Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.329
Filtrar
1.
Nat Commun ; 12(1): 632, 2021 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-33504791

RESUMO

Consuming the milk of other species is a unique adaptation of Homo sapiens, with implications for health, birth spacing and evolution. Key questions nonetheless remain regarding the origins of dairying and its relationship to the genetically-determined ability to drink milk into adulthood through lactase persistence (LP). As a major centre of LP diversity, Africa is of significant interest to the evolution of dairying. Here we report proteomic evidence for milk consumption in ancient Africa. Using liquid chromatography tandem mass spectrometry (LC-MS/MS) we identify dairy proteins in human dental calculus from northeastern Africa, directly demonstrating milk consumption at least six millennia ago. Our findings indicate that pastoralist groups were drinking milk as soon as herding spread into eastern Africa, at a time when the genetic adaptation for milk digestion was absent or rare. Our study links LP status in specific ancient individuals with direct evidence for their consumption of dairy products.


Assuntos
Indústria de Laticínios , Comportamento Alimentar , Proteínas do Leite/metabolismo , África Oriental , Sequência de Aminoácidos , Animais , Arqueologia , Osso e Ossos/metabolismo , Bovinos , Colágeno/metabolismo , Cálculos Dentários/metabolismo , Geografia , Humanos , Marcação por Isótopo , Lactase/metabolismo , Lactoglobulinas/química , Proteínas do Leite/química , Modelos Moleculares
2.
Food Chem ; 340: 128154, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33010641

RESUMO

Numerous bacteria are responsible for hydrolysis of proteins during cheese ripening. The raw milk flora is a major source of bacterial variety, starter cultures are needed for successful acidification of the cheese and proteolytic strains like Lactobacillus helveticus, are added for flavor improvement or acceleration of ripening processes. To study the impact of higher bacterial diversity in cheese on protein hydrolysis during simulated human digestion, Raclette-type cheeses were produced from raw or heat treated milk, with or without proteolytic L. helveticus and ripened for 120 days. Kinetic processes were studied with a dynamic (DIDGI®) in vitro protocol and endpoints with the static INFOGEST in vitro digestion protocol, allowing a comparison of the two in vitro protocols at the level of gastric and intestinal endpoints. Both digestion protocols resulted in comparable peptide patterns after intestinal digestion and higher microbial diversity in cheeses led to a more diverse peptidome after simulated digestion.


Assuntos
Queijo/microbiologia , Proteínas do Leite/metabolismo , Leite/microbiologia , Aminoácidos/análise , Animais , Queijo/análise , Cromatografia Líquida de Alta Pressão , Digestão , Microbiologia de Alimentos , Humanos , Lactobacillus helveticus/genética , Lactobacillus helveticus/crescimento & desenvolvimento , Lactobacillus helveticus/metabolismo , Espectrometria de Massas , Leite/metabolismo , Peptídeos/análise , Proteólise , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo
3.
Food Chem ; 339: 128099, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33152884

RESUMO

Microbial diversity in kefir grains is responsible for the production of goat milk kefir with unique peptides composition and volatile profile. High-throughput sequencing technique was used to analyze bacterial and fungal diversity of three different kefir grains which were originated from China, Europe Germany and United States. Peptides and volatile profile in goat milk kefir were determined by proteomic platform and Gas Chromatography-Ion Mobility Spectrometry, respectively. Clustering analysis indicated that the different content of Lactobacillus genera in different kefir grains was highly associated with the proteolytic ability in goat milk kefir. Contents of volatile compounds in goat milk kefir were also correlated to the bacteria and fungi in kefir grains (especially for Lactobacillus spp. and Saccharomyces spp.). The innovation of this study was to find a new way in exploration of the correlation of microbiota in kefir grains with the proteolytic ability and volatile profile of goat milk kefir.


Assuntos
Kefir/análise , Kefir/microbiologia , Proteínas do Leite/análise , Compostos Orgânicos Voláteis/análise , Animais , Bactérias/genética , China , Europa (Continente) , Microbiologia de Alimentos , Fungos/genética , Alemanha , Cabras , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillus/genética , Microbiota/genética , Leite/microbiologia , Proteínas do Leite/metabolismo , Proteólise , Saccharomyces/genética , Estados Unidos
4.
Int J Food Microbiol ; 335: 108903, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33065381

RESUMO

Societal demand for plant-based foods is increasing. In this context, soya products fermented using lactic acid bacteria (LAB) are appealing because of their potential health and nutritional benefits. The thermophilic LAB Streptococcus thermophilus is an essential starter species in the dairy industry. However, while its physiology is well characterized, little is known about its general metabolic activity or its techno-functional properties when it is grown in soya milk. In this study, S. thermophilus LMD-9 growth, sugar production, and lactic acid production in soya milk versus cow's milk were measured. Additionally, the main metabolic pathways used by the bacterium when growing in soya milk were characterized using a proteomic approach. Streptococcus thermophilus LMD-9 growth decreased soya milk pH, from 7.5 to 4.9, in 5 h. During fermentation, acidification thus occurred in tandem with lactate production and increasing population size (final population: 1.0 × 109 CFU/ml). As growth proceeded, sucrose was consumed, and fructose was produced. The proteomic analysis (LC-MS/MS) of the strain's cytosolic and cell envelope-associated proteins revealed that proteins related to amino acid transport and nitrogen metabolism were the most common among the 328 proteins identified (63/328 = 19.2% of total proteins). The cell-wall protease PrtS was present, and an LMD-9 deletion mutant was constructed by interrupting the prtS gene (STER_RS04165 locus). Acidification levels, growth levels, and final population size were lower in the soya milk cultures when the ΔprtS strain versus the wild-type (wt) strain was used. The SDS-PAGE profile of the soluble proteins in the supernatant indicated that soya milk proteins were less hydrolyzed by the ΔprtS strain than by the wt strain. It was discovered that S. thermophilus can grow in soya milk by consuming sucrose, can hydrolyze soya proteins, and can produce acidification levels comparable to those in cow's milk. This study comprehensively examined the proteomics of S. thermophilus grown in soya milk and demonstrated that the cell-wall protease PrtS is involved in the LAB's growth in soya milk and in the proteolysis of soya proteins, which are two novel findings. These results clarify how S. thermophilus adapts to soya milk and can help inform efforts to develop new fermented plant-based foods with better-characterized biochemical and microbiological traits.


Assuntos
Proteínas de Bactérias/metabolismo , Serina Endopeptidases/metabolismo , Leite de Soja/metabolismo , Streptococcus thermophilus/crescimento & desenvolvimento , Streptococcus thermophilus/metabolismo , Animais , Fermentação , Ácido Láctico/análise , Ácido Láctico/metabolismo , Redes e Vias Metabólicas , Leite/química , Leite/metabolismo , Leite/microbiologia , Proteínas do Leite/metabolismo , Nitrogênio/metabolismo , Proteômica , Leite de Soja/química , Proteínas de Soja/metabolismo , Streptococcus thermophilus/enzimologia , Sacarose/metabolismo , Açúcares/análise , Açúcares/metabolismo
5.
Proc Natl Acad Sci U S A ; 117(38): 23925-23931, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32900929

RESUMO

Medin is the most common amyloid known in humans, as it can be found in blood vessels of the upper body in virtually everybody over 50 years of age. However, it remains unknown whether deposition of Medin plays a causal role in age-related vascular dysfunction. We now report that aggregates of Medin also develop in the aorta and brain vasculature of wild-type mice in an age-dependent manner. Strikingly, genetic deficiency of the Medin precursor protein, MFG-E8, eliminates not only vascular aggregates but also prevents age-associated decline of cerebrovascular function in mice. Given the prevalence of Medin aggregates in the general population and its role in vascular dysfunction with aging, targeting Medin may become a novel approach to sustain healthy aging.


Assuntos
Envelhecimento/metabolismo , Amiloide/metabolismo , Antígenos de Superfície/metabolismo , Proteínas do Leite/metabolismo , Doenças Vasculares/metabolismo , Idoso de 80 Anos ou mais , Amiloide/genética , Animais , Antígenos de Superfície/genética , Aorta/metabolismo , Aorta/patologia , Química Encefálica/fisiologia , Circulação Cerebrovascular/fisiologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Leite/genética , Doenças Vasculares/patologia
6.
Anim Sci J ; 91(1): e13441, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32885570

RESUMO

Microbiota of individual cow milk, bulk tank milk, and feces of Jersey cows were examined. Samples were collected from two farms (F1 and F2) in cool (November, Nov) and hot (July, Jul) seasons. Milk yield and milk composition were similar between the two farms and between the two seasons. Prevalent taxa of the fecal microbiota, i.e. Ruminococcaceae, Bacteroidaceae, Lachnospiraceae, Rikenellaceae, and Clostridiaceae, were unaffected by the farm and season. Relative abundance of milk microbiota for Pseudomonadaceae, Enterobacteriaceae, and Streptococcaceae (F1 > F2) and Lactobacillaceae, Bifidobacteriaceae, and Cellulomonadaceae (F1 < F2) were different between the two farms, and those for Staphylococcaceae, Bacillaceae, Ruminococcaceae, and Veillonellaceae (Nov < Jul) and Methylobacteriaceae and Moraxellaceae (Nov > Jul) were different between the two seasons. The microbiota of bulk tank milk was numerically different from that of individual cow milk. Principal coordinate analysis indicated that the milk microbiota was unrelated to the fecal microbiota. The finding that relative abundance of Pseudomonadaceae and Moraxellaceae appeared greater than those reported for Holstein milk suggested that higher protein and fat content may result in a greater abundance of proteolytic and lipolytic taxa in Jersey cow milk.


Assuntos
Bovinos/metabolismo , Bovinos/microbiologia , Temperatura Baixa , Indústria de Laticínios , Fazendas , Gorduras/metabolismo , Fezes/microbiologia , Temperatura Alta , Proteínas do Leite/metabolismo , Leite/metabolismo , Leite/microbiologia , Estações do Ano , Animais , Feminino , Moraxellaceae , Proteólise , Pseudomonadaceae
7.
J Dairy Sci ; 103(8): 7110-7123, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32505393

RESUMO

Hydrolyzed feather meal (HFM) is high in crude protein, most of which bypasses rumen degradation when fed to lactating dairy cows, allowing direct supply of AA to the small intestine. Compared with other feeds that are high in bypass protein, such as blood meal or heat-treated soybean meal, HFM is low in His and Lys. The objectives of this study were to determine the effects of supplementing rumen-protected (RP) Lys and His individually or in combination in a diet containing 5% HFM on milk production and composition as well as energy and N partitioning. Twelve multiparous Jersey cows (mean ± SD: 91 ± 18 d in milk) were used in a triplicated 4 × 4 Latin square with 4 periods of 28 d (24-d adaptation and 4-d collection). Throughout the experiment, all cows were fed the same TMR, with HFM included at 5% of diet DM. Cows were grouped by dry matter intake and milk yield, and cows within a group were randomly assigned to 1 of 4 treatments: no RP Lys or RP His; RP Lys only [70 g/d of Ajipro-L (24 g/d of digestible Lys), Ajinomoto Co. Inc., Tokyo, Japan]; RP His only [32 g/d of experimental product (7 g/d of digestible His), Balchem Corp., New Hampton, NY]; or both RP Lys and His. Plasma Lys concentration increased when RP Lys was supplemented without RP His (77.7 vs. 66.0 ± 4.69 µM) but decreased when RP Lys was supplemented with RP His (71.4 vs. 75.0 ± 4.69 µM). Plasma concentration of 3-methylhistidine decreased with RP Lys (3.19 vs. 3.40 ± 0.31 µM). With RP His, plasma concentration of His increased (21.8 vs. 18.7 ± 2.95 µM). For milk production and milk composition, no effects of Lys were observed. Supplementing RP His increased milk yield (22.5 vs. 21.6 ± 2.04 kg/d) and tended to increase milk protein yield (0.801 vs. 0.772 ± 0.051 kg/d). Across treatments, dry matter intake (18.5 ± 0.83 kg/d) and energy supply (32.2 ± 2.24 Mcal of net energy for lactation) were not different. Supplementing RP His did not affect N utilization; however, supplementing RP Lys increased N balance (25 vs. 16 ± 9 g/d). The lack of production responses to RP Lys suggests that Lys was not limiting or that the increase in Lys supply was not large enough to cause an increase in milk protein yield. However, increased N balance and decreased 3-methylhistidine with RP Lys suggest that increased Lys supply increased protein accretion and decreased protein mobilization. Furthermore, His may be a limiting AA in diets containing HFM.


Assuntos
Bovinos/psicologia , Suplementos Nutricionais/análise , Histidina/administração & dosagem , Lisina/administração & dosagem , Leite/metabolismo , Nitrogênio/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Ingestão de Alimentos , Plumas , Feminino , Histidina/sangue , Lactação/efeitos dos fármacos , Lisina/sangue , Metilistidinas/sangue , Proteínas do Leite/metabolismo , Distribuição Aleatória , Rúmen/metabolismo , Soja
8.
J Dairy Sci ; 103(8): 7431-7450, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32475659

RESUMO

Rations including high amounts of corn silage are currently very common in dairy production. Diets with corn silage as forage source result in a low supply of essential fatty acids, such as α-linolenic acid, and may lead to low conjugated linoleic acid (CLA) production. The present study investigated the effects of abomasal infusion of essential fatty acids, especially α-linolenic acid, and CLA in dairy cows fed a corn silage-based diet on performance, milk composition, including fatty acid (FA) pattern, and lipid metabolism from late to early lactation. Rumen-cannulated Holstein cows (n = 40) were studied from wk 9 antepartum to wk 9 postpartum and dried off 6 wk before calving. The cows were assigned to 1 of 4 treatment groups. Cows were abomasally supplemented with coconut oil (CTRL, 76 g/d), linseed and safflower oil (EFA, 78 and 4 g/d; linseed/safflower oil ratio = 19.5:1; n-6/n-3 FA ratio = 1:3), Lutalin (CLA, 38 g/d; BASF SE, Ludwigshafen, Germany; isomers cis-9,trans-11 and trans-10,cis-12 each 10 g/d) or EFA+CLA. Milk composition was analyzed weekly, and blood samples were taken several times before and after parturition to determine plasma concentrations of metabolites related to lipid metabolism. Liver samples were obtained by biopsy on d 63 and 21 antepartum and on d 1, 28, and 63 postpartum to measure triglyceride concentration. Body composition was determined after slaughter. Supplementation of CLA reduced milk fat concentration, increased body fat mass, and improved energy balance (EB) in late and early lactation, but EB was lowest during late lactation in the EFA group. Cows with CLA treatment alone showed an elevated milk citrate concentration in early lactation, whereas EFA+CLA did not reveal higher milk citrate but did have increased acetone. Milk protein was increased in late lactation but was decreased in wk 1 postpartum in CLA and EFA+CLA. Milk urea was reduced by CLA treatment during the whole period. After calving, the increase of nonesterified fatty acids in plasma was less in CLA groups; liver triglycerides were raised lowest at d 28 in CLA groups. Our data confirm an improved metabolic status with CLA but not with exclusive EFA supplementation during early lactation. Increased milk citrate concentration in CLA cows points to reduced de novo FA synthesis in the mammary gland, but milk citrate was less affected in EFA+CLA cows, indicating that EFA supplementation may influence changes in mammary gland FA metabolism achieved by CLA.


Assuntos
Abomaso , Bovinos/fisiologia , Suplementos Nutricionais , Ácidos Graxos Essenciais/farmacologia , Animais , Composição Corporal/efeitos dos fármacos , Bovinos/sangue , Dieta/veterinária , Ácidos Graxos Essenciais/administração & dosagem , Ácidos Graxos não Esterificados/sangue , Feminino , Lactação/efeitos dos fármacos , Ácidos Linoleicos Conjugados/farmacologia , Leite , Proteínas do Leite/metabolismo , Período Pós-Parto , Gravidez , Rúmen/metabolismo
9.
J Dairy Sci ; 103(8): 7210-7221, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32475662

RESUMO

The objective of this study was to analyze the impact of incorporating enteric methane into the breeding objective of dairy cattle in Spain, and to evaluate both genetic and economic response of traits in the selection index under 4 scenarios: (1) the current ICO (Spanish total merit index), used as benchmark; (2) a hypothetical penalization of methane emissions through a carbon tax; (3) considering methane as a net energy loss for the animal; and (4) desired genetic response to reduce methane production by 20% in 10 yr. A bio-economic model was developed to derive the economic values for production and methane traits in each scenario. The estimated economic values for methane were estimated at -€1.21/kg and -€0.32/kg for scenarios 2 and 3, respectively. When merged with other traits in the selection index, methane had less economic importance (1-5%) than milk protein yield (39-42%) or milk fat yield (27-28%). Under these scenarios, selection resulted in an unfavorable response in methane emissions when it was included with an economic weight, with an increase in methane estimated from 0.52 to 0.60 kg/cow per year. Small differences in total profit per cow per year were observed between indices. The incorporation of methane production into the breeding objective had a negligible effect on production, with minor reductions in the expected genetic gain for fat and protein yields and in total economic benefits. However, total methane emissions in the dairy industry in Spain were estimated to decrease between 2 and 5% in the next 10 yr due to positive genetic trends for milk yield and an expected decrease in the total number of dairy cows. Additionally, methane intensity per 1 billion liters of milk would decrease in all scenarios. The uncertainty in the genetic parameters of methane and in carbon prices were tested in a sensitivity analysis, resulting in small deviations from the benchmark scenario. A major effect was observed only under the desired genetic response scenario. In this case, it was possible to achieve a 20% reduction of methane production in 10 yr via selective breeding but at the expense of a larger ad hoc weight (33%) of methane in the selection index and decelerating the genetic gain for production traits from 6 to 18%. This study shows the potential of including environmental traits in the selection indices while retaining populations profitable for producers.


Assuntos
Bovinos/genética , Metano/metabolismo , Leite/metabolismo , Seleção Genética , Animais , Cruzamento , Bovinos/fisiologia , Indústria de Laticínios , Feminino , Objetivos , Gases de Efeito Estufa , Lactação , Proteínas do Leite/metabolismo , Modelos Econômicos , Fenótipo , Espanha
10.
J Dairy Sci ; 103(8): 6858-6868, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32534931

RESUMO

Milk that does not coagulate after rennet addition, also called noncoagulating (NC) milk, is unwanted in cheese production due to prolonged processing time. Amounts of whey and casein proteins, genetic variants, as well as posttranslational modifications (PTM) of proteins are all contributing factors in rennet-induced coagulation of milk. In this study, we conducted a wide-ranging investigation of milk proteins in milk samples from 616 Swedish Red dairy cattle using liquid chromatography-high resolution mass spectrometry. Relative concentration of proteins, genetic variants, and PTM were compared between NC milk and coagulating milk. The PTM investigated were phosphorylation of caseins and glycosylation of κ-casein. Several genetic variants and PTM were found, including rare phosphorylation variants of the αS-caseins. Genetic variants were found to effect the expressed amount of different proteins. Further, the effect of protein amounts and PTM on a binary NC milk trait was modeled using a generalized linear model. The model showed that NC milk significantly correlated with higher relative concentrations of α-lactalbumin and ß-casein and lower relative concentrations of ß-lactoglobulin and κ-casein. Regarding PTM of caseins, an effect on NC milk from a lower relative concentration of αS1-casein with 8 phosphate groups were found, even though an effect from total relative concentration of αS1-casein was not found. This study has provided insights into protein variants and PTM important for NC milk to improve this undesirable property.


Assuntos
Proteínas do Leite/metabolismo , Leite/química , Processamento de Proteína Pós-Traducional , Animais , Caseínas/química , Bovinos , Cromatografia Líquida , Quimosina/química , Feminino , Genótipo , Lactalbumina/metabolismo , Lactoglobulinas/metabolismo , Espectrometria de Massas , Fosforilação , Suécia
11.
Clin Interv Aging ; 15: 695-714, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32546988

RESUMO

Skeletal muscle aging manifests as a decline in muscle quantity and quality that accelerates with aging, increasing the risk of sarcopenia. Sarcopenia is characterized by a loss of muscle strength and mass, and contributes to adverse health outcomes in older adults. Intervention studies have shown that sarcopenia may be treated by higher protein intake in combination with resistance exercise (RE). In comparison, less is known about the role of whole protein-containing foods in preventing or treating sarcopenia. Liquid milk contains multiple nutrients and bioactive components that may be beneficial for muscle, including proteins for muscle anabolism that, alone or with RE, may have myoprotective properties. However, there is a lack of evidence about the role of milk and its effects on muscle aging. This narrative review considers evidence from three observational and eight intervention studies that used milk or fortified milk, with or without exercise, as an intervention to promote muscle health and function in older adults (aged 50-99 years). The observational studies showed no association between higher habitual milk consumption and muscle-related outcomes. The results of intervention studies using fortified milk in relation to elements of sarcopenia were also negative, with further inconclusive results from the studies using a combination of (fortified) milk and exercise. Although milk contains nutrients that may be myoprotective, current evidence does not show beneficial effects of milk on muscle health in older adults. This could be due to high habitual protein intakes (>1.0 g/kg BW/d) in study participants, differences in the type of milk (low-fat vs whole) and timing of milk consumption, length of interventions, as well as differences in the sarcopenia status of participants in trials. Adequately powered intervention studies of individuals likely to benefit are needed to test the effectiveness of a whole food approach, including milk, for healthy muscle aging.


Assuntos
Envelhecimento/fisiologia , Senescência Celular/fisiologia , Proteínas do Leite/metabolismo , Músculo Esquelético/fisiologia , Sarcopenia , Idoso , Exercício Físico/fisiologia , Comportamento Alimentar , Humanos , Força Muscular , Estudos Observacionais como Assunto , Sarcopenia/fisiopatologia , Sarcopenia/prevenção & controle
13.
J Dairy Sci ; 103(7): 6627-6634, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32389479

RESUMO

The l-type amino acid transporter 1 (LAT1; also known as SLC7A5) is a transporter that allows the uptake of large neutral amino acids into mammalian cells. In dairy cows, LAT1 is highly expressed in lactating mammary tissues and involved in milk protein synthesis. Prolactin (PRL) has a lactogenic role and is capable of inducing milk production in ruminants. However, the relationship between PRL stimulation and LAT1 expression in dairy cow mammary gland has not been well understood. In this study, we showed that PRL stimulation increased expression of LAT1 and ß-casein in mammary epithelial cells of dairy cows. The stimulatory effect of PRL on milk protein production was inhibited by LAT1-specific inhibitor or LAT1 knockdown, suggesting that PRL-induced milk protein production is involved in LAT1 expression. To determine whether the PRL signaling pathway participates in regulation of LAT1 expression, PRLR (PRL receptor) or STAT5 (signal transducer and activator of transcription 5) was knocked down by short interfering (si)RNA in mammary epithelial cells of dairy cows. Western blot results showed that knockdown of PRLR or STAT5 with siRNA markedly decreased PRL-stimulated LAT1 expression. In addition, we observed a marked increase in plasma membrane expression of LAT1 in PRL-stimulated cells compared with control cells. These observations indicated that PRL signaling can regulate LAT1 expression and activity in mammary epithelial cells of dairy cows, contributing to increased amino acid availability and milk protein synthesis in mammary gland of dairy cow.


Assuntos
Bovinos/fisiologia , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Leite/química , Prolactina/farmacologia , Fator de Transcrição STAT5/metabolismo , Transdução de Sinais , Animais , Caseínas/metabolismo , Células Epiteliais/metabolismo , Feminino , Lactação , Transportador 1 de Aminoácidos Neutros Grandes/genética , Glândulas Mamárias Animais/metabolismo , Proteínas do Leite/metabolismo , Biossíntese de Proteínas , Fator de Transcrição STAT5/genética
14.
J Dairy Sci ; 103(7): 6576-6582, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32448581

RESUMO

The objectives of this study were (1) to evaluate if hyperketonemia in dairy cows (defined as plasma ß-hydroxybutyrate ≥1.0 mmol/L) can be predicted using on-farm cow data either in current or previous lactation week, and (2) to study if adding individual net energy intake (NEI) can improve the predictive ability of the model. Plasma ß-hydroxybutyrate concentration, on-farm cow data (milk yield, percentage of fat, protein and lactose, fat- and protein-corrected milk yield, body weight, body weight change, dry period length, parity, and somatic cell count), and NEI of 424 individual cows were available weekly through lactation wk 1 to 5 postpartum. To predict hyperketonemia in dairy cows, models were first trained by partial least square discriminant analysis, using on-farm cow data in the same or previous lactation week. Second, NEI was included in models to evaluate the improvement of the predictability of the models. Through leave-one trial-out cross-validation, models were evaluated by accuracy (the ratio of the sum of true positive and true negative), sensitivity (68.2% to 84.9%), specificity (61.5% to 98.7%), positive predictive value (57.7% to 98.7%), and negative predictive value (66.2% to 86.1%) to predict hyperketonemia of dairy cows. Through lactation wk 1 to 5, the accuracy to predict hyperketonemia using data in the same week was 64.4% to 85.5% (on-farm cow data only), 66.1% to 87.0% (model including NEI), and using data in the previous week was 58.5% to 82.0% (on-farm cow data only), 59.7% to 85.1% (model including NEI). An improvement of the accuracy of the model due to including NEI ranged among lactation weeks from 1.0% to 4.4% when using data in the same lactation week and 0.2% to 6.6% when using data in the previous lactation week. In conclusion, trained models via partial least square discriminant analysis have potential to predict hyperketonemia in dairy cows not only using data in the current lactation week, but also using data in the previous lactation week. Net energy intake can improve the accuracy of the model, but only to a limited extent. Besides NEI, body weight, body weight change, milk fat, and protein content were important variables to predict hyperketonemia, but their rank of importance differed across lactation weeks.


Assuntos
Doenças dos Bovinos/sangue , Ingestão de Energia , Cetose/veterinária , Leite/metabolismo , Ácido 3-Hidroxibutírico/sangue , Animais , Peso Corporal , Bovinos , Análise Discriminante , Fazendas , Feminino , Cetose/sangue , Lactação , Lactose/metabolismo , Análise dos Mínimos Quadrados , Leite/química , Proteínas do Leite/metabolismo , Paridade , Período Pós-Parto , Gravidez , Sensibilidade e Especificidade
15.
Am J Clin Nutr ; 112(2): 318-333, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32438401

RESUMO

BACKGROUND: Mycoprotein is a fungal-derived sustainable protein-rich food source, and its ingestion results in systemic amino acid and leucine concentrations similar to that following milk protein ingestion. OBJECTIVE: We assessed the mixed skeletal muscle protein synthetic response to the ingestion of a single bolus of mycoprotein compared with a leucine-matched bolus of milk protein, in rested and exercised muscle of resistance-trained young men. METHODS: Twenty resistance-trained healthy young males (age: 22 ± 1 y, body mass: 82 ± 2 kg, BMI: 25 ± 1 kg·m-2) took part in a randomized, double-blind, parallel-group study. Participants received primed, continuous infusions of L-[ring-2H5]phenylalanine and ingested either 31 g (26.2 g protein: 2.5 g leucine) milk protein (MILK) or 70 g (31.5 g protein: 2.5 g leucine) mycoprotein (MYCO) following a bout of unilateral resistance-type exercise (contralateral leg acting as resting control). Blood and m. vastus lateralis muscle samples were collected before exercise and protein ingestion, and following a 4-h postprandial period to assess mixed muscle fractional protein synthetic rates (FSRs) and myocellular signaling in response to the protein beverages in resting and exercised muscle. RESULTS: Mixed muscle FSRs increased following MILK ingestion (from 0.036 ± 0.008 to 0.052 ± 0.006%·h-1 in rested, and 0.035 ± 0.008 to 0.056 ± 0.005%·h-1 in exercised muscle; P <0.01) but to a greater extent following MYCO ingestion (from 0.025 ± 0.006 to 0.057 ± 0.004%·h-1 in rested, and 0.024 ± 0.007 to 0.072 ± 0.005%·h-1 in exercised muscle; P <0.0001) (treatment × time interaction effect; P <0.05). Postprandial FSRs trended to be greater in MYCO compared with MILK (0.065 ± 0.004 compared with 0.054 ± 0.004%·h-1, respectively; P = 0.093) and the postprandial rise in FSRs was greater in MYCO compared with MILK (Delta 0.040 ± 0.006 compared with Delta 0.018 ± 0.005%·h-1, respectively; P <0.01). CONCLUSIONS: The ingestion of a single bolus of mycoprotein stimulates resting and postexercise muscle protein synthesis rates, and to a greater extent than a leucine-matched bolus of milk protein, in resistance-trained young men. This trial was registered at clinicaltrials.gov as 660065600.


Assuntos
Proteínas Fúngicas/metabolismo , Proteínas do Leite/metabolismo , Proteínas Musculares/biossíntese , Adulto , Aminoácidos/metabolismo , Método Duplo-Cego , Exercício Físico , Proteínas Fúngicas/química , Humanos , Masculino , Proteínas do Leite/química , Músculo Esquelético/metabolismo , Treinamento de Resistência , Adulto Jovem
16.
PLoS One ; 15(4): e0232066, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32320437

RESUMO

ß-lactoglobulin is one of the most abundant milk whey proteins in many mammal species, including the domestic horse. The aim of this study was to screen for polymorphism in the equine LGB1 and LGB2 gene sequences (all exons, introns, and 5'-flanking region) and to assess potential relationship of particular genotypes with gene expression levels (measured in milk somatic cells) and milk composition traits (protein, fat, lactose, and total ß-lactoglobulin content). Direct DNA sequencing analysis was performed for twelve horse breeds: Polish Primitive Horse (PPH), Polish Coldblood Horse (PCH), Polish Warmblood Horse (PWH), Silesian, Hucul, Fjording, Haflinger, Shetland Pony, Welsh Pony, Arabian, Thoroughbred, and Percheron-and revealed the presence of 83 polymorphic sites (47 and 36 for LGB1 and LGB2 genes, respectively), including eight that were previously unknown. Association analysis of the selected polymorphisms, gene expression, and milk composition traits (conducted for the PPH, PCH, and PWH breeds) showed several statistically significant relationships; for example, the two linked LGB1 SNPs (rs1143515669 and rs1144647991) were associated with total milk protein content (p < 0.01). Our study also confirmed that horse breed had significant impact on both gene transcript levels (p < 0.01) and on milk LGB content (p < 0.05), whereas an influence of lactation period was seen only for gene relative mRNA abundances (p < 0.01).


Assuntos
Cavalos/genética , Lactoglobulinas/genética , Proteínas do Leite/genética , Leite/química , Polimorfismo de Nucleotídeo Único , Animais , Éxons , Feminino , Regulação da Expressão Gênica , Íntrons , Lactação , Leite/fisiologia , Proteínas do Leite/metabolismo
17.
J Dairy Sci ; 103(6): 5090-5101, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32229110

RESUMO

The objective of this study was to evaluate the effects of a commercially available fermentation by-product in a diet containing adequate rumen-degradable protein (RDP) on milk performance, intake, and total-tract nutrient digestion in lactating dairy cattle. Primiparous (n = 48) and multiparous (n = 144) lactating dairy cattle were stratified by milk production and randomly allocated into 12 pens containing 4 primiparous and 12 multiparous animals each. Cattle averaged 118 d in milk and 712 kg of body weight at trial start. Treatment diets, on a dry matter (DM) basis, consisted of 42% corn silage, 13% alfalfa hay and silage, 20% grain corn, and 25% protein premix containing either soybean meal, wheat middlings, and urea (SBM+U), soybean meal and fermentation by-product (SBM+F), or soybean meal and rumen-protected soybean meal (RP-SBM). All 3 diets provided a similar level (DM basis) of neutral detergent fiber analyzed using α-amylase and sodium sulfite and corrected for ash content (31%), crude protein (CP, 14.9%), starch (26%), and metabolizable energy (2.7 Mcal/kg), and differed in sources of RDP. The trial consisted of a 2-wk adaptation and covariate period during which all cows were fed the RP-SBM diet and covariate measurements were taken. Pens were then randomly allocated to treatments, and weekly measurements of milk production, intake, body weight, and condition score were taken for 10 wk. All data were analyzed using the Proc Mixed procedure in SAS (SAS Institute Inc., Cary, NC). Increased DM intake was observed for cows fed SBM+F compared with cows fed SBM+U and RP-SBM (28.3 vs. 26.9 and 26.7 kg/d, respectively). Cows fed SBM+F produced more energy-corrected milk (45.3 kg/d) compared with cows fed SBM+U and RP-SBM (43.6 and 43.7 kg/d, respectively). Milk protein yield was also increased in cows fed SBM+F. No differences were observed with body weight or condition score gain throughout the trial. Apparent total-tract digestibility of fiber was decreased in cows fed SBM+F, likely as a result of increased intake. Responses are consistent with previous research in our laboratory that demonstrated a decrease in ruminal CP degradation, leading to an increase in metabolizable protein supply in the small intestine. The fermentation by-product might be useful in diets containing adequate amounts of RDP from soybean meal or alfalfa. The results from this experiment demonstrate beneficial milk performance responses to fermentation by-product when fed with a source of RDP.


Assuntos
Bovinos/crescimento & desenvolvimento , Digestão , Leite , Rúmen/metabolismo , Animais , Bovinos/metabolismo , Dieta/veterinária , Fibras na Dieta/metabolismo , Feminino , Fermentação , Lactação , Medicago sativa , Proteínas do Leite/metabolismo , Nutrientes , Silagem , Soja , Amido/metabolismo , Triticum , Ureia , Zea mays
18.
J Dairy Sci ; 103(6): 5550-5560, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32229128

RESUMO

The efficacy of an electric heat blanket (EHB) has previously been confirmed as an alternative method to evaluate heat stress (HS). However, a pair-feeding design has not been used with the EHB model. Therefore, study objectives were to determine the contribution of the nutritional plane to altered metabolism and productivity during EHB-induced HS. Multiparous Holstein cows (n = 18; 140 ± 10 d in milk) were subjected to 2 experimental periods (P); during P1 (4 d), cows were in thermoneutral conditions with ad libitum feed intake. During P2 (4 d), cows were assigned to 1 of 2 treatments: (1) thermoneutral conditions and pair-fed (PF; n = 8) or (2) EHB-induced HS with ad libitum feed intake (n = 10). Overall, the EHB increased rectal temperature, vaginal temperature, skin temperature, and respiration rate (1.4°C, 1.3°C, 0.8°C, and 42 breaths/min, respectively) relative to PF cows. The EHB reduced dry matter intake (DMI; 47%) and, by design, PF cows had a similar pattern and extent of decreased DMI. Milk yield decreased in EHB and PF cows by 27.3% (12.1 kg) and 13.4% (5.4 kg), respectively, indicating that reduced DMI accounted for only ∼50% of decreased milk synthesis. Milk fat content tended to increase (19%) in the EHB group, whereas in the PF cows it remained similar relative to P1. During P2, milk protein and lactose contents tended to decrease or decreased (1.3 and 2.2%, respectively) in both EHB and PF groups. Milk urea nitrogen remained unchanged in PF controls but increased (34.2%) in EHB cows relative to P1. The EHB decreased blood partial pressure of CO2, total CO2, HCO3, and base excess levels (17, 16, 17, and 81%, respectively) compared with those in PF cows. During P2, the EHB and PF cows had similar decreases (4%) in plasma glucose content, but no differences in circulating insulin were detected. However, a group by day interaction was detected for plasma nonesterified fatty acids; levels progressively increased in PF controls but remained unaltered in the EHB cows. Blood urea nitrogen increased in the EHB cows (61%) compared with the PF controls. In summary, utilizing the EHB model indicated that reduced nutrient intake explains only about 50% of the decrease in milk yield during HS, and the postabsorptive changes in nutrient partitioning are similar to those obtained in climate-controlled chamber studies. Consequently, the EHB is a reasonable and economically feasible model to study environmental physiology of dairy cows.


Assuntos
Bovinos/fisiologia , Ingestão de Alimentos , Ácidos Graxos não Esterificados/sangue , Resposta ao Choque Térmico , Proteínas do Leite/metabolismo , Leite/metabolismo , Animais , Roupas de Cama, Mesa e Banho/veterinária , Nitrogênio da Ureia Sanguínea , Dieta/veterinária , Feminino , Temperatura Alta , Insulina/sangue , Lactação , Leite/química , Proteínas do Leite/química , Taxa Respiratória
19.
J Dairy Sci ; 103(6): 5143-5147, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32307178

RESUMO

Milk fat is secreted from the mammary gland in the form of milk fat globules (MFG). Although milk fat depression has been studied since the beginning of the last century, the extent to which this phenomenon alters MFG synthesis is not fully understood. The aim of this study was to evaluate the effect of conjugated linoleic acid (CLA) on the size and distribution of MFG during milk fat depression in dairy cows. Twelve Holstein cows in mid lactation (145 ± 31 d in milk, 583 ± 34.6 kg of body weight, and 27.2 ± 2.4 kg of milk/d) were randomly assigned to a control diet or control plus Ca-protected CLA at 15 g/kg of dry matter for a 6-d period. The average diameter and particle size distribution of MFG were measured using a Mastersizer 3000 laser particle size analyzer (Malvern Instruments Ltd., Malvern, UK). Feeding CLA did not affect dry matter intake (16.2 ± 0.4 kg/d), milk production (28.4 ± 0.4 kg/d), milk protein, or lactose, but it decreased milk fat content (3.46 vs. 2.52%). In addition, surface area-related mean diameter of fat globules in cows fed CLA was lower compared with controls (3.02 vs. 3.45 µm). The percentage of large fat globules decreased and that of small fat globules increased in response to CLA. Overall, the data suggest that the milk fat depression induced by CLA is accompanied by a decrease in average diameter of MFG.


Assuntos
Bovinos/fisiologia , Suplementos Nutricionais/análise , Glicoproteínas/efeitos dos fármacos , Ácidos Linoleicos Conjugados/farmacologia , Leite/química , Animais , Peso Corporal , Dieta/veterinária , Ingestão de Alimentos , Ácidos Graxos/metabolismo , Feminino , Glicolipídeos/análise , Glicoproteínas/análise , Lactação/efeitos dos fármacos , Lactose/metabolismo , Gotículas Lipídicas , Leite/metabolismo , Proteínas do Leite/metabolismo , Distribuição Aleatória
20.
Oxid Med Cell Longev ; 2020: 3894309, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32273941

RESUMO

The aim of this study was to investigate the mechanisms underlying the reduced milk production during mastitis. We hypothesized that bacterial endotoxin induces hypoxia, oxidative stress, and cell apoptosis while inhibiting milk gene expression in the mammary gland. To test this hypothesis, the left and right sides of the 4th pair of mouse mammary glands were alternatively injected with either lipopolysaccharide (LPS, E. coli 055: B5, 100 µL of 0.2 mg/mL) or sterile PBS through the teat meatus 3 days postpartum. At 10.5 and 22.5 h postinjection, pimonidazole HCl, a hypoxyprobe, was injected intraperitoneally. At 12 or 24 h after the LPS injection, the 4th glands were individually collected (n = 8) and analyzed. LPS treatment induced mammary inflammation at both 12 and 24 h but promoted cell apoptosis only at 12 h. Consistently, H2O2 content was increased at 12 h (P < 0.01), but dropped dramatically at 24 h (P < 0.01) in the LPS-treated gland. Nevertheless, the total antioxidative capacity in tissue tended to be decreased by LPS at both 12 and 24 h (P = 0.07 and 0.06, respectively). In agreement with these findings, LPS increased or tended to increase the mRNA expression of antioxidative genes Nqo1 at 12 h (P = 0.05) and SLC7A11 at 24 h (P = 0.08). In addition, LPS inhibited mammary expression of Csn2 and Lalba across time and protein expression of Csn1s1 at 24 h (P < 0.05). Furthermore, hypoxyprobe staining intensity was greater in the alveoli of the PBS-treated gland than the LPS-treated gland at both 12 and 24 h, demonstrating a rise in oxygen tension by LPS treatment. In summary, our observations indicated that while intramammary LPS challenge incurs inflammation, it induces oxidative stress, increases cell apoptosis and oxygen tension, and differentially inhibits the milk protein expression in the mammary gland.


Assuntos
Hipóxia Celular/fisiologia , Endotoxinas/efeitos adversos , Escherichia coli/patogenicidade , Glândulas Mamárias Animais/fisiologia , Proteínas do Leite/metabolismo , Estresse Oxidativo/fisiologia , Animais , Feminino , Camundongos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...