Betaine can partially spare choline in chicks but only when added to diets containing a minimal level of choline.
The ability of betaine to serve as a methyl donor in chicks was assessed in 3 bioassays using a choline-free purified diet that contained adequate methionine (Met). In assay 1, choline and betaine were each supplemented at 300 mg/kg in a 2 x 2 factorial arrangement of diets. Supplemental choline improved (P < 0.05) growth performance over the 9-d growth period, whereas betaine alone had no effect. In assay 2, graded supplements of choline produced a linear increase (P < 0.05) in growth performance criteria over a 9-d growth period. Additionally, hepatic betaine-homocysteine (Hcy) methyltransferase (BHMT) activity decreased linearly (P < 0.05), whereas plasma total Hcy remained unchanged. Addition of 260 or 600 mg/kg betaine to the choline-free basal diet did not affect growth performance or BHMT activity, but 600 mg/kg betaine reduced (P < 0.05) plasma total Hcy. Assay 3 was designed to quantify the ability of betaine to spare choline. Minimal supplemental choline requirements of 20.8 +/- 1.50 mg/d (722 mg/kg diet) and 10.5 +/- 1.03 mg/d (412 mg/kg diet) were estimated in the absence and presence of 1000 mg/kg supplemental betaine, respectively. Based on these estimates, 50% of the dietary choline requirement must be supplied as choline per se, but the remaining 50% can be replaced by betaine. Collectively, these data suggest betaine and Met have minimal choline-sparing activity in chicks fed purified diets devoid of preformed choline. However, addition of betaine to diets containing minimal choline allows a marked reduction in the total dietary choline requirement.
Dilger
Ryan N
RN
Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Garrow
Timothy A
TA
Baker
David H
DH
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001622:Betaine / Q000378:metabolism* / Q000494:pharmacology*; D002645:Chickens / Q000254:growth & development* / Q000378:metabolism*; D002794:Choline / Q000378:metabolism*; D004032:Diet / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D009751:Nutritional Requirements; D015430:Weight Gain / Q000187:drug effects
D001622:Betaine; D002794:Choline