Studies on the Effect of Raw Soybean Meal on Fat Absorption in Young Chicks

A series of experiments indicated that dietary raw soybean meal depressed fat absorption in chicks of two breeds at two weeks of age but not at four weeks of age. Apparently fat absorption is affected by raw meal feeding rather than digestion since absorption of soybean oil or soybean fatty acid was equally affected. As little as 5% of protein from raw meal in a diet containing 25% of total crude protein was sufficient to cause nearly maximal depression of fat absorption. Changes in protein level of the diet could not influence fat absorption to the same extent as raw meal. A crystalline preparation of “Kunitz” soybean trypsin inhibitor did not affect fat absorption when fed to chicks. Chicks receiving a diet containing heated soybean meal plus the trypsin inhibitor had an enlarged pancreas, grew more slowly and metabolized the diet slightly less than chicks fed a comparable diet containing heated meal.