Assessment of the Quantity of Biologically Available Choline in Soybean Meal

Abstract

Growth assays were conducted with 8-dayold crossbred chicks to evaluate the available choline in 44 and 49% protein soybean meals, and also in whole heat-treated soybeans. A choline-free (experimental basal diet)pretest diet was imposed from day 5 to 8 posthatching to diminish choline stores. Soybean sources were added at 5 and 10% to the basal diet, and a choline response curve was generated using 0, 175, and 350 ppm choline contributed from crystalline choline chloride. Slope-ratio and standard curve techniques were used to quantify the available choline content of each ingredient tested. Two sources of dehulled soybean meal were found to contain 1,614 and 2,026 ppm available choline, respectively. The latter sample was also evaluated in the presence of 2-amino-2-methyl-l-propanol, a specific inhibitor of choline biosynthesis, and a value of 2,024 ppm was obtained. The whole bean and 44% CP soybean meal were found to contain 1,844 and 1,664 ppm available choline, respectively. Using accepted table values (2,850, 2,743 and 2,420 ppm for dehulled, regular and whole bean, respectively) the availability of choline in the soybean products tested appears to range between 60 and 75%.

Performance of Broilers Fed Different Dietary Choline Sources and Levels

“…Choline requirements for WG were determined as 778, 632, and 645 mg/kg for the ages of 1-7, 1-35, and 1-42 d, respectively (Table 6). These values are close to those obtained with purified diets, of 600 (14,40) to 720 mg/kg (8) , but much lower than those determined in studies using practical diets. The WG regression equation was not significant for the phase of 1-21 d, allowing us to conclude that the choline level of the basal diet was sufficient to supply the birds' requirements.…”

Factors Influencing the Assessment of the Availability of Choline in Feedstuffs

“…Ideally, the growth response should be directly proportional to the concentration of the first-limiting nutrient when it is added to the diet. Molitoris and Baker (1976a) used this type of assay in determining the available choline in soybean meal (SBM). They added SBM to their basal diet (at the expense of corn starch) and compared the growth of chicks fed this test diet to that of chicks fed the basal diet containing graded levels of crystalline choline CI.…”

“…2 H & N Inc., Redmond, WA 98052, furnished the chicks used as breeding stock for the chicks in these experiments. encountered with the work of Molitoris and Baker (1976a), who distinguish between the terms "available choline" (mg/kg) and "choline availability" (% available), claiming "available choline" should be based on bioassay and "choline availability" on "accepted table values". Berry et al (1943) and Molitoris and Baker (1976a) used the growtii response of chicks to additional choline as their criterion of choline availability.…”

“…encountered with the work of Molitoris and Baker (1976a), who distinguish between the terms "available choline" (mg/kg) and "choline availability" (% available), claiming "available choline" should be based on bioassay and "choline availability" on "accepted table values". Berry et al (1943) and Molitoris and Baker (1976a) used the growtii response of chicks to additional choline as their criterion of choline availability. The appropriateness of using growth as the criterion is questionable, since growth is also influenced by other constituents of SBM in diets limiting choline, particularly methionine (Marvel et al;1944, Quillin et al, Acres 3 chicks in Experiment 5).…”

Modelos matemáticos para predição das exigências nutricionais da colina para frangos de corte

“…O NRC (1994) preconiza uma exigência de 1.300 mg/kg de colina para frangos de corte de 1 a 21 dias de idade, este valor de exigência é baseado em vários trabalhos (WEST et al, 1951;QUIILIN, 1961;FRITZ et al, 1967;MOLITORIS;BAKER, 1976a;LIPSTEIN et al, 1977;DERILO;BALNAVE, 1980;BAKER et al, 1983;LOWRY et al, 1987;TSIAGBE et al, 1987).…”