The impact of maternal protein malnutrition on pre-weaning skeletal and visceral organ growth in neonatal offspring of Rattus norvegicus

Most studies of malnutrition focus on adult size, or limited durations of malnutrition. Little is known about the impact of life-long maternal malnutrition on young, pre-weaning offspring, in part because working with such infants is difficult. We created a maternal generation of malnourished dams by feeding female Sprague-Dawley rats, from weaning, either a control diet high in protein (CT) or an isocaloric low protein diet (LPT). The offspring of matings between these dams and control fathers were weighed daily and radiographed three times before sacrifice at 22d, when several visceral organs and muscles were dissected out and weighed. We compared lengths of craniofacial and limb bones, and organ and muscle weights, between the two diet treatments. Allometric cancellation was used to assess integration of growth among organs and muscles. The offspring of LPT dams had body, organ and muscle weights smaller than the offspring of CT dams. When scaled to body mass, some organs of the LPT offspring were relatively larger. Although the CT offspring skeletons were significantly larger than the LPT skeletons, considerable variation existed in the patterns of growth between the two treatments. The CT offspring had a higher level of correlation among muscles, and most organs, than did the offspring of LPT dams. The organs that did maintain a correlation in growth, or linkage, were pairs of organs more likely to be protected (heart-lung or eye-brain) from the insult of protein malnutrition. The ability to protect some organs may be the result of their tighter developmental program, one that is more resistant to differences in available nutrition.