Choline requirement of young swine.

Three experiments were conducted to study the dietary choline requirement of young swine. Ninety pigs (three replicates), in the first experiment, and 120 pigs (four replicates), in the second experiment, were allotted to the five choline treatments (0, 330, 660, 990 or 1320 mg choline/kg of diet), fed in a 23% crude protein, semi-purified diet (.31% methionine, .33% cystine). The combined results of these experiments indicated a minimum dietary choline requirement of 330 mg/kg for pigs from 3 to 8 weeks of age (6 to 14 kg). Pigs fed 990 mg choline/kg of diet gained faster (P<.01) than pigs fed 0, 660 or 1320 mg choline/kg of diet but not faster than those fed 330 mg choline/kg of diet. Hematocrit of the pigs fed the basal diet was lower (P<.05) than that of pigs fed the other diets. Hemoglobin concentration of pigs fed the basal diet was lower (P<.05) than that of pigs fed all other diets, except the 330 mg/kg choline diet. There was no difference in hematocrit:hemoglobin ratio across all treatments. There was a significant linear trend (P<.05)for both hematocrit and hemoglobin concentration. Plasma alkaline phosphatase was higher (P<.05) for pigs fed the basal diet and lower for pigs fed the 660 mg choline/kg of diet as compared to the pigs fed the other diets. In the third experiment, 72 pigs (three replicates) were fed an 18% crude protein, corn-isolated soy protein diet (.23% cystine) from 4 weeks of age (7 kg) to 20 kg average live weight. The 3 x 2 factorial arrangement of treatments included 520, 760 and 1,000 mg/kg dietary choline and .22% and .46% methionine. There was no significant treatment effect on daily gain or feed conversion, indicating that the starter pig's dietary choline requirement does not exceed 520 mg/kilogram. (