Short and long term effects of malnutrition in rats during lactation on the body weight of offspring

Epidemiological data suggests that mother nutritional condition can influen ce offspring body weight by means of metabolic imprinting. However, there a re few experimental reports relating mother nutritional condition during la ctation to offspring body weight in adulthood. The short and long term effe cts of maternal protein or energy malnutrition during lactation on offsprin g body weight were determined using lactating rats fed a 8% protein-restric ted diet (PR), a control 23% protein diet (C), and an energy-restricted pai r-fed to PR group (PF). Milk was analyzed for protein, lipid and lactose co ncentrations on days 4, 8, 12, 16 and 21 after birth. After weaning all ani mals received a normal diet and body weight was monitored until day 180 of age. PR group had a lower (p < 0.01) milk protein concentration on day 12 a nd 21. PF group presented: a higher (p < 0.01) milk lipid concentration fro m day 12, and a higher (p < 0.01) protein concentration from day 16, both u ntil weaning. Total milk energy was always lower (p < 0.001) in the PR grou p. During lactation, pups in the PR and PF groups had lower body weight (p < 0.001), but after weaning body weight in the PF group surpassed that of c ontrols on day 80 (p < 0.05), while that of the PR group remained lower (p < 0.05) until day 180. These results support epidemiological evidence in hu mans suggesting that body weight in adulthood may depend on maternal nutrit ional condition during gestation and/or lactation and that milk composition is a critical factor for this metabolic imprinting. (C) 2000 Elsevier Scie nce Inc..