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.