101
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Arriola Apelo S, Singer L, Ray W, Helm R, Lin X, McGilliard M, St-Pierre N, Hanigan M. Casein synthesis is independently and additively related to individual essential amino acid supply. J Dairy Sci 2014; 97:2998-3005. [DOI: 10.3168/jds.2013-7422] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 01/07/2014] [Indexed: 12/17/2022]
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102
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Šamanc H, Kirovski D, Lakić N, Celeska I, Bojković-Kovačević S, Sladojević Ž, Ivanov I. A comparison of the concentrations of energy-balance-related variables in jugular and mammary vein blood of dairy cows with different milk yield. Acta Vet Hung 2014; 62:52-63. [PMID: 24334081 DOI: 10.1556/avet.2013.055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of this study was to compare the concentrations of blood variables obtained simultaneously from the jugular and mammary veins of dairy cows. Eighty Holstein cows were divided into four equal groups: dry, low- (LY), medium- (MY) and high-yielding (HY). Blood insulin, glucose, non-esterified fatty acid (NEFA), beta-hydroxybutyrate (BHBA) and urea concentrations were measured. The jugular and mammary vein (J/M) ratio between concentrations of each variable was calculated. Differences between the groups of cows in concentrations of variables in the jugular vein were not in accordance with those obtained for the mammary vein. J/M values for insulin and glucose concentrations were above 1.0 in all groups of cows. The ratios for NEFA and BHBA concentrations were under or equal to 1.0 in dry and LY cows but above 1.0 in the MY and HY groups, indicating that in MY and HY cows those metabolites are apparently utilised by the mammary gland. J/M values for urea were above 1.0 in dry and LY cows but less than 1.0 in groups MY and HY, indicating that in the latter case urea is apparently released by the mammary gland. In conclusion, J/M for NEFA, BHBA and urea may be useful for estimation of the critical point when the mammary gland receives insufficient energy precursors for its current activity.
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Affiliation(s)
- Horea Šamanc
- 1 University of Belgrade Department of Farm Animal Diseases Bulevar Oslobođenja 18 Belgrade 11 000 Serbia
| | - Danijela Kirovski
- 2 University of Belgrade Department of Physiology and Biochemistry Bulevar Oslobođenja 18 Belgrade 11 000 Serbia
| | - Nada Lakić
- 3 University of Belgrade Department of Agroeconomy, Faculty of Agriculture Belgrade Serbia
| | - Irena Celeska
- 4 Faculty of Veterinary Medicine Department of Pathophysiology Skopje Macedonia
| | | | - Željko Sladojević
- 6 Veterinary Station ‘Veterina System Sladojević’ Gradiška Republic of Srpska, Bosnia and Herzegovina
| | - Ivan Ivanov
- 1 University of Belgrade Department of Farm Animal Diseases Bulevar Oslobođenja 18 Belgrade 11 000 Serbia
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103
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Appuhamy J, Nayananjalie W, England E, Gerrard D, Akers R, Hanigan M. Effects of AMP-activated protein kinase (AMPK) signaling and essential amino acids on mammalian target of rapamycin (mTOR) signaling and protein synthesis rates in mammary cells. J Dairy Sci 2014; 97:419-29. [DOI: 10.3168/jds.2013-7189] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/23/2013] [Indexed: 12/19/2022]
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104
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Curtis R, Kim J, Bajramaj D, Doelman J, Osborne V, Cant J. Decline in mammary translational capacity during intravenous glucose infusion into lactating dairy cows. J Dairy Sci 2014; 97:430-8. [DOI: 10.3168/jds.2013-7252] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 10/08/2013] [Indexed: 01/30/2023]
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105
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Arriola Apelo SI, Singer LM, Lin XY, McGilliard ML, St-Pierre NR, Hanigan MD. Isoleucine, leucine, methionine, and threonine effects on mammalian target of rapamycin signaling in mammary tissue. J Dairy Sci 2013; 97:1047-56. [PMID: 24359813 DOI: 10.3168/jds.2013-7348] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 11/02/2013] [Indexed: 12/20/2022]
Abstract
Improved representation of postabsorptive N metabolism in lactating dairy cows requires a better understanding of protein synthesis regulation in the mammary glands. This study aimed to determine the quantitative effects of Ile, Leu, Met, and Thr on the phosphorylation state of signaling proteins that regulate protein synthesis. The experiment used a composite design with a central point, 2 axial points per AA, and a complete 2(4) factorial. All of the other AA were provided at the concentrations in Dulbecco's modified Eagle's medium. The experiment was replicated with tissues from 5 lactating cows. Mammary tissue slices (0.12 ± 0.02 g) were incubated for 4h. Total and site-specific phosphorylated mammalian target of rapamycin (mTOR; Ser2448), eukaryotic elongation factor (eEF) 2 (Thr56), ribosomal protein S6 (Ser235/236), and eukaryotic initiation factor 2α (Ser51) were determined by western immunoblotting. Tissue concentrations of the 4 AA studied responded linearly to media supply. Addition of Ile, Leu, Met, or Thr had no effect on eukaryotic initiation factor 2α phosphorylation. Isoleucine and Thr positively affected mTOR phosphorylation. However, the 2 AA had an antagonistic relationship. Similarly, Ile linearly increased ribosomal protein S6 phosphorylation, and Thr inhibited the Ile effect. In addition, eEF2 phosphorylation was linearly decreased by Ile and Leu. Threonine curvilinearly decreased eEF2 phosphorylation, Ile and Leu negatively interacted on eEF2, and Thr tended to inhibit Leu effects on eEF2. This work demonstrated saturable responses and interactions between AA on activation of the mTOR pathway. Incorporation of these concepts into milk protein response models will help to improve milk and milk protein yield predictions and increase postabsorptive N efficiency and reduce N excretion by dairy cows.
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Affiliation(s)
| | - L M Singer
- Department of Dairy Science, Virginia Tech, Blacksburg 24061
| | - X Y Lin
- Animal Science and Technology College, Shandong Agriculture University, 271018, China
| | - M L McGilliard
- Department of Dairy Science, Virginia Tech, Blacksburg 24061
| | - N R St-Pierre
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - M D Hanigan
- Department of Dairy Science, Virginia Tech, Blacksburg 24061
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106
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Winkelman L, Overton T. Long-acting insulins alter milk composition and metabolism of lactating dairy cows. J Dairy Sci 2013; 96:7565-77. [DOI: 10.3168/jds.2012-6498] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 08/20/2013] [Indexed: 02/04/2023]
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107
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Velázquez-Villegas LA, Tovar AR, López-Barradas AM, Torres N. The dietary protein/carbohydrate ratio differentially modifies lipogenesis and protein synthesis in the mammary gland, liver and adipose tissue during gestation and lactation. PLoS One 2013; 8:e69338. [PMID: 23874950 PMCID: PMC3712928 DOI: 10.1371/journal.pone.0069338] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 06/08/2013] [Indexed: 11/25/2022] Open
Abstract
During gestation and lactation, a series of metabolic changes that are affected by the diet occurs in various organs of the mother. However, little is known about how the dietary protein (DP)/carbohydrate (DCH) ratio regulates the expression of metabolic genes in the mother. Therefore, the purpose of this work was to study the effect of consuming different percentages of DP/DCH, specifically 10/73, 20/63 and 30/53%, on the expression of genes involved in lipogenesis and protein synthesis in the mammary gland, liver and adipose tissue during gestation and lactation in dams. While the amount of weight gained during gestation was similar for all groups, only dams fed with 30/53% DP/DCH maintained their weight during lactation. In the mammary gland, the expression of the genes involved in lipogenesis, specifically SREBP1 and FAS, was dramatically increased, and the expression of the genes involved in protein synthesis, such as mTOR1, and the phosphorylation of its target protein, S6K, were also increased throughout pregnancy and lactation, regardless of the concentration of DP/DCH. In the liver and adipose tissue, the expression of the genes and proteins involved in lipid metabolism was dependent on the proportion of DP/DCH. The consumption of a low-protein/high-carbohydrate diet increased the expression of lipogenic genes in the liver and adipose tissue and the amount of lipid deposition in the liver. Conversely, the consumption of a high-protein/low-carbohydrate diet increased the expression of genes involved in amino acid oxidation in the liver during gestation. The metabolic adaptations reflected by the changes in the expression of metabolic genes indicate that the mammary gland has a priority for milk synthesis, whereas the adaptations in the liver and adipose tissue are responsible for providing nutrients to the mammary gland to sustain milk synthesis.
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Affiliation(s)
- Laura A. Velázquez-Villegas
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición, México, D.F., México
| | - Armando R. Tovar
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición, México, D.F., México
| | - Adriana M. López-Barradas
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición, México, D.F., México
| | - Nimbe Torres
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición, México, D.F., México
- * E-mail:
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108
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Higgs R, Sheahan A, Mandok K, Van Amburgh M, Roche J. The effect of starch-, fiber-, or sugar-based supplements on nitrogen utilization in grazing dairy cows. J Dairy Sci 2013; 96:3857-66. [DOI: 10.3168/jds.2012-6117] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 02/04/2013] [Indexed: 11/19/2022]
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109
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Roche J, Kay J, Rius A, Grala T, Sheahan A, White H, Phyn C. Short communication: Immediate and deferred milk production responses to concentrate supplements in cows grazing fresh pasture. J Dairy Sci 2013; 96:2544-2550. [DOI: 10.3168/jds.2012-4626] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 12/18/2012] [Indexed: 11/19/2022]
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110
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Ferraretto L, Crump P, Shaver R. Effect of cereal grain type and corn grain harvesting and processing methods on intake, digestion, and milk production by dairy cows through a meta-analysis. J Dairy Sci 2013; 96:533-50. [DOI: 10.3168/jds.2012-5932] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 10/02/2012] [Indexed: 01/13/2023]
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111
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Titgemeyer EC, Spivey KS, Parr SL, Brake DW, Jones ML. Relationship of whole body nitrogen utilization to urea kinetics in growing steers1. J Anim Sci 2012; 90:3515-26. [DOI: 10.2527/jas.2011-4621] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
| | | | - S. L. Parr
- Department of Animal Sciences and Industry
| | | | - M. L. Jones
- Department of Clinical Sciences, Kansas State University, Manhattan 66506
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112
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Ramirez HAR, Nestor K, Tedeschi LO, Callaway TR, Dowd SE, Fernando SC, Kononoff PJ. The effect of brown midrib corn silage and dried distillers' grains with solubles on milk production, nitrogen utilization and microbial community structure in dairy cows. CANADIAN JOURNAL OF ANIMAL SCIENCE 2012. [DOI: 10.4141/cjas2011-133] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ramirez, H. A. R., Nestor, K., Tedeschi, L. O., Callaway, T. R., Dowd, S. E., Fernando, S. C. and Kononoff, P. J. 2012. The effect of brown midrib corn silage and dried distillers' grains with solubles on milk production, nitrogen utilization and microbial community structure in dairy cows. Can. J. Anim. Sci. 92: 365–380. Thirty-six Holstein cows (24 multiparous and 12 primiparous), four multiparous were ruminally cannulated, (mean±SD, 111±35 days in milk; 664±76.5 kg body weight) were used in replicated 4×4 Latin squares with a 2×2 factorial arrangement of treatments to investigate the effects of brown midrib (bm3) and conventional (DP) corn silages, and the inclusion of dried distillers' grains with solubles (DDGS) on milk production and N utilization. Experimental periods were 28 d in length. Treatments were DP corn silage and 0% DDGS; bm3 corn silage and 0% DDGS; DP corn silage and 30% DDGS; and bm3 corn silage and 30% DDGS. Compared with DP hybrid, total tract fiber digestibility was greater for cows consuming bm3 (32.5 vs. 38.1±1.79%) and DDGS (40.0 vs. 35.2±1.76%). Milk yield was not affected by treatment, and averaged 30.5±1.09 kg d−1. Milk protein yield was positively affected by bm3 corn silage and the inclusion of DDGS. An interaction between hybrid and DDGS on milk fat was also observed. The nature of the interaction was such that milk fat was only affected when DDGS were included in the diet and the lowest milk fat was observed when bm3 corn silage was fed (3.46, 3.59, 2.84 and 2.51±0.10% DP 0% DDGS, bm3 0% DDGS, DP 30% DDGS and bm3 30% DDGS, respectively). As a proportion of the total N consumed, manure N was significantly reduced by the inclusion of bm3 corn silage and DDGS (64.1, 57.1, 52.0, 51.2% for DP 0% DDGS, bm3 0% DDGS, DP 30% DDGS and bm3 30% DDGS, respectively). The Firmicutes:Bacteriodetes ratio in the rumen decreased when cattle consumed DDGS. When cows were fed bm3 corn silage, the population of Fibrobacter sp. tended to represent a larger proportion of the total bacterial population (1.8 vs. 2.3±0.28% for DP and bm3, respectively) and this shift may have been driven by the fact that bm3 corn silage has less lignin, therefore the cellulose digesting bacteria may have more access to the cellulose.
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Affiliation(s)
- H. A. Ramirez Ramirez
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, 68583-0908, USA
| | - K. Nestor
- Mycogen Seed, 1236 Point of View Dr., Wooster, OH, 44691, USA
| | - L. O. Tedeschi
- Department of Animal Science, Texas A&M University, College Station, TX, 77843-2471, USA
| | - T. R. Callaway
- Food and Feed Safety Research Unit, USDA-ARS, College Station, TX, 77845, USA
| | - S. E. Dowd
- MR DNA (Molecular Research LP), Shallowater, TX, 79363, USA
| | - S. C. Fernando
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, 68583-0908, USA
| | - P. J. Kononoff
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, 68583-0908, USA
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113
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Whelan S, Pierce K, Flynn B, Mulligan F. Effect of supplemental concentrate type on milk production and metabolic status in early-lactation dairy cows grazing perennial ryegrass-based pasture. J Dairy Sci 2012; 95:4541-9. [DOI: 10.3168/jds.2011-5292] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/13/2012] [Indexed: 01/27/2023]
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114
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Whelan S, Pierce K, McCarney C, Flynn B, Mulligan F. Effect of supplementary concentrate type on nitrogen partitioning in early lactation dairy cows offered perennial ryegrass-based pasture. J Dairy Sci 2012; 95:4468-77. [DOI: 10.3168/jds.2011-4689] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 01/17/2012] [Indexed: 11/19/2022]
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115
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Lapierre H, Lobley GE, Doepel L, Raggio G, Rulquin H, Lemosquet S. TRIENNIAL LACTATION SYMPOSIUM: Mammary metabolism of amino acids in dairy cows1,2. J Anim Sci 2012; 90:1708-21. [DOI: 10.2527/jas.2011-4645] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- H. Lapierre
- Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, Québec, J1M 0C8 Canada
| | - G. E. Lobley
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, AB21 9SB, United Kingdom
| | - L. Doepel
- Faculty of Veterinary Medicine, University of Calgary, Alberta, T6G 2P5 Canada
| | - G. Raggio
- Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, Québec, J1M 0C8 Canada
| | - H. Rulquin
- Unité Mixte de Recherche, 1080 Dairy Production, INRA, 35590 Saint-Gilles, France
| | - S. Lemosquet
- Unité Mixte de Recherche, 1080 Dairy Production, INRA, 35590 Saint-Gilles, France
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116
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Rius A, Weeks H, Cyriac J, Akers R, Bequette B, Hanigan M. Protein and energy intakes affected amino acid concentrations in plasma, muscle, and liver, and cell signaling in the liver of growing dairy calves. J Dairy Sci 2012; 95:1983-91. [DOI: 10.3168/jds.2011-4688] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 11/26/2011] [Indexed: 01/26/2023]
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117
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Hall MB. Isotrichid protozoa influence conversion of glucose to glycogen and other microbial products. J Dairy Sci 2011; 94:4589-602. [PMID: 21854932 DOI: 10.3168/jds.2010-3878] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 05/16/2011] [Indexed: 11/19/2022]
Abstract
The goal of this in vitro study was to determine the influence of isotrichid protozoa (IP) on the conversion of glucose (Glc) to glycogen (Glyc) and transformation of Glc into fermentation products. Treatments were ruminal inoculum mechanically processed (blended) to destroy IP (B+, verified microscopically) or not mechanically processed (B-). Accumulated microbial Glyc was measured at 3h of fermentation with (L+; protozoa+bacteria) or without (L- predominantly protozoa) lysis of bacterial cells in the fermentation solids with 0.2 N NaOH. Two 3-h in vitro fermentations were performed using Goering-Van Soest medium in batch culture vessels supplemented with 78.75 mg of Glc/vessel in a 26.5-mL liquid volume. Rumen inoculum from 2 cannulated cows was filtered through cheesecloth, combined, and maintained under CO(2) for all procedures. At 3h, 0.63 and 0.38 mg of Glc remained in B- and B+. Net microbial Glyc accumulation (and Glc in Glyc as % of added Glc) detected at 3h of fermentation were 3.32 (4.69%), -1.42 (-2.01%), 6.45 (9.10%), and 3.65 (5.15%) mg for B-L-, B+L-, B-L+ and B+L+, respectively. Treatments B+ and L+ gave lower Glyc values than B- and L-, respectively. Treatment B+L- demonstrated net utilization of α-glucan contributed by inoculum with no net Glyc production. With destruction of IP, total Glyc accumulation declined by 44%, but estimated bacterial Glyc increased. Microbial accumulation of N increased 17.7% and calculated CH(4) production decreased 24.7% in B+ compared with B-, but accumulation of C in microbes, production of organic acids or C in organic acids, calculated CO(2), and carbohydrates in cell-free medium did not differ between B+ and B-. Given the short 3-h timeframe, increased N accumulation in B+ was attributed to decreased Glyc sequestration by IP rather than decreased predation on bacteria. After correction for estimates of C from AA and peptides utilized by microbes, 15% of substrate Glc C could not be accounted for in measured products in B+ or B-. Approximately 30% of substrate Glc was consumed by energetic costs associated with Glc transport and Glyc synthesis. The substantial accumulation of Glyc and changes in microbial N and Glyc accumulation related to presence of IP suggest that these factors should be considered in predicting profiles and amounts of microbial products and yield of nutrients to the cow as related to utilization of glucose. Determination of applicability of these findings to other soluble carbohydrates could be useful.
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Affiliation(s)
- M B Hall
- US Dairy Forage Research Center, USDA-ARS, Madison, WI 53706, USA.
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118
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Whelan S, Mulligan F, Flynn B, McCarney C, Pierce K. Effect of forage source and a supplementary methionine hydroxy analog on nitrogen balance in lactating dairy cows offered a low crude protein diet. J Dairy Sci 2011; 94:5080-9. [DOI: 10.3168/jds.2011-4174] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 06/01/2011] [Indexed: 11/19/2022]
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119
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Appuhamy JADRN, Bell AL, Nayananjalie WAD, Escobar J, Hanigan MD. Essential amino acids regulate both initiation and elongation of mRNA translation independent of insulin in MAC-T cells and bovine mammary tissue slices. J Nutr 2011; 141:1209-15. [PMID: 21525255 DOI: 10.3945/jn.110.136143] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Current nutrient requirement models assume fixed efficiencies of absorbed amino acid (AA) conversion to milk protein. Regulation of mammary protein synthesis (PS) potentially violates this assumption by changing the relationship between AA supply and milk protein output. The objective of this study was to investigate the effects of essential AA (EAA) and insulin on cellular signaling and PS rates in bovine mammary cells. MAC-T cells were subjected to 0 or 100% of normal EAA concentrations in DMEM/F12 and 0 or 100 μg insulin/L in a 2 × 2 factorial arrangement of treatments. Lactogenic bovine mammary tissue slices (MTS) were subjected to the same treatments, except low-EAA was 5% of normal DMEM/F12 concentrations. In MAC-T cells, EAA increased phosphorylation of mammalian target of rapamycin (mTOR; Ser2448), ribosomal protein S6 kinase 1 (S6K1; Thr389), eIF4E binding protein 1 (4EBP1; Thr37/46), and insulin receptor substrate 1 (IRS1; Ser1101), and reduced phosphorylation of eukaryotic elongation factor 2 (eEF2; Thr56) and eukaryotic initiation factor (eIF) 2-α (Ser51). In the presence of insulin, phosphorylation of Akt (Ser473), mTOR, S6K1, 4EBP1, and IRS1 increased in MAC-T cells. In MTS, EAA had similar effects on phosphorylation of signaling proteins and increased mammary PS rates. Insulin did not affect MTS signaling, perhaps due to inadequate levels. Effects of EAA and insulin were independent and additive for mTOR signaling in MAC-T cells. EAA did not inhibit insulin stimulation of Akt phosphorylation. PS rates were strongly associated with phosphorylation of 4EBP1 and eEF2 in MTS. EAA availability affected translation initiation and elongation control points to more strongly regulate PS than insulin.
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120
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Bionaz M, Loor JJ. Gene networks driving bovine mammary protein synthesis during the lactation cycle. Bioinform Biol Insights 2011; 5:83-98. [PMID: 21698073 PMCID: PMC3118679 DOI: 10.4137/bbi.s7003] [Citation(s) in RCA: 217] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A crucial role for both insulin and mTOR in the regulation of milk protein synthesis is emerging. Bovine mammary biopsies harvested during late-pregnancy through end of subsequent lactation were used to evaluate via quantitative PCR the expression of 44 genes involved in pathways of insulin, mTOR, AMPK, and Jak2-Stat5 signalling and also glucose and amino acid (AA) transporters. We observed an increased expression during lactation of ELF5, AA and glucose transporters, insulin signaling pathway components, MAPK14, FRAP1, EIF4EBP2, GSK3A and TSC1 among mTOR signaling-related genes. Among ribosomal components RPL22 was down-regulated. The overall data support a central role of AA and glucose transporters and insulin signaling through mTOR for the regulation of protein synthesis in bovine mammary gland. Furthermore, the existence of translational competition favoring the translation of milk protein transcripts was inferred from the combined dataset.
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Affiliation(s)
- Massimo Bionaz
- Mammalian NutriPhysio Genomics, Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA
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121
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Ferraretto L, Shaver R, Espineira M, Gencoglu H, Bertics S. Influence of a reduced-starch diet with or without exogenous amylase on lactation performance by dairy cows. J Dairy Sci 2011; 94:1490-9. [DOI: 10.3168/jds.2010-3736] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 11/29/2010] [Indexed: 11/19/2022]
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