Long-term feeding and reproduction studies on emulsifier YN in rats

Abstract

Emulsifier YN was fed to groups of 48 male and 48 female rats at dietary levels of 0 (control), 2 or 6 % for 2 yr. A similar group of rats was fed on diet containing 4 % soya lecithin. These treatments did not adversely affect mortality, rate of body-weight gain, haematology, urine constituents, renal concentrating ability, serum constituents or the incidence of tumours. Thyroid weight was increased in all treated groups, but this was the result of an increased incidence of parathyroid hyperplasia, thought to be due to spontaneous renal changes combined with an elevated intake of phosphate. A slightly increased incidence of myocardial fibrosis was also associated with the parathyroid hyperplasia. The incidence and severity of other histopathological changes were not influenced by feeding YN or lecithin. A two-generation study, in which the parent animals were fed diets containing 0 or 6 % YN for 13 wk before mating, revealed no effects on fertility, the number of young or the growth of young during lactation, and no abnormalities were seen. The no-untoward-effect level for YN in this study was 6 %, approximately equivalent to an intake by the rat of 3 g/kg/day.