AbstractThis study examined the body composition and serum and liver lipids in weanling rats fed diets containing distillers' dried grains with solubles (DDGS) from either white wheat (WW), red wheat (RW), corn (CO) or WW fortified with essential amino acids (FWW) as a sole protein source (1.6 % N in the diet). Although the DDGS‐fed groups had significantly lower body weights compared with the casein control (RC) after a 28‐day feeding trial, there were no significant differences among the dietary groups in percentages of body water, protein, lipid or ash. Serum cholesterol was significantly higher in rats fed the RW diet, and serum triglyceride was higher in the RC and FWW groups compared with the other dietary groups. Liver cholesterol and triglyceride concentrations (mg g−1 liver) were not significantly different among the five dietary groups.