Noise and vibrations in an animal facility commonly cause what changes in rodents?

• A. Reduced fertility
• B. Retinal injury
• C. Epilepsy
• D. Adrenal tumors

Answer: (A)

Stress from noise and vibrations triggers a physiological response in rodents that primarily disrupts their reproductive system. When rodents experience chronic or intense noise, the body activates the hypothalamic-pituitary-adrenal axis, raising stress hormone levels. This hormonal shift can dampen the hypothalamic-pituitary-gonadal axis, leading to irregular or suppressed estrous cycles, reduced mating success, lower conception rates, and, consequently, smaller litter sizes or longer times to pregnancy. In short, the reproductive function is highly sensitive to stress, and noise/vibration is a common stressor in facilities, making reduced fertility the most likely change.

Retinal injury is not a typical outcome of routine facility noise or vibration; epilepsy would depend on individual susceptibility and isn’t a common or expected consequence for a general rodent population; adrenal tumors aren’t linked to noise exposure in a standard laboratory setting.