Free AA Research Articles

Effects provided by sugar substitutes upon the quality indicators of model systems of sweetened condensed milk in storage

Sweetened condensed milk (SCM) is a product widely used by both consumers and other food production branches. However, it contains a lot of sucrose. This study aimed to examine the effects provided by sugar substitutes-trehalose, isomaltulose, and polydextrose-upon the SCM sensory profile and valuable quality indicators, such as water activity (Aw), viscosity, acidity, crystal size, and Maillard reaction potential (browning index, color change, loss of free AA). The study was performed by making model systems of SCM (MSCM) using the method of reconstitution of powdered ingredients. All the presented carbohydrate compositions in MSCM provided Aw value typical of intermediate-moisture food, which contributes to the long-term shelf life of the product. However, only 2 MSCM showed stability of Aw within a 14-d storage period: a composition of isomaltulose and trehalose (each at 22.55%), and a composition of trehalose (28.19%), sucrose (5.64%), polydextrose (5.64%), and isomaltulose (5.64%). Trehalose and polydextrose in MSCM with monocarbohydrate added fraction demonstrated their high structure-forming ability, expressed in high values of dynamic viscosity (>30 Pa·s). The MSCM containing a predominant amount of trehalose in the carbohydrate compositions (≥50%) showed lower average crystal size (<16 μm) compared with MSCM with di- and tetra-carbohydrate added fractions with predominant amounts of isomaltulose or polydextrose. Isomaltulose and polydextrose added to MSCM led to pronounced browning, whereas trehalose and sucrose reduced this effect in MSCM with di- and tetra-carbohydrate added fractions. Polydextrose added at 22.55% to carbohydrate fraction of MSCM caused bitterness, whereas the addition at 5.64% did not affect the taste. Based on the results of all the research conducted, the optimal carbohydrate compositions to produce SCM with fewer calories, lower sucrose content, and stable, adequate values of processing and sensory properties were trehalose (22.55%) with isomaltulose (22.55%), and trehalose (28.19%) with sucrose (5.64%), polydextrose (5.64%), and isomaltulose (5.64%).

Utilization of waste tea leaves as metal-free catalyst for hydrogen generation via ethanolysis of Sodium Borohydride

In the present study, waste green and black tea leaves have been used to synthesize metal–free catalysts for hydrogen generation by ethanolysis of sodium borohydride by the acetic acid activation and carbonization. The FTIR, BET, SEM-EDS, and XPS characterizations have been performed to analyze the synthesized catalysts' properties. The parameters such as amounts of catalysts, SB, and reaction temperature were studied while performing the experiments. They were optimized using the Response Surface Methodology (RSM) to obtain the highest values of Hydrogen Generation Rates (HGR) of 1350 ml min−1 g catalyst−1 and 2700 ml min−1 g catalyst−1 using the acetic acid activated black tea (AA – BT) and acetic acid activated green tea (AA – GT) catalysts respectively with the activation energies of 13.14 kJ mol−1 and 37 kJ mol−1. The BET analysis has revealed that the AA – GT and AA – BT catalysts have surface areas of 22.96 m2 g−1 and 3.28 m2 g−1, pore diameters of 1.72 nm and 1.70 nm and pore volumes of 0.0047 and 0.0331785 m3 g−1 respectively. The electrochemical analysis has revealed that the synthesized metal–free catalysts AA – BT and AA - GT possess good specific capacitances of 63.77 mF cm−2 and 121 mF cm−2, which shows that both can be used as electrode material for energy storage applications. Hence, it can be believed that both metal–free catalysts can act as dual functional materials, which can act as catalysts and energy storage materials.

Asiatic acid cyclodextrin inclusion micro-cocrystal for insoluble drug delivery and acute lung injury therapy enhancement

BackgroundAcute lung injury (ALI) is a fatal respiratory disease caused by overreactive immune reactions (e.g., SARS-CoV-2 infection), with a high mortality rate. Its treatment is often compromised by inefficient drug delivery barriers and insufficient potency of the currently used drugs. Therefore, developing a highly effective lung-targeted drug delivery strategy is a pressing clinical need.ResultsIn this study, the micro-sized inclusion cocrystal of asiatic acid/γ-cyclodextrin (AA/γCD, with a stoichiometry molar ratio of 2:3 and a mean size of 1.8 μm) was prepared for ALI treatment. The dissolution behavior of the AA/γCD inclusion cocrystals followed a “spring-and-hover” model, which meaned that AA/γCD could dissolve from the cocrystal in an inclusion complex form, thereby promoting a significantly improved water solubility (nine times higher than free AA). This made the cyclodextrin-based inclusion cocrystals an effective solid form for enhanced drug absorption and delivery efficiency. The biodistribution experiments demonstrated AA/γCD accumulated predominantly in the lung (Cmax = 50 µg/g) after systemic administration due to the micron size-mediated passive targeting effect. The AA/γCD group showed an enhanced anti-inflammatory therapeutic effect, as evidenced by reduced levels of pro-inflammatory cytokines in the lung and bronchoalveolar lavage fluids (BALF). Histological examination confirmed that AA/γCD effectively inhibited inflammation reactions.ConclusionThe micro-sized inclusion cocrystals AA/γCD were successfully delivered into the lungs by pulmonary administration and had a significant therapeutic effect on ALI.Graphic abstract

Assessment of blood sampling time points to determine the relative bioavailability of ruminally protected methionine supplements using the plasma free amino acid dose-response technique

The calculation of the relative bioavailability (RBV) of rumen-protected AA supplements using the plasma free AA dose-response technique currently relies on blood samples obtained 2, 4, 6, and 8 h after the 0500 h feeding during the last 3 d of each period in Latin square experiments with cows fed every 8 h (0500, 1300, and 2100 h). The objective of this study was to determine if this current blood sampling protocol captures the changes that may occur in plasma Met concentrations within a 24-h day to adequately determine the RBV of Met from Smartamine M (SM). Five multiparous lactating Holstein cows were used in a 5 × 5 Latin square design with 7-d periods. Treatments were: 1) control (abomasal infusion of tap water), 2) 12 g/d of abomasally infused Met, 3) 24 g/d of abomasally infused Met, 4) 15 g/d of fed Met from SM, and 5) 30 g/d of fed Met from SM. Blood samples were collected via jugular catheters every 2 h after the 0500 h feeding starting on d 5 and ending on d 7 of each period. Plasma Met analysis was conducted using gas chromatography after chloroformate derivatization. Plasma Met concentration was averaged across days for 2–8 h after the 0500 h feeding, 2–8 h after the 1300 h feeding, 2–8 h after the 2100 h feeding, and 2–24 h after the 0500 h feeding. In addition, plasma Met concentration was regressed on 0, 12, and 24 g of infused Met and 0, 15, and 30 g of fed Met. The calculated RBV of Met from SM averaged 83.8, 83.6, 87.4, and 83.0% for the 2–8 h, 10–16 h, 18–24 h, and 2–24 h sampling periods, respectively. The similarity in the estimations of RBV for the 2–8 h and 2–24 h sampling periods indicates that our original blood sampling protocol seems reliable for determining the RBV of ruminally protected Met products.

Appearance of choline metabolites in plasma and milk when choline is infused into the abomasum with or without methionine

Four lactating, ruminally cannulated Jersey cows, (mean ± standard deviation) 264 ± 54.2 d in milk and 484 ± 24.1 kg of body weight, were arranged in a 4 × 4 Latin square design to measure the effects of abomasal infusion of choline chloride with or without dl-Met on milk and plasma choline metabolites and plasma AA in cows fed a Met-deficient diet. Cows were randomly assigned to 1 of 4 experimental treatments: (1) control; no supplemental Met or choline (CON), (2) 13 g/d of choline ion delivered via abomasal infusion (CHO), (3) 13 g/d of Met delivered via abomasal infusion (MET), and (4) 13 g/d of choline and 13 g/d of Met delivered via abomasal infusion (CHO + MET). Cows received the same basal diet throughout the experiment, which was formulated to be deficient in Met (−5.0 g of Met using the NASEM, 2021, model). Periods were 7 d in length with d 1 to 2 serving as a wash-out period and cows being infused on d 3 to 7. Milk samples were collected twice daily on d 5 to 7 and were analyzed for fat, true protein, lactose, and choline metabolites including betaine, phosphocholine, and free choline using hydrophilic interaction liquid chromatography-tandem mass spectrometry. Blood samples were collected via venipuncture of the coccygeal vein at 1100, 1300, and 1500 h on d 7 of each period and were analyzed for free AA as well as choline metabolites. Plasma Met increased in response to Met infusion and an interaction with choline and Met infusion was observed in the plasma concentration of branched-chain AA. Cows receiving choline exhibited the greatest Cho yield in milk. Milk phosphocholine yield tended to be highest when both choline and Met were infused.

Spontaneous stairlike fracture of sternum in multiple myeloma.

Free and peptide-bound AA act as building blocks and key regulators of milk protein. To improve milk protein production, mammary epithelial cells of lactating mammals require extensive AA movement across the plasma membrane via multiple transport systems. Recent studies on bovine mammary cells/tissues have expanded the number of AA transporter systems identified and the knowledge on their contribution to AA utilization for milk protein synthesis and the regulatory machinery. However, in lactating cows, the exact intracellular location of mammary AA transporters and the extent of mammary net AA utilization for milk protein production remain unclear. This review highlights the existing knowledge on various characteristics, such as substrate specificity, kinetics, their effects on AA uptake and utilization, and regulatory mechanism, of recently examined bovine mammary free and peptide-bound AA transporters.

Valorisation of fresh waste grape through fermentation with different exogenous probiotic inoculants

The disposal of fresh waste grape berries restraining the sustainable development of vineyards. The aims of this study were to evaluate the effects of different exogenous probiotic inoculants on the fermentation of fresh waste grape berries. In the fermentation process, the variations of pH and EC value, chemical characteristics of the fermentation products, as well as the microbial communities' composition were simultaneously observed. In addition, the feasibility of using the fermentation products as chemical fertilizer substitute in agricultural production also has been verified in this study. The results indicated that the different probiotic inoculants has shown clear impacts on the variation trends of pH and EC value in the grape waste fermentation. Lactobacillus casei and Zygosaccharomyces rouxii are ideal probiotics for the fermentation of waste grape, which enhanced the contents of free Aa and other nutrients in fermentation products. Compared with Fn treatment (without exogenous inoculants), the total free Aa contents in Fs (inoculation with Z. rouxii) and Fm (inoculation with L. casei and Z. rouxii mixture) treatments have improved by 199.1% and 325.5%, respectively. The microbial communities’ composition during the fermentation process also been greatly influenced by the different inoculants. At the genus level, Lactobacillus and Pseudomonas were the dominant bacteria, while Saccharomyces and Candida were the dominant fungi in the fermentation. Using the fermentation products as chemical fertilizer substitute has enhanced the quality of Kyoho grape. Compared with traditional chemical fertilization treatment (T1), application with fermented grape waste (T2) has significantly improved VC and soluble solid contents in grape berries by 16.89% and 20.12%, respectively. In conclusion, fermentation with suitable probiotics was an efficient approach for the disposal and recycling of fresh waste grape in vineyards.

Influence of storage time on protein composition and simulated digestion of UHT milk and centrifugation presterilized UHT milk in vitro

The centrifugation presterilizing UHT (C-UHT) sterilization method removes 90% of the microorganism and somatic cells from raw milk using high-speed centrifugation following UHT treatment. This study aimed to study the changes in protein composition and plasmin in the UHT and C-UHT milk. The digestive characteristics, composition, and peptide spectrum of milk protein sterilized with the 2 technologies were studied using a dynamic digestive system of a simulated human stomach. The Pierce bicinchoninic acid assay, laser scanning confocal microscope, liquid chromatography-tandem mass spectrometry, and AA analysis were used to study the digestive fluid at different time points of gastric digestion in vitro. The results demonstrated that C-UHT milk had considerably higher protein degradation than UHT milk. Different processes resulted during the cleavage of milk proteins at different sites during digestion, resulting in different derived peptides. The results showed there was no significant effect of UHT and C-UHT on the peptide spectrum of milk proteins, but C-UHT could release relatively more bioactive peptides and free AA.

Effect of dl-methionine supplementation above requirement on performance; intestinal morphology, antioxidant activity, and gene expression; and serum concentration of amino acids in heat stressed pigs.

The intestinal morphology and function can be compromised in pigs exposed to heat stress (HS), partly due to increased production of reactive-oxygen species. Because methionine (Met) functions as intracellular antioxidant, the requirement of Met may be increased in HS-pigs. The effect of dietary supplementation with dl-Met above requirement on performance, small intestine morphology, antioxidant enzymes activity, amino acid transporters expression, and serum concentration (SC) of free AA in HS-pigs was evaluated. A basal wheat-soybean meal diet was formulated to meet 100% Met requirement with the other indispensable AA exceeding at least 20% their requirement. Sixty individually housed pigs (23.0 ± 2.4 kg BW, 12 pigs per treatment) were randomly assigned to five treatments: TN100, thermal-neutral (22.7 °C) housed pigs fed the basal diet; HS100, HS120, HS140, HS160; HS-pigs (29.6 °C to 39.4 °C) fed the basal diet supplemented with dl-Met to contain 0%, 20%, 40%, and 60% dl-Met above the requirement, respectively. Pigs had free access to feed and water during the 21-d trial. Blood samples were collected on day 18 to analyze the absorptive AA-SC. The effect of ambient temperature (HS100 vs. TN100), as well as the linear and quadratic effects of increasing Met levels in the diets for HS-pigs were analyzed. The HS100 pigs gained less weight than TN100 and HS120 pigs (P < 0.01); gain:feed was also higher in HS120 pigs than in HS100 pigs (P ≤ 0.05). Feed intake of TN100 pigs was higher than that of HS-pigs fed the dl-Met supplemented diets (P < 0.05). Villi height reduced in pigs HS, but Met supplementation quadratically increased it (P < 0.05). Superoxide dismutase and catalase activities, reduced glutathione concentration, and relative expression of B0AT2 in ileum decreased (P < 0.05), but glutathione peroxidase activity increased in HS-pigs. dl-Met supplementation linearly affected catalase and glutathione peroxidase activities, as well as the relative expression of b0,+AT in jejunum (P < 0.05) of HS-pigs. The SC of Ile, Leu, Lys, Phe, and Val were higher in HS100 pigs than in TN100 pigs (P < 0.05). Graded levels of supplemental dl-Met in diets for HS-pigs linearly decreased SC of Ile, Leu, and Val (P < 0.05), tended to decrease His, Lys, and Thr (P < 0.10), and increased Met (P < 0.01). In conclusion, HS had negative effect on weight gain and intestinal morpho-physiology; however, it was ameliorated by adding 20% Met above the requirement in diets for growing pigs.

Growth Retardation Induced by Protein and Indispensable Amino Acid Deficiencies Can Not Be Catch Up by a Supplementation in Growing Rats

ObjectivesIn developing countries, children are exposed to a risk of growth retardations due to their low protein (LP) intake or poor quality of protein sources with unbalanced indispensable amino acid (IAA) composition. However, the specificity of each IAA and the ability of children to catch-up their growth retardation remains unclear. The aim of this study was to assess the supplementation efficiency following a protein or IAA (lysine, threonine, and methionine) deficiencies in growing rats, and to identify the specific IAA deficiency effect. MethodsSixty growing rats were fed by a control (20% of proteins; P20), a LP (5% of proteins; LP) or IAA deficient (25% of the rat’s requirement in lysine, threonine, or methionine; L25, T25 and M25) diets for 3w. Thereafter, all rats were supplemented by the control (P20) or a control-equivalent diet containing free AA. Body weight (BW) and food intake were daily recorded. Naso-anal length (NAL), bone mineral density (BMD) and body composition were measured at the end of each period. ResultsDuring the deficiency, IAA as LP diets reduced BW gain from day 2 for LP, L25 and M25 and from day 1 for T25. At the end of the deficiency, BW was reduced by 30% for L25 and M25, 50% for LP and 60% for T25. NAL was also reduced by 9, 18, 25% for L25/M25, LP and T25. At the end of the deficiency, all groups had less lean body mass (LBM), whereas only LP and T25 had a decreased BMD. Furthermore, the fat mass was only decreased for LP and T25 groups. During the supplementation, growth resumes and the weight’s gap between each group was reduced, but remains after supplementation. The BW were reduced by 15, 25 and 35% for L25/M25, LP and T25, respectively. For NAL and LBM, the gap slightly reduced too, but the difference remains after the supplementation. Indeed, the NAL was reduced by 5% for L25 and M25, 8% for LP and 10% for T25. All groups had reduced kidney, muscle and carcass weight, and LP and T25 had a reduced liver weight and BMD. The T25 group was the most affected by the deficiency, even more than LP. ConclusionsA single IAA deficiency as LP induced growth retardation, and the LBM is highly affected. A supplementation allows growth resume, but the growth retardation cannot be catch up. The stronger effect observed for threonine deficiency, could be due to a wrong estimation of threonine requirement. Funding SourcesThis work was supported by CEFIPRA and AlimH -INRAe.

Comparison of plasma methionine response to 3 rumen-protected methionine products in lactating Holstein dairy cows

The primary aim of this work was to compare the plasma Met response to supplementation with 3 rumen-protected Met products. Secondary aims were to evaluate how time of sampling affected results and how pooling of samples may have affected results. Ten multiparous Holstein cows (280 ± 73 DIM) were used in a replicated 3 × 3 Latin square design with 7-d experimental periods. Cows were fed every 8 h, and treatments consisted of supplementation of 12 g/d (4 g/feeding) of 1 of 3 rumen-protected Met (RPM) products. The products evaluated were the newly developed RPM-K and 2 existing products, RPM-S and RPM-M, with known differences in bioavailability. During d 5 to 7 of each period, blood samples were collected at 2, 4, 6, and 8 h after the morning feeding for plasma free AA analysis. Plasma Met data were analyzed using the full data set as well as mean values from individual cows for each day or each period. Plasma Met was not different between RPM-S and RPM-K (32.7 vs. 33.0 μ M , respectively; P = 0.79), and both were greater than RPM-M (30.1 μ M ; P ≤ 0.001). Plasma Met was affected by time of sampling ( P = 0.001), due to reduced plasma Met at 4 h (30.2 μ M ) than at 2, 6, and 8 h (31.9–33.0 μ M ). Using the daily and period mean values of plasma Met, differences observed in the full model were maintained when daily means were evaluated, but period means resulted in only a tendency for a treatment effect. Bioavailability of RPM-K was similar to RPM-S and greater than RPM-M. Pooling samples by day within cow would have likely yielded similar results.

Cheese ripening in nonconventional conditions: A multiparameter study applied to Protected Geographical Indication Canestrato di Moliterno cheese

A multiparameter study was performed to evaluate the effect of fondaco, a traditional ripening cellar without any artificial temperature and relative humidity control, on the chemical, microbiological, and sensory characteristics of Protected Geographical Indication Canestrato di Moliterno cheese. Ripening in such a nonconventional environment was associated with lower counts of lactococci, lactobacilli, and total viable bacteria, and higher presence of enterococci, in comparison with ripening in a controlled maturation room. Moreover, fondaco cheese underwent accelerated maturation, as demonstrated by faster casein degradation, greater accumulation of free AA, and higher formation of volatile organic compounds. Secondary proteolysis, as assessed by liquid chromatography-mass spectrometry of free AA and low molecular weight peptides, did not show any qualitative difference among cheeses, but fondaco samples evidenced an advanced level of peptidolysis. On the other hand, significant qualitative differences were observed in the free fatty acid profiles and in the sensory characteristics. Principal component analysis showed a clear separation of the fondaco and control cheeses, indicating that ripening in the natural room conferred unique sensory features to the product.

Lactational performance and plasma and muscle amino acid concentrations in dairy cows fed diets supplying 2 levels of digestible histidine and metabolizable protein

The objective of this experiment was to investigate the effect of dietary levels of digestible histidine (dHis) and MP on lactational performance and plasma and muscle concentrations of free AA in dairy cows. A randomized block design experiment was conducted with 48 Holstein cows, including 20 primiparous, averaging (±SD) 103 ± 22 d in milk and 45 ± 9 kg/d milk yield at the beginning of the experiment. A 2-wk covariate period preceded 12 experimental wk, of which 10 wk were for data and sample collection. Experimental treatments were (1) MP-adequate (MPA) diet with 2.1% dHis of MP (MPA2.1), (2) MPA with 3.0% dHis (MPA3.0), (3) MP-deficient (MPD) diet with 2.1% dHis (MPD2.1), and (4) MPD with 3.0% dHis (MPD3.0). Actual dHis supply was estimated at 64, 97, 57, and 88 g/d, respectively. Diets supplied MP at 110% (MPA) and 96% (MPD) of NRC 2001 dairy model requirements calculated based on DMI and production data during the experiment. Dry matter intake and milk yield data were collected daily, milk samples for composition and blood samples for AA analysis were collected every other week, and muscle biopsies at the end of covariate period, and during wk 12 of the experiment. The overall DMI was not affected by dHis or MP level. Milk yield tended to be increased by 3.0% dHis compared with 2.1% dHis. Milk true protein concentration and yield were not affected by treatments, whereas milk urea nitrogen concentration was lower for MPD versus the MPA diet. Milk fat concentration was lower for MPD versus MPA. There was a MP × dHis interaction for milk fat yield and energy-corrected milk; milk fat was lower for MPD3.0 versus MPD2.1, but similar for cows fed the MPA diet regardless of dHis level whereas energy-corrected milk was greater for MPA3.0 versus MPA2.1 but tended to be lower for MPD3.0 versus MPD2.1. Plasma His concentration was greater for cows fed dHis3.0, and concentration of sum of essential AA was greater, whereas carnosine, 1-Methyl-His and 3-Methyl-His concentrations were lower for cows fed MPA versus MPD diet. Muscle concentration of His was greater for cows fed dHis3.0 treatment. The apparent efficiency of His utilization was increased at lower MP and His levels. Overall, cows fed a corn silage-based diet supplying MP at 110% of NRC (2001) requirements tended to have increased ECM yield and similar milk protein yield to cows fed a diet supplying MP at 96% of requirements. Supplying dHis at 3.0% of MP (or 86 and 96 g/d, for MPD3.0 and MPA3.0, respectively) tended to increase milk yield and increased plasma and muscle concentrations of His but had minor or no effects on other production variables in dairy cows.

The relationship between microbial dynamics and dominant chemical components during Liupao tea processing

Liupao tea is one kind of dark tea with a unique flavor that can be attributed to the microbiome. Howerver, the role of the microbiome is unknown in pile fermention of Liupao tea. Illumina MiSeq sequencing technology was used in this study to analyze microbial community composition during Liupao tea pile-fermentation. The relationship between microbial colonies and dominant chemical components was also evaluated using Pearson analysis. The result shown that contents of cafeine, gallic acid, free amino acids (Free AA), water-soluble pectins (WSP), tea polysaccharides (TPS), and water-soluble carbohydrate (WSC) all increased during fermentation while contents of epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), gallocatechin gallate (GCG), epicatechin (EC), catechins (+C), water extract (WE), tea polyphenols (TP) and flavonoids decreased. The dominant microbial community succession comprised Sphingomonas (23.68%), Methylobacterium (17.67%), Chryseobacterium (12.55), Aspergillus (16.70%), Cladosporium (8.36%), Penicillium (6.07%), and Blastobotrys (1.54%) in the early stage of fermentation, followed by Staphylococcus (59.05%), Brachybacterium (9.66%), Kocuria (9.81%), Blastobotrys (65.07%), Aspergillus (21.10%), and Rasamsonia (11.06%) at later stages. Amongst these, relative abundances of Lactobacillus in probiotics in middle and late fermentation remained relatively high. Genus of Aspergillus, Blastobotrys, Brachybacterium and Kocuria were signifcantly (P< 0.05) correlated with TP, WSP, WSC, FreeAAs, catechins, flavonoids, cafeine and gallic acid. Therefore, the dominant microbiome in pile fermention of Liupao tea were mainly characterized by Staphylococcus, Aspergillus and other genus, meanwhile Aspergillus, Blastobotrys, Brachybacterium and other genus played an important role in quality formation. This research provides new insights into the relationship between microorganisms and product quality and the development of functional Liupao tea.

Synthesis of Modified Polycarboxylate and Its Application in Ultra-High Performance Concrete

Modified polyurethane prepolymer was prepared using the segmental synthesis method. Then, pectiniform polycarboxylate was synthesized at normal temperature in the complex initiation system of H2O2, APS, sodium bisulfite, Vc, and Rongalit according to the free radical polymerization reaction mechanism, using TPEG, AA, and PEG as raw materials and TGA as the chain transfer agent. Compared with commercial Sika polycarboxylate, its flowability, strength, drying shrinkage, and auto-shrinkage were studied. The experimental results show that the synthesized polycarboxylate could be better dispersed. Adding silica fume can enhance the compressive strength of ultra-high performance concrete (UHPC), while slag may decline its strength. By incorporating slag and silica fume, the drying shrinkage of UHPC was reduced, but its auto-shrinkage was increased.

Effects of varying extracellular amino acid concentrations on bidirectional amino acid transport and intracellular fluxes in mammary epithelial cells

Understanding the regulation of cellular AA uptake as protein supply changes is critical for predicting milk component yields because intracellular supplies partly regulate protein synthesis. Our objective was to evaluate cellular uptake and kinetic behavior of individual AA when cells are presented with varying extracellular AA supplies. Bovine primary mammary epithelial cells were grown to confluency and transferred to medium with an AA profile and concentration similar to that of plasma from dairy cows for 24 h. Treatments were 4 AA concentrations, 0.36, 2.30, 4.28, and 6.24 mM, which represented 16, 100, 186, and 271% of typical plasma AA concentrations, respectively, in lactating dairy cows. Twenty-four plates of cells (89.4 × 19.2 mm) were assigned to each treatment. Cells were first subjected to treatment medium enriched with 15N-labeled AA for 24 h and then incubated with treatment medium enriched with 13C-labeled AA for 0, 15, 60, 300, 900, 1,800, and 3,600 s. Intracellular free AA, intracellular protein-bound AA, and extracellular medium free AA were analyzed for concentrations and isotopic enrichment using gas chromatography-mass spectrometry. A dynamic, 12-pool model was fitted to the data for 14 AA to derive unidirectional uptake and efflux, protein turnover, transamination, oxidation, and synthesis. The derived concentration for half the maximal uptake (km) indicated no saturation of AA uptake at typical in vivo concentrations for 11 of the 14 AA. Arginine, Pro, and Val appeared to exhibit saturation kinetics. Net uptake of all essential AA except Phe was positive across treatments. Most nonessential AA exhibited negative net uptake values. Efflux of AA was quite high, with several AA exhibiting greater than 100% efflux of the respective influx. Intracellular pool turnover was rapid for most AA (e.g., 2 min for Arg), demonstrating plasticity in matching needs for protein translation to supplies. Intracellular AA concentrations increased linearly in response to treatment for most AA, whereas 9 AA exhibited quadratic responses. Amino acid uptake is responsive to varying extracellular supplies to maintain homeostasis. No saturation of uptake was evident for most AA, indicating that transporter capacity is likely not a limitation for most AA except possibly Arg, Val, and Pro in mammary epithelial cells.

164 Effect of Supplemental Dl-met Above Requirement on Performance and Serum Concentration of Amino Acids in Heat Stressed Pigs

Abstract The intestinal morphology can be compromised in pigs when exposed to heat stress (HS), partly due to increased production of reactive-oxygen species. Because methionine (Met) functions as intracellular antioxidant, requirement of Met may be increased in HS-pigs. The effect of dietary supplementation with DL-Met above requirement on performance and serum concentration (SC) of free AA in HS-pigs was evaluated. A basal wheat-soybean meal diet was formulated to meet 100% Met requirement with the other indispensable AA exceeding at least 20% their requirement. Sixty individually housed pigs (23.0 ± 2.4 kg BW, 12 pigs/treatment) were randomly assigned to 5 treatments: TN100, thermal-neutral (22.7 °C) housed pigs fed the basal diet; HS100, HS120, HS140, HS160; HS pigs (29.6 to 39.4°C) fed the basal diet supplemented with DL-Met to contain 0, 20, 40, and 60% DL-Met above the requirement, respectively. Pigs had free access to feed and water during the 21-d trial. Blood samples were collected on d18 to analyze the absorptive AA-SC. The effect of ambient temperature (HS100 vs. TN100), as well as the linear and quadratic effects of increasing Met levels in the diets for HS pigs were analyzed. The performance results for the TN100, HS100, HS120, HS140, HS160 pigs were: Average daily gain (ADG), 728, 612, 720, 716, 719 g/d; average daily feed intake, 1.40, 1.34, 1.30, 1.30, 1.29 kg/d; gain:feed, 0.522, 0.474, 0.569, 0.563, 0.562, respectively. The ADG reduced (P &amp;lt; 0.01) in HS100 compared with TN100 pigs, but linearly increased in HS-pigs, besides gain:feed (P ≤ 0.05), in response to DL-Met supplementation. The SC of Ile, Leu, Lys, Phe, and Val were higher in HS100 pigs than in TN100 pigs (P &amp;lt; 0.05). Graded supplemental DL-Met in diets for HS-pigs linearly decreased SC of Ile, Leu, and Val (P &amp;lt; 0.05), tended to decrease His, Lys, and Thr (P &amp;lt; 0.10), and increased Met (P &amp;lt; 0.01). In conclusion, HS had negative effect on weight gain; however, it was ameliorated by adding 20% Met above the requirement.

Preweaning nutrient supply alters serum metabolomics profiles related to protein and energy metabolism and hepatic function in Holstein heifer calves

Lifting the preweaning milk restriction in dairy calves has been causally associated with beneficial effects on growth and future lactation performance. However, the biological mechanisms linking early-life nutrient supply and future performance remain insufficiently understood. Thus, the objective of this study was to characterize growth and the metabolic profiles of calves fed a restricted (RES) and an elevated (ELE) milk supply preweaning. A total of 86 female Holstein Friesian calves were blocked in pairs by maternal parity and received identical colostrum supply within block. Treatments randomized within block consisted of a milk replacer (MR; 24% crude protein, 18% crude fat, and 45% lactose) supplied at either 5.41 Mcal of ME in 8 L of MR/d (ELE) or 2.71 Mcal of ME in 4 L of MR/d (RES) from d 2 after birth until they were stepped down by 50% during wk 7 and fully weaned at wk 8. All calves had ad libitum access to pelleted calf starter (17.3% crude protein, 24.4% neutral detergent fiber, 2.0% crude fat, and 18.2% starch), chopped wheat straw, and water. At 2 and 49 d of age, blood samples were taken for metabolomics analysis. The ELE group by design consumed more milk replacer, resulting in a lower starter intake and a greater body weight and average daily gain. The ELE calves consumed 20.7% more ME and 9.7% more crude protein. However, efficiency of growth was not different between groups. Metabolomic profiling using 908 identified metabolites served to characterize treatment-dependent biochemical differences. Principal component analysis revealed clearly distinct metabolic profiles at 49 d of age in response to preweaning milk supply. Changes in energy (fatty acid metabolism and tricarboxylic acid metabolites), protein (free AA, dipeptides, and urea cycle), and liver metabolism (bile acid and heme metabolism) were the main effects associated with the dietary differences. The ELE group consumed proportionately more glucogenic nutrients via milk replacer, whereas the RES group consumed proportionately more ketogenic nutrients from the digestion of the calf starter, comprising a larger portion of total intake. Associated with the higher growth rate of the ELE group, hepatic changes were expressed as differences in bile acid and heme metabolism. Furthermore, energy metabolism differences were noted in fatty acid and AA metabolism and the urea cycle. The metabolic profile differences between the ELE and RES groups reflect the broad differences in nutrient intake and diet composition and might point to which metabolic processes are responsible for greater dairy performance for cows fed a greater milk supply preweaning.

Production performance and nitrogen metabolism in dairy cows fed supplemental blends of rumen undegradable protein and rumen-protected amino acids in low- compared with high-protein diets containing corn distillers grains

Feeding corn dried distillers grains with solubles (DDGS) in low crude protein (CP) diets could limit N waste in lactating cows. However, it also could possibly reduce metabolizable AA supply, especially Lys, and compromise milk production. Therefore, the objective of this study was to evaluate the effects of feeding supplemental blends of rumen undegradable protein (RUP) and rumen-protected (RP) AA in a low compared with high CP diet containing corn DDGS on milk production and selected measures of N utilization. Six multiparous Holstein cows (619.3 ± 49.8 kg of body weight; 26.8 ± 6.2 d in milk) were subjected to a split-plot, 3 × 3 Latin square design (21-d periods) with dietary CP content [low (14.6%; LP) or high (16.6%; HP)] as the whole-plot factor, and blend of RUP and RP-AA [control (CON), no supplement; blend A (0.11 kg/cow per d); or blend B (0.45 kg/cow per d)] as the sub-plot factor. All diets contained 10% corn DDGS; blends of RUP and RP-AA were top-dressed during morning feeding. There was no dietary CP content × supplemental blend interaction for all measured variables. Nutrient (dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and CP), milk and milk component yields, and feed and apparent N efficiency did not differ for cows fed the low- compared with the high-protein diet. However, apparent total-tract CP digestibility, blood and milk urea-N concentrations, and urinary excretion (g/d) of N and urea-N were lower for cows fed the low-protein compared with the high-protein diet. There was no supplemental blend effect on nutrient intake and apparent total-tract digestibility, and milk and milk component yields. Except for a tendency for total urinary purine derivative excretion and microbial N flow to be lower for cows fed blend B compared with CON but not blend A, there was no supplemental blend effect on measures of N utilization. Both dietary CP content and supplemental blend of RUP and RP-AA had a marginal effect on the plasma free AA profile. In summary, reducing dietary CP content in diets containing corn DDGS had no effect on lactation performance, possibly accounting for the lack of a positive response following the provision of supplemental blends of RUP and RP-AA. However, reducing dietary CP content resulted in a decrease in blood and milk urea-N concentrations, and urinary excretion of N and urea-N, suggestive of an improvement in the efficiency of N use.

Measuring seasonal and agro-ecological effects on nutritional status in tropical ranging dairy cows

Despite high numbers of cattle, milk production in many tropical countries such as Ethiopia is very low. Animals are managed traditionally, meaning they mostly depend on seasonal availability of natural pasture, grass, and crop residues with no supplementary feeds. Due to the lack of pasture management, there is overgrazing and soil erosion, and the land still must deal with extremely dry periods. All this has a negative effect on dairy cow productivity. Identification of the specific nutritional deficits would enable targeted interventions to improve milk yield performance, but nutrient and energy intakes are difficult to assess in ranging conditions. The aim of this research was, therefore, to evaluate the nutritional status of ranging dairy cows through blood metabolites, milk yield, and body condition in relation to environmental factors such as agro-ecology and season. The study was performed in a tropical region that is known to be exposed to the above-mentioned situation, the Arba Minch region in the southern Ethiopian Rift Valley. Blood samples were collected from 170 ranging dairy cows in 6 different districts, along a transect extending from the lowlands to the highlands, in both seasons (dry and rainy). Body condition score and milk yield of all cows were also determined for both seasons. Serum urea, creatinine, triglyceride, and nonesterified fatty acid concentrations were quantified spectrophotometrically. Dried serum spots were subject to quantitative electrospray tandem mass spectrometry to estimate changes in nutrient metabolism based on selected free AA and carnitine esters. Based on these measurements, nutritional status varied with season and geographical region. It can also be concluded that extensive metabolite analysis such as mass spectrometry can provide detailed insights, but the simpler spectrophotometric metabolite analysis can estimate the nutritional status of ranging animals.