3To whom correspondence should be addressed. A New Method for Determining the Availability of Choline in Soybean Meal1

ABSTRACT Studies were conducted to evaluate the availability of choline in soybean meal, using a new approach: The basal diet contained soybean meal with a lowered choline content (partially extracted with methanol). Choline was added to the basal diet 1) by substituting intact soybean meal for the methanol washed soybean meal; or 2) from crystalline choline Cl. Four experiments were conducted with day-old male broilers housed in battery brooders and fed the experimental diets from 4 to 18 d posthatching. The basal diet contained corn, soybean meal, and isolated soy protein in Experiments 1 to 3, and also glucose in Experiment 4. In Experiment 1, chicks fed the basal diet (1,140 mg/kg choline, 0.61 % sulfur amino acids) had a growth response to 1,000 mg/kg choline or 0.10% methionine (P < 0.05), but not to 0.10 % cysteine (P> 0.05) supplementation. Supplementation of choline (0