The composition and nutritional quality of biorefined lucerne protein depend on precipitation method.

BACKGROUND: Lucerne protein extract is a novel high-quality protein source with excellent amino acid (AA) composition of interest for human consumption. In this study, protein from screw-pressed lucerne juice was extracted by different precipitation methods to evaluate the effect on the chemical composition and nutritional quality of the extracted protein. Methods based on heat, acidification or fermentation were used for protein precipitation, and the nutritional value of protein was evaluated in a rat digestibility trial. RESULTS: Heat precipitation at 85 °C produced a protein product with a crude protein (CP) content of 589 g kg-1 dry matter (DM), a balanced AA composition and a high standardized nitrogen (N) digestibility (82.8%). Precipitation by acidification, at a lower temperature (60 °C) or by fermentation, resulted in lower CP content (425-488 g kg-1 DM). Nitrogen digestibility for the pH-adjusted precipitate was equal to the 85 °C heat-precipitated protein, while the fermented and 60 °C precipitated proteins showed lower N digestibility (76.5% and 78.6%, respectively). By applying a two-step heat precipitation method (60 °C followed by 80 °C), a protein content of 712 g kg-1 DM and an N digestibility of 93.6% was reached, which are comparable to high-quality animal-based protein sources such as milk, whey, casein, and eggs, covering the AA requirements for children >6 months. CONCLUSION: High-quality protein can be extracted from lucerne, but the future focus should be on increased yield as the current low yields of the refined product will challenge the environmental and economic sustainability of production. © 2023 Society of Chemical Industry.

Determining Optimal Nonlinear Regression Models for Studying the Kinetics of Fatty Acid Ruminal Biohydrogenation In Vitro.

The accurate estimation of in vitro ruminal biohydrogenation (BH) kinetics of fatty acids (FA) allows for a more accurate understanding of their dynamics and develop targeted strategies to enhance desirable FA bypass. This study comprises a comprehensive evaluation of 33 nonlinear regression models to determine the most suitable model for accurately estimating the in vitro BH kinetics of individual FA. The data set utilized in the present research originates from a recent investigation on the effects of micronization and vitamin E on the in vitro ruminal BH of rapeseed. For the nonlinear regression analysis, data comprising FA concentrations (expressed as g FA/100 g FA) at the conclusion of 2, 4, 8, 12, 24, and 48 h incubation periods were employed. The evaluation of nonlinear regression models focused on identifying the ideal model based on criteria including the highest R2 value, the lowest RMSE value, and statistically significant coefficients. The results pinpoint the Gompertz model as an effective choice for estimating the in vitro ruminal BH kinetics of upward-trending fatty acids, including intermediate unsaturated fatty acids and saturated end FA. Additionally, the first-order kinetic model of Ørskov and McDonald emerges as the preferred model for investigating the BH kinetics of downward-trending fatty acids, including oleic acid, linoleic acid, and alpha-linolenic acid. In summary, this rigorous evaluation led to the identification of the most appropriate model, one that not only exhibited an exceptional fit to the data but also provided profound insights into the intricate relationships between predictors and the dynamic behavior of FA. The established nonlinear regression models will serve as invaluable tools for future research investigating FA biohydrogenation kinetics.

Effect of reduced-calcium and high-calcium cheddar cheese consumption on the excretion of faecal fat: a 2-week cross-over dietary intervention study.

PURPOSE: Studies show that dairy fat consumed in the form of cheese reduce LDL-cholesterol concentration (LDL-c) compared to butter and mechanistic suggestions include the calcium content of cheese leading to enhanced faecal fat excretion. The aim of this study was to test the effect of varying the calcium content within a cheese, on faecal fat excretion as a primary outcome, and blood lipid markers, fasting glucose and calcium excretion as secondary outcomes. METHODS: 7 healthy males (BMI 18-25) participated in this randomized, cross-over control intervention, of 3 × 2 week periods. Diets contained 240 g/day cheese; a High Calcium Cheese (HCC) diet, a Reduced Calcium Cheese (RCC) diet, and a control arm: Reduced Calcium Cheese + CaCO3 Supplement (RCC + Supp) diet. Diets differed in calcium content and form but were otherwise controlled for energy and key macronutrients. Blood and 5-day faecal samples were collected. RESULTS: There was no significant difference in faecal fat excretion (g/day) between the diets (P = 0.066). Percent fat of faecel excretion was higher after RCC + Supp (P = 0.016). None of the individual fatty acids were different. Fasting LDL-c was significantly lower following the HCC diet vs. the other arms (P = 0.002). Faecal Ca was different across all diets (P = 0.001), lowest after RCC, and greatest after RCC + Supp. No differences were observed for fasting blood parameters or changes in anthropometry. CONCLUSION: Varying the calcium content within a cheese matrix significantly affected fasting LDL-c values. Results did not support higher faecal fat excretion as an underlying mechanism, but the high attrition rate was a limitation. Trial registerer Trial Registered at ISRCTN.org, registration number ISRCTN11663659 on 12.07.2022. Retrospectively registered.

Natural Vitamin E Supplementation during Pregnancy in Rats Increases RRR-α-Tocopherol Stereoisomer Proportion and Enhances Fetal Antioxidant Capacity, Compared to Synthetic Vitamin E Administration.

INTRODUCTION: Low dietary intake of vitamin E is a global public health issue. RRR-α-tocopherol (RRR-αT) is the only naturally occurring vitamin E stereoisomer, but the equimolecular mixture of all eight stereoisomers, synthetic vitamin E (S-αT), is commonly consumed. The objective of this study was to evaluate bioavailability and antioxidant activity of RRR-αT versus S-αT, in both mother and fetus, after maternal supplementation during pregnancy. METHODS: Female rats (7 weeks of age) received a modified AIN-93G diet supplemented with 75 IU/kg of RRR-αT (NVE, n = 20) or S-αT (SVE, n = 17). At delivery, the levels of αT, stereoisomer distribution, and antioxidant capacity were analyzed in maternal and fetal plasma. RESULTS: NVE administration significantly increased the proportion of RRR-αT stereoisomer in maternal and fetal plasma. The percentage of RRR-αT increased from 32.76% to 88.33% in maternal plasma, and 35.25% to 97.94% in fetal plasma, in the NVE group compared to SVE. Fetal plasma from the NVE group was found to have higher total antioxidant capacity compared to SVE. Lastly, fetal plasma RRR-αT stereoisomer percentage was positively associated with expression levels of scavenger receptor class B type 1 (SR-B1) in the placenta. CONCLUSIONS: Both natural and synthetic sources of vitamin E showed similar bioavailability. Still, NVE supplementation increased the proportion of RRR-αT and promoted higher antioxidant activity in fetal plasma at birth. Placental SR-B1 might be involved in the stereoselective transfer of RRR-αT stereoisomer across the placenta and may improve αT bioactivity in the fetus.

Nutritional values of forage-legume-based silages and protein concentrates for growing pigs.

In organic pig production systems, one of the main challenges is to meet the demand for resources rich in protein. Among the resources available, temperate green plants, such as forage legumes, are potential sources of energy and protein. The aim of the study was to determine the nutritional value of silages (S) from the whole plant of lucerne (L) and red clover (R) and protein pastes (PPs) obtained from L and R leaves. In a first trial, 30 pigs were used in a factorial design to determine the total tract digestibility (TTD) of dietary nutrients and energy in five dietary treatments. The control group was fed a control diet (C1). The lucerne silage (LS) and red clover silage (RS) groups were fed a 78%:22% mixture (on a DM basis) of the C1 diet and LS or RS. The lucerne protein paste (LPP) and the red clover protein paste (RPP) groups were fed an 81%:19% mixture (on a DM basis) of the C1 diet and LPP or RPP. In the second trial, five pigs were used in a 5 × 5 Latin square design to evaluate the standardised ileal digestibility (SID) of amino acids (AAs) in the four legume products. The control diet (C2) was formulated with casein as the sole protein source. The LS and RS groups were fed an 85%:15% mixture (on a DM basis) of the C2 diet and LS or RS. The LPP and RPP groups were fed an 80%:20% mixture (on a DM basis) of the C2 diet and LPP or RPP. Regardless of the plant species, silages obtained from L and R leaves contained less AA and more fibre than protein pastes. While the fresh forages contained the same percentage of protein N in total N (63.6%), lucerne lost more protein N during ensiling than red clover (-75.5 vs -33.8%). The calculated TTD coefficient of energy was higher in silages than in protein pastes and lower in R than in L products (72.8, 71.5, 67.7, and 61.3 for LS, RS, LPP and RPP, respectively). The SID of total essential AA was higher in LPP than in RPP (87.2 vs 79.2%) whereas it was lower in LS than in RS (33.2 vs 56.8%). The lower SID values in silages were explained by the protein degradation during the ensiling process and a high proportion of AA linked to the NDF fraction. The results of the present study show that protein pastes obtained from lucerne and red clover are valuable protein sources for pig. In contrast, legume silages have to be considered as an energy source rather than a protein source.

Effects of dairy and plant protein on growth and growth biomarkers in a piglet model.

The increasing world population with improved living conditions has increased the demand for food protein. This has intensified the search for sustainable alternative plant-derived high-quality protein sources for human nutrition. To study the effect of plant and milk proteins on growth in weaned pigs as a model for humans, 96 weaned pigs were divided into 48 pens and fed one of 4 different diets for 3 weeks. The dietary protein originated from either 50% rice + 50% 00-rapeseed protein (RICE + RAPE), 50% milk protein (MPC) + 50% 00-rapeseed protein (MPC + RAPE), 50% milk + 50% rice protein (MPC + RICE), or 100% MPC, and were supplemented with crystalline amino acids to meet the amino acid requirements. Weekly feed intake and body weights were recorded and after 3 weeks, a blood sample was taken 1 hour after a fixed meal, while organ weights were measured, and liver- and muscle tissue, and bone samples were collected at euthanasia. All pigs had a high daily gain and a low feed-to-gain ratio (F : G, feed intake per kg weight gain), but feed intake and daily gain was lowest and F : G highest in the RICE + RAPE diet. Metacarpal bones were longer and heavier in MPC + RICE and MPC fed pigs compared to pigs fed diet RICE + RAPE (P < 0.05), and intermediate in MPC + RAPE fed pigs, with no differences in bone thickness (P > 0.05). Plasma levels of all essential amino acids except Cys and Lys decreased markedly when fed a diet containing only plant protein. The differences were not associated with differences in plasma insulin or IGF-1, nor in the abundance of mRNA related to growth in liver and longissimus dorsi muscle. In conclusion, the growth of piglets fed a combination of milk and rice protein did not differ from the pure dairy-based diet, whereas the pure plant-based diet consisting of rice and rapeseed protein led to reduced growth. This was most likely caused by a lower feed intake and a lower than expected amino acid digestibility of the 00-rapeseed protein. There were no indications that the milk protein, beyond a favourable amino acid composition and high digestibility, specifically stimulated growth factors or other biomarkers of growth via the IGF-1 and insulin signalling pathways.

Linking Protein Quality in Biorefinery Output to Forage Crop Crude Protein Input via the Cornell Net Carbohydrate and Protein System.

The biorefinery technology aiming at protein extraction is rising and identification of suitable plant biomass input with valuable protein compounds for extraction is needed. Forage crops have been evaluated by the Cornell Net Carbohydrate and Protein System (CNCPS), and the result used as proxy of extractable protein in a biorefinery process. This serves as a helpful link between crop production and refinery output; however, the method has never been validated. Such validation is the main aim of this study. Five forage species-white clover, red clover, lucerne, perennial ryegrass, and tall fescue-were cut at four dates during spring and processed in a lab-scale refinery (screw press and subsequent protein precipitation from the green juice). The pulp fraction and the precipitated protein concentrate were both CNCPS analyzed to follow the initial crude protein (CP) plant input into these two fractions. Total recovery in concentrate was highest for the legumes, which points to an advantage of these species in protein extraction setups. High recovery of B1 and B2 (50% or higher for the grasses) in the pulp demonstrated a large proportion of soluble protein ending up in the fibrous pulp and shed light on the reason behind high feed quality of the pulp fraction. In conclusion, the existing tentative assumption of extractable protein being equal to CNCPS fractions of B1 and B2 and partly B3 was shown to be too simplified. The presented findings can improve crop species screening in terms of expected extractable protein yield.

Robust and highly sensitive micro liquid chromatography-tandem mass spectrometry method for analyses of polar pesticides (glyphosate, aminomethylphosfonic acid, N-acetyl glyphosate and N-acetyl aminomethylphosfonic acid) in multiple biological matrices.

Glyphosate is the most used herbicide in agriculture. To monitor glyphosate exposure, analytical methods have to fulfill requirements with regard to sensitivity, reproducibility, ease of handling/high-throughput and applicability to multiple biological matrices. Furthermore, the methods have to include the degradation product of glyphosate, aminomethylphosfonic acid (AMPA) and preferably metabolites of glyphosate and AMPA, N-acetyl AMPA and N-acetyl glyphosate. Majority of the published methods for glyphosate and AMPA require derivatization to be able to achieve high sensitivity. In this work, we present highly sensitive microLC-MS/MS method for simultaneous quantification of glyphosate, AMPA, N-acetyl AMPA and N-acetyl glyphosate in multiple biological matrices without derivatization. The combination of simple sample clean-up procedures for simultaneous handling of 96 sample and short chromatographic run of only 3.4 min, meets the requirements for high-throughput methods. Simple mobile phase of water containing formic and medronic acids and isocratic run provided robust chromatographic separation on hypercarb column. The use of micro-flow system decreased the background noise, increasing the sensitivity. Achieved Low Limits of Quantification (LOQs) for liquid samples (plasma/serum/urine) were 0.00005 mg L-1 and 0.0001 mg kg-1 for solid samples (grain and soybean based feed/stomach/gizzard/intestinal content), which is more than 100 time more sensitive compared to QuPPe-Method. The method was validated in representative matrices with minimum of five fortification levels, six measurements per spiked concentration and three batches. All the samples were spiked with corresponding internal standards for all four analytes before sample clean-up procedures, ensuring high accuracy and precision. Recoveries for plasma/serum ranged between 86-108%, urine 93-120%, feed 91-115% and stomach/gizzard/intestinal content 92-110% with precision below 20%. The method's applicability was tested on 2000 samples measured during one year period.

Piglet performance and physiological effects linked to reduced glucosinolate transformations in feed products based on rapeseed pressed cakes.

The nutritional quality of rapeseed press cakes (RPCs) in piglet feed is closely linked to its digestibility and the content of glucosinolates. This study investigates the significance of intact glucosinolate (glc) levels and degree of glc transformations on piglets performance. Four different RPCs were made from a low glc (11 µmol/g seed DM) containing B. napus L. seed variety Lioness (RPC-LW, RPC-LXW, RPC-LC, RPC-LCD). RPC made from the variety Excalibur containing the upper level of glc (24 µmol/g seed DM) of double rapeseed and produced at higher and prolonged temperature (RPC-UXW) served as negative control, while soya bean protein concentrate served as positive control. Piglets (8 kg) were fed ad libitum diets balanced for RPC protein content, with RPC inclusion of 84-98 g/kg (day 0-14) and 151-178 g/kg (day 15-50). Glc transformation was reduced from 42% to 24% (7.3-4.2 µmol/g RPC) when the temperature input was lowered in the warm pressing of oil, while the glc loss was less pronounced (17%) when cold pressing was applied. The following feed pelleting process further reduced Glc concentration from 11% to 40% in warm-pressed RPCs and 54 to 85% in cold-pressed RPCs. The RPC products replaced soya bean protein without any negative effects on performance, except for piglets served cold-pressed RPC, which had a reduction in average daily weight gain (ADG) (5%-7%, p < 0.05, Day 15-50). RPC in the feed led to increased liver weight in all piglets (p = 0.026). This may point at long-term effects from feeding with RPC. Intestinal absorption of intact glcs was proven by their detection in urine. In conclusion, warm-pressed RPC can be used as feed for piglet, while the presence of active myrosinase may have a negative effect on performance and cakes should either be included in lower amounts than used in the present study (18%) or include myrosinase inactivation before use.

Effects of Heat Treatment of Green Protein on in Situ Protein Disappearance and in Vitro Fatty Acid Biohydrogenation.

Soluble protein extracted from leaves and stems of grasses and forage legumes is defined as green protein. The present study was conducted to evaluate in situ green protein degradability, intestinal protein disappearance, and in vitro fatty acids biohydrogenation (BH) in dairy cows. Three green protein concentrates (red clover, ryegrass, and grass clover) were heat treated as follows: oven-drying at 70 °C, subsequent autoclaving at 121 °C for 45 min, and for grass clover also spin flash-drying. Freeze-dried green protein was considered as a control (untreated). Autoclaving and oven-drying of green protein reduced the crude protein and dry matter degradability. The linolenic acid BH rate was lowest in heat-treated grass clover concentrate ( P < 0.01). In conclusion, green proteins are heat sensitive, and oven-drying can be an appropriate method to increase the amount of protein and unsaturated fatty acids escaping from the rumen.

Effect of vitamin D treatments on plasma metabolism and immune parameters of healthy dairy cows.

The objective of this study was to investigate the possible beneficial effect of vitamin D repletion on certain immune parameters of vitamin D insufficient dairy cows. Twenty dairy cows in late lactation were treated daily with vitamin D in five different ways: sunlight exposure (SUN), D2 supplementation combined with sunlight exposure (D2SUN), D2 supplementation (D2), D3 supplementation (D3), and D2 and D3 supplementation combined (D2D3). The cows had very low vitamin D levels at d 0 because of the vitamin D deprivation before the study. After 1 month of vitamin D repletion, all cows had plasma 25(OH)D levels within the normal range. Total 25(OH)D concentration was significantly higher in SUN, D2SUN and D2D3 than D2 or D3 at the end of the study. However, milk yield, as well as protein and fat content of the milk, was not influenced by vitamin D treatments. There was no difference obtained in the measured immune parameters: Leucocyte populations, somatic cell count, immunoglobulin concentrations in plasma and milk, and antigen-stimulated cytokine productions did not change in response to vitamin D repletion or difference in vitamin D sources, and no relations to plasma 25(OH)D levels were identified. Despite the fact that plasma 25(OH)D increased from a very low level to normal range, the present study did not show any effect of vitamin D repletion on the tested immune parameters of healthy dairy cows. Therefore, in this study, it was concluded that repletion to physiologically normal plasma 25-hydroxyvitamin D levels of vitamin D-depleted healthy dairy cows had no influence on immune parameters.

A Review on the Role of Chromium Supplementation in Ruminant Nutrition-Effects on Productive Performance, Blood Metabolites, Antioxidant Status, and Immunocompetence.

With the increase in the global herd, the use of metabolic modifiers has become an important area for many researchers looking for a supraphysiological diet to improve production parameters. For improving the performance of high yielding cows, the optimal balance of all nutrients including microminerals is important. Chromium (Cr) is one of the important micronutrients which plays an important role in metabolism of ruminants. Experimental studies have found that Cr could change performance, immune responses, glucose and fatty acid metabolism, and antioxidant status in dairy cows. In some studies, Cr supplementation improved dry matter intake, milk production, and milk composition of dairy cows in the early, mid, or late stage of lactation. Also, in some studies, performance of growing animal, immune response, and some blood parameters responded positively to Cr supplementation. In conclusion, the effects of Cr supplementation on performance of ruminants are inconsistent; however, its long-term effects on health, productivity, immune system, and antioxidant activity of ruminants still need to be investigated.

α-Tocopherol and ß-carotene concentrations in feed, colostrum, cow and calf serum in Swedish dairy herds with high or low calf mortality.

BACKGROUND: A study of herd-level risk factors for calf mortality in large Swedish dairy herds showed low serum concentrations of α-tocopherol and ß-carotene in 1-7 day old calves to be more common in high mortality herds. Therefore, we aimed to investigate if calf mortality risk at herd level is associated with concentrations of α-tocopherol and/or ß-carotene at individual level in feed, colostrum, cow and calf serum, while controlling for herd level covariates. Inclusion criteria were affiliation to the Swedish official milk recording scheme, herd size of ≥ 120 milking cows/year, calf mortality risk (day 1-90) of at least 6% (high mortality; HM) or less than 1% (low mortality; LM) and located within one of two regions in southern Sweden. This cross-sectional study was performed in 2010 in 19 (nHM = 9; nLM = 10) dairy herds. Questionnaires were used to collect information about feed and routines for colostrum feeding. Feed (n = 57), colostrum (n = 162), cow serum (n = 189) and calf serum samples (n = 187) were collected and analysed for α-tocopherol and ß-carotene. Other analyses e.g. total serum protein, fat content, and total solids in colostrum were also performed. Linear regression models with vitamin concentrations in feed, colostrum, cow and calf serum as outcome were performed. RESULTS: Calves in HM herds had lower concentrations of α-tocopherol in serum than calves in LM herds, but the effect depended on total protein status in serum of the calf (P = 0.036). Calves from herds that fed transition milk for 3 days or more had higher α-tocopherol concentrations in serum than calves from herds feeding transition milk up to 2 days (P = 0.013). Fat percentage in colostrum was positively associated with α-tocopherol (P < 0.001) and ß-carotene concentrations in colostrum (P < 0.001). A diet containing ≥ 20% (in kg dry matter) maize silage of the total ration was negatively associated with ß-carotene concentration in cow serum (P = 0.001). CONCLUSIONS: High calf mortality risks were associated with lower concentrations of α-tocopherol in calf serum for calves with failure of passive transfer. Feeding transition milk longer was associated with higher concentrations of α-tocopherol in calf serum. In HM herds, evaluation of the calves' α-tocopherol status is recommended.

Short-term effect of oral amoxicillin treatment on the gut microbial community composition in farm mink (Neovison vison).

It is well documented that antibiotics have pronounced modulatory effects on the intestinal bacterial community of both humans and animals, with potential health consequences. The gut microbiota of mink has however attracted little attention due to low bacterial load and fast gastrointestinal transit time, questioning its relevance. In this study, we hypothesise that oral amoxicillin treatment affects the gut microbiota in mink. This was investigated in a controlled trial including 24 animals of which 12 were treated with amoxicillin for 7 days. By applying 16S rRNA gene sequencing, we found that the faecal microbiota was markedly altered already after 2 days of treatment, with a surprising increase in diversity to resemble the feed. The diversity within the mucosa at termination was however reduced, which indicates this compartment as an important colonisation site in mink. No impact on blood biochemistry, lipid metabolism, serum amyloid A, vitamins A and E and histomorphology of the gut and liver was found; however, a slight decrease in fat digestibility was observed. We suggest that early-life use of amoxicillin in mink production may be counteractive as dysbiosis of the microbiota during infancy is increasingly being recognised as a risk factor for future health.

Ruminal Biohydrogenation Kinetics of Defatted Flaxseed and Sunflower Is Affected by Heat Treatment.

The effect of heat treatment on biohydrogenation of linoleic acid (LA) and linolenic acid (LNA) and formation of stearic acid (SA), cis-9, trans-11 conjugated LA (CLA), trans-10, cis-12 CLA and trans-vaccenic acid (VA) was studied in in vitro incubations with diluted rumen fluid as inoculum and partly defatted flaxseed (DF) and partly defatted sunflower (DS) as test feeds. Feeds were heated in a laboratory oven at 110 °C for 0 (unheated), 45, or 90 min. Michaelis-Menten kinetics was applied for quantifying biohydrogenation rate. The DF heated for 90 min showed the lowest biohydrogenation rate of LNA and LA, indicated by the lowest Vmax value (P < 0.04 and P < 0.03, respectively). The DS heated for 45 min had the lowest biohydrogenation rate of LNA, indicated by the lowest Vmax value (P < 0.04). In conclusion, heat treatment decreased biohydrogenation of LA and LNA in DF and LNA in DS.

Short communication: artificial ultraviolet B light exposure increases vitamin D levels in cow plasma and milk.

The number of dairy cows without access to pasture or sunlight is increasing; therefore, the content of vitamin D in dairy products is decreasing. Ultimately, declining vitamin D levels in dairy products will mean that dairy products are a negligible source of natural vitamin D for humans. We tested the ability of a specially designed UVB lamp to enhance the vitamin D3 content in milk from dairy cows housed indoors. This study included 16 cows divided into 4 groups. Each group was exposed daily to artificial UVB light simulating 1, 2, 3, or 4 h of summer sun at 56°N for 24 d, and the group with simulated exposure to 2 h of summer sun daily continued to be monitored for 73 d. We found a significant increase in 25-hydroxyvitamin D3 (25OHD3) levels in plasma as well as vitamin D3 and 25OHD3 levels in milk after daily exposure for 24 d in all treatment groups. Extending daily exposure to artificial UVB light to 73 d did not lead to an increase of vitamin D3 or 25OHD3 level in the milk. In conclusion, the change in production facilities for dairy cows providing cows with no access to pasture and sunlight causes a decrease of vitamin D levels in dairy products. This decrease may be prevented by exposing cows to artificial UVB light in the stable.

Interrelations between herbage yield, α-tocopherol, ß-carotene, lutein, protein, and fiber in non-leguminous forbs, forage legumes, and a grass-clover mixture as affected by harvest date.

Pastures with diverse botanical composition may enhance animal-derived product quality. A recent study demonstrated high vitamin concentrations and yields in some forb species. The objectives of the present study were to investigate interrelations between herbage yields, vitamin concentrations, protein and fiber contents and analyze the effect of harvest date. We hypothesized that interrelations would be similar across investigated forage species. Four nonleguminous forbs: salad burnet (Sanguisorba minor), caraway (Carum carvi), chicory (Cichorium intybus), and ribwort plantain (Plantago lanceolata), three legumes: yellow sweet clover (Melilotus officinalis), lucerne (Medicago sativa), and birdsfoot trefoil (Lotus corniculatus) and a perennial ryegrass (Lolium perenne)-white clover (Trifolium repens) mixture were sown in a field trial with two replicated and randomized blocks. Forage in 1.5 m × 9 m plots was grown in two consecutive years and cut four times per year (May-October). Analyses of variance were performed. In most herbages, α-tocopherol and ß-carotene were positively correlated as were ß-carotene and lutein; all vitamins were negatively correlated with fiber content and herbage yield. ß-Carotene was positively correlated with protein content. α-Tocopherol and ß-carotene contents were generally highest in October and lowest in July. Our results showed similar interrelationships in most investigated species, and we suggest that these species may be mixed when designing novel biodiverse mixtures for particular product quality characteristics.

Absorption and intermediary metabolism of purines and pyrimidines in lactating dairy cows.

About 20 % of ruminal microbial N in dairy cows derives from purines and pyrimidines; however, their intermediary metabolism and contribution to the overall N metabolism has sparsely been described. In the present study, the postprandial patterns of net portal-drained viscera (PDV) and hepatic metabolism were assessed to evaluate purine and pyrimidine N in dairy cows. Blood was sampled simultaneously from four veins with eight hourly samples from four multi-catheterised Holstein cows. Quantification of twenty purines and pyrimidines was performed with HPLC-MS/MS, and net fluxes were estimated across the PDV, hepatic tissue and total splanchnic tissue (TSP). Concentration differences between veins of fifteen purine and pyrimidine nucleosides (NS), bases (BS) and degradation products (DP) were different from zero (P≤ 0·05), resulting in the net PDV releases of purine NS (0·33-1·3 mmol/h), purine BS (0·0023-0·018 mmol/h), purine DP (7·0-7·8 mmol/h), pyrimidine NS (0·30-2·8 mmol/h) and pyrimidine DP (0·047-0·77 mmol/h). The hepatic removal of purine and pyrimidine was almost equivalent to the net PDV release, resulting in no net TSP release. One exception was uric acid (7·9 mmol/h) from which a large net TSP release originated from the degradation of purine NS and BS. A small net TSP release of the pyrimidine DP ß-alanine and ß-aminoisobutyric acid (-0·032 to 0·37 mmol/h) demonstrated an outlet of N into the circulating N pool. No effect of time relative to feeding was observed (P>0·05). These data indicate that considerable amounts of N are lost in the dairy cow due to prominent intermediary degradation of purines, but that pyrimidine N is reusable to a larger extent.

Effect of ß-glucan supplementation on acute postprandial changes in fatty acid profile of lymph and serum in pigs.

Triglycerides are absorbed by the lymphatic system and have various functions in the body. It has been shown that some types of ß-glucans have a positive effect on the systemic concentrations of cholesterol and lipid, presumably through interference with the absorption of lipid and/or reabsorption of bile acids. In the current study we investigated the acute effects of ingesting 2 g of ß-glucan concentrates derived from barley ß-(1→3)(1→4)-D-glucan or yeast ß-(1→3)(1→6)-D-glucan on fatty acid content and composition in lymph and serum of 10 female pigs (initial weight 34.7±1.1 kg) fitted with a permanent catheter in the jejunal lymphatic trunk in a cross-over design. Lymph was collected continuously for 8 h followed by a spot sample taken 24 h after. A significant effect of time after feeding was observed for all fatty acids in serum and for 18:0, 18:2ω6 and 18:3ω3 in lymph, but a significant effect of ß-glucan was only observed for 14:0 (p=0.049) and 22:6ω3 (p=0.048) in lymph and 18:0 (p=0.019) in serum. While the concentration of dietary fatty acids increased postprandially in lymph, the concentration of arachidonic and docahexanoic acid tended to decrease. Furthermore, there was a drop in concentration of all fatty acid in serum 1 h after the meal.

Simultaneous quantification of purine and pyrimidine bases, nucleosides and their degradation products in bovine blood plasma by high performance liquid chromatography tandem mass spectrometry.

Improved nitrogen utilization in cattle is important in order to secure a sustainable cattle production. As purines and pyrimidines (PP) constitute an appreciable part of rumen nitrogen, an improved understanding of the absorption and intermediary metabolism of PP is essential. The present work describes the development and validation of a sensitive and specific method for simultaneous determination of 20 purines (adenine, guanine, guanosine, inosine, 2'-deoxyguanosine, 2'-deoxyinosine, xanthine, hypoxanthine), pyrimidines (cytosine, thymine, uracil, cytidine, uridine, thymidine, 2'-deoxyuridine), and their degradation products (uric acid, allantoin, ß-alanine, ß-ureidopropionic acid, ß-aminoisobutyric acid) in blood plasma of dairy cows. The high performance liquid chromatography-based technique coupled to electrospray ionization tandem mass spectrometry (LC-MS/MS) was combined with individual matrix-matched calibration standards and stable isotopically labelled reference compounds. The quantitative analysis was preceded by a novel pre-treatment procedure consisting of ethanol precipitation, filtration, evaporation and reconstitution. Parameters for separation and detection during the LC-MS/MS analysis were investigated. It was confirmed that using a log-calibration model rather than a linear calibration model resulted in lower CV% and a lack of fit test demonstrated a satisfying linear regression. The method covers concentration ranges for each metabolite according to that in actual samples, e.g. guanine: 0.10-5.0 µmol/L, and allantoin: 120-500 µmol/L. The CV% for the chosen quantification ranges were below 25%. The method has good repeatability (CV%≤25%) and intermediate precision (CV%≤25%) and excellent recoveries (91-107%). All metabolites demonstrated good long-term stability and good stability within-runs (CV%≤10%). Different degrees of absolute matrix effects were observed in plasma, urine and milk. The determination of relative matrix effects revealed that the method was suitable for almost all examined PP metabolites in plasma drawn from an artery and the portal hepatic, hepatic and gastrosplenic veins and, with a few exceptions, also for other species such as chicken, pig, mink, human and rat.