46F-5 |
Dose response of azoxymethane (AOM)-induced aberrant crypt foci (ACF) to dietary bifidobacteria in Fisher 344 male weanling rats |
M. VERGHESE1, D. R. Rao2, C. B. Chawan1, and L. Shackelford1. (1) Food and Animal Sciences, Alabama A & M University, Nutrition and Carcinogenesis Laboratory, P.O. Box 1628, Normal, AL 35762, (2) USDA-CSREES/PAS, 800 9th St. SW Room 3305, Washington, DC, 20024 Cancer of the colon is one of the leading causes of cancer morbidity and mortality among men and women in the Western countries, including the US. Recent studies have identified several beneficial attributes of probiotics in human health. The objective of this study was to test the dose response effect of Bifidobacterium longum (BB536) on the incidence of AOM-induced ACF in Fisher 344 male weanling rats. After an acclimatization period of 1 wk, 40 male weanling rats were divided into 4 groups and were fed different levels (0, 0.5%, 1%, 2%) of bifidobacteria (1 X 108 viable cells/g lyophilized powder) in AIN 93G (Control) diet. B.longum was added at the expense of cornstarch. Weekly body weights and daily feed intakes were recorded. All the rats received 16 mg/kg body weight of AOM (s/c) dissolved in saline at 7 wk followed by a second injection at 8 wk of age. The animals continued to receive the assigned diets until sacrifice by CO2 asphyxiation at 17 wk of age. There were no significant differences in weight gain or feed intake between control and experimental groups. B.longum significantly (p<0.05) reduced ACF in the colon in a dose-dependant manner. Compared to the control group, the percent reductions of ACF in 0.5%, 1% and 2% B.longum groups were 29.7, 40.2, 49.0, respectively. The results of this study indicate that dietary B.longum (BB536) suppressed AOM-induced ACF formation, a preneoplastic marker in the process of colon carcinogenesis in Fisher 344 male rats. These observations suggest that bifidobacteria in the gut could potentially inhibit colon tumorigenesis.
Session 46F, Nutrition
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