Comparison of endpoints relevant to toxicity assessments in 3 generations of CD-1 mice fed irradiated natural and purified ingredient diets with varying soy protein and isoflavone contents

• Published in: Food and chemical toxicology Vol. 94; pp. 39 - 56
• Main Authors: Camacho, Luísa, Lewis, Sherry M., Vanlandingham, Michelle M., Juliar, Beth E., Olson, Greg R., Patton, Ralph E., Gamboa da Costa, Gonçalo, Woodling, Kellie, Sepehr, Estatira, Bryant, Matthew S., Doerge, Daniel R., Basavarajappa, Mallikarjuna S., Felton, Robert P., Delclos, K. Barry
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-08-2016
• Subjects: Animals; CD-1 mouse; Diet; Female; Isoflavones; Isoflavones - analysis; Male; Mice; Natural ingredient diet; Purified ingredient diet; Soy; Soybean Proteins - analysis; Thiamine; Toxicity Tests; Natural ingredient diet; CD-1 mouse; Soy; Thiamine; Purified ingredient diet; Isoflavones
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2016.05.014

Diet is an important variable in toxicology. There are mixed reports on the impact of soy components on energy utilization, fat deposition, and reproductive parameters. Three generations of CD-1 mice were fed irradiated natural ingredient diets with varying levels of soy (NIH-41, 5K96, or 5008/5001), purified irradiated AIN-93 diet, or the AIN-93 formulation modified with ethanol-washed soy protein concentrate (SPC) or SPC with isoflavones (SPC-IF). NIH-41 was the control for pairwise comparisons. Minimal differences were observed among natural ingredient diet groups. F0 males fed AIN-93, SPC, and SPC-IF diets had elevated glucose levels and lower insulin levels compared with the NIH-41 group. In both sexes of the F1 and F2 generations, the SPC and SPC-IF groups had lower body weight gains than the NIH-41 controls and the AIN-93 group had an increased percent body fat at postnatal day 21. AIN-93 F1 pups had higher baseline glucose than NIH-41 controls, but diet did not significantly affect breeding performance or responses to glucose or uterotrophic challenges. Reduced testes weight and sperm in the AIN-93 group may be related to low thiamine levels. Our observations underline the importance of careful selection, manufacturing procedures, and nutritional characterization of diets used in toxicological studies.
•CD-1 mice fed irradiated natural or purified ingredient diets were evaluated over three generations.•Groups fed natural ingredient diets were similar, but differed significantly from the groups fed purified diets.•Unanticipated low thiamine levels in the AIN-93 diet may have contributed to the decreased spermatogenesis in this group.•Diet choice in toxicology requires careful consideration and interaction of nutrients with toxicants warrants attention.