Abstract: 【Objective】This study was conducted to evaluate the relative bioavailability (RBV) of choline in corn, soybean meal, canola meal and distillers dried grains with soluble (DDGS). 【Method】A total of 132 one-day-old broilers were divided into 22 groups (6 replicates per group and each replicate had 1 broiler). Groups S1-S6 were standard curve group, Groups A1-A4 were corn groups, Group B1-B4 were soybean meal groups, Group C1-C4 were canola meal groups, and Groups D1-D4 were DDGS groups. The basic diet contained the four feedstuffs above with lower choline content through being extracted with methanol/alcohol. All the test diets had the same composition as that of the basic diet except choline content. A choline response curve was generated using crystalline choline chloride added to the basic diet. The experiment diets were made from the basic diet in which the washed feedstuff was replaced with the intact one with 10%, 20%, 40%, and 100%. In the slope ratio assays to determine choline availability, measured by average daily gain (ADG) and choline concentration in blood.【Result】 Using ADG as response criterion, the choline RBV of corn, soybean meal, canola meal, and DDGS were 63.95%, 104.7%, 37.98%, and 72.09%. Using choline concentration in blood as response criterion, the RBV of corn, soybean meal, canola meal, and DDGS were 94.73%, 184.11%, 23.63%, and 134.23%.【Conclusion】It is possible to evaluate the bioavailability of choline in feedstuffs using ADG and choline concentration in blood as criteria. But the values will be different in different criteria. From high to low, choline RBV of the four feedstuffs were soybean meal, DDGS, corn and canola meal, respectively.

Key words: corn, soybean meal, canola meal, DDGS, RBV, choline