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1.
Braz J Biol ; 83: e275539, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37878961

RESUMEN

The search for healthy foods has attracted the industry's attention to developing products that use natural ingredients, including natural antioxidants. Antioxidants act as free radicals or oxygen scavengers, inhibiting lipid oxidation and adversely affecting meat products' sensory and nutritional quality. Several synthetic antioxidants have been used in the meat industry; however, studies point to health risks related to their consumption. Such fact drives research into natural antioxidants extracted from grains, oilseeds, spices, fruits, and vegetables, which may have a health-promoting effect. This manuscript evaluates the effectiveness of several natural antioxidants in improving the quality and shelf life of chicken meat products during processing, storage, and distribution. The potential effects of natural antioxidants widely used in chicken products are also discussed. It can be concluded that these natural antioxidants are possible substitutes for synthetic ones. However, their use can affect the product's characteristics.


Asunto(s)
Antioxidantes , Productos de la Carne , Animales , Antioxidantes/farmacología , Pollos , Carne/análisis , Productos de la Carne/análisis , Extractos Vegetales/farmacología
2.
J Dairy Sci ; 106(9): 6567-6576, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37532623

RESUMEN

Rumen-protected Lys (RPL) fed to Holstein cows prepartum resulted in a greater intake and improved health of their calves during the first 6 wk of life. However, whether increased supply of Lys in late gestation can influence placental tissue and, if so, which pathways are affected remain to be investigated. Therefore, we hypothesize that feeding RPL during late gestation could modulate placental metabolism, allowing for improved passage of nutrients to the fetus and thus influencing the offspring development. Therefore, we aimed to determine the effects of feeding RPL (AjiPro-L Generation 3, Ajinomoto Health and Nutrition North America) prepartum (0.54% DM of TMR) on mRNA gene expression profiles of placental samples of Holstein cows. Seventy multiparous Holstein cows were randomly assigned to 1 of 2 dietary treatments, consisting of TMR top-dressed with RPL (PRE-L) or without (control, CON), fed from 27 ± 5 d prepartum until calving. After natural delivery (6.87 ± 3.32 h), placentas were rinsed with physiological saline (0.9% sodium chloride solution) to clean any dirtiness from the environment and weighed. Then, 3 placentomes were collected, one from each placental region (cranial, central, and caudal), combined and flash-frozen in liquid nitrogen to evaluate the expression of transcripts and proteins related to protein metabolism and inflammation. Placental weights did not differ from cows in PRE-L (15.5 ± 4.03 kg) and cows in CON (14.5 ± 4.03 kg). Feeding RPL prepartum downregulated the expression of NOS3 (nitric oxide synthase 3), involved in vasodilation processes, and SOD1, which encodes the enzyme superoxide dismutase, involved in oxidative stress processes. Additionally, feeding RPL prepartum upregulated the expression of transcripts involved in energy metabolism (SLC2A3, glucose transporter 3; and PCK1, phosphoenolpyruvate carboxykinase 1), placental metabolism and cell proliferation (FGF2, fibroblast growth factor 2; FGF2R, fibroblast growth factor 2 receptor; and PGF, placental growth factor), Met metabolism (MAT2A, methionine adenosyltransferase 2-α), and tended to upregulate IGF2R (insulin-like growth factor 2 receptor). Placental FGF2 and LRP1 (low-density lipoprotein receptor-related protein 1) protein abundance were greater for cows that received RPL prepartum than cows in CON. In conclusion, feeding RPL to prepartum dairy cows altered uteroplacental expression of genes and proteins involved in cell proliferation, and in metabolism and transport of glucose. Such changes are illustrated by increased expression of SLC2A3 and PCK1 and increased protein abundance of FGF2 and LRP1 in uteroplacental tissue of cows consuming RPL.


Asunto(s)
Suplementos Dietéticos , Lisina , Femenino , Embarazo , Animales , Bovinos , Lisina/metabolismo , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Factor 2 de Crecimiento de Fibroblastos/farmacología , Lactancia , Rumen/metabolismo , Leche/metabolismo , Placenta , Factor de Crecimiento Placentario/metabolismo , Factor de Crecimiento Placentario/farmacología , Dieta/veterinaria , Periodo Posparto
4.
J Dairy Sci ; 105(9): 7787-7804, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35879168

RESUMEN

We investigated effects of rumen-protected Met (RPM) during a heat stress (HS) challenge on (1) hepatic abundance of mTOR, insulin, and antioxidant signaling proteins, (2) enzymes in 1-carbon metabolism, and (3) innate immunity. Holstein cows (n = 32; mean ± standard deviation, 184 ± 59 d in milk) were randomly assigned to 1 of 2 environmental groups, and 1 of 2 diets [total mixed ration (TMR) with RPM (Smartamine M; 0.105% dry matter as top-dress) or TMR without (CON); n = 16/diet] in a split-plot crossover design. There were 2 periods with 2 phases. During phase 1 (9 d), all cows were in thermoneutral conditions (TN; temperature-humidity index = 60 ± 3) and fed ad libitum. During phase 2 (9 d), half the cows (n = 8/diet) were exposed to HS using electric heat blankets. The other half (n = 8/diet) remained in TN, but was pair-fed to HS counterparts. After a 14-d washout and 7-d adaptation period, the study was repeated (period 2) and environmental treatments were inverted relative to phase 2, but dietary treatments were the same. Blood was collected on d 6 of each phase 2 to measure immune function and isolate whole-blood RNA. Liver biopsies were performed at the end of each period for cystathione ß-synthase (CBS) and methionine adenosyltransferase activity, glutathione concentration, and protein abundance. Data were analyzed using PROC MIXED in SAS. Abundance of CUL3, inhibitor of antioxidant responses, tended to be downregulated by HS suggesting increased oxidative stress. Heat-shock protein 70 abundance was upregulated by HS. Phosphorylated mTOR abundance was greater overall with RPM, suggesting an increase in pathway activity. An environment × diet (E × D) effect was observed for protein kinase B (AKT), whereas there was a tendency for an interaction for phosphorylated AKT. Abundance of AKT was upregulated in CON cows during HS versus TN, this was not observed in RPM cows. For phosphorylated AKT, tissue from HS cows fed CON had greater abundance compared with all other treatments. The same effect was observed for EIF2A (translation initiation) and SLC2A4 (insulin-induced glucose uptake). An E × D effect was observed for INSR due to upregulation in CON cows during HS versus TN cows fed CON or RPM. There was an E × D effect for CBS, with lower activity in RPM versus CON cows during HS. The CON cows tended to have greater CBS during HS versus TN. An E × D effect was observed for methionine adenosyltransferase, with lower activity in RPM versus CON during HS. Although activity increased in CON during HS versus TN, RPM cows tended to have greater activity during TN. Neutrophil and monocyte oxidative burst and monocyte phagocytosis decreased with HS. An (E × D) effect was observed for whole-blood mRNA abundance of CBS, SOD1 and CSAD; RPM led to upregulation during TN versus HS. Regardless of diet, CDO1, CTH, and SOD1 decreased with HS. Although HS increased hepatic HSP70 and seemed to alter antioxidant signaling, feeding RPM may help cows maintain homeostasis in mTOR, insulin signaling, and 1-carbon metabolism. Feeding RPM also may help maintain whole-blood antioxidant response during HS, which is an important aspect of innate immune function.


Asunto(s)
Enfermedades de los Bovinos , Trastornos de Estrés por Calor , Animales , Antioxidantes/metabolismo , Carbono/metabolismo , Bovinos , Enfermedades de los Bovinos/metabolismo , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Trastornos de Estrés por Calor/metabolismo , Trastornos de Estrés por Calor/veterinaria , Respuesta al Choque Térmico , Insulina/metabolismo , Lactancia/fisiología , Hígado/metabolismo , Metionina/metabolismo , Metionina Adenosiltransferasa , Leche/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Rumen/metabolismo , Superóxido Dismutasa-1 , Serina-Treonina Quinasas TOR/metabolismo
5.
J Dairy Sci ; 105(1): 856-865, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34635354

RESUMEN

Enhanced postruminal supply of methionine (Met) during the peripartal period alters protein abundance of insulin, AA, and antioxidant signaling pathways in subcutaneous adipose tissue (SAT). Whether SAT is directly responsive to supply of Met and can induce molecular alterations is unknown. Our objective was to examine whether enhanced Met supply during an oxidative stress challenge in vitro alters insulin, AA, inflammation, and antioxidant signaling-related protein networks. Four late-lactation Holstein cows (average 27.0 kg of milk per day) were used for SAT collection. Tissue was incubated in duplicate for 4 h in a humidified incubator with 5% CO2 at 37°C according to the following experimental design: control medium with an "ideal" profile of essential AA (CTR; Lys:Met 2.9:1), CTR plus 100 µM H2O2 (HP), or CTR with greater Met supply plus 100 µM H2O2 (HPMET; Lys:Met 2.5:1). Molecular targets associated with insulin signaling, lipolysis, antioxidant nuclear factor, erythroid 2 like 2 (NFE2L2), inflammation, and AA metabolism were determined through reverse-transcription quantitative PCR and western blotting. Data were analyzed using the MIXED procedure of SAS 9.4 (SAS Institute Inc.). Among proteins associated with insulin signaling, compared with CTR, HP led to lower abundance of phosphorylated AKT serine/threonine kinase (p-AKT) and solute carrier family 2 member 4 (SLC2A4; insulin-induced glucose transporter). Although incubation with HPMET restored abundance of SLC2A4 to levels in the CTR and upregulated abundance of fatty acid synthase (FASN) and phosphorylated 5'-prime-AMP-activated protein kinase (p-AMPK), it did not alter p-AKT, which remained similar to HP. Among proteins associated with AA signaling, compared with CTR, challenge with HP led to lower abundance of phosphorylated mechanistic target of rapamycin (p-MTOR), and HPMET did not restore abundance to CTR levels. Among inflammation-related targets studied, incubation with HPMET led to greater protein abundance of nuclear factor kappa B subunit p65 (NFKB-RELA). The response in NFKB observed with HPMET was associated with a marked upregulation of the antioxidant transcription regulator NFE2L2 and the antioxidant enzyme glutathione peroxidase 1 (GPX1). No effects of treatment were detected for mRNA abundance of proinflammatory cytokines or antioxidant enzymes, underscoring the importance of post-transcriptional regulation. Overall, data indicated that short-term challenge with H2O2 was particularly effective in reducing insulin and AA signaling. Although a greater supply of Met had little effect on those pathways, it seemed to restore the protein abundance of the insulin-induced glucose transporter. Overall, the concomitant upregulation of key inflammation and antioxidant signaling proteins when a greater level of Met was supplemented to oxidant-challenged SAT highlighted the potential role of this AA in regulating the inflammatory response and oxidant status. Further studies should be conducted to assess the role of postruminal supply of Met and other AA in the regulation of immune, antioxidant, and metabolic systems in peripartal cow adipose tissue.


Asunto(s)
Antioxidantes , Metionina , Tejido Adiposo , Animales , Bovinos , Dieta , Suplementos Dietéticos , Femenino , Peróxido de Hidrógeno , Insulina , Lactancia
6.
J Dairy Sci ; 105(3): 2256-2274, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34955262

RESUMEN

Providing adequate concentrations of AA in the prepartum diet is pivotal for the cow's health and performance. However, less is known about the potential in utero effects of particular AA on early-life performance of calves. This experiment was conducted to determine the effects on dairy calves when their dams were fed rumen-protected lysine (RPL; AjiPro-L Generation 3, Ajinomoto Heartland Inc.; 0.54% dry matter of total mixed ration as top dress) from 26 ± 4.6 d (mean ± standard deviation) before calving until calving. Seventy-eight male (M) and female (F) Holstein calves were assigned to 2 treatments based on their dams' prepartum treatment, RPL supplementation (PRE-L) or without RPL (CON). At the time of birth (0.5-2 h after calving), before colostrum was fed, blood samples were collected. An initial body weight was obtained at 1 to 3 h after birth. Calves were fed 470 g of colostrum replacer (Land O'Lakes Bovine IgG Colostrum Replacer, Land O'Lakes, Inc.) diluted in 3.8 L of water. Calves were provided water ad libitum and fed milk replacer (Advance Excelerate, Milk Specialties Global Animal Nutrition; 28.5% crude protein, 15% fat) at 0600 h and 1700 h until 42 d of age. Calves were measured weekly, at weaning (d 42), and at the end of the experimental period (d 56). Plasma concentrations of AA were measured on d 0, 7, and 14 d using ultra-performance liquid chromatography-mass spectrometry (Waters) with a derivatization method (AccQ-Tag Derivatization). Final body weight was greater for M (87 ± 11 kg) than F (79 ± 7 kg). Calves in PRE-L tended to have greater dry matter (814 ± 3 g/d) and crude protein (234 ± 6 g/d) intakes than those in CON (793 ± 9 g/d and 228 ± 11 g/d, respectively). Calves in PRE-L had greater average daily gain (0.96 ± 0.04 kg/d) than calves in CON (0.85 ± 0.03 kg/d) during wk 6 to 8. Calves in PRE-L tended to be medicated fewer days than CON (4.7 ± 1.2 d vs. 6.2 ± 3.4 d, respectively). Calves in PRE-L-M and CON-F (2,916 ± 112 µM and 2,848 ± 112 µM, respectively) had greater total AA concentration in plasma than calves in PRE-L-F and CON-M (2,684 ± 112 µM and 2,582 ± 112 µM, respectively). Calves in PRE-L-F and CON-M (4.09 ± 0.11% and 4.16 ± 0.11%, respectively) had greater concentration of Lys as a percentage of total AA compared with calves in CON-F and PRE-L-M (3.91 ± 0.11% and 3.90 ± 0.11%, respectively). Calves in PRE-L tended to have greater percentage of phagocytic neutrophils (39.6 ± 1.59%) than calves in CON (35.9 ± 1.59%). In conclusion, increasing the metabolizable lysine provided to prepartum dairy cows had modest effect over offspring performance, with the major result being a greater average daily gain for calves in PRE-L during the preweaning phase (wk 6-8).


Asunto(s)
Lisina , Rumen , Alimentación Animal/análisis , Animales , Peso Corporal , Bovinos , Calostro , Dieta/veterinaria , Femenino , Lisina/metabolismo , Masculino , Leche/metabolismo , Embarazo , Rumen/metabolismo , Destete
7.
Theriogenology ; 173: 102-111, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34365138

RESUMEN

The objective of the present study was to evaluate the effect of feeding rumen-protected methionine (RPM) during the peripartal period and early lactation on mRNA gene expression profiles of uterine cytological smear and endometrial samples of Holstein cows (n = 20). Treatments consisted of a supplementation with RPM [MET; n = 11; RPM at a rate of 0.08 % of DM: Lys:Met = 2.8:1, (Smartamine® M Adisseo, Alpharetta, GA, USA)] and no supplementation (CON; n = 9; Lys:Met = 3.5:1). Uterine cytology smears and endometrial samples were collected at 15, 30, and 73 days in milk (DIM) and analyzed for expression of genes related with metabolism, inflammation, and methionine metabolism. Regarding the cytological smear samples, RPM supplementation tended to increase mRNA expression of methionine adenosyltransferase 1 alpha (MAT1A) and increased the mRNA expression of fibroblast growth factor 7 (FGF7), with an effect of time for the latter. On the other hand, RPM decreased mRNA expression for glucose transporter 4 (GLUT4), interleukin 1 beta (IL-1ß), interleukin 6 (IL-6), interleukin 8 (IL-8), prostaglandin E synthase 3 (PTGES3), translocator protein 18 kDa (TSPO), mucin 1 (MUC1) and superoxide dismutase (SOD1) in cytological smear samples. There was an effect of time for all variables except MAT1A, with decreasing expression over time. There was a TRT × TIME interaction for GLUT4 mRNA expression, with higher GLUT4 mRNA expression for cows fed CON than for cows fed RPM at time 15 and a tendency to higher expression for cows fed CON on time 30 when compared with cows fed RPM. For uterine tissue samples, feeding RPM increased the mRNA expression of lecithin-cholesterol acyltransferase (LCAT), S-adenosyl-l-homocysteine hydrolase (SAAH), FGF7, GLUT4, and apolipoproteins 3 (APOL3), with an effect of time for APOL3 where its expression increased over time. There was a tendency for cows fed RPM to have decreased IL1ß mRNA expression. In conclusion, feeding RPM during transition period and early lactation is beneficial for uterine immune response and metabolism in early lactation as indicated by the favorable expressions of genes affecting the uterine immunometabolism during such a challenging period.


Asunto(s)
Metionina , Periodo Periparto , Animales , Bovinos , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Expresión Génica , Lactancia , Leche
8.
Ann Oncol ; 29(8): 1634-1657, 2018 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-30032243
9.
J Dairy Sci ; 101(9): 8532-8543, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29935830

RESUMEN

Trace minerals are vital in the antioxidant response during oxidative stress; however, limited research is available on the effects of trace mineral supplementation during an aflatoxin (AF) challenge. The objective of the study was to determine the effects of 2 subcutaneous injections of 15 mg/mL of Cu, 5 mg/mL of Se, 60 mg/mL of Zn, and 10 mg/mL of Mn (Multimin 90, Multimin North America, Fort Collins, CO) given at 1 mL/90.7 kg of average body weight in response to an AF challenge. Fifty-eight Holstein cows [body weight (mean ± SD) = 734 ± 6 0kg; days in milk = 191 ± 93] were assigned to 1 of 3 treatments in a randomized complete block design. The experimental period (63 d) was divided into an adaptation phase (d 1-56) and a measurement phase (d 57-63). From d 57 to 59, cows received an AF challenge that consisted of 100 µg of aflatoxin B1/kg of dietary dry matter intake (DMI) administered orally via balling gun. Treatments were saline injection and no AF challenge (NEG), saline injection and AF challenge (POS), and trace mineral injection and AF challenge (MM). Injections were performed subcutaneously on d 1 and 29. Milk was sampled 3 times daily from d 56 to 63, blood was sampled on d 0, 56, 60, and 63, and liver samples were taken on d 0 and 60. Two treatment orthogonal contrasts [CONT1 (NEG vs. POS) and CONT2 (POS vs. MM)] were made. Cows in NEG had lower AF excretion in milk and greater 3.5% fat-corrected milk (32.1 ± 1.37 kg/d) compared with cows in POS (28.6 ± 1.43 kg/d). Feed efficiencies (3.5% fat-corrected milk/DMI, energy-corrected milk/DMI, and milk/DMI) were greater for cows in NEG (1.42 ± 0.07, 1.46 ± 0.07, and 1.45 ± 0.07, respectively) than cows in POS (1.16 ± 0.08, 1.18 ± 0.08, and 1.22 ± 0.07, respectively). Cows in POS had greater milk urea nitrogen and blood urea nitrogen than cows in MM. Liver concentrations of Se and Fe were greater for cows in MM compared with cows in POS. Cows in MM tended to have greater plasma glutathione peroxidase activity compared with cows in POS. An upregulation of liver GPX1 was observed for cows in POS compared with cows in MM. In conclusion, subcutaneous injection of trace minerals maintained an adequate antioxidant response when an AF challenge was present.


Asunto(s)
Aflatoxinas/toxicidad , Enfermedades de los Bovinos/tratamiento farmacológico , Inflamación/veterinaria , Estrés Oxidativo/efectos de los fármacos , Oligoelementos/farmacología , Alimentación Animal , Animales , Bovinos , Cobre/farmacología , Dieta , Suplementos Dietéticos , Femenino , Inflamación/tratamiento farmacológico , Lactancia , Manganeso/farmacología , Embarazo , Selenio/farmacología , Zinc/farmacología
10.
Theriogenology ; 114: 116-125, 2018 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-29609181

RESUMEN

During the transition from prepartum to early lactation, dairy cows often experience negative energy balance (NEB) that may result in reproductive stress and decreased fertility. The objective of this study was to observe the effects of rumen-protected methionine (RPM) on plasma amino acid concentrations, uterine cytology, immunohistochemistry (IHC) of glutathione peroxidase 1 (GPX) and superoxide dismutase 1 (SOD), and to confirm neutrophil extracellular trap (NET) formation. Multiparous Holstein cows (n = 20) were randomly assigned to two treatments starting at 21 d before calving until 73 days in milk (DIM). Treatments were: CON (n = 9, no supplementation, TMR with a Lys:Met = 3.5:1) and MET (n = 11, TMR + Smartamine® M with a Lys:Met = 2.8:1). Uterine endometrial biopsies, uterine cytology, and blood samples from the coccygeal artery or vein were collected at 15, 30, and 73 DIM. Blood plasma samples were analyzed for amino acids and metabolites. Uterine biopsies were analyzed for NET formation, neutrophil numbers, as well as GPX and SOD by IHC. Additionally, uterine cytology was analyzed for polymorphonuclear neutrophil (PMN) to epithelial cell percentage. Cows in CON had lower methionine plasma concentrations (18.05 ±â€¯2.0 µM) than cows in MET (30.39 ±â€¯1.6 µM). Cows in CON had greater cystine plasma concentrations (3.62 ±â€¯0.3 µM) than cows in MET (2.8 ±â€¯0.3 µM). No treatment differences were observed for SOD or GPX in the endometrium. Cows in CON tended to have a high score for positively immunolabeled GPX cells at 15 DIM than cows in MET. No treatment differences were observed for the percentage of PMN in uterine cytology, number of neutrophils, or extent of NET formation in the endometrium. A treatment by time interaction was observed for PMN percentage and the number of neutrophils: cows in MET tended to have greater PMN percentages than cows in CON at 15 DIM which decreased for subsequent days and cows in MET had greater neutrophil numbers in the endometrium at 30 DIM than cows in CON. In conclusion, dietary supplementation of RPM altered plasma amino acid concentrations and increased neutrophil infiltration in the postpartum period, suggesting improved uterine immunity.


Asunto(s)
Bovinos , Trampas Extracelulares/fisiología , Metionina/farmacología , Neutrófilos/fisiología , Útero/fisiología , Animales , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Lactancia , Metionina/administración & dosificación , Rumen , Útero/inmunología
11.
J Dairy Sci ; 101(1): 480-490, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29103714

RESUMEN

The periparturient period is the most critical phase in the productive cycle of dairy cows and is characterized by impairment of the immune system. Our objective was to evaluate the effect of feeding ethyl-cellulose rumen-protected methionine (RPM) starting at d -28 from expected parturition through 60 d in milk on biomarkers of inflammation, oxidative stress, and liver function as well as leukocyte function. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or the control plus ethyl-cellulose RPM (Mepron, Evonik Nutrition & Care GmbH). Mepron was supplied from -28 to 60 d in milk at a rate of 0.09% and 0.10% dry matter during the prepartum and postpartum period. That rate ensured that the ratio of Lys to Met in the metabolizable protein was close to 2.8:1. Blood samples from 15 clinically healthy cows per treatment were collected at d -30, -14, 1, 7, 21, 30, and 60 and analyzed for biomarkers of liver function, inflammation, and oxidative stress. Neutrophil and monocyte function in whole blood was measured in vitro at -14, 1, 7, 21, and 30 d in milk. The statistical model included the random effect of block and fixed effect of treatment, time, and its interaction. Compared with control, ethyl-cellulose RPM increased plasma cholesterol and paraoxonase after parturition. Among the inflammation biomarkers measured, ethyl-cellulose RPM led to greater albumin (negative acute-phase protein) and lower haptoglobin than control cows. Although concentration of IL-1ß was not affected by treatments, greater IL-6 concentration was detected in response to ethyl-cellulose RPM. Cows supplemented with ethyl-cellulose RPM had greater plasma concentration of ferric-reducing antioxidant power, ß-carotene, tocopherol, and total and reduced glutathione, whereas reactive oxygen metabolites were lower compared with control cows. Compared with control, ethyl-cellulose RPM enhanced neutrophil phagocytosis and oxidative burst. Overall, the results indicate that ethyl-cellulose RPM supply to obtain a Lys-to-Met ratio of 2.8:1 in the metabolizable protein during the periparturient period and early lactation is an effective approach to help mitigate oxidative stress and inflammation as well as enhance liver and neutrophil function in dairy cows.


Asunto(s)
Antioxidantes/farmacología , Suplementos Dietéticos , Inflamación/veterinaria , Metionina/farmacología , Leche/metabolismo , Estrés Oxidativo/efectos de los fármacos , Animales , Biomarcadores/análisis , Bovinos , Celulosa/análogos & derivados , Celulosa/farmacología , Femenino , Inflamación/prevención & control , Lactancia , Hígado/efectos de los fármacos , Hígado/metabolismo , Modelos Estadísticos , Neutrófilos/efectos de los fármacos , Periodo Periparto , Embarazo , Rumen/metabolismo
12.
J Dairy Sci ; 100(9): 7455-7467, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28711252

RESUMEN

The onset of lactation in dairy cows is characterized by severe negative energy and protein balance. Increasing Met availability during this time may improve milk production, hepatic lipid metabolism, and immune function. The aim of this study was to evaluate the effect of feeding ethyl-cellulose rumen-protected methionine (RPM; Mepron, Evonik Nutrition and Care GmbH, Hanau-Wolfgang, Germany) on the performance of dairy cows during prepartum and early-lactation periods. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or an ethyl-cellulose RPM diet. Ethyl-cellulose RPM was supplied from -28 to 60 d relative to parturition at a rate of 0.09% and 0.10% of dry matter during the prepartum and postpartum periods, respectively. That rate ensured that the ratio of Lys to Met in metabolizable protein was close to 2.8:1. Cows fed ethyl-cellulose RPM had dry matter intakes (DMI) that were 1.2 kg/d greater during the prepartum period and consequently had overall greater cumulative DMI than cows in the control group. Compared with controls, during the fresh period (1-30 d in milk; DIM) feeding ethyl-cellulose RPM increased DMI by 1.7 kg/d, milk yield by 4.1 kg/d, fat yield by 0.17 kg/d, milk protein yield by 0.20 kg/d, 3.5% fat-corrected milk by 4.3 kg/d, and energy-corrected milk by 4.4 kg/d. Although ethyl-cellulose RPM supplementation increased milk protein content by 0.16 percentage units compared with the control during the fresh period, no differences were observed for milk fat, lactose, and milk urea nitrogen concentration. During the high-producing period (31-60 DIM), cows fed ethyl-cellulose RPM increased DMI and milk yield by 1.45 and 4.4 kg/d, respectively. Ethyl-cellulose RPM also increased fat yield by 0.19 kg/d, milk protein yield by 0.17 kg/d, 3.5% fat-corrected milk by 4.7 kg/d, and energy-corrected milk by 4.8 kg/d compared with controls. Ethyl-cellulose RPM supplementation reduced plasma fatty acids in the fresh period and decreased γ-glutamyl transferase, indicating better liver function. In conclusion, when lysine was adequate, feeding ethyl-cellulose RPM to achieve a ratio close to 2.8:1 in metabolizable protein improved dairy cow performance from parturition through 60 DIM. The greater milk production was, at least in part, driven by the greater voluntary DMI and better liver function.


Asunto(s)
Celulosa/análogos & derivados , Lactancia/metabolismo , Metabolismo de los Lípidos , Hígado/metabolismo , Metionina/metabolismo , Leche/metabolismo , Animales , Bovinos , Celulosa/administración & dosificación , Dieta , Grasas de la Dieta/metabolismo , Femenino , Alemania , Sistema Inmunológico/fisiología , Lactosa/metabolismo , Lisina/administración & dosificación , Lisina/metabolismo , Metionina/administración & dosificación , Proteínas de la Leche/biosíntesis , Periodo Posparto , Embarazo , Rumen
13.
Theriogenology ; 96: 1-9, 2017 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-28532823

RESUMEN

Multiparous Holstein cows were assigned in a randomized complete block design into four treatments from 21 d before calving to 30 d in milk (DIM). Treatments were: MET [n = 19, fed the basal diet + rumen-protected methionine at a rate of 0.08% (w/w) of the dry matter, Smartamine® M], CHO (n = 17, fed the basal diet + choline 60 g/d, Reashure®), MIX (n = 21, fed the basal diet + Smartamine® M at a rate of 0.08% (w/w) of the dry matter and 60 g/d Reashure®), and CON (n = 20, no supplementation, fed the close-up and fresh cow diets). Follicular development was monitored via ultrasound every 2 d starting at 7 DIM until ovulation (n = 37) or aspiration (n = 40) of the first postpartum dominant follicle (DF). Follicular fluid from 40 cows was aspirated and cells were retrieved immediately by centrifugation. Gene expression of TLR4, TNF, IL1-ß, IL8, IL6, LHCGR, STAR, 3ß-HSD, P450scc, CYP19A1, IRS1, IGF, MAT1A, and SAHH, was measured in the follicular cells of the first DF. Cows in CON had higher TNF, TLR4, and IL1-ß mRNA expression (11.70 ± 4.6, 21.29 ± 10.4, 6.28 ± 1.4, respectively) than CHO (2.77 ± 0.9, 2.16 ± 0.9, 2.29 ± 0.7, respectively), and MIX (2.23 ± 0.7, 1.46 ± 0.6, 2.92 ± 0.8, respectively). Cows in CON had higher IL1-ß expression (6.27 ± 1.4) than cows in MET (3.28 ± 0.6). Expression of IL8 mRNA was lower for cows in CHO (0.98 ± 0.3) than cows in CON (4.90 ± 0.7), MET (6.10 ± 1.7), or MIX (5.05 ± 1.8). Treatments did not affect mRNA expression of LHCGR, STAR, P450scc, CYP19A, SAHH, MAT1A, or IL6 however, 3ß-HSD expression was higher for cows in MET (1.46 ± 0.3) and MIX (1.25 ± 0.3) than CON (0.17 ± 0.04) and CHO (0.26 ± 0.1). Supplementation of methionine, choline, and both methionine and choline during the transition period did not affect days to first ovulation or number of cows that ovulated the first follicular wave. Plasma and follicular fluid estradiol and progesterone concentrations were not different among treatments. Methionine concentrations in the follicular fluid of the first postpartum DF was higher for cows in MET (18.2 ± 0.1 µM) than cows in CON (11.1 ± 0.9 µM). In conclusion, supplementing choline and methionine during the transition period changed mRNA expression in follicular cells and dietary methionine supplementation increased plasma and follicular fluid concentrations of methionine of the first postpartum DF in Holstein cows.


Asunto(s)
Bovinos/fisiología , Colina/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Metionina/farmacología , Folículo Ovárico/efectos de los fármacos , Animales , Bovinos/sangre , Bovinos/inmunología , Colina/administración & dosificación , Colina/química , Formas de Dosificación , Estradiol/sangre , Femenino , Regulación de la Expresión Génica/inmunología , Metionina/administración & dosificación , Metionina/química , Leche , Periodo Posparto , Embarazo
14.
J Dairy Sci ; 99(11): 9027-9039, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27614833

RESUMEN

Previous studies with calves and other species have provided evidence that blood serum-derived proteins and fructooligosaccharides (FOS) may benefit intestinal health. We assessed the effects of supplementing products containing serum proteins as a component of arrival fluid support or serum proteins plus FOS (in addition to additional solids, minerals, and vitamins) in an early life dietary supplement on performance, morbidity, and mortality of stressed (transport, cold) male calves. Male Holstein calves (n=93) <1 wk old were stratified by arrival body weight (BW) and plasma protein concentration, and then randomly assigned to 1 of 4 treatment groups in a 2×2 factorial arrangement of one-time administration of fluid support [either control electrolyte solution (E) or the serum protein-containing arrival formula (AF)] and 14d of either no supplementation (NG) or supplementation with Gammulin (G; APC Inc., Ankeny, IA), which contains serum proteins and FOS in addition to other solids, minerals, and vitamins. Upon arrival at the research facility, calves were orally administered either AF or E. At the next feeding, half of the calves from each fluid support treatment received either milk replacer (20% crude protein, 20% fat) or the same milk replacer supplemented with G (50g/d during the first 14d). Starter and water were freely available. Feed offered and refused was recorded daily. Calf health was assessed by daily assignment of fecal and respiratory scores. Stature measures and BW were determined weekly. Blood samples were obtained at d 0 (before treatments), 2, 7, 14, and 28. Calves were weaned at d 42 and remained in the experiment until d 56. After 2 wk of treatments, calves previously fed AF had greater body length (66.6 vs. 66.0cm), intakes of dry matter (38.7 vs. 23.5g/d) and crude protein (9.2 vs. 5.6g/d) from starter, and cortisol concentration in blood (17.0 vs. 13.9 ng/mL) than calves fed E. Supplementation with G resulted in greater BW gain during the first 2 wk, increased intakes of dry matter and CP, and decreased respiratory scores. For the 8-wk experiment, G supplementation resulted in lower mean fecal score (1.6 vs. 1.8) and fewer antibiotic treatments per calf (1.5 vs. 2.5) than NG. Survival was greater in G than in NG calves (98 vs. 84%). Despite the marked reduction in morbidity and mortality, blood indicators of acute-phase response, urea N, and total protein were not affected by AF or G in transported cold-stressed male calves.


Asunto(s)
Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Proteínas Sanguíneas/administración & dosificación , Dieta/veterinaria , Alimentos Formulados/análisis , Estrés Fisiológico , Reacción de Fase Aguda/sangre , Animales , Animales Recién Nacidos , Biomarcadores/sangre , Peso Corporal , Bovinos/crecimiento & desarrollo , Heces/química , Inmunoglobulina G/sangre , Masculino , Micronutrientes/administración & dosificación , Micronutrientes/análisis , Nitrógeno/orina , Oligosacáridos/administración & dosificación
15.
J Dairy Sci ; 99(11): 8956-8969, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27592438

RESUMEN

The immunometabolic status of peripartal cows is altered due to changes in liver function, inflammation, and oxidative stress. Nutritional management during this physiological state can affect the biological components of immunometabolism. The objectives of this study were to measure concentrations of biomarkers in plasma, liver tissue, and milk, and also polymorphonuclear leukocyte function to assess the immunometabolic status of cows supplemented with rumen-protected methionine (Met) or choline (CHOL). Forty-eight multiparous Holstein cows were used in a randomized complete block design with 2×2 factorial arrangement of Met (Smartamine M, Adisseo NA, Alpharetta, GA) and CHOL (ReaShure, Balchem Inc., New Hampton, NY) level (with or without). Treatments (12 cows each) were control (CON), no Met or CHOL; CON and Met (SMA); CON and CHOL (REA); and CON and Met and CHOL (MIX). From -50 to -21d before expected calving, all cows received the same diet [1.40Mcal of net energy for lactation (NEL)/kg of DM] with no Met or CHOL. From -21d to calving, cows received the same close-up diet (1.52Mcal of NEL/kg of DM) and were assigned randomly to each treatment. From calving to 30d, cows were on the same postpartal diet (1.71Mcal of NEL/kg of DM) and continued to receive the same treatments until 30d. The Met supplementation was adjusted daily at 0.08% DM of diet, and CHOL was supplemented at 60g/cow per day. Liver (-10, 7, 21, and 30d) and blood (-10, 4, 8, 20, and 30d) samples were harvested for biomarker analyses. Neutrophil and monocyte phagocytosis and oxidative burst were assessed at d 1, 4, 14, and 28d. The Met-supplemented cows tended to have greater plasma paraoxonase. Greater plasma albumin and IL-6 as well as a tendency for lower haptoglobin were detected in Met- but not CHOL-supplemented cows. Similarly, cows fed Met compared with CHOL had greater concentrations of total and reduced glutathione (a potent intracellular antioxidant) in liver tissue. Upon a pathogen challenge in vitro, blood polymorphonuclear leukocyte phagocytosis capacity and oxidative burst activity were greater in Met-supplemented cows. Overall, liver and blood biomarker analyses revealed favorable changes in liver function, inflammation status, and immune response in Met-supplemented cows.


Asunto(s)
Colina/farmacología , Metionina/farmacología , Periodo Periparto/efectos de los fármacos , Rumen/efectos de los fármacos , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Antioxidantes/farmacología , Arildialquilfosfatasa/sangre , Biomarcadores/sangre , Bovinos , Colina/sangre , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Glutatión/sangre , Inflamación/tratamiento farmacológico , Inflamación/veterinaria , Interleucina-6/sangre , Hígado/efectos de los fármacos , Hígado/metabolismo , Metionina/sangre , Estrés Oxidativo/efectos de los fármacos , Periodo Periparto/sangre , Rumen/metabolismo , Albúmina Sérica/metabolismo
16.
J Dairy Sci ; 99(10): 8028-8040, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27522430

RESUMEN

Oral supplementation of clay has been reported to function as buffer in dairy cows. However, its effects on rumen, blood, and fecal pH have varied among studies. Our objective was to determine the effects of 3 concentrations of dietary clay supplementation after a grain challenge. Ten multiparous rumen-cannulated Holstein cows [body weight (mean ± standard deviation)=648±12kg] with 142±130 (60 to 502) days in milk were assigned to 1 of 5 treatments in a replicated 5×5 Latin square design balanced to measure carryover effects. Periods (21d) were divided into an adaptation phase (d 1 to 18, with regular total mixed ration fed ad libitum) and a measurement phase (d 19 to 21). Feed was restricted on d 18 to 75% of the average of the total mixed ration fed from d 15 to 17 (dry matter basis), and on d 19 cows received a grain challenge. The challenge consisted of 20% finely ground wheat administered into the rumen via a rumen cannula, based on the average dry matter intake obtained on d 15 to 17. Treatments were POS (no clay plus a grain challenge), 3different concentrations of clay (0.5, 1, or 2% of dietary dry matter intake), and control (C; no clay and no grain challenge). Statistical analysis was performed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Contrasts 1 (POS vs. C) and 2 (POS vs. the average of 0.5, 1, or 2%) were compared, along with linear and quadratic treatment effects. Rumen, fecal, and blood pH, along with blood metabolites, were measured at 0, 4, 8, 12, 16, 20, 24, 36, and 48h relative to the grain challenge. Cows fed POS had lower rumen pH [(mean ± standard error) 6.03±0.06] than cows fed C (6.20±0.06). Cow fed POS had lower fecal pH (6.14±0.04) than cows fed C (6.38±0.04). We observed a linear treatment effect for rumen pH and fecal pH. Fecal pH (6.22±0.04) was higher for cows fed clay (contrast 2) then for cows fed POS (6.14±0.04). We also observed a treatment difference (contrast 2) for negative incremental area under the curve, pH below 5.6 × h/d, (0.5% clay=7.93±0.83, 1% clay=8.56±0.83, and 2% clay=7.79±0.83) compared with POS (11.0±0.83). Cows fed clay tended to have higher milk yield (0.5% clay=28.8±3.4kg, 1% clay=30.2±3.4kg, and 2% clay=29.1±3.4kg, contrast 2), and had higher 3.5% fat-corrected milk (0.5% clay=29.9±3.5kg, 1% clay=34.1±3.5kg, and 2% clay=33.1±3.4kg), and higher energy-corrected milk (0.5% clay=29.1±3.3kg, 1% clay=32.8±3.4kg, and 2% clay=31.6±3.3kg) than cows fed POS (27.7±3.4kg, 28.0±3.4kg, 27.7±3.3kg, respectively). In conclusion, cows fed clay had higher rumen pH, energy-corrected milk, fat-corrected milk, and a trend for milk yield than cows fed POS.


Asunto(s)
Silicatos de Aluminio/administración & dosificación , Grano Comestible , Heces/química , Leche/química , Rumen/metabolismo , Alimentación Animal/análisis , Animales , Bovinos , Arcilla , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Concentración de Iones de Hidrógeno , Lactancia
17.
Theriogenology ; 85(9): 1669-1679, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26928647

RESUMEN

Our objective was to determine the effects of supplementing methionine and choline during the prepartum and postpartum periods on preimplantation embryos of Holstein cows. Multiparous cows were assigned in a randomized complete-block design into four treatments from 21 days before calving to 30 days in milk (DIM). Treatments (TRT) were MET (n = 9, fed the basal diet + rumen-protected methionine at a rate of 0.08% [w:w] of the dry matter [DM], Smartamine M), CHO (n = 8, fed the basal diet + choline 60 g/d, Reashure), MIX (n = 11, fed the basal diet + Smartamine M and 60 g/d Reashure), and CON (n = 8, no supplementation, fed the close-up and fresh cow diets). Cows were randomly reassigned to two new groups (GRP) to receive the following diets from 31 to 72 DIM; control (CNT, n = 16, fed a basal diet) and SMT (n = 20, fed the basal diet + 0.08% [w:w] of the dry matter intake as methionine). An progesterone intravaginal insert (CIDR) device was inserted in all cows after follicular aspiration (60 DIM) and superovulation began at Day 61.5 using FSH in eight decreasing doses at 12-hour intervals over a 4-day period. On Days 63 and 64, all cows received two injections of PGF2α, and CIDR was removed on Day 65. Twenty-four hours after CIDR removal, ovulation was induced with GnRH. Cows received artificial insemination at 12 hours and 24 hours after GnRH. Embryos were flushed 6.5 days after artificial insemination. Global methylation of the embryos was assessed by immunofluorescent labeling of 5-methylcytosine, whereas lipid content was assessed by staining with Nile red. Nuclear staining was used to count the total number of cells per embryo. There was no difference between TRT, GRP, or their interaction (P > 0.05) for embryo recovery, embryos recovered, embryo quality, embryo stage, or cells per embryo. Methylation of the DNA had a TRT by GRP interaction (P = 0.01). Embryos from cows in CON-CNT had greater (P = 0.04) methylation (0.87 ± 0.09 arbitrary units [AU]) than embryos from cows in MET-CNT (0.44 ± 0.07 AU). The cytoplasmic lipid content was not affected (P > 0.05) by TRT or their interaction, but lipid content was greater (P = 0.04) for SMT (7.02 ± 1.03 AU) than that in CNT (3.61 ± 1.20 AU). In conclusion, cows in MET-CNT had embryos with lower methylation, and SMT cows had a higher lipid content than CNT. Methionine supplementation seems to impact the preimplantation embryo in a way that enhances its capacity for survival because there is strong evidence that endogenous lipid reserves serve as an energy substrate.


Asunto(s)
Blastocisto/efectos de los fármacos , Bovinos/embriología , Colina/uso terapéutico , Suplementos Dietéticos , Metionina/uso terapéutico , Animales , Metilación de ADN/efectos de los fármacos , Desarrollo Embrionario/efectos de los fármacos , Metabolismo de los Lípidos
18.
Homo ; 67(3): 203-15, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27016326

RESUMEN

The objective of this paper was to contribute to the discussion regarding the socio-political organization of south-western Iberian Middle Neolithic populations. To that end, the preservation and distribution of human remains and the dispersion of grave goods within two rooms of the Bom Santo Cave (Rooms A and B) were investigated and combined with genetic and isotopic data previously published. Grave goods distribution and skeletal analyses highlighted an important diversity in terms of funerary practices thus corroborating data from ancient DNA and Sr/O isotopic analyses that suggested a great genetic and geographic diversity. Grave goods presented an uneven spatial distribution and were made of raw materials from different sources and using different pottery manufacturing styles albeit typologically homogeneous. The preservation and distribution of human remains suggested that Room A was mainly used for secondary depositions while Room B was used for both primary and secondary depositions. No link between the two rooms was found since remains from the same individuals were apparently exclusive of one room or another. The results suggest that this society presented substantial inner genetic, social and geographical heterogeneity. Most probably, this was due to the presence of distinct but coeval groups in the cave that shared a larger-scale social identity (as in "segmentary societies") or, less likely, to the presence of one single, but internally heterogeneous society (as in fully sedentary societies) that assimilated foreigners.


Asunto(s)
Fósiles/historia , Antropología Física , Cementerios/historia , Femenino , Fósiles/anatomía & histología , Genética de Población , Historia Antigua , Humanos , Masculino , Portugal
19.
J Dairy Sci ; 99(1): 234-44, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26585478

RESUMEN

The availability of Met in metabolizable protein (MP) of a wide range of diets for dairy cows is low. During late pregnancy and early lactation, in particular, suboptimal Met in MP limits its use for mammary and liver metabolism and also for the synthesis of S-adenosylmethionine, which is essential for many biological processes, including DNA methylation. The latter is an epigenetic modification involved in the regulation of gene expression, hence, tissue function. Thirty-nine Holstein cows were fed throughout the peripartal period (-21 d to 30 d in milk) a basal control (CON) diet (n=14) with no Met supplementation, CON plus MetaSmart (MS; Adisseo NA, Alpharetta, GA; n=12), or CON plus Smartamine M (SM; Adisseo NA; n=13). The total mixed ration dry matter for the close-up and lactation diets was measured weekly, then the Met supplements were adjusted daily and top-dressed over the total mixed ration at a rate of 0.19 (MS) or 0.07% (SM) on a dry matter basis. Liver tissue was collected on -10, 7, and 21 d for global DNA and peroxisome proliferator-activated receptor alpha (PPARα) promoter region-specific methylation. Several PPARα target and putative target genes associated with carnitine synthesis and uptake, fatty acid metabolism, hepatokines, and carbohydrate metabolism were also studied. Data were analyzed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC) with the preplanned contrast CON versus SM + MS. Global hepatic DNA methylation on d 21 postpartum was lower in Met-supplemented cows than CON. However, of 2 primers used encompassing 4 to 12 CpG sites in the promoter region of bovine PPARA, greater methylation occurred in the region encompassing -1,538 to -1,418 from the transcription start site in cows supplemented with Met. Overall expression of PPARA was greater in Met-supplemented cows than CON. Concomitantly, PPARA-target genes, such as ANGPTL4, FGF21, and PCK1, were also upregulated overall by Met supplementation. The upregulation of PPARα target genes indicates that supplemental Met, likely through the synthesis of S-adenosylmethionine, activated PPARA-regulated signaling pathways. Upregulation of hepatic PPARA has been associated with improved lipid metabolism and immune function, both of which were reported in companion publications from this study. In turn, those positive effects resulted in improved postpartal health and performance. Further research is needed to study more closely the mechanistic connections between global DNA and promoter region-specific PPARA methylation with PPARA expression and functional outcomes in liver.


Asunto(s)
Bovinos/fisiología , Suplementos Dietéticos , Metionina/administración & dosificación , Leche/metabolismo , PPAR alfa/genética , Animales , ADN/genética , Metilación de ADN , Dieta/veterinaria , Femenino , Regulación de la Expresión Génica , Lactancia , Hígado/metabolismo , Periodo Posparto , Embarazo , Regiones Promotoras Genéticas/genética , Rumen/metabolismo , Regulación hacia Arriba
20.
J Dairy Sci ; 98(6): 4062-73, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25795491

RESUMEN

Dairy cows experiencing heat stress have reduced intake and increased reliance on glucose, making feeding strategies capable of improving diet digestibility plausible for improving postrumen nutrient flow and performance. The effect of yeast on digestion and performance of lactating cows during the warm summer months of southeastern Brazil was evaluated. Cows were individually fed in tie stalls and temperature-humidity index was above 68 during 75.6% of the experiment. Twenty-eight Holstein cows (207±87 d in milk) received a standard diet for 14 d and then a treatment for 70 d, in a covariate-adjusted, randomized block design with repeated measures over time. Treatments were yeast (Saccharomyces cerevisiae) or control. Yeast was top dressed to the diet in the morning, equivalent to 25×10(10) cfu of live cells and 5×10(10) cfu of dead cells. The diet contained corn silage (37.7%), Tifton silage (7.1%), raw soybeans (4.1%), soybean meal (16.5%), finely ground corn (20.7%), and citrus pulp (11.9%). Yeast increased milk (26.7 vs. 25.4 kg/d) and solids yield (3.06 vs. 2.92 kg/d), especially lactose. Response in milk yield was consistent over time and started at d 5. The daily intake of digestible OM, total-tract digestibility of nutrients, urinary allantoin excretion, chewing pattern throughout the day, and dry matter intake did not respond to yeast. A trend was observed for increased plasma glucose with yeast (62.9 vs. 57.3mg/dL), lowered respiratory frequency (48 vs. 56 breaths/min), and increased plasma niacin content (1.31 vs. 1.22 µg/mL), though cows had similar rectal temperature. Ruminal lactate and butyrate as proportions of ruminal organic acids were reduced by yeast, but no effects on other organic acids, ruminal pH, or protozoa content were detected. Plasma urea N over 24h was increased by yeast. On d 72 to 74, citrus pulp was abruptly replaced with finely ground corn to induce acidosis. The increased load of starch increased dry matter intake between 0700 and 1300 h, jugular blood partial pressure of CO2, HCO3-, and base excess, and decreased blood pH for both treatments. The yeast treatment had a higher blood pH compared with the control, 7.34, and 7.31, respectively. Yeast supplementation improved lactation performance of dairy cows under heat stress. Improvement in lactation performance apparently involved the regulation of body homeothermia, rather than improved digestibility.


Asunto(s)
Bovinos/fisiología , Suplementos Dietéticos , Leche/metabolismo , Levadura Seca/farmacología , Acidosis/inducido químicamente , Acidosis/veterinaria , Animales , Brasil , Dieta/veterinaria , Digestión/efectos de los fármacos , Femenino , Lactancia/fisiología , Lactosa/metabolismo , Masticación , Rumen/metabolismo , Ensilaje/análisis , Glycine max , Almidón/metabolismo , Zea mays
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