Effects of protein restriction in early life on growth and function of the gastrointestinal tract of the rat.

BACKGROUND

Undernutrition during early life may have both immediate and later consequences. This study was undertaken to measure the long-term effects of perinatal undernutrition on the growth and function of the gastrointestinal tract.

METHODS

Pregnant rats were assigned to one of four groups that received isocaloric diets restricted in protein during pregnancy or lactation and during both or neither. Thereafter, their pups were followed until aged 1 year.

RESULTS

At 21 days the body weights of the young of those born of dams with postnatal protein restriction were halved, with comparable reductions in the weights of the stomach and caecum, compared with those of control animals. The lengths of the small and large intestines and mucosal weights of the foregut were also significantly reduced. Lactase activities were significantly increased and sucrase and maltase activities significantly reduced. By 42 days all the effects were less marked, and at 1 year the dimensions of the organs of the gastrointestinal tract and the composition and enzyme levels of the mucosa were all insignificantly different relative to body weight.

CONCLUSIONS

Prenatal protein restriction alone had no significant long-term negative effects on body weight, growth, or mucosal hydrolase activity of the gastrointestinal tract. Postnatal protein restriction had a marked effect on these indices in early life and delayed the changes in mucosal hydrolases usually seen at weaning. In contrast with other organs and their functions, long-term growth of the gut and activity of small intestinal hydrolases are preserved in the face of perinatal protein restriction.