Plasma protein derivative (amyloid-like substance) in livers of rapeseed-fed fowls.

Amyloid-like material in the livers of fowls fed on rapeseed diets was subjected to a battery of histochemical tests in comparison with amyloid from man, horse, ox and dog. The mammalian amyloids gave positive reactions of varying intensity with iodine, thioflavine T, Congo red, standard toluidine blue and for tryptophan. They resisted digestion by pepsin. Further tests indicated that human, equine and bovine amyloid contained both carboxylated and sulphated mucosubstances. Avian amyloid-like material gave weak reactions with iodine and thioflavine T only but was strongly positive in staining methods for fibrin. It was PAS-positive but histochemical indications of the type of muco-substance were not elicited. It was easily digested with pepsin and did not have the characteristic fibrillar ultrastructure of the equine amyloid. It is concluded that the avian hepatic material is not amyloid but a derivative of plasma proteins with staining characteristics similar to fibrin. Small amounts of similar material were observed in the livers of birds which had not been on a rapeseed diet.