Interrelationships Among Sulfur Amino Acids, Choline and Betaine in the Chicken: Effects on Betaine-Homocysteine Methyltransferase Activity, Homocysteine Utilization and Choline Bioavailability
Emmert, Jason Lee
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https://hdl.handle.net/2142/84972
Description
Title
Interrelationships Among Sulfur Amino Acids, Choline and Betaine in the Chicken: Effects on Betaine-Homocysteine Methyltransferase Activity, Homocysteine Utilization and Choline Bioavailability
Author(s)
Emmert, Jason Lee
Issue Date
1997
Doctoral Committee Chair(s)
Baker, David H.
Department of Study
Nutritional Sciences
Discipline
Nutritional Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Animal Physiology
Language
eng
Abstract
Chick assays (10 to 22-d-old chicks) were conducted to determine choline bioavailability in fluid lecithin (FL), deoiled lecithin (DL), soybean meal (SBM), canola meal (CM) and peanut meal (PM). A basal diet containing soy protein isolate and 2-amino-2-methyl-1-propanol (an inhibitor of choline biosynthesis) was severely deficient in choline, and weight gain of chicks fed this diet responded to choline, but not methionine or betaine. In Assay 1, weight gain of chicks increased linearly $(P<0.01)$ with increasing concentrations of choline from choline chloride, FL or DL. Multiple linear regression analysis indicated bioavailable choline concentrations of 2.0 and 3.5% for FL and DL, respectively. In Assay 2, weight gain of chicks increased linearly $(P<0.01)$ with increasing concentrations of choline from choline chloride, SBM, CM or PM. Multiple linear regression analysis indicated bioavailable choline concentrations of 1,708, 1,545 and 1,203 mg/kg for SBM, CM and PM, respectively. In Assay 3, similar methodology gave bioavailable choline estimates of 2,002, 1,464 and 1,320 mg/kg for SBM, CM and PM, respectively, and bioavailability was not $(P>0.05)$ affected by severely overheating the oilseed meals. Combined estimates indicated bioavailable choline levels were 87, 27 and 77% of analytically determined total choline levels in SBM, CM and PM, respectively. Three chick assays were conducted to determine effects of dietary changes on hepatic betaine-homocysteine methyltransferase (BHMT) activity. In Assay 1, use of a methionine-deficient purified diet caused a 3-fold increase $(P<0.05)$ in BHMT activity, and addition of choline or betaine further increased $(P<0.05)$ activity. In Assay 2, use of a methionine-deficient corn-peanut meal diet increased $(P<0.05)$ BHMT activity relative to methionine-supplemented chicks, and activity was increased further $(P<0.05)$ by addition of surfeit choline to the basal diet. The additive effect of methionine deficiency and surfeit choline or betaine was observed again in Assay 3. Large increases in BHMT activity occur under methionine-deficient conditions, especially in the presence of excess choline or betaine.
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