Effects of type and level of dietary fat during the pre-initiation phase of mammary carcinogenesis in rats
1998
Imrhan, V.L. | Hsueh, A.M.
The effects of feeding two types (corn and menhaden) and two levels (5% and 20%, w/w) of dietary fat administered during the pre-initiation phase of chemically-induced mammary carcinogenesis on serum fatty acid profiles, and on tumorigenesis were studied in female Sprague-Dawley rats. One hundred and twenty 4-wk old rats were randomly divided into 4 groups and given the experimental diets for 4 weeks. When the rats were 8 weeks old, a single dose (5 mg/100 g body wt) of 7,12 dimethylbenz(alpha) anthracene (DMBA) was administered intragastrically to each rat. Thereafter, all the rats were fed the AIN-76A diet until the termination of the experiment. All the rats were necropsied 14 weeks after carcinogen administration. Body weights among the four groups of rats were similar throughout the study and was not different at necropsy. At the end of the experiment (14 weeks post-DMBA), the palpable tumor incidence was not significantly different (P > 0.05) among the four groups of rats, but at 12 weeks post-DMBA, the 20% corn oil (HCO) and the 5% menhaden oil (LMO) groups had significantly higher tumor incidence than the 20% menhaden oil (HMO) and the 5% corn oil (LCO) groups. Tumor burden (total tumor weight/rat) and mean latent period were not significantly different. Serum fatty acid profiles reflected the type of dietary oils consumed by the rats. These results showed that neither the type (corn, menhaden) nor the amount (5%, 20%) of dietary fat fed during pre-initiation influenced the final outcome of mammary carcinogenesis in female Sprague-Dawley rats.
显示更多 [+] 显示较少 [-]