The influence of premature weaning and the nature of the fat in the diet during development on adult plasma lipids and adipose cellularity in pair-fed rats.

Long-term effects of the nature of the fat in the diet of developing rats on plasma lipids and adipose cellularity were investigated. During the developmental period (less than 95 days of age) rats were fed purified diets containing either polyunsaturated vegetable oil (VO) or cholesterol-supplemented animal fat (AF). Half of the rats of each diet fat group was weaned at 14 days of age (PW). From age 95 days to the time of death at 333 days all of the rats were fed the AF diet. In both early diet fat groups PW and normally suckled (MN) rats were pair-fed after 21 days of age. Adult MN rats fed the AF diet had the lowest total plasma cholesterol concentration of any group and a lower level of high density lipoprotein cholesterol than MN rats fed the VO diet during development. All four groups of rats had approximately the same average body weight at 333 days, but MN rats that had been fed the VO diet had significantly fewer, but larger, adipocytes per gram of ovarian fat pad than any other group. Despite virtually equivalent food consumption and no known nutrient deficiencies or excesses, these data demonstrate some significant adult metabolic responses to variations in early diet.