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|Title:||Amino Acid Balance and Imbalance in the Pig With Emphasis on Urea-Cycle Metabolism and Interorgan Amino Acid Transfers|
|Author(s):||Edmonds, Michael Stephen|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Animal Culture and Nutrition|
|Abstract:||Several experiments were conducted to investigate amino acid metabolism in pigs as affected by arginine deficiency, fasting and amino acid imbalances. Supplemental citrulline replaced arginine for growth in pigs fed arginine-deficient diets whereas ornithine supplementation was without effect. Excess ornithine increased free ornithine and proline in liver, kidney and muscle whereas free citrulline increased only in liver.
Pigs fasted for 4 days or fed a diet containing 30% protein excreted more urea-N in the urine and had elevated arginase and ornithine transcarbamoylase activities in liver compared to pigs fed 3% protein. Pigs fed 3% protein had much lower levels of free threonine, tyrosine, cystathionine, taurine and branched-chain amino acids in plasma, liver, kidney, muscle and brain than fasted pigs or those fed 30% protein. Fasted pigs had decreased free alanine levels in plasma, and decreased free serine levels in plasma and liver when compared to fed pigs. Interorgan comparisons provided evidence that both alanine and serine were important gluconeogenic amino acids during fasting.
The effect of excess lysine was evaluated in diets marginal in arginine (.53%) but adequate in lysine (1.15%). Pigs fed this diet supplemented with 3.45% lysine exhibited decreases in both weight gain and feed intake but not in feed efficiency. Dramatic increases in free lysine as well as $\alpha$-aminoadipic acid were observed in plasma, liver, kidney and muscle of pigs fed excess lysine. Arginase activity in renal tissue, however, was uninfluenced by excess lysine. In addition, urinary spillage of lysine accounted for 26.2% of the lysine intake in pigs fed 3.45% supplemental lysine.
Supplementation of corn-soybean meal diets with 1% excesses of individual amino acids (i.e., methionine, tryptophan, threonine or leucine) did not affect growth rate of young pigs. In fact, addition of 4% threonine or leucine to this diet was also innocuous. In self-selection studies, pigs clearly preferred non-imbalanced diets over imbalanced diets whereas chicks showed no clear preference. In addition, excesses of lysine and threonine were far more growth depressing in chicks than in pigs but excess arginine was more growth depressing in pigs than in chicks.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
|Date Available in IDEALS:||2014-12-15|