Protein Malnutrition Affects the Growth Trajectories of the Craniofacial Skeleton in Rats

Abstract

To investigate the effects of protein malnutrition on a normal growth trajectory, we radiographed Rattus norvegicus from 22 d (weaning) and continuing past adult size. We took measurements from longitudinal radiographs of rats fed a control diet and littermates fed an isocaloric low protein experimental diet. A Gompertz model was fit to each individual rat for body weight and 22 measurements of the craniofacial skeleton, producing parameters that described the rate and timing of growth. We tested for differences in these parameters due to diet, sex and litter with a mixed-model three-way ANOVA. Allometric analysis examined the scaling relationships between and within various regions of the skull. For most measurements, final sizes predicted by the model were not significantly different between rats fed the two diets, although the differences in final measurements showed small, but significant differences in growth between rats in the two diet groups. The instantaneous initial rate of growth, maximum rate of growth and deceleration of growth were significantly higher in the control rats for every measurement. Rats fed the low protein diet grew for a significantly longer period of time. The shape of the neurocranium was relatively conserved between diet groups; however, rats fed the low protein diet had shorter and relatively wider skulls than the controls. These results suggest that functional demands of the viscerocranium were greater after birth, and that growth in this area was faster. The viscerocranium reached functional adult proportions earlier and was therefore more susceptible to epigenetic perturbations such as dietary protein level. Protein malnutrition did not affect many aspects of adult size, but strongly altered the growth trajectory to achieve that size.

Experimental diet based on the foods listed in the Family Budget Survey is more detrimental to growth than to the reflex development of rats

“…Their neurocrania also grew 6% less but the difference was not significant. These findings are in agreement with those of Miller & German 4 who reported the vulnerability of this axis to a low-protein diet during perinatal life. However, the differences found in Miller & German's 4 study stemmed from a very low-protein diet (4%) with normal fat content.…”

“…At birth, this part has already completed much of its growth. Thus, after birth the viscerocranium grows faster than the neurocranium, in accordance with the functional demand 4 . The viscerocranium of rats fed a low-protein diet (4%) grow less, probably because of faster growth 4 .…”

“…Rats. [grupo-controle: 12,00 (9,(0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)00) dias; POFG=9,50 (9,(0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)00) dias] e queda livre [grupo-controle:18,00 (17,00); POFG=16,00 (13,(0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)…”

“…Protein is essential not only for the maturation of the nervous system but also a determinant of cranial and body growth 4 . Its availability depends on appropriate protein intake by dams and quality of the protein source, consequently, the bioavailability of essential amino acids.…”

Repercussões do exercício físico durante a gestação e da desnutrição proteica durante a gestação e lactação sobre o desenvolvimento e crescimento do fêmur da prole

“…1 A low-protein diet during critical periods of development severely affects all tissues, causing harmful effects on the growth of several organs, mainly the bone tissue in patients undergoing such aggression. 13,14 In this study, protein malnutrition imposed to the mother rats during pregnancy and lactation periods resulted in a deficit observed until the end of the study regarding the body weight of the offspring. Similar to these findings, Golstein & Bond 15 observed that mice that underwent protein deprivation during lactation weighed less than the control animals, which persisted even with nutritional supplementation.…”