The effect of a low protein diet on the anatomical development of the rat brain

Albino rats were conceived and suckled by mothers maintained on a 8% or an isocaloric 25% casein diet. After weaning, pups were maintained on their respective diets ad libitum. By most parameters of CNS maturation, rats on the low protein diet closely resembled their age-matched controls. only by the parameter of the ratio of brain weight to body weight did they resemble rats of a younger age. Camera lucida drawings of comparable Rapid Golgi-impregnated cortical neurons of 10-day-old control and experimental rats were nearly identical to each other. A similar finding was also noted in 30-day-old rats. However, with quantitative studies, the 30-day-old experimental animals showed a decrease in synaptic spine density and reduced dendritic length for some but not all dendritic processes. At all ages, experimental animals closely resembled age matched controls in the proportion of their brain weight that was neocortex, archicortex, and cerebellum. In these results we concur with Dobbing and Sands that developmental timetables for the brain are not affected by undernutrition, though extent of development may be.