in numerous in vivo systems it has been shown that diets high in menhaden oil ( a fish oil high in omega-3 fatty acids ) can inhibit the carcinogenic process . in the present study , we have assessed the effects of a diet containing menhaden oil on 2-amino-3-methylimidazo[4,5-f]quinoline ( iq)-dna adduct formation in target tissues of the male fischer 344 rat . 
 young adult male fischer 344 rats were maintained on either a ) an ain-76a diet containing 5% corn oil , b ) an isocaloric ain-76a diet modified to contain 2% corn oil and 19% menhaden oil ( mo diet ) , or c ) a regular laboratory rodent diet ( chow diet ) for 6 weeks prior to receiving a single oral dose of 10 or 50 mg iq / kg . 
 groups of four animals were killed 1 or 6 days after iq administration . using 32p - postlabeling assays , 
 iq - dna adducts were isolated and quantitated in the liver , small intestine , and large intestine . 
 adduct patterns were similar in all cases . 
 adduct levels , expressed as relative adduct labeling values ( ral x 10(7 ) ) , were related to dose in all three tissues , with liver levels up to 10-fold higher than the large intestine and up to 20-fold higher than the small intestine . on day one , liver adduct levels in animals on the ain-76a diet were similar to those in animals on the chow diet , but those in animals on the mo diet were approximately 2-fold lower.(abstract truncated at 250 words)imagesfigure 1 . 
 afigure 1 . 
 bfigure 1 . 
 c