Effects of postnatal environment perturbations on the patterns of canalization and integration of the skull

GONZALEZ P.; HALLGRIMSSON B; OYHENART E.

Punta del Este

Congreso; International Congress of Vertebrate Morphology; 2010

This study uses a rat model to analyze the effects of environmental stress at different postnatal stages on the patterns of variation and correlation of craniofacial traits. Adult female rats (Wistar), were fed on stock diet ad libitum during gestation. Dams and their pups were submitted at delivery to one of the following treatments: Control (C): dams and their pups received stock diet ad libitum; Early malnutrition (EM): dams received half of the amount of the stock diet, after weaning their pups were fed on control diet; Late malnutrition (LM): dams received control diet and their pups were fed on a low protein diet (2%) after weaning; Total malnutrition (TM): dams received half of the amount of the stock diet, and their pups a low protein diet (2%) after weaning. Animals were sampled at 63 days of age. Skulls were cleaned and micro-CT scanned at 35μm resolution. Sixty-two three-dimensional landmarks, which describe the face, cranial vault and base, were collected. Significant differences in mean shape were found between treatments for all regions, except between LM and TM. Levene’s test showed a higher among-individual phenotypic variance in size and shape in the EM group for all of the regions. No significant differences in the eigenvalue variance of correlation matrices between treatments for any of the regions were found. The correlations between correlation matrices for each treatment were low, ranging between 0.33-0.67; with the highest values between LM and TM. Contrary to expectations, the cranial base was as affected as other regions.