SOCIAL STRESS IMPACT ON DEVELOPMENTAL STABILITY OF LABORATORY RAT RATTUS-NORVEGICUS

Developmental stability of the progeny of pregnant female rats Rattus norvegicus Berkenhout, 1769 kept under different conditions was studie d. In two experimental groups, females were exposed to social stress b y keeping them in crowded cages at different stages of pregnancy, from the Ist to the 15th and from the 16th to the 21th days, respectively. In the control group, pregnant females were kept under normal conditi ons. Fluctuating asymmetry of 20 skull characters (number of foramina for small blood vessels and nerves) was used as a measure of developme ntal stability. Variance of the difference in foramen number between t he left and right sides of the skull (l-r) as well as mean number of a symmetrical traits per individual revealed an increase of fluctuating asymmetry in both experimental groups compared with the control group. These results imply the deterioration of developmental stability unde r impact of social stress.