ALCOHOL-SOLUBLE COMPONENTS IN SOYBEANS CAUSE MORPHOLOGICAL-CHANGES INTHE DISTAL INTESTINE OF ATLANTIC SALMON, SALMO-SALAR L

Standard soybean meal, heat treated to differing degrees and containin g varying levels of soybean lectin and trypsin inhibitor, was used to study the effect of soybean-containing diets on the morphology of the distal intestine in Atlantic salmon, Salmo salar L. A reference diet b ased on fish meal and a fish meal diet mixed with an alcohol extract o f soybean meal were used. The fish (145 g) were kept in 27 m(3) net pe ns (200 fish per pen) in sea water with an average temperature of 11 d egrees C for 12 weeks. Whereas a normal morphology of the distal intes tine was seen in the fish fed the reference diet, all soybean diets ca used alterations in the distal intestine irrespective of heat treatmen t. Similar changes were observed with the diet which had added alcohol solubles. It is concluded that alcohol-soluble components in the soyb eans are responsible for the observed changes. It cannot be determined which of the soybean antinutrients is causing the alterations from th e present study. Oligosaccharides and saponines are possible candidate s. However, intestine should not be overlooked.