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1.
J Dairy Sci ; 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38580148

RESUMO

While there is generally no consensus about how nutrients determine milk synthesis in the mammary gland, it is likely that the mechanistic target of rapamycin complex 1 (mTORC1) plays a role as a key integrator of nutritional and mitogenic signals that can influence a multitude of catabolic and anabolic pathways. The objectives of this study were to evaluate acute changes (<24 h) in translational signaling, in addition to chronic changes (14 d) in mammary gland structure and composition, in response to a severe feed restriction. Fourteen lactating Holstein dairy cows were assigned to either ad libitum feeding (n = 7), or a restricted feeding program (n = 7). Feed-restricted cows had feed removed after the evening milking on d 0. Mammary biopsies and blood samples were collected 16 h after feed removal, after which cows in the restricted group were fed 60% of their previously observed ad lib intake for the remainder of the study. On d 14, animals were sacrificed and mammary glands dissected. In response to feed removal, an acute increase in plasma nonesterified fatty acid concentration was observed, concurrent to a decrease in milk yield. In mammary tissue, we observed downregulation of the mTORC1-S6K1 signaling cascade, in addition to reductions in mRNA expression of markers of protein synthesis, endoplasmic reticulum biogenesis, and cell turnover (i.e., transcripts associated with apoptosis or cell proliferation). During the 14 d of restricted feeding, animals underwent homeorhetic adaptation to 40% lower nutrient intake, achieving a new setpoint of 14% reduced milk yield with 18% and 29% smaller mammary secretory tissue dry matter and crude protein masses, respectively. On d 14, no treatment differences were observed in markers of protein synthesis or mammary cell turnover evaluated using gene transcripts and immunohistochemical staining. These findings implicate mTORC1-S6K1 in the early phase of the adaptation of the mammary gland's capacity for milk synthesis in response to changes in nutrient supply. Additionally, changes in rates of mammary cell turnover may be transient in nature, returning to basal levels following brief alterations that have sustained effects.

2.
Transl Anim Sci ; 7(1): txad104, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37701127

RESUMO

Prebiotic compounds may be supplemented in the diet to improve animal health and performance in a variety of ways. In dairy cattle, the transition from pregnancy through parturition and lactation represents a critical life stage with many concurrent stressors. The objectives of this study were to evaluate responses to the provision of a hindgut-targeted prebiotic compound (calcium gluconate; HFCG) when supplemented prepartum and/or postpartum in a 2 × 2 factorial design. One hundred and sixty-four multiparous Holstein cattle were enrolled and followed from approximately 21 d prior to calving until 100 d of lactation. Treatments were administered as a pelleted compound feed offered in the rotary milking parlor once daily prepartum and thrice daily postpartum. Information pertaining to milk production and body weight were automatically recorded by the milking equipment, and information pertaining to reproductive and health performance was recorded by farm staff. Cattle that received HFCG prepartum were confirmed pregnant approximately 21 d earlier (P = 0.024). Cattle that received HFCG both pre- and postpartum had 9% to 10% higher yields of milk protein, fat, and energy-corrected milk (P ≤ 0.037) from weeks 4 to 9 of lactation relative to those that received HFCG exclusively prepartum. Conversely, cattle that received HFCG exclusively postpartum had 9% to 10% higher yields of milk protein, fat, and energy-corrected milk (P ≤ 0.037) from weeks 9 to 14 of lactation relative to those that received exclusively the negative control in both periods. The mechanism underlying these responses remains unclear, however, we hypothesize that these responses are due to localized reductions in inflammation in the gut and/or signaling to extragastrointestinal tissues altering energy partitioning and balance.

3.
J Dairy Sci ; 104(7): 7711-7724, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33896629

RESUMO

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.


Assuntos
Ração Animal , Substitutos do Leite , Ração Animal/análise , Animais , Peso Corporal , Bovinos , Dieta/veterinária , Metabolismo Energético , Feminino , Metabolômica , Leite , Nutrientes , Gravidez , Desmame
4.
J Dairy Sci ; 104(7): 7845-7855, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33865576

RESUMO

There is growing evidence suggesting that by improving gut integrity and function, less energy is partitioned toward immune responses related to xenobiotic infiltration, sparing energy for productive purposes. Gluconic acid and its salts have previously shown prebiotic effects in the lower gut of nonruminant animals, where they serve as a precursor for butyrate, although evidence in ruminants is limited. Butyrate and its fermentative precursors have demonstrated multiple beneficial effects to gastrointestinal ecology, morphology, and function, such as the stimulation of epithelial cell proliferation and improvement of gut barrier function and ecology. The objective of this study was to evaluate changes in milk production, milk fatty acid composition, and fecal and blood parameters in lactating dairy cattle fed a hydrogenated fat-embedded calcium gluconate (HFCG) supplement designed to target the hindgut for calcium gluconate delivery. In addition, the effects of a compound feed processing method (i.e., incorporated into a mash or an extruded pellet) were tested to evaluate the effect of extrusion on product efficacy. Forty-five lactating Holstein cows at approximately 165 d in milk were used in a 3 × 3 Latin square consisting of three 28-d periods, during which animals were offered a basal ration mixed with 3 different compound feeds: a negative control in mash form containing no HFCG, or the HFCG supplement fed at a target rate of 16 g/d, delivered in either a mash or pelleted form. Supplementation of HFCG tended to increase yields of milk fat and fat- and energy-corrected milk. Total yields and concentrations of milk fatty acids ≥18 carbons in length tended to increase in response to HFCG. Plasma nonesterified fatty acids and milk urea increased in HFCG treatments. No differences were observed in fecal pH or fecal concentrations of volatile fatty acids, with the exception of isobutyrate, which decreased in HFCG-fed cows. Changes in milk fatty acid profile suggest that increased milk fat yield was driven by increased incorporation of preformed fatty acids, supported by increased circulating nonesterified fatty acid. Future research investigating the mode of action of HFCG at the level of the hindgut epithelium is warranted, as measured fecal parameters showed no response to treatment.


Assuntos
Gluconato de Cálcio , Lactação , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Suplementos Nutricionais , Digestão , Ácidos Graxos , Feminino , Leite , Rúmen
5.
J Dairy Sci ; 102(8): 7150-7167, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31155242

RESUMO

We investigated mammary gland metabolism in lactating dairy cattle in response to energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels. According to a 6 × 6 Latin square design, 6 rumen-fistulated second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were abomasally infused with saline (LMP-C); isoenergetic infusions (digestible energy basis) of 1,319 g/d glucose (LMP-GG), 676 g/d palm olein (LMP-LG), or 844 g/d essential AA (EAA; HMP-C); or isoenergetic infusions of 1,319 g/d glucose + 844 g/d EAA (HMP-GG) or 676 g/d palm olein + 844 g/d EAA (HMP-LG). Each experimental period consisted of 5 d of continuous infusion followed by 2 d of rest. A total mixed ration (42% corn silage, 31% grass silage, and 27% concentrate on a dry matter basis) formulated to meet 100 and 83% of net energy and metabolizable protein requirements, respectively, was fed at 90% of ad libitum intake by individual cow. Arterial and venous blood samples were collected on d 5 of each period. Infusing GG or LG at the HMP level did not affect milk yield or composition differently than at the LMP level. Neither GG nor LG infusion stimulated milk protein or lactose yield, but fat yield tended to decrease with GG and tended to increase with LG. Infusion of GG increased arterial plasma concentrations of glucose and insulin and decreased concentrations of ß-hydroxybutyrate (BHB), nonesterified fatty acids, long-chain fatty acids (LCFA), total AA, EAA, and group 2 AA. Infusion of LG increased arterial triacylglycerides (TAG) and LCFA but did not affect EAA concentrations. Compared with the LMP level, the HMP level increased arterial concentrations of BHB, urea, and all EAA groups and decreased the concentration of total non-EAA. Mammary plasma flow increased with GG and was not affected by LG or protein level. Uptake and clearance of total EAA and group 2 AA were affected or tended to be affected by GG × AA interactions, with their uptakes being lower and their clearances higher with GG, but only at the LMP level. Infusion of LG did not affect uptake or clearance of any AA group. The HMP level increased uptake and decreased clearance of all EAA groups and decreased non-EAA uptake. Infusion of GG tended to increase mammary glucose uptake, and tended to decrease BHB uptake only at the LMP level. Infusion of LG increased mammary uptake of TAG and LCFA and increased or tended to increase clearance of TAG and LCFA. We suspect GG increased mammary plasma flow to maintain intramammary energy and AA balance and stimulated lipogenesis in adipose, accounting for depressed arterial BHB and group 2 AA concentrations. Mammary glucose uptake did not cover estimated requirements for lactose and fat synthesis at the HMP level, except during HMP-GG infusion. Results of this study illustrate flexibility in mammary metabolite utilization when absorptive supply of glucogenic, lipogenic, and aminogenic substrate is increased.


Assuntos
Ração Animal/análise , Bovinos/metabolismo , Ácidos Graxos/farmacologia , Glucose/farmacologia , Proteínas do Leite/metabolismo , Leite/metabolismo , Ácido 3-Hidroxibutírico/metabolismo , Abomaso/metabolismo , Aminoácidos Essenciais/metabolismo , Animais , Dieta/veterinária , Ácidos Graxos/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Feminino , Glucose/metabolismo , Lactação , Lactose/metabolismo , Lipogênese , Glândulas Mamárias Animais/efeitos dos fármacos , Glândulas Mamárias Animais/metabolismo , Leite/química , Rúmen/metabolismo , Silagem/análise
6.
J Dairy Sci ; 100(8): 6139-6150, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28601462

RESUMO

The objective of this study was to determine if the addition of glycerol to the diet of dairy cows would stimulate milk protein yield in the same manner as the addition of corn grain. Twelve multiparous lactating dairy cows at 81 ± 5 d in milk were subjected to 3 dietary treatments in a replicated 3 × 3 Latin square design for 28-d periods. The diets were a 70% forage diet considered the basal diet, the basal diet with 19% ground and high-moisture corn replacing forages, and the basal diet with 15% refined glycerol and 4% added protein supplements to be isocaloric and isonitrogenous with the corn diet. Cows were milked twice a day and samples were collected on the last 7 d of each period for compositional analysis. Within each period, blood samples were collected on d 26 and 27, and mammary tissue was collected by biopsy on d 28 for Western blot analysis. Dry matter intake increased from 23.7 kg/d on the basal diet to 25.8 kg/d on the corn diet and 27.2 kg/d on the glycerol diet. Dry matter intake tended to be higher with glycerol than corn. Milk production increased from 39.2 kg/d on the basal diet to 43.8 kg/d on the corn diet and 44.2 kg/d on the glycerol diet. However, milk yield did not differ between corn and glycerol diets. Milk lactose yields were higher on the corn and glycerol diets than the basal diet. Milk fat yield significantly decreased on the glycerol diet compared with the basal diet and tended to decrease in comparison with the corn diet. Mean milk fat globule size was reduced by glycerol feeding. Milk protein yield increased 197 g/d with addition of corn to the basal diet and 263 g/d with addition of glycerol, and the glycerol effect was larger than the corn effect. The dietary treatments had no effects on plasma glucose concentration, but plasma acetate levels decreased 27% on the glycerol diet. Amino acid concentrations were not affected by dietary treatments, except for branched-chain amino acids, which decreased 22% on the glycerol diet compared with the corn diet. The decreases in plasma acetate and branched-chain amino acid concentrations with glycerol and the larger effects of glycerol than corn on milk protein and fat yields suggest that glycerol is more glucogenic for cows than corn grain.


Assuntos
Ração Animal , Bovinos/metabolismo , Glicerol/administração & dosagem , Proteínas do Leite/biossíntese , Animais , Dieta/veterinária , Feminino , Lactação/metabolismo , Leite/química , Rúmen , Zea mays
7.
J Dairy Sci ; 100(7): 5390-5399, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28527802

RESUMO

The benefits of feeding elevated quantities of milk to dairy calves have been well established. However, there is a reluctance to adopt this method of feeding in commercial dairy production because of concerns around growth, health, and ruminal development during weaning. The objective of this study was to characterize the effect of an abrupt (0 d step-down) or gradual (12 d step-down) feeding scheme when calves are fed an elevated plane of nutrition (offered 1.35 kg of milk replacer/d). For this experiment, a total of 54 calves were randomly assigned to an abrupt or a gradual weaning protocol before weaning at 48 d of life. Calves were housed and sampled in individual pens for the duration of the experiment, and milk, starter, and straw intake were measured on a daily basis. Body weight was measured every 6 d, whereas blood, rumen fluid, and fecal samples were collected on d 36 (pre-step-down), 48 (preweaning), and 54 (postweaning) of the experiment. Although the growth rates of the step-down calves were lower from d 37 to weaning (0.62 ± 0.04 vs. 1.01 ± 0.04 kg/d), the postweaning average daily gain was greater compared with the group that was abruptly weaned (0.83 ± 0.06 vs. 0.22 ± 0.06 kg/d). Total ruminal volatile fatty acid was greater in the step-down group on the day of weaning (d 48; 59.80 ± 2.25 vs. 45.01 ± 2.25 mmol), whereas the fecal starch percentage was lower during postweaning compared with the abruptly weaned calves (d 54; 3.31 ± 0.76 vs. 6.34 ± 0.76%). Analysis of the digestive tract of bull calves on d 55 revealed minimal differences between gross anatomy measurements of gut compartments as well as no morphological differences in rumen papillae development, yet the total mass of rumen when full of contents was larger in the step-down calves (7.83 ± 0.78 vs. 6.02 ± 0.78 kg). Under the conditions of this study, the results showcase the benefits of a step-down feeding strategy from an overall energy balance standpoint, due to increased adaptation of the gastrointestinal tract preweaning.


Assuntos
Animais Recém-Nascidos/crescimento & desenvolvimento , Leite , Desmame , Fatores Etários , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peso Corporal , Bovinos , Ácidos Graxos/análise , Fezes/química , Masculino , Estado Nutricional , Distribuição Aleatória , Rúmen/química
8.
J Dairy Sci ; 100(7): 5909-5921, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28478014

RESUMO

The phosphorylation of mammalian target of rapamycin complex 1 (mTORC1) components and integrated stress response networks in the mammary glands of lactating cows have not accounted for the stimulation of milk protein yield by chronic supplementation with AA or glucose. Faster milk protein synthesis could be a consequence of increased milk protein mRNA per cell, the number of ribosomes per cell, the secretory capacity of cells, or the mammary cell number. To investigate these 4 possibilities using a translational and transcriptional approach, we performed protein and gene expression analyses of mammary and longissimus dorsi tissue collected from lactating dairy cows after 5 d of abomasal infusion with saline or 844 or 1,126 g/d of an essential AA (EAA) mixture, with and without 1,000 g/d glucose. Infusion with EAA increased milk protein yield but did not affect the phosphorylation of mTORC1-related proteins in the mammary gland. In skeletal muscle, phosphorylation of 4EBP1 (eIF4E-binding protein 1) increased in response to both EAA and glucose, and phosphorylated S6K1 (70-kDa ribosomal protein S6 kinase) increased with glucose. In response to EAA, mammary mRNA expression of the marker genes for milk proteins, ribosome biogenesis, and cell proliferation were not upregulated. Instead, reciprocal regulation of 2 arms of the unfolded protein response occurred. Infusion of EAA for 5 d activated XBP1 (X-box binding protein 1) mRNA, encoding a transcription factor for endoplasmic reticulum biogenesis, and it decreased the mRNA expression of genes encoding pro-apoptotic protein CHOP (C/EBP homologous protein) and downstream GADD34 (growth arrest and DNA damage-inducible 34). These findings implicate non-stress-related, adaptive capabilities of the unfolded protein response in the long-term nutritional regulation of milk protein yield in lactating dairy cows.


Assuntos
Aminoácidos Essenciais/farmacologia , Bovinos , Glândulas Mamárias Animais/metabolismo , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Aminoácidos , Animais , Feminino , Lactação , Leite , Proteínas do Leite , Transdução de Sinais , Serina-Treonina Quinases TOR
9.
J Dairy Sci ; 99(2): 1145-1160, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26627857

RESUMO

To determine how glucose modulates protein synthesis when essential AA are in abundant supply, 5 early-lactation, rumen-fistulated Holstein dairy cows were fed a diet containing 6.95 MJ/kg of net energy for lactation and 12.4% crude protein and abomasally infused for 5 d with saline, 844 or 1,126 g/d of a complete essential AA mix, with and without the inclusion of 1,000 g/d of glucose, in a 5×5 Latin square design. Infusion of essential AA increased milk yield by 4.1 kg/d, milk protein by 256 g/d, milk fat by 95 g/d, and milk urea nitrogen by 70% compared with saline, with no differences between the level of essential AA infusion. The addition of glucose to essential AA infusate did not stimulate milk protein yield or concentration, but reduced milk urea nitrogen by 17% and decreased milk fat yield. Arterial concentrations of total essential AA increased 3- to 4-fold, mammary clearance decreased 61%, and mammary uptake of essential AA increased 65% in response to essential AA infusion. Arterial branched-chain AA concentrations declined 29% in response to glucose and mammary clearance increased 48%, but mammary AA uptake was unchanged. Essential AA infusion increased plasma 3-methylhistidine by 50% and reduced muscle branched-chain α-keto acid dehydrogenase kinase abundance by 14%, indicating stimulation of muscle protein turnover and branched-chain AA catabolism, respectively. Glucose had no further effect on muscle branched-chain α-keto acid dehydrogenase kinase abundance but decreased mRNA expression of branched chain aminotransferase 1. Lack of further increases in plasma 3-methylhistidine or greater stimulation of muscle branched-chain AA catabolism indicates that muscle protein degradation was unchanged with glucose but that accretion may have been stimulated. The decrease in circulating branched-chain AA concentrations and nitrogen excretion in response to glucose suggests that surplus essential AA were redirected to peripheral, extra-mammary tissues.


Assuntos
Aminoácidos de Cadeia Ramificada/metabolismo , Aminoácidos Essenciais/administração & dosagem , Bovinos/metabolismo , Glucose/administração & dosagem , Lactação/fisiologia , Proteínas do Leite/biossíntese , Abomaso/efeitos dos fármacos , Aminoácidos/análise , Aminoácidos de Cadeia Ramificada/sangue , Animais , Dieta/veterinária , Feminino , Glândulas Mamárias Animais/metabolismo , Metilistidinas/análise , Metilistidinas/sangue , Leite/química , Proteínas do Leite/análise , Proteínas Musculares/metabolismo , Músculo Esquelético/química , Rúmen/metabolismo , Ureia/análise
10.
J Dairy Sci ; 98(7): 4499-508, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25912861

RESUMO

Essential amino acid (EAA) deficiencies and imbalances were created in lactating cows by using an infusion subtraction protocol to explore effects on milk protein yield and activity state of regulators of mRNA translation in the mammary glands. Six lactating cows on a diet of 11.2% protein were infused abomasally for 5d with saline, 563g/d of a complete EAA mix, or EAA without His, Met, Phe, or Trp in a 6×6 Latin square design. Infusion of complete and imbalanced EAA solutions increased mammalian target of rapamycin (mTOR) signaling in the mammary glands, as evidenced by higher ribosomal S6 kinase 1 (S6K1) phosphorylation compared with saline infusion. Total S6K1 abundance was decreased by imbalanced AA infusions. Except for the mixture lacking Phe, infusion of EAA, whether imbalanced or not, increased abundance of total eukaryotic initiation factor 2Bε (eIF2Bε). A correlation of 0.33 between phosphorylation state of S6K1 and total eIF2Bε abundance suggests that an mTOR-mediated upregulation of eIF2Bε translation occurred. Despite increased mTOR/eIF2Bε signaling, milk protein yields increased only with the complete EAA mixture compared with saline. Low plasma concentrations of His, Met, and Phe during their respective imbalances likely interfered with protein synthesis. Total abundance and phosphorylation state of eukaryotic initiation factor 2α were not responsible for the interference. Further study of eIF2Bε as a regulator of milk protein yield is warranted.


Assuntos
Aminoácidos Essenciais/administração & dosagem , Fator de Iniciação 2B em Eucariotos/genética , Expressão Gênica/efeitos dos fármacos , Glândulas Mamárias Animais/metabolismo , Proteínas do Leite/metabolismo , Abomaso/efeitos dos fármacos , Animais , Bovinos , Dieta , Feminino , Lactação/fisiologia , Fosforilação , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/fisiologia
11.
J Dairy Sci ; 97(1): 430-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24268408

RESUMO

The objective of this study was to determine effects of glucose on milk protein yield and mammary mammalian target of rapamycin (mTOR) activity in dairy cattle in early lactation. Eight multiparous cows at 73 ± 8 d in milk were randomly assigned to 2 treatments in a crossover design for two 6-d periods. Treatments were jugular infusion of either saline (Sal) or 896 g/d glucose (Glc). All cows were fed a total mixed ration with 42% neutral detergent fiber, had free access to water, and were milked twice a day. Within each period, blood samples were taken (d 5) and mammary tissue was collected by biopsy (d 6) from each hindquarter for Western blot analysis. In addition to Sal and Glc treatments, on d 6, rapamycin dissolved in 50% dimethyl sulfoxide was administered via the teat canals into the left quarters, with a control solution administered into the right quarters. Rapamycin had no effect on milk protein yields or phosphorylation state of mTOR signaling proteins. Infusions of Glc significantly increased milk yield but only tended to increase milk protein yields. Milk fat tended to be decreased in cows infused with Glc, whereas lactose yields were significantly increased. Glucose infusion did not increase plasma glucose levels, but insulin and nonessential AA concentrations increased by 21 and 16%, respectively, branched-chain AA concentrations decreased 24%, and essential AA concentrations tended to decrease by 14%. Infusion of Glc significantly decreased abundances of both phosphorylated and total ribosomal S6 kinase 1 (S6K1) in mammary tissue by 27 and 11%, respectively. Abundance of phosphorylated eukaryotic initiation factor 4E-binding protein 1 (4EBP1) decreased significantly by 25%, whereas total 4EBP1 exhibited a tendency to decrease by 16%. We conclude that the mTOR signaling pathway is not the only regulator of milk protein synthesis. Decreases in essential AA concentrations in plasma suggest that protein synthesis was stimulated in nonmammary tissues of the body, presumably skeletal muscle.


Assuntos
Glucose/administração & dosagem , Lactação/fisiologia , Glândulas Mamárias Animais/metabolismo , Transdução de Sinais , Animais , Glicemia/metabolismo , Bovinos , Estudos Cross-Over , Feminino , Infusões Intravenosas , Insulina/sangue , Lactose/metabolismo , Leite/química , Proteínas do Leite/análise , Fosforilação , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo
12.
J Dairy Sci ; 95(1): 318-27, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22192211

RESUMO

The objective of this study was to characterize the mRNA expression of metabolic and proliferative genes in the rumen epithelium during ruminal acidosis. To meet our objectives, 16 rumen-fistulated, lactating Holstein dairy cattle (618±35 kg of body weight, 221±32 d in milk) were used in a randomized complete block design. All cattle were fed a high-forage diet (HF; 88.9% of dry matter) for 5 wk before the experiment. After the baseline week (wk 0), half of the cattle were randomly assigned and transitioned to a high-concentrate diet (HC; 62.2% of dry matter) which was fed for 3 wk (wk 1, 2, and 3). For the last 48 h of each week, continuous ruminal pH, short-chain fatty acids, and plasma ß-hydroxybutyrate were assessed, followed by a rumen papillae biopsy. Milk production was higher in HC cattle compared with HF during wk 1, 2, and 3 (17.4±0.5 vs. 23.4±0.9 kg/d, respectively); however, the mean ruminal pH was decreased (5.75±0.03 vs. 6.30±0.02). The HC cattle spent more time below pH 5.6 (594±54 vs. 3±3 min/d) and displayed greater concentrations of ruminal butyrate (15.8±0.9 vs. 10.2±0.4 mmol) and plasma ß-hydroxybutyrate (1,036±63 vs. 778±20 µM) compared with the HF cattle. The mRNA expression of genes involved in ketogenesis (HMGCS2 and PPARA) and short-chain fatty acid transport (MCT1) was unchanged by treatment. However, a downregulation in HMGCS1 (0.72±0.09), one of the cholesterol biosynthesis genes, was observed in HC cattle during wk 1 of the grain challenge. In addition, the relative mRNA expression value of insulin-like growth factor-binding protein 3 was lower (0.78±0.06), whereas insulin-like growth factor-binding protein 5 was higher (1.79±0.15) in HC compared with HF cattle. These results suggest that grain-induced ruminal acidosis alters the mRNA expression of IGF-binding proteins and a cholesterolgenic enzyme in the rumen epithelium of lactating dairy cattle.


Assuntos
Acidose/veterinária , Adaptação Fisiológica/fisiologia , Colesterol/biossíntese , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/fisiologia , Rúmen/fisiologia , Ácido 3-Hidroxibutírico/análise , Ácido 3-Hidroxibutírico/sangue , Acidose/fisiopatologia , Animais , Bovinos , Dieta/veterinária , Epitélio/fisiologia , Ácidos Graxos Voláteis/análise , Feminino , Regulação da Expressão Gênica/fisiologia , Concentração de Íons de Hidrogênio , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/biossíntese , Lactação/fisiologia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Rúmen/química
13.
Eur J Neurol ; 16(11): 1173-7, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19538204

RESUMO

BACKGROUND AND PURPOSE: Complaints about side-effects of antiepileptic drugs (AEDs) may be overlooked in clinical practice. We assessed the value and risks of an active intervention policy for reported complaints in a randomized controlled pragmatic trial. METHODS: This randomized controlled pragmatic trial included 111 adults treated for epilepsy in seven general hospitals. They were considered well-managed by their treating physician, but reported moderate to severe complaints on a questionnaire (SIDAED, assessing SIDe effects in AED treatment). The intervention was adjustment of AED treatment (53 patients), either reduction of dose or switch of AED, versus continuation of treatment unchanged (58 control patients) during 7 months. Primary outcomes were quality of life (Qolie-10) and complaints score. Secondary outcome measures were the occurrence of seizures or adverse events. RESULTS: After 7 months, the relative risk (RR) for improvement in quality of life was 1.80 (1.04-3.12) for the intervention group compared to control and the RR of decrease in complaints was 1.34 (0.88-2.05). In 58% of patients randomized to adjustment, the medication had indeed been changed. DISCUSSION: In conclusion, despite a possible risk of seizure recurrence, adjustment of drug treatment in well-managed patients with epilepsy, who report considerable complaints, improves the quality of life.


Assuntos
Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/efeitos adversos , Epilepsia/tratamento farmacológico , Qualidade de Vida , Adulto , Esquema de Medicação , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Convulsões/tratamento farmacológico , Inquéritos e Questionários , Resultado do Tratamento
14.
J Dairy Sci ; 91(10): 3998-4001, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18832224

RESUMO

An experiment was conducted to test the hypothesis that a sufficient proportion of histidine (His) included in the drinking water of lactating cows bypasses the rumen to have an effect on milk synthesis. Eight dairy cows (45 +/- 15 d in milk) were given either 0 or 2.5 g/L of His in the drinking water in a crossover design of two 7-d periods. Cows were offered a corn and alfalfa silage-based total mixed ration for ad libitum intake. Water was provided ad libitum to each cow in an individual automatic drinking vessel with a flow meter attached. Water intake tended to increase from 85.1 to 92.1 L/d when His was added. Concentrations of His in plasma samples collected on the last day of each period tended to increase from 14.6 to 21.6 muM, corresponding to an estimated 0.4% bypass of the imbibed histidine. Other amino acid concentrations in plasma were not affected by His supplementation. Milk yield increased by 1.7 L/d with His treatment, lactose yield increased by 90 g/d, and there were tendencies for protein yield to increase, fat percentage to decrease, and protein to fat ratio to increase. An improvement in postruminal histidine flow can influence milk production and composition but the proportion of imbibed water that bypasses the rumen will have to be increased to take advantage of drinking water as a vehicle to transfer His postruminally.


Assuntos
Suplementos Nutricionais , Água Doce , Histidina/farmacologia , Lactação/efeitos dos fármacos , Aminoácidos/sangue , Animais , Bovinos , Ingestão de Líquidos/efeitos dos fármacos , Feminino , Água Doce/química , Histidina/administração & dosagem , Leite/química , Leite/metabolismo
15.
Seizure ; 15(4): 242-8, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16551504

RESUMO

OBJECTIVES: Side-effects of anti-epileptic drugs (AEDs) may be overlooked in patients with epilepsy in everyday clinical practice. The aim of this study was to assess the prevalence and severity of subjective complaints in patients who were considered to be well-controlled and to assess whether these complaints are related to medication, personality traits, or other determinants. METHODS: We included patients with epilepsy who were considered to be well-controlled in a cross-sectional study in seven hospitals in the Netherlands. Their medication had not been changed for six months and an apparent reason to change the medication was lacking at the time of enrolment. Subjective complaints were assessed with a 46-item questionnaire. Using multivariable linear regression modeling, we assessed whether patient characteristics, epilepsy characteristics, medication, quality of life (Qolie-10), and personality traits (SCL-90) explained the presence and severity of complaints. RESULTS: Of 173 included patients, 67% reported moderate to severe subjective complaints on the questionnaire. Cognitive complaints were reported most frequently. Multivariate modeling showed that 61% of the variance in reported complaints could be explained by included determinants. The prevalence and severity of complaints was associated with AED polytherapy and higher scores on psycho neuroticism. CONCLUSIONS: Patients who were considered to be well-controlled proved to report an unexpectedly high number of subjective complaints. Both medication and aspects of personality contributed to the level of complaints. Our study illustrates that subjective side-effects are easily overlooked in everyday clinical practice, possibly because in practice a generally phrased question is used to detect side-effects.


Assuntos
Anticonvulsivantes/efeitos adversos , Transtornos Cognitivos/epidemiologia , Epilepsia/tratamento farmacológico , Satisfação do Paciente , Qualidade de Vida , Adolescente , Adulto , Cognição/efeitos dos fármacos , Transtornos Cognitivos/etiologia , Estudos Transversais , Quimioterapia Combinada , Epilepsia/psicologia , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Inquéritos e Questionários
16.
Epilepsia ; 41(9): 1167-78, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10999556

RESUMO

PURPOSE: This study compares the cognitive effects of topiramate (TPM) with those of valproate (VPA) using efficacious doses of each drug when used as adjunctive therapy to carbamazepine (CBZ). A key question of the study is to what extent a more gradual introduction of TPM improves tolerability and prevents cognitive impairment. METHODS: The study is a multicenter, randomized, observer-blinded, parallel-group clinical trial with VPA or TPM given as first-line add-on therapy to steady-state treatment with CBZ. TPM is introduced at 25 mg and increased with weekly 25mg/d increments to a minimum dosage of 200 mg/d. The target dosage ranges from 200 to 400 mg/d for TPM and is 1800 mg/d for VPA. The study evaluates cognitive function changes from baseline to end point (after 20 weeks of treatment) and during titration (after 8 weeks of treatment). The primary outcome measure is the difference between the treatments (TPM versus VPA) in change from baseline to end point and change from baseline to titration, using a 95% confidence interval approach. RESULTS: For the 10 baseline-to-end point comparisons, one test measuring short-term verbal memory (Rey Auditory Verbal Learning Test) yields a statistically significant difference between the treatments (p = 0.02), showing worsening for TPM and improvement of scores for VPA. The 10 baseline-to-titration comparisons also show one statistically significant difference, again for a test measuring short-term memory (Recognition of Words; p = 0.04), showing a larger change in the negative direction for TPM. None of the mood tests or the test for subjective complaints shows statistically significant differences between the treatments, although more scores are in the negative direction for TPM during titration. CONCLUSION: Although the pattern of changes in the negative direction seems consistent with clinical information, the differences found between the treatments are small. An important finding of our study is that, when the results are compared with those of other studies, it is clear that gradual introduction of TPM can reduce the extent of cognitive impairment (with a maximum of about 0.6 SD).


Assuntos
Anticonvulsivantes/uso terapêutico , Carbamazepina/uso terapêutico , Cognição/efeitos dos fármacos , Epilepsias Parciais/tratamento farmacológico , Frutose/análogos & derivados , Ácido Valproico/uso terapêutico , Adolescente , Adulto , Anticonvulsivantes/efeitos adversos , Anticonvulsivantes/farmacologia , Carbamazepina/efeitos adversos , Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/diagnóstico , Quimioterapia Combinada , Epilepsias Parciais/psicologia , Feminino , Frutose/efeitos adversos , Frutose/farmacologia , Frutose/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Placebos , Desempenho Psicomotor , Topiramato , Resultado do Tratamento , Ácido Valproico/efeitos adversos , Ácido Valproico/farmacologia
17.
Clin Neurol Neurosurg ; 100(2): 126-32, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9746301

RESUMO

The linear naevus sebaceus syndrome (LNSS) is a phakomatosis, characterized in general by a triad consisting of naevus sebaceus of Jadassohn, seizures, and mental retardation. In addition, a broad spectrum of neurological, ophthalmological, skeletal, urogenital and cardiovascular symptoms may be encountered. According to our literature review, seizures and mental retardation were reported in 67 and 61% of cases, respectively. Because ophthalmological abnormalities (59%) and involvement of other organ systems (61%) occur frequently, we advise avoidance of adhering to the classical triad for recognizing or describing LNSS. Gross structural abnormality of the cerebrum or cranium was frequently observed (72%), consisting mainly of enlargement of one lateral ventricle, hemimegalencephaly and hemimegacranium. We report a case of a male patient with the clinical features of LNSS, but without cerebral developmental abnormalities at autopsy examination.


Assuntos
Córtex Cerebral/anormalidades , Nevo/complicações , Glândulas Sebáceas/patologia , Neoplasias Cutâneas/complicações , Adulto , Autopsia , Humanos , Deficiência Intelectual , Masculino , Nevo/patologia , Convulsões/etiologia , Neoplasias Cutâneas/patologia , Síndrome
18.
Eur J Clin Pharmacol ; 54(2): 185-92, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9626926

RESUMO

OBJECTIVE: In this study our aim was to assess pharmacokinetic effects and adverse cognitive effects of switches between generic and branded formulations of carbamazepine (CBZ). METHOD: Twelve patients were included in a randomized open-label, observer-blind, cross-over design with a double-baseline period, comparing three different formulations of carbamazepine in monotherapy--the innovatory branded form Tegretol and two generic forms, CBZ Pharmachemie and CBZ Pharbita. Cognitive assessment was carried out at baseline and 3 days after a cross-over. RESULTS: Area under the curve and a number of pharmacokinetic properties (serum concentration day curves, change in serum concentration (delta scores), peak/trough concentrations and peak time) did not differ among the three CBZ formulations. Therefore, the basic assumption for this study, i.e. to test pharmacokinetic-related differences in cognitive profile, was not met. In line with these findings, none of the cognitive variables showed statistically significant differences with respect to the cognitive profile during the day. CONCLUSION: Switches between the investigated generic CBZ formulations and the branded product did not result in any difference in cognitive profiles. These results are not necessarily valid, though, for other generic forms of CBZ, for other types of antiepileptic drugs or for CBZ treatment in higher doses or in polytherapy.


Assuntos
Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/farmacocinética , Carbamazepina/administração & dosagem , Carbamazepina/farmacocinética , Cognição/efeitos dos fármacos , Adulto , Anticonvulsivantes/sangue , Disponibilidade Biológica , Carbamazepina/sangue , Química Farmacêutica , Estudos Cross-Over , Medicamentos Genéricos , Epilepsia/sangue , Epilepsia/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Método Simples-Cego , Solubilidade
19.
Int J Biomed Comput ; 42(1-2): 135-41, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8880280

RESUMO

An epilepsy information system is described that supports routine patient care, research, and medical management. The patient's clinical data is ordered in time by the date of the patient contact when the data was collected. The clinical data is also classified into six categories. An unrestricted text group has text subjects in each of these groups as well as in a general free text area. The system is integrated with other information subsystems (e.g. patient registration, clinical chemistry laboratory, EEG department and pharmacy) as well as with the routinely used text processor. Data inquiries for research and medical management purposes are programmed in a Structured Query Language (SQL). The data needed to answer these queries are taken from the data collected in daily routine. The integration of the system is very useful because data only have to be entered once and can be used when and where needed. Patient data stored in this system is more accessible in general as well as more usable for research purposes compared with the patient data previously stored only on paper.


Assuntos
Epilepsia/diagnóstico , Sistemas de Informação Hospitalar , Armazenamento e Recuperação da Informação , Sistemas Computadorizados de Registros Médicos , Linguagens de Programação , Coleta de Dados , Progressão da Doença , Epilepsia/terapia , Humanos , Países Baixos , Integração de Sistemas
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