Liver Damage in Rainbow Trout (Salmo gairdneri) Fed Cyclopropenoid Fatty Acids

Histological changes in livers of rainbow trout (Salmo gairdneri) repeatedly fed diets containing cyclopropenoid fatty acids (CPFA) revealed that these fish were unable to develop resistance to liver damage caused by CPFA. One group of trout was fed 150 ppm CPFA in the basal diet for 49 days followed by the basal diet for the remainder of the experimental period. Another group of trout was fed 150 ppm CPFA for 49 days, basal diet for 65 days, and 150 ppm CPFA for 45 days. At this time this group was divided into two subgroups; one received basal diet for 15 days, the other for 30 days, after which both subgroups were placed on a diet containing 360 ppm CPFA for 36 days. Analysis of the livers for histological changes showed that the parenchymal cells underwent cyclic changes of injury and recovery each time the trout were fed CPFA. Complete recovery of parenchymal cells occurred after the fish were removed from the diets containing CPFA for 30 days. Bile duct and blood vessel hyperplasia was observed for as long as 7 mo after CPFA was eliminated from the trout diet.