Rearing in a Shelved Environment Chronically Modifies Offspring Behaviour and Physiology

Area of Science:

• Animal behavior and welfare
• Developmental neuroscience
• Laboratory animal science

Background:

• Environmental enrichment studies in rodents typically focus on adolescents and adults, with limited data on nursing dams and pups.
• Previous observations suggest behavioral and physiological differences in pups reared in shelved versus single-level cages.

Purpose of the Study:

• To investigate the long-term effects of rearing rodent pups in shelved (enriched) versus single-level (standard) cages.
• To assess the impact of rearing environment on pup development, stress physiology, behavior, and spatial memory.
• To evaluate stress-related behaviors in dams housed in different cage environments.

Main Methods:

• Pups were assessed for body weight, ultrasonic vocalizations, hair corticosterone levels, open field and elevated plus maze behavior, and spatial working memory.
• Dams were evaluated for stress-related behaviors using open field and elevated plus maze tests.
• Comparison between rats reared in enriched (shelved) and standard (single-level) cages.

Main Results:

• Adult rats reared in enriched cages exhibited lower body weight and higher hair corticosterone concentrations.
• Enriched-reared rats showed reduced exploration in the open arms of the elevated plus maze and fewer frequency-modulated ultrasonic vocalizations.
• Dams housed in enriched cages displayed less time in the center of the open field, indicating altered stress responses.

Conclusions:

• Rearing conditions significantly influence long-term behavioral and physiological traits in rodents.
• Environmental enrichment during early development has lasting effects on stress reactivity and behavior.
• Optimizing rearing conditions is essential for enhancing laboratory animal welfare and improving the reproducibility of research findings.