Alergia a las proteínas de la leche de vaca: proceso diagnóstico. Consenso interdisciplinario de expertos / Cow's milk allergy: diagnostic process. Expert consensus

Las proteínas de la leche de vaca pueden causar alergia alimentaria. Los distintos mecanismos de acción involucrados y la variabilidad clínica según la etapa de la vida pediátrica en la que se manifieste ocasionan dificultades en su abordaje, con riesgo de sub- o sobrediagnóstico. En este proceso, intervienen profesionales de diversas áreas y es recomendable su interacción. Es por ello que el objetivo de este consenso ha sido reflejar el conocimiento actualizado desde la interdisciplina, generando recomendaciones para su correcto diagnóstico. Hemos trabajado con el método de Delphi para sumarle a la evidencia científica, la experiencia proveniente de neonatólogos, pediatras, especialistas en alergia, nutrición y gastroenterología. Pensamos que este enfoque interdisciplinario de trabajo va a resultar de utilidad práctica y promoverá una atención más integral de estos pacientes.

Cow's milk protein can cause food allergy. The different mechanisms of action involved, the clinical variability depending on the stage of pediatric life in which it manifests, leads to difficulties in its approach, with the risk of under- or over-diagnosis. Professionals from various areas intervene in this process and their interaction is recommended. That is why the objective of this consensus has been to reflect the updated knowledge in an interdisciplinary mode, generating recommendations for its correct diagnosis. We have worked with the Delphi method to add to the scientific evidence, the experience from neonatologists, pediatricians, experts in allergy, nutrition and gastroenterology. We think that this interdisciplinary approach will be of practical use and will promote more comprehensive care for these patients.

Relationship Between Maternal Age and Macronutrient Content of Colostrum.

BACKGROUND: Little is known about the relationship between maternal age and the macronutrient content of colostrum. RESEARCH AIMS: This study aimed to evaluate the relationship between maternal age and human milk macronutrient content by comparing the concentrations of lactose, proteins, and lipids in the colostrum of women with younger, moderate, and advanced maternal age. METHODS: An observational, cross-sectional study was designed to compare the macronutrient concentrations in the colostrum of women aged < 20 years, 20 to 34 years, and > 34 years (younger, moderate, and advanced maternal age, respectively; n = 33 per group). For each participant, 3 ml of colostrum was collected by manual extraction from the right breast at 10 am, 39-48 hr after delivery, and analyzed using a Miris Human Milk Analyzer. Macronutrient concentrations were compared between the groups using analysis of variance. P < 0.05 was considered significant. RESULTS: Mothers with moderate maternal age had a higher colostrum lipid concentration than those with younger or advanced maternal age (2.3 mg, SD = 1.4 mg vs. 1.5 mg, SD = 1.0 mg vs. 1.6 mg, SD = 0.9 mg, respectively; p = 0.007). Lactose and protein contents in the analyzed samples did not differ among the three study groups. CONCLUSION: This study lends support to the potential variation of lipids in colostrum by maternal age and suggests individual adaptation to the nutritional components of milk to the needs of the infant may be beneficial.

Soybean Isoflavones Ameliorates Lactation Performance in Postpartum Mice by Alleviating Oxidative Stress and Regulating Gut Microflora.

Postpartum dysgalactiae syndrome (PPDS) is one of the key issues affecting breastfeeding, usually occurring as breast swelling, a low milk yield, and at length a stop of breast milk secretion. Therefore, there is a need to investigate the effectiveness of Traditional Chinese Medicine (TCM) diet therapy in treating or preventing PPDS. This study aims to analyze the effect of soybean isoflavone (SIF), a natural estrogen found in plants, on postpartum lactation performance in mice and to evaluate its potential as a treatment for PPDS. Adult female BALB/c mice at 8 weeks of age (25 ± 3 g) are randomly divided into four groups fed with different levels of SIF and a normal diet for 14 days. SIF (0, 50, 100, 200 mg kg-1 BW) is provided via intra-gastric route to the experimental mice. Using a high-throughput sequencing of microbial diversity and mammary gland metabolites, it is found that SIF-treated mice potentially show an improved milk performance via enhanced antioxidant capacity and altered gut microbiota. SIF from plant sources at a high dosage promotes the lactation in normal postpartum mice.

Rumen-protected lysine supplementation improved amino acid balance, nitrogen utilization and altered hindgut microbiota of dairy cows.

This study was conducted to evaluate the effects of dietary crude protein (CP) and rumen-protected lysine (RPL) supplementation on lactation performance, amino acid (AA) balance, nitrogen (N) utilization and hindgut microbiota in dairy cows. Treatments were in a 2 × 2 factorial arrangement, and the main effects were CP concentration (16% vs. 18%) and RPL supplementation (with or without RPL at 40 g/cow per day). Forty cows were randomly allocated to 4 groups: low-CP diet (LP), low-CP diet plus RPL (LPL), high-CP diet (HP), high-CP diet plus RPL (HPL). The experiment was conducted for 8 weeks. Results showed that RPL increased the dry matter intake (P < 0.01), milk protein yield (P = 0.04) and energy corrected milk (P = 0.04), and tended to increase milk fat yield (P = 0.06) and fat corrected milk (P = 0.05). Cows in the HP group tended to have higher milk urea N (P = 0.07). Plasma concentrations of Arg, Ile, Lys, Met, Pro, total essential AA and total nonessential AA were increased by RPL (P < 0.05). The total essential AA, total nonessential AA and most AA (except Ile, Phe, Gly and Pro) were increased in the HP group (P < 0.05). N excretion was increased in the HP group through an increase in urea N excretion (P < 0.01) and an upward trend in plasma urea N (P = 0.07). In addition, RPL tended to increase milk protein N secretion (P = 0.08), milk N (P = 0.07) and microbial protein synthesis (P = 0.06), and decreased plasma urea N (P < 0.001). In the hindgut, the bacterial community were different between the LP and LPL groups (P < 0.01). The probiotic abundances of Christensenellaceae_R-7_group and Acinetobacter were increased by RPL (P = 0.03 and 0.03, respectively). The pathogenic abundances of Clostridium_sensu_stricto_1 (P < 0.001) and Turicibacter (P < 0.01) were decreased by RPL. In conclusion, supplementing RPL with low dietary CP could balance AA supply and increase milk protein yield, resulting in an improvement in N utilization efficiency, and altered the composition of the hindgut microbiota to favor the lactation performance of dairy cows.

Impact of Incorporating Free Calcium and Magnesium on the Heat Stability of a Dairy- and Soy-Protein-Containing Model Emulsion.

This study investigated the impact of calcium chloride (CaCl2) and magnesium chloride (MgCl2) at varying concentrations on a model milk formulation's physical and chemical properties after thermal treatment. The model milk was subjected to two-stage homogenization and pasteurization before being supplemented with different concentrations of CaCl2 or MgCl2. The findings revealed that elevating the concentration of either calcium or magnesium resulted in the milk emulsion having a higher viscosity and median particle size following heating. CaCl2 had a slightly stronger impact than MgCl2, particularly at higher concentrations. The milk samples also exhibited a reduction in the zeta potential as the ionic strength of the salt solution increased, with the CaCl2-fortified milk displaying a slightly lower negative surface charge than the MgCl2-fortified milk at the same dose. The model milk's viscosity was evaluated after adding various salt concentrations and a temperature ramp from 20 to 80 °C. Notably, the viscosity and particle size changes demonstrated a non-linear relationship with increasing mineral levels, where a significant increase was observed at or above 5.0 mM. An emulsion stability analysis also revealed that the de-stabilization pattern of the high salt concentration sample differed significantly from its low salt concentration counterparts. These findings could serve as a basis for the future development of fortified UHT milk with nutritionally beneficial calcium and magnesium in industrial applications.

Effects of supplementation with milk protein on glycemic parameters: a GRADE-assessed systematic review and dose-response meta-analysis.

BACKGROUND: It is suggested that supplementation with milk protein (MP) has the potential to ameliorate the glycemic profile; however, the exact impact and certainty of the findings have yet to be evaluated. This systematic review and dose-response meta-analysis of randomized controlled trials (RCTs) assessed the impact of MP supplementation on the glycemic parameters in adults. METHODS: A systematic search was carried out among online databases to determine eligible RCTs published up to November 2022. A random-effects model was performed for the meta-analysis. RESULTS: A total of 36 RCTs with 1851 participants were included in the pooled analysis. It was displayed that supplementation with MP effectively reduced levels of fasting blood glucose (FBG) (weighted mean difference (WMD): -1.83 mg/dL, 95% CI: -3.28, -0.38; P = 0.013), fasting insulin (WMD: -1.06 uU/mL, 95% CI: -1.76, -0.36; P = 0.003), and homeostasis model assessment of insulin resistance (HOMA-IR) (WMD: -0.27, 95% CI: -0.40, -0.14; P < 0.001) while making no remarkable changes in serum hemoglobin A1c (HbA1c) values (WMD: 0.01%, 95% CI: -0.14, 0.16; P = 0.891). However, there was a significant decline in serum levels of HbA1c among participants with normal baseline body mass index (BMI) based on sub-group analyses. In addition, HOMA-IR values were significantly lower in the MP supplement-treated group than their untreated counterparts in short- and long-term supplementation (≤ 8 and > 8 weeks) with high or moderate doses (≥ 60 or 30-60 g/d) of MP or whey protein (WP). Serum FBG levels were considerably reduced upon short-term administration of a low daily dose of WP (< 30 g). Furthermore, the levels of serum fasting insulin were remarkably decreased during long-term supplementation with high or moderate daily doses of WP. CONCLUSION: The findings of this study suggest that supplementation with MP may improve glycemic control in adults by reducing the values of fasting insulin, FBG, and HOMA-IR. Additional trials with longer durations are required to confirm these findings.

Relationships between dietary rumen-protected lysine and methionine with the lactational performance of dairy cows - A meta-analysis.

OBJECTIVE: Our objective was to examine the relationships of supplemental rumen-protected lysine (RPL) or lysine + methionine (RPLM) on lactational performance, plasma amino acids (AA) concentration, and nitrogen use efficiency of lactating dairy cows by using a meta-analysis approach. METHODS: A total of 56 articles comprising 77 experiments with either RPL or RPLM supplementation were selected and analyzed using a mixed model methodology by considering the treatments and other potential covariates as fixed effects and different experiments as random effects. RESULTS: In early lactating cows, milk yield was linearly increased by RPL (ß1 = 0.013; p<0.001) and RPLM (ß1 = 0.014; p<0.028) but 3.5% fat-corrected milk (FCM) and energy-corrected milk (ECM) (kg/d) was increased by only RPL. RPL and RPLM did not affect dry matter intake (DMI) but positively increased (p<0.05) dairy efficiency (Milk yield/DMI and ECM/DMI). As a percentage, milk fat, protein, and lactose were unchanged by RPL or RPLM but the yield of all components was increased (p<0.05) by feeding RPL while only milk protein was increased by feeding RPLM. Plasma Lys concentration was linearly increased (p<0.05) with increasing supplemental RPL while plasma Met increased (p<0.05) by RPLM supplementation. The increase in plasma Lys had a strong linear relationship (R2 = 0.693 in the RPL dataset and R2 = 0.769 in the RPLM dataset) on milk protein synthesis (g/d) during early lactation. Nitrogen metabolism parameters were not affected by feeding RPL or RPLM, either top-dress or when supplemented to deficient diets. Lactation performance did not differ between AA-deficient or AA-adequate diets in response to RPL or RPLM supplementation. CONCLUSION: RPL or RPLM showed a positive linear relationship on the lactational performance of dairy cows whereas greater improvement effects were observed during early lactation. Supplementing RPL or RPLM is recommended on deficient-AA diet but not on adequate-AA diet.

The skeletal safety of milk-derived proteins: A meta-analysis of randomized controlled trials.

PURPOSE: There has been a persistent claim that dairy products contain calcium-leaching proteins, although the soundness of such a claim has been challenged. A meta-analysis of randomized controlled trials (RCTs) on the effects of milk-derived protein supplementation on bone health indices in adults was performed to reconcile the controversy surrounding the potential skeletal safety concerns of proteins of dairy origin. METHODS: The PubMed and Web of Science databases were searched for relevant RCTs. A random-effects model was used to generate pooled effect sizes and 95% confidence intervals. RESULTS: Milk-derived protein supplementation did not significantly affect whole-body BMD (n = 7 RCTs) and BMD at the lumbar spine (n = 10), hip (n = 8), femoral neck (n = 9), trochanter (n = 5), intertrochanter (n = 2), and ultradistal radius (n = 2). The concentrations of bone formation markers (bone-specific alkaline phosphatase [n = 11], osteocalcin [n = 6], procollagen type 1 amino-terminal propeptide [n = 5]), bone resorption markers (N-terminal telopeptide of type 1 collagen [n = 7], C-terminal telopeptide of type 1 collagen [n = 7], deoxypyridinoline [n = 4]), and parathyroid hormone (n = 7) were not significantly affected. However, increased insulin-like growth factor-1 (IGF-1) concentrations (n = 13) were observed. Reduced IGF-1 concentrations were observed when soy protein was used as a comparator, and increased IGF-1 concentrations were observed when carbohydrate was used. CONCLUSION: Our findings do not support the claim that proteins of dairy origin are detrimental to bone health.

The effect of combined ß-lactoglobulin supplementation and resistance exercise training prior to limb immobilisation on muscle protein synthesis rates in healthy young adults: study protocol for a randomised controlled trial.

BACKGROUND: The decline in skeletal muscle mass experienced following a short-term period (days to weeks) of muscle disuse is mediated by impaired rates of muscle protein synthesis (MPS). Previous RCTs of exercise or nutrition prehabilitation interventions designed to mitigate disuse-induced muscle atrophy have reported limited efficacy. Hence, the aim of this study is to investigate the impact of a complex prehabilitation intervention that combines ß-lactoglobulin (a novel milk protein with a high leucine content) supplementation with resistance exercise training on disuse-induced changes in free-living integrated rates of MPS in healthy, young adults. METHODS/DESIGN: To address this aim, we will recruit 24 healthy young (18-45 years) males and females to conduct a parallel, double-blind, 2-arm, randomised placebo-controlled trial. The intervention group will combine a 7-day structured resistance exercise training programme with thrice daily dietary supplementation with 23 g of ß-lactoglobulin. The placebo group will combine the same training programme with an energy-matched carbohydrate (dextrose) control. The study protocol will last 16 days for each participant. Day 1 will be a familiarisation session and days 2-4 will be the baseline period. Days 5-11 represent the 'prehabilitation period' whereby participants will combine resistance training with their assigned dietary supplementation regimen. Days 12-16 represent the muscle disuse-induced 'immobilisation period' whereby participants will have a single leg immobilised in a brace and continue their assigned dietary supplementation regimen only (i.e. no resistance training). The primary endpoint of this study is the measurement of free-living integrated rates of MPS using deuterium oxide tracer methodology. Measurements of MPS will be calculated at baseline, over the 7-day prehabilitation period and over the 5-day immobilisation period separately. Secondary endpoints include measurements of muscle mass and strength that will be collected on days 4 (baseline), 11 (end of prehabilitation) and 16 (end of immobilisation). DISCUSSION: This novel study will establish the impact of a bimodal prehabilitation strategy that combines ß-lactoglobulin supplementation and resistance exercise training in modulating MPS following a short-term period of muscle disuse. If successful, this complex intervention may be translated to clinical practice with application to patients scheduled to undergo, for example, hip or knee replacement surgery. TRIAL REGISTRATION: NCT05496452. Registered on August 10, 2022. PROTOCOL VERSION: 16-12-2022/1.

Effect of Milk Protein and Whey Permeate in Large-Quantity Lipid-Based Nutrient Supplement on Early Child Development among Children with Stunting: A Randomized 2 × 2 Factorial Trial in Uganda.

Stunting affects 22% children globally, putting them at risk of adverse outcomes including delayed development. We investigated the effect of milk protein (MP) vs. soy and whey permeate (WP) vs. maltodextrin in large-quantity, lipid-based nutrient supplement (LNS), and LNS itself vs. no supplementation, on child development and head circumference among stunted children aged 1-5 years. We conducted a randomized, double-blind, community-based 2 × 2 factorial trial in Uganda (ISRCTN1309319). We randomized 600 children to one of four LNS formulations (~535 kcal/d), with or without MP (n = 299 vs. n = 301) or WP (n = 301 vs. n = 299), for 12 weeks or to no supplementation (n = 150). Child development was assessed using the Malawi Development Assessment Tool. Data were analyzed using linear mixed-effects models. Children had a median [interquartile range] age of 30 [23; 41] months and mean ± standard deviation height-for-age z-score of -3.02 ± 0.74. There were no interactions between MP and WP for any of the outcomes. There was no effect of either MP or WP on any developmental domain. Although LNS itself had no impact on development, it resulted in 0.07 (95%CI: 0.004; 0.14) cm higher head circumference. Neither dairy in LNS, nor LNS in itself, had an effect on development among already stunted children.

Milk protein ingestion does not enhance recovery from muscle-damaging resistance exercise in untrained males and females: a randomized controlled trial.

Milk-based proteins are a common choice of post-exercise nutrition to enhance exercise recovery and adaptation. Peri-exercise milk protein ingestion may attenuate exercise-induced muscle damage (EIMD), which is a particular risk to untrained individuals. However, most research has been conducted with males, and due to potential sex differences in EIMD, research with both sexes is required. This parallel-group randomized controlled trial examined the impact of milk protein ingestion on recovery from EIMD. Untrained males and females performed a single bout of leg-based resistance exercise and consumed a milk protein (MILK-PRO: n = 4 males, n = 8 females) or isoenergetic control (CON: n = 4 males, n = 8 females) supplement over 4 days post-exercise (17 doses total). Maximum strength was assessed ≥3 wk pre- and 72 and 168 h post-exercise, and measures of leg circumference, range of motion, muscle soreness, pressure-pain threshold (PPT), and serum creatine kinase concentration ([CK]) were conducted pre-, immediately post-, and 24, 48, 72, and 168 h post-exercise. Resistance exercise induced mild muscle damage that was not attenuated with MILK-PRO relative to CON. Peak increases in [CK] and reductions in PPT were greater in males compared with females. Changes in other markers were comparable between sexes. We conclude that moderate resistance exercise in naïve individuals induces muscle damage without compromising muscle strength. We support sex differences in EIMD and emphasize the need for further research with both sexes. Milk protein ingestion was not beneficial for recovery from EIMD, thus alternative management strategies should be investigated. This trial was prospectively registered at ClinicalTrials.gov PRS (protocol ID: 290580A).

Increased Amino Acid Absorption Mediated by Lacticaseibacillus rhamnosus IDCC 3201 in High-Protein Diet-Fed Mice.

The use of dietary protein products has increased with interests in health promotion, and demand for sports supplements. Among various protein sources, milk protein is one of the most widely employed, given its economic and nutritional advantages. However, recent studies have revealed that milk protein undergoes fecal excretion without complete hydrolysis in the intestines. To increase protein digestibility, heating and drying were implemented; however, these methods reduce protein quality by causing denaturation, aggregation, and chemical modification of amino acids. In the present study, we observed that Lacticaseibacillus rhamnosus IDCC 3201 actively secretes proteases that hydrolyze milk proteins. Furthermore, we showed that co-administration of milk proteins and L. rhamnosus IDCC 3201 increased the digestibility and plasma concentrations of amino acids in a high-protein diet mouse model. Thus, food supplementation of L. rhamnosus IDCC 3201 can be an alternative strategy to increase the digestibility of proteins.

Antioxidant pectins from eggplant (Solanum melongena) fruit exocarp, calyx and flesh isolated through high-power ultrasound and sodium carbonate.

Dried and milled eggplant fruit peel and calyces (PC) and mesocarp, placenta and core (Mes) were utilized as natural sources of valuable chemicals. Pectins were extracted with 0.1 M Na2CO3 (1 h; 23 °C). A high-power ultrasound (US) pretreatment (10 min net time; 12.76 W/cm2 power intensity) in 10:200 (g/mL) powder:water ratio led to the lowest solvent and energy consumptions after the subsequent 0.1 M Na2CO3 stirring, permitting the highest recoveries of uronic acid (UA) from PC and Mes (80.25 and 93.8 %, respectively). Homogalacturonans (>65 % w/w UA) of low degree of methylesterification, of acetylation, and 90,214-138,184 Da molecular weights with low polydispersity (≈1.32-1.40) were obtained. They included released ferulate (≈3.5 mg/100 g) esterified pectins. Antioxidants (caffeoylquinic acid, putrescine and spermidine derivatives, ß-carotene, lutein) gave additional technological value to their thickening effect as pectins protected tryptophan, tyrosine, alkyl side chains and sulfhydryl of skim milk proteins from UV-C photo-oxidation.

The long-term clinical course of protein-losing enteropathy combined with iron deficiency anemia in Korean toddlers: Possible association with cow's milk protein.

BACKGROUND: Protein-losing enteropathy (PLE), a rare condition with excessive gastrointestinal protein loss, presents with hypoalbuminemia, edema, or ascites. Several cases of PLE combined with severe iron deficiency anemia (IDA) have been reported in infants and toddlers that were considered to result from excessive cow's milk consumption, although the mechanism has not been clearly established. METHODS: We retrospectively reviewed the clinical, laboratory, endoscopic, and radiologic characteristics of patients diagnosed and treated for PLE with IDA between 2015 and 2021. Long-term outcomes were analyzed according to dietary intervention during the follow-up period. RESULTS: A total of 10 patients aged 7.0-26.7 months were enrolled in the study and the median follow-up duration of them was 9.4 months (range, 1.3-18.0). Six of them were fed powdered formula, while two were fed whole cow's milk, and their median daily intake was 700 mL (range, 300-900). The times to normalization of hemoglobin, albumin, and eosinophil count were shorter in patients with dietary elimination of cow's milk protein immediately after diagnosis compared to those with reduced intake or no dietary change. CONCLUSION: Early complete elimination of cow's milk protein should be considered, especially if the laboratory parameters are not normalized with adequate iron supplementation even though the clinical symptoms show improvement. We would like to draw attention to the possibility of the cow's milk protein in the pathogenesis of the condition through the non-IgE-mediated immune reactions.

Milk-cereal mix supplementation during infancy and impact on neurodevelopmental outcomes at 12 and 24 months of age: a randomised controlled trial in India.

Inadequate protein intake and lack of micronutrients may affect neurodevelopment in infants. This randomised controlled trial was conducted to measure the effect of two milk-cereal mixes with modest and high amounts of protein and enriched with multiple micronutrients, given between 6 and 12 months, on cognitive, language, motor and behavioural scores at 12 and 24 months of age, compared with no-supplementation. The two supplements were also compared with each other. The study was conducted in urban Delhi, India, and the infants were randomised in a 1:1:1 ratio to the three study groups. At 12 and 24 months of age, 1134 and 1214 children were available, respectively. At 12 months of age, compared with no-supplement group, an increase in the motor scores (mean difference, MD 1·52, 95 % CI: 0·28, 2·75) and a decrease in the infant temperament scores (MD - 2·76, 95 % CI: -4·23, -1·29) in the modest-protein group was observed. Those in the high-protein group had lower socio-emotional scores (MD - 1·40, 95 % CI: -2·43, -0·37) and higher scores on Infant Temperament Scale (MD 2·05, 95 % CI: 0·62, 3·48) when compared with modest-protein group. At 24 months, no significant differences in any of the neurodevelopment scores between the three study groups was found. In conclusion, supplementation with modest amount of protein and multiple micronutrients may lead to short-term small improvements in motor function and infant temperament. There appears no advantage of supplementing with high protein, rather negative effects on infant behaviour were observed.

Milk Protein Hydrolysis by Actinidin-Kinetic and Thermodynamic Characterisation and Comparison to Bromelain and Papain.

Plant proteases, including actinidin, papain and bromelain, have been widely used in the food industry but with limited application in dairy systems. This research aimed to establish and compare operational parameters (kinetics, temperature, enzyme type, time and thermodynamics) relevant to the applications of these enzymes in the hydrolysis of whey protein isolates (WPI), whey protein concentrates (WPC) or milk protein concentrates (MPC). The degree of hydrolysis (DH) increased with the rise in temperature, and the maximum DH was achieved at 60 °C for all three dairy systems. The addition of papain resulted in a greater %DH of whey proteins in comparison to bromelain. The cleavage of proteins was clearly time-dependent (p < 0.05), while the pH did not change significantly (p > 0.05) during this time. PAGE analysis revealed that all three enzymes mainly acted on α-lactalbumin and αs-casein in WPI and MPC, respectively. Kinetic parameters from the Lineweaver-Burk plot at 60 °C using WPC and MPC as a substrate varied widely, establishing that WPC hydrolysis was characterised by a lower KM, higher kcat, kcat/KM and Vmax compared to MPC in the case of all three enzymes. The difference in kcat/KM values amongst all enzymes (actinidin > papain > bromelain) indicated the difference in the strength of substrate binding sites. The thermodynamic parameters of these enzymes with MPC and WPC were also determined at a temperature range of 15-60 °C, and the results indicate the potential application of papain and actinidin in the dairy industry.

Increased protein intake derived from leucine-enriched protein enhances the integrated myofibrillar protein synthetic response to short-term resistance training in untrained men and women: a 4-day randomized controlled trial.

Leucine is a critical amino acid stimulating myofibrillar protein synthesis (MyoPS). The consumption of higher leucine-containing drinks stimulates MyoPS, but we know less about higher leucine solid foods. Here, we examined the effect of short-term resistance exercise training (STRT) combined with supplementation of a protein and leucine-enriched bar, compared with STRT alone, on integrated (%/day) rates of MyoPS and anabolic protein signaling. In a nonblinded, randomized crossover trial, eight young adults performed four sessions of STRT without or while consuming the study bar (STRT+Leu, 16 g of protein containing ∼3 g of leucine) for two 4-day phases, separated by 2 days nonexercise (Rest) washout. In combination with serial muscle biopsies, deuterated water permitted the measurement of MyoPS and protein signaling phosphorylation. MyoPS during STRT (1.43 ± 0.06%/day) and STRT+Leu (1.53 ± 0.06%/day) were greater than Rest (1.31 ± 0.05%/day), and MyoPS during STRT+Leu (1.53 ± 0.06%/day) was greater than STRT alone (1.43 ± 0.06%/day). STRT+Leu increased the ratio of phosphorylated to total mechanistic target of rapamycin and 4EBP1 compared to Rest. Engaging in STRT increased integrated MyoPS and protein signaling in young adults and was enhanced with increased protein intake derived from a leucine-enriched protein bar. This study was registered at clinicaltrials.gov as NCT03796897.

Effects of pigeon pea leaves and concentrate mixture on feed intake, milk yield, and composition of crossbred dairy cows fed native pasture hay.

Protein supplements are expensive and not easily accessible under small-scale livestock production systems in Ethiopia and other developing countries, which necessitates investigating the alternative protein sources for cost-effective livestock production. Pigeon pea (Cajanus cajan L. Millsp) leaves (PPLs) are rich in protein and are well-suited for feeding small ruminants; however, the effect of inclusion of PPL in the concentrate mixture (CM) on the performance of dairy cows was not well documented. This experiment was conducted to evaluate the effect of supplementation of PPL and CM to native pasture hay-based rations on feed intake, milk yield and composition, and blood metabolites of crossbred dairy cows (Holstein × Zebu). A 4 × 4 Latin square design with three replications, balanced for carryover effects, was used for this study. The treatments included native pasture hay provided ad libitum as a basal diet, supplemented with a CM alone (T1), the inclusion of 10% of PPL in the CM (T2), 20% PPL in the CM (T3), or 30% PPL in the CM (T4). Supplements were isocaloric and isonitrogenous. Total DM intake (hay + supplement intake) was similar (P > 0.05) among treatments. Hay intake was greater (P = 0.05) for T1 and T2 than for T4, while supplement intake was the least for T1 (P < 0.05). The treatment groups T2, T3, and T4, where PPL was included, had similar (P > 0.05) supplement intake. Feed intake, milk yield and composition, feed conversion efficiency, body condition score, serum total protein, albumin, globulin, glucose, triglyceride, urea N, creatinine, and cholesterol were similar (P > 0.05) among treatments. The inclusion of up to 30% of PPL in the CM resulted in a comparable performance of crossbred dairy cows as supplementation with CM under the conditions of the current experiment. Therefore, further study is required to evaluate the effect of the inclusion of a higher level of PPL in the concentrate mixture on the performance of lactating crossbred dairy cows.

Effect of 24-Week, Late-Evening Ingestion of a Calcium-Fortified, Milk-Based Protein Matrix on Biomarkers of Bone Metabolism and Site-Specific Bone Mineral Density in Postmenopausal Women with Osteopenia.

Dietary calcium intake is a modifiable, lifestyle factor that can affect bone health and the risk of fracture. The diurnal rhythm of bone remodelling suggests nocturnal dietary intervention to be most effective. This study investigated the effect of daily, bed-time ingestion of a calcium-fortified, milk-derived protein matrix (MBPM) or control (CON), for 24 weeks, on serum biomarkers of bone resorption (C-terminal telopeptide of type I collagen, CTX) and formation (serum pro-collagen type 1 N-terminal propeptide, P1NP), and site-specific aerial bone mineral density (BMD), trabecular bone score (TBS), in postmenopausal women with osteopenia. The MBPM supplement increased mean daily energy, protein, and calcium intake, by 11, 30, and 107%, respectively. 24-week supplementation with MBPM decreased CTX by 23%, from 0.547 (0.107) to 0.416 (0.087) ng/mL (p < 0.001) and P1NP by 17%, from 60.6 (9.1) to 49.7 (7.2) µg/L (p < 0.001). Compared to CON, MBPM induced a significantly greater reduction in serum CTX (mean (CI95%); −9 (8.6) vs. −23 (8.5)%, p = 0.025 but not P1NP −19 (8.8) vs. −17 (5.2)%, p = 0.802). No significant change in TBS, AP spine or dual femur aerial BMD was observed for CON or MBPM. This study demonstrates the potential benefit of bed-time ingestion of a calcium-fortified, milk-based protein matrix on homeostatic bone remodelling but no resultant treatment effect on site-specific BMD in postmenopausal women with osteopenia.