Synergism between cyclopropenoid fatty acids and chemical carcinogens in rainbow trout (Salmo gairdneri).

Summary The synergistic activities of cyclopropenoid fatty acids (CPFA), epoxyoleic acid, sesame seed oil, and autoxidized salmon oil with aflatoxin B1 were studied in rainbow trout. Sterculia foetida oil (49% sterculic, 7% malvalic acids) and Hibiscus syriacus oil (2% sterculic and 19% malvalic acids) were used as sources of CPFA. The combination of both 112 and 56 ppm CPFA procured from S. foetida oil and 210 ppm CPFA procured from H. syriacus oil promoted early tumor development, increased tumor incidence, and caused a severalfold increase in tumor growth rate over the positive control. Trout fed 100 ppm 2-acetylaminofluorene for 15 months did not develop hepatomas, but the addition of H. syriacus oil to the diet induced a 20% incidence of liver tumors. Diets containing 200 ppm epoxyoleic acid (in Vernonia anthelmintica oil), 5% sesame seed oil, or 5% autoxidized salmon oil (peroxide value 200–300) did not alter the carcinogenicity of aflatoxin B1. Some unusual lipid deposits were noted in the livers of fish receiving sesame seed oil.