נגישות
menu      
חיפוש מתקדם
תחביר
חפש...
הספר "אוצר וולקני"
אודות
תנאי שימוש
ניהול
קהילה:
אסיף מאגר המחקר החקלאי
פותח על ידי קלירמאש פתרונות בע"מ -
High rates of mammary tissue protein turnover in lactating goats are energetically costly
Year:
2009
Source of publication :
Journal of Nutrition
Authors :
מבג'יש, סמיר
;
.
Volume :
139
Co-Authors:
Hanigan, M.D., Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
France, J., Centre for Dairy Research, School of Agriculture, Policy and Development, University of Reading, Reading, Berkshire RG6 6AR, United Kingdom, Centre for Nutrition Modeling, Department of Animal and Poultry Science, University of Guelph, Guelph, ON N1G 2W1, Canada
Mabjeesh, S.J., Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel
McNabb, W.C., Food, Metabolism and Microbiology, Food and Textiles Group, AgResearch Grasslands, Palmerston North 4442, New Zealand
Bequette, B.J., Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, United States
Facilitators :
From page:
1118
To page:
1127
(
Total pages:
10
)
Abstract:
The high energetic demands and metabolism of amino acids (AA) within the lactating mammary gland have been ascribed to the requirements for milk component synthesis and tissue maintenance. Our objective in this work was to assess rates of protein synthesis from several AA so that the energetic costs of tissue maintenance could be better reflected. Lactating goats (n = 4) were given staggered infusions of 5 labeled forms of phenylalanine (Phe) initiated at 30, 12, 9, 6, and 3 h before goats were killed. [5-13CH3] Methionine (Met), [1-13C] leucine, and [1-13C] valine were also infused for 30 h, during which time, the glands were milked hourly and arteriovenous flux measurements were performed the last 6 h. A dynamic, compartmental model capable of simulating fluxes of AA through extracellular and intracellular free, slow and fast turnover tissue-bound, and milk protein pools was developed and fitted to the observed data. The udder removed 81% of the Phe present in plasma using 31% for milk protein synthesis and releasing 66% back into plasma. Transamination accounted for 40% of Phe flux in the mammary and transmethylation accounted for a portion of mammary Met flux. Mammary tissue protein synthesis was >300% the value of milk protein synthesis with fractional protein synthesis rates >130%/d. Assuming 4 mol of ATP/mol of peptide bond formed, we estimate that ∼;50% of ATP generated by the lactating mammary glands is used for synthesis of tissue (nonmilk) protein. © 2009 American Society for Nutrition.
Note:
Related Files :
Amino Acids
animal experiment
Animals
Female
goats
lactation
Phenylalanine
עוד תגיות
תוכן קשור
More details
DOI :
10.3945/jn.108.103002
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
23911
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:03
Scientific Publication
High rates of mammary tissue protein turnover in lactating goats are energetically costly
139
Hanigan, M.D., Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
France, J., Centre for Dairy Research, School of Agriculture, Policy and Development, University of Reading, Reading, Berkshire RG6 6AR, United Kingdom, Centre for Nutrition Modeling, Department of Animal and Poultry Science, University of Guelph, Guelph, ON N1G 2W1, Canada
Mabjeesh, S.J., Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel
McNabb, W.C., Food, Metabolism and Microbiology, Food and Textiles Group, AgResearch Grasslands, Palmerston North 4442, New Zealand
Bequette, B.J., Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, United States
High rates of mammary tissue protein turnover in lactating goats are energetically costly
The high energetic demands and metabolism of amino acids (AA) within the lactating mammary gland have been ascribed to the requirements for milk component synthesis and tissue maintenance. Our objective in this work was to assess rates of protein synthesis from several AA so that the energetic costs of tissue maintenance could be better reflected. Lactating goats (n = 4) were given staggered infusions of 5 labeled forms of phenylalanine (Phe) initiated at 30, 12, 9, 6, and 3 h before goats were killed. [5-13CH3] Methionine (Met), [1-13C] leucine, and [1-13C] valine were also infused for 30 h, during which time, the glands were milked hourly and arteriovenous flux measurements were performed the last 6 h. A dynamic, compartmental model capable of simulating fluxes of AA through extracellular and intracellular free, slow and fast turnover tissue-bound, and milk protein pools was developed and fitted to the observed data. The udder removed 81% of the Phe present in plasma using 31% for milk protein synthesis and releasing 66% back into plasma. Transamination accounted for 40% of Phe flux in the mammary and transmethylation accounted for a portion of mammary Met flux. Mammary tissue protein synthesis was >300% the value of milk protein synthesis with fractional protein synthesis rates >130%/d. Assuming 4 mol of ATP/mol of peptide bond formed, we estimate that ∼;50% of ATP generated by the lactating mammary glands is used for synthesis of tissue (nonmilk) protein. © 2009 American Society for Nutrition.
Scientific Publication
You may also be interested in