Functional features concerned with low proallergic natures were examined using an allergy-inducible rat strain (Brown Norway rat; BN rat) on hen's eggs which have been empirically mentioned as hypoallergenic
for patients suffering from food allergies (experimental eggs). BN rats were fed on feed containing
whole experimental eggs (feed E) and whole normal eggs (control feed, feed C). The densities of immunoglobulin E (IgE)-positive cells, have reported to be IgE-bearing mast cells, in the jejunum and ileum of BN rats fed on experimental-egg-containing feed were lower than those of BN rats fed on normal-egg-containing feed. The number of blood eosinophils was also lower in BN rats fed on feed E. Serum IgE levels were no different between BN rats fed on feed E and feed C. These results indicate that the low proallergic nature of hen's eggs studied in the present study is due to the dereased ability of experimental eggs to facilitate the proliferation and induction of mast cells in the intestinal tissue.