Effect of prenatal and postnatal environmental enrichment on laboratory rats' welfare

Research Abstract

The welfare of laboratory animals is one of the most distrusted issues concerning animals under human control. Environmental and biologic factors can influence experimental results by exerting subtle influences on an animal's physiologic characteristics, behavior, or both. Therefore great attention must be paid to the wellbeing of every laboratory species to ensure the high quality of both science and ethical practice. A total number of 30 female rats were randomly divided into two groups, control group (raised under standard housing conditions) and enriched group (raised under enriched housing conditions from zero day of pregnancy). Offspring from enriched group were divided into two groups; one raised under standard and the other raised under enriched condition from day 23 to day 35 postnatal meanwhile the neonates 'behaviour was observed, on day 36postnatal, rats subjected to elevated plus maze and open field tests, and on day 42 postnatal, rats were blood sampled and humanely sacrificed to obtain brain samples for histopathological examination. The results showed significant (p<0.05) increase in sleeping behaviour in prenatally enriched group and significant (p<0.01) increased in E+EC group. Play and fighting behaviour were significantly (p<0.05) increased in duration in enriched group. E+EC group showed high exploratory behaviour but not statistically significant. The behavioural tests results revealed significant (p<0.05) increased time spent in open arm, open arm entries and time in center in E+EC group and USAP were significantly (p<0.01) increased in E+EC group. Freezing time in open field test were significantly (p<0.01) decreased in enriched group, while grooming frequency were significantly increased (p<0.05) in E+EC group. Corticosterone level were significantly (p<0.05) decreased in E+EC group and the mean of tertiary processes of cytoplasmic processes in cross section of hippocampal region were significantly increased (p<0.05) in E+EC group.

Research Keywords

corticosteron- welfare - enrichment