DIETARY PLANT MATERIALS AND DEVELOPMENT OF DIABETES IN THE BB RAT

The present study was designed to examine further the impact of individual plant protein sources found in a diabetogenic, cereal-based, rodent laboratory diet, NIH-07 [open formula, nonpurified rat and mouse diet (positive control)], on the development of diabetes. Diabetes-prone BB rats that were pan-T(OX19+)-lymphopenic were fed a low diabetogenic diet during gestation and lactation. Progeny of these rats were fed a normal or autoclaved NIH-07 diet, or one of eight other diets based on the AIN-76A formulation, with modified protein sources as follows: hydrolyzed casein (HC), soybean meal, HC + trypsin inhibitor (TI) in water (2 mg/mL), wheat germ, alfalfa seeds, Brewer's yeast, red lentils and a plant protein mixture. Feeding soybean meal increased the incidence of diabetes compared with the negative control, HC diet (47% vs. 12% incidence, P = 0.02). Wheat germ, alfalfa seeds and plant protein mixture resulted in an intermediate incidence of diabetes of 33%; the incidence was lower for Brewer's yeast and lentils (20% and 13%). Autoclaving (121-degrees-C, 10 min) the NIH-07 diet or the presence of TI in drinking water had a minimal effect on diabetes frequency, suggesting heatlabile plant toxicants were not directly involved. Thus, certain dietary plant protein sources or associated agents may influence the development of spontaneous diabetes in the BB rat.