A dietary two-generation reproductive toxicity study of (2R,4R)-monatin salt in Crl:CD(SD) rats.

(2R,4R)-Monatin salt [sodium/potassium 2R,4R-2-amino-4-carboxy-4-hydroxy-5-(3-indolyl) pentanoate] was fed at 5000, 15,000, or 35,000 ppm to Crl:CD(SD) rats over two generations. Reduced body weights were observed at all dose levels. Sustained effect on body weight gain at 35,000 ppm in the F0 and F1 parental animals was associated with lower feed efficiency, soft stool, and slightly lower numbers of implantation sites. Lower numbers of pups born and live litter size at 35,000 ppm were considered secondary to slightly lower numbers of former implantation sites in the dams. Spermatogenic endpoints, estrous cyclicity, reproductive performance, mean gestation length, and parturition were unaffected in the F0 and F1 generations. There were no effects on F1 and F2 generation postnatal survival. Reduced pre-weaning pup body weights at 35,000 ppm resulted in lower F1 and F2 body weights at study termination. Slight delays in pubertal landmarks in the F1 offspring were considered secondary to the reduced pup body weights. The no-observed-adverse-effect level (NOAEL) was 15,000 ppm for systemic, reproductive, and neonatal effects based on test article-related effects on body weight and food efficiency, slight decrease in maternal implantation sites and corresponding reduction in live litter size, and reductions in pre-weaning pup body weights at 35,000 ppm.