The effects of a lengthy period of undernutrition on food intake and on body and organ growth during rehabilitation.

Studies were carried out on male black and white hooded Lister rats to examine the influence of a lengthy period of undernutrition on subsequent somatic growth and food consumption. Animals were undernourished from about birth until 100 days of age followed, in some cases, by nutritional rehabilitation to 200 days. At weaning, body weight was reduced by 45 g and all organ weights were significantly less in undernourished rats compared with controls. In percentage terms the liver, kidney, adrenal, testis and spleen showed the largest deficits (-45 to -60%) whereas the eyeball (-30%) and brain regions (-14 to -19%) were relatively spared. The deficits in most of the organ weights in rats undernourished until 100 days of age were, in percentage terms, similar to those seen in the 25 days old animals. The testis, spleen and adrenal gland showed smaller deficits at 100 days of age than those observed earlier. Nutritional rehabilitation caused complete catch-up growth in eyeball weight and some catch-up in the weight of other organs studied. During the period of nutritional rehabilitation, previously undernourished rats ate significantly more food per kilogram body weight than controls and were more efficient at converting this food into body mass than age-matched controls.