Growth and survival of RCS dystrophic rats fed modifications of the AIN-76 diet

The RCS dystrophic rat is a hooded, pigmented-eyed strain widely used as a model for retinal degeneration. In addition to progressive photoreceptor loss, this strain suffers from unexplainable high mortality during the suckling period when reared on commercial cereal-based diets. Supplementation of these diets with 25% sunflower seeds greatly reduces this problem. This report presents the results of a study undertaken to test the effectiveness of the purified AIN-76 diet in controlling the high mortality. Growth of F1 rats and percent survival of the F2 offspring were determined for RCS dystrophic rats provided one of 5 diets: (Control) modified AIN-76 diet (15% additional sucrose in place of starch, nd vitamin and mineral mixes made up in cellulose rather than powdered sucrose); control with double the content of vitamin mix; control with double the content of fat; control with double the content of mineral mix; and control with double the content of protein. The percent survival of the F2 offspring was increased from 73% to 92% by vitamin supplementation. Doubling the mineral or protein content proved lethal to 54% and 79% of offspring on these respective diets. Increasing the vitamin content also resulted in an improvement in the initial growth of females. Increased fat, mineral or protein content all decreased the growth rate of males. Likewise, growth of females was decreased when the mineral and protein content of the diet was raised.