SOYBEAN TRYPSIN-INHIBITORS IN DIETS FOR ATLANTIC SALMON (SALMO-SALAR,L) - EFFECTS ON NUTRIENT DIGESTIBILITIES AND TRYPSIN IN PYLORIC CECA HOMOGENATE AND INTESTINAL CONTENT

Atlantic salmon (Salmo salar, L), 180 g, were fed diets containing a c rude trypsin inhibitor from soybean at five levels. The five levels re sulted in trypsin inhibitor activities (TIA) corresponding to an inclu sion of 0 to about 100% commercial soybean meal. Digestibility of prot ei and fat, weight gain and trypsin activity in intestinal content wer e significantly reduced with increasing dietary TIA. The response curv es for nutrient digestibility and growth indicated that the Atlantic s almon were able to compensate for a certain TIA, equivalent to about 5 mg bovine trypsin inhibited per g feed. This compensation seemed to b e due to increased trypsin secretion as suggested by the values for to tal content of trypsin in the pyloric caeca homogenate. At the highest level of TIA, the pancreatic capacity of trypsin synthesis seemed to be exhausted.