Research note: effect of soybeans varying in trypsin inhibitor content on performance of laying hens.

A 6-wk experiment was conducted with commercial laying hens (35 wk of age) to study the effects of feeding raw, conventional, full-fat soybeans (CSB) and raw, Kunitz trypsin inhibitor-free, full-fat soybeans (KFSB) on layer performance. Dietary treatments consisted of corn and soybean meal diets formulated to contain 16% total protein with 100, 72, or 48% of the soybean protein from CSB or KFSB. The remainder of the dietary soybean protein was provided as dehulled soybean meal (DSBM). Egg production, egg weight, egg yield (grams of egg per hen per day) and feed efficiency increased as the level of CSB and KFSB decreased. In general, diets containing KFSB resulted in better performance than those containing CSB. The diet containing 48% of the soybean protein from KFSB yielded performance that was not different (P greater than .05) than that obtained from a corn-DSBM diet. Performance from all other diets was inferior to that from the corn-DSBM diet. Pancreas weight (as a percentage of body weight) was greater for hens fed CSB compared with those fed KFSB, and both were greater than pancreas weight of hens fed the corn-DSBM diet. The dietary treatments had no consistent effect on egg specific gravity or Haugh units.