Alterations in gastrointestinal contents induced by elemental diets

The effects of elemental diets on selected aspects of the rat colon were studied. Forty young male Sprague-Dawley rats were divided into 4 diet groups of 10 rats each: Purina Rat Chow (control); Flexical; Precision L-R; and Vivonex. All diets were fed ad lib to rats housed in pairs in wire-bottom cages. Two weeks after weight stabilization had been achieved all rats were killed and colon contents were collected for culture and short-chain fatty acid analysis on the Perkins-Elsoner 3920 gas chromatograph. Colon fecal butyric/acetic acid ratios of the rats in the 4 groups were: Rat Chow, 2.56; Flexical, 0.28; Precision L-R, 0.16; and Vivonex, 0.26. Bacterial cultures showed increased coliform and enterococcal species in the rats consuming elemental diets.