Role in Texture

Sugarbeet, a form of Beta vulgaris var vulgaris, fails to soften completely after heating at 100°C for several hours. This is due to thermal stability of the cell–wall polymers involved in cell–cell adhesion. In contrast, beetroot softens within 25–30 min due to a relatively rapid increase in the ability of the cells to separate. Information concerning the cell–wall polymers responsible for cell–cell adhesion was obtained by subjecting sugarbeet and beetroot tissues to a range of chemical and biochemical treatments designed to cleave cell–wall chemical bonds selectively. Treatment of sugarbeet tissues with chelating agents, weak base (Na₂CO₃, 0·05 M ) or a purified, specific endoxylanase did not facilitate vortex-induced cell separation. However, this could be induced after extraction in dilute, cold alkali (0·05–0·1 M KOH) or dilute, hot acid (0·1 M TFA, 100°C). Tissues from beetroot behaved similarly. Furthermore, the cell walls of sugarbeet and beetroot were similar in yield and neutral carbohydrate composition; the cell–wall-galacturonic acid content of beetroot was 50% higher as compared with sugarbeet. They were also rich in ferulic acid (FA) and its derivatives (6–7 mg g^-1 CWM), and exhibited pH-dependent autofluorescence which disappeared during alkali-induced cell separation. In sugarbeet, over 20% of the FA was in dimer form. In beetroot, however, the value was only 10%. The main FA dimers were 8-O-4′DiFA and 8,5′DiFA (benzofuran form). The results indicate that the degree of thermal stability of cell–cell adhesion and, therefore, texture in Beta vulgaris tissues is related to the degree of FA-cross linking between pectic polysaccharides. © 1997 SCI.     

A Novel Fluorescent Probe for Detecting Hydrogen Sulfide in Wine

Hydrogen sulfide (H₂S) has recently been recognized as the third endogenous gaseous signaling molecule besides NO and CO. At the same time, H₂S is responsible for an important proportion of faulty wines with potentially large economic losses. Thus, the H₂S in wine not only contributes negatively to wine aroma but also faces a problem of food safety. So an efficient and practical sensor to detect H₂S in wine was needed. A new fluorescent probe 4-methyl-2-oxo-2H-chromen-7-yl-thiophene-2-carboxylate (probe 1) was designed and synthesized for detection of H₂S. Addition of H₂S caused the fluorescence intensity of probe 1 increased and fluorescence saturation was reached in 15 min. The fluorescence of probe 1 was found turn-on under UV light at 365 nm. This noticeable change of probe 1 indicates that probe 1 could be employed as a visible detection agent for H₂S. H₂S can be detected quantitatively in the concentration range 0–20 μM, and the detection limit on fluorescence response of the probe was 18 nM. Moreover, probe 1 can be conveniently used as a signal tool to determine the H₂S levels in wine.     

Surfactant-Alumina-Coated Magnetic Nanoparticles as an Efficient Aldehydes Adsorbent Prior Their Determination by HPLC

Separation and determination of trace levels of low-molecular weight aldehydes are very important from water suppliers’ point of view. Modified magnetic nanoparticles can be used for this propose. Alumina-coated magnetic nanoparticles modified with sodium dodecyl sulfate (SDS/Al₂O₃/Fe₃O₄) are used for extraction of formaldehyde (FA) and acetaldehyde (AA) from drinking water samples. In this manner, the aldehydes were converted to their corresponding hydrazones by the reaction with 2,4-dinitrophenylhydrazine (DNPH). After preconcentration, the HPLC technique was used for the determination of the aldehydes and the results were compared with the commercial C₁₈ solid-phase extraction (SPE) columns. The results showed that the extraction with SDS/Al₂O₃/Fe₃O₄ is more efficient and faster than the commercial columns. A very good repeatability (RSD was 3.3 and 2.4% for FA and AA, respectively, n = 7, C = 50 ppb) was obtained. Linear regression analysis indicated that the responses for two investigated compounds were linear over about two orders of magnitude above the LOD (LOD was 3.6 ppb for FA and 3.2 ppb for AA), with correlation coefficients >0.9990. Determination of FA and AA in tap water and various brands of bottled waters were carried out using the modified nanoparticles. Based on the obtained results, the aldehyde content of the commercial bottled waters was particularly apparent after exposure to direct sunlight.     

Spectrofluorometric Method for Determination of Al3+ with 3-Hydroxy-2-Naphthalenecarboxylic Acid and its Application to Milk Samples

On the basis of affinity of Al³⁺ ions toward functional groups of 3-hydroxy-2-naphthalenecarboxylic acid (3H2NA), a high stable complex between Al³⁺ and 3H2NA in 5 % methanol/water solution was established. The mole ratio method showed that a stable complex by taking part of acetate and 3H2NA with the stoichiometric ratio of 1:1:1 and stability constant of 8.6?×?10⁶ is formed. Under the optimum conditions for the complex formation, a rapid spectrofluorometric determination of trace amounts of Al³⁺ (λ _ex?=?366 nm, λ _em?=?460 nm) was proposed. The optimum conditions involve 3H2NA concentration of 1.0?×?10^?5 M, buffering pH of 4.5 (acetic/acetate system), and ionic strength of 0.01 M. The fluorescence intensity exhibited a good linearity against the Al³⁺ concentration in the range 5.0?×?10^?8–5.0?×?10^?6 M with the detection limit of 1.3?×?10^?8 M. No considerable interference was observed due to the presence of coexisting anions and cations. The method was applied successfully to the determination of trace amounts of Al³⁺ in milk. Validation of the measurements was confirmed using graphite furnace atomic absorption spectrophotometry.     

气相色谱-氢火焰离子化检测器测定婴幼儿乳粉中37种脂肪酸含量

目的：建立气相色谱-氢火焰离子化检测器测定乳粉中37种脂肪酸含量的分析方法。方法：婴幼儿乳粉样品运用乙酰氯-甲醇法（10%乙酰氯甲醇溶液于80℃±1℃水浴2 h）甲酯化,离心取上清液过0.22μm的有机滤膜后经SP-2560(100 m×250μm×0.2μm)分离,气相色谱法检测,外标法定量。结果：37种脂肪酸甲酯在0.002～0.2 mg/mL浓度范围内线性良好,相关系数均大于0.999,回收率低梯度在85.5%～100.0%之间,中梯度在91.2%～104.2%之间,高梯度在86.8%～103.8%之间,精密度在0.88%～3.81%之间,实际样品测定结果符合相关标准要求。结论：该方法是在国标基础上建立了一种更为快速、分离度更好的脂肪酸检测技术,有很好的实用价值,方法稳定性好,成本低,重现性好,准确度高,适用于婴幼儿乳粉中37种脂肪酸含量的测定。     

Determination of Menbutone in Bovine Milk and Meat Using Micellar Liquid Chromatography: Application to Injectable Dosage Forms

A simple, sensitive, and rapid method was developed for the routine identification and quantification of menbutone in different matrices by micellar liquid chromatography. Separation was performed in less than 4 min using a C₁₈ column with UV detection at 234 nm. A micellar solution composed of 0.12 M sodium dodecyl sulfate, 8 % n-butanol, and 0.3 % triethylamine in 0.02 M phosphoric acid at pH 6.0 was used as the mobile phase. The method was fully validated in accordance with International Conference on Harmonization (ICH) guidelines. The limits of detection and quantitation were 0.95 and 2.86 ng mL^?1, respectively. The method showed good repeatability, linearity, and sensitivity according to the evaluation of the validation parameters. The micellar method was successfully applied for the analysis of menbutone in its commercial injections with a mean % recovery value of 99.73?±?1.634 % and in spiked bovine milk and meat samples with a mean % recovery values in the range of 98.00–100.60 %. High extraction efficiency was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. No organic solvent was used during the pretreatment step. Hence, this method can be considered as an interesting example for green chemistry.     

Fatty acid profile characterization in colostrum,transition milk,and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 16% and 27% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 42% higher in PP cows throughout the milking period, as well as 15% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 13% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 23% higher in colostrum than mature milk and 25% higher in MP cows. Linoleic acid was also 13% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 63% higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 25% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.     

Fatty acid profile characterization in colostrum,transition milk,and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 38% and 19% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 72% higher in PP cows throughout the milking period, as well as 13% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 25% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 29% higher in colostrum than mature milk and 33% higher in MP cows. Linoleic acid was also 15% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 2.7-fold higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 40% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.     

Effects of replacement of barley with oats on milk fatty acid composition in dairy cows fed grass silage-based diets

This study consists of milk fatty acid (FA) data collected during 2 in vivo experiments. For this study, 8 cows from each experiment were included in a replicated 4 × 4 Latin square design. At the start of experiment 1 (Exp1) cows were at (mean ± standard deviation) 87 ± 34.6 d in milk, 625 ± 85.0 kg of body weight, and 32.1 ± 4.17 kg/d milk yield and at the start of experiment 2 (Exp2) cows were at 74 ± 18.2 d in milk, 629 ± 87.0 kg of body weight, and 37.0 ± 3.2 kg/d milk yield. In Exp1, we examined the effects of gradual replacement of barley with hulled oats (oats with hulls) on milk FA composition. The basal diet was grass silage and rapeseed meal (58 and 10% of diet DM, respectively), and the 4 grain supplements were formulated so that barley was gradually replaced by hulled oats at levels of 0, 33, 67, and 100% on dry matter basis. In Exp2, we examined (1) the effects of replacing barley with both hulled and dehulled oats (oats without hulls) and (2) the effects of gradual replacement of hulled oats with dehulled oats on milk FA composition. The basal diet was grass silage and rapeseed meal (60 and 10% of diet DM, respectively), and the 4 pelleted experimental concentrates were barley, hulled oats, a 50:50 mixture of hulled and dehulled oats, and dehulled oats on dry matter basis. In Exp1, gradual replacement of barley with hulled oats decreased relative proportions of 14:0, 16:0, and total saturated FA (SFA) in milk fat linearly, whereas proportions of 18:0, 18:1, total monounsaturated FA, and total cis unsaturated FA increased linearly. Transfer efficiency of total C18 decreased linearly when barley was replaced by hulled oats in Exp1. In Exp2, relative proportions of 14:0, 16:0, and total SFA were lower, whereas proportions of 18:0, 18:1, monounsaturated FA, and cis unsaturated FA were higher in milk from cows fed the oat diets than in milk from cows fed the barley diet. Moreover, in Exp2, gradual replacement of hulled oats with dehulled oats slightly decreased the relative proportion of 14:0 in milk fat but did not affect the proportions of 16:0, 18:0, 18:1, total SFA, monounsaturated FA, trans FA, or polyunsaturated FA. In Exp2, transfer efficiency of total C18 was lower when cows were fed the oat diets than when fed the barley diet and decreased linearly when hulled oats were replaced with dehulled oats. Predictions of daily CH₄ emissions (g/d) using the on-farm available variables energy-corrected milk yield and body weight were not markedly improved by including milk concentrations of individual milk FA in prediction equations. In conclusion, replacement of barley with oats as a concentrate supplement for dairy cows fed a grass silage-based diet could offer a practical strategy to change the FA composition of milk to be more in accordance with international dietary guidelines regarding consumption of SFA.     

Evaluation of SPE as Preparative Technique for the Analysis of Phenolic Metabolites in Human Feces

Solid phase extraction (SPE) methodology has been evaluated as a cleanup strategy prior to the analysis of phenolic metabolites in fecal samples by UPLC–DAD–ESI–TQ MS. Among the sorbents tested, Oasis® HLB led to the higher phenolic standard recoveries. Sample acidification (0.4 M HCl, final concentration) before SPE considerably improved standard recoveries. Values of the process efficiency (C_SPE/C_{Without SPE}) for a standard solution containing gallic acid, protocatechuic acid, caffeic acid, benzoic acid, 3-phenylpropionic acid, (+)-catechin, (?)-epicatechin, procyanidin B2, and 4-hydroxybenzoic 2,3,5,6 d₄ acid were acceptable (>90 %) for all compounds, except for procyanidin B2 (26 %). The developed SPE methodology was applied to fecal samples of individuals subjected to a wine intervention study. Phenolic metabolites, including intermediate metabolites (phenyl-γ-valerolactones and phenylvaleric acid derivatives) and end products (simple phenols, hydroxyphenylpropionic, hydroxyphenylacetic, hydroxycinnamic, and hydroxybenzoic acids) were identified. Most of the compounds (n?=?14) exhibited values of process efficiency between 85 and 115 %. Although some compounds (n?=?4) showed process efficiency>115 %, there was a group of metabolites (4-O-methylgallic acid, syringic acid, and 4-hydroxy-5-(3′,4′-dihydroxyphenyl)-valeric acid) whose process efficiency was <85 %, which represented a serious limitation and made us to discard SPE as a preparative technique for the analysis of these phenolic metabolites. Finally, the paper reports the concentrations of phenolic metabolites in a randomized set of human fecal samples from healthy volunteers (n?=?15) without any previous SPE application. Large inter-individual variability was observed, which was attributed to differences in human gut microbiota composition.