Sickness-induced changes in physiology do not affect fecundity or same-sex behavior

Area of Science:

• Reproductive biology
• Neuroendocrinology
• Behavioral ecology

Background:

• Early-life infection can impact reproductive physiology and social behavior.
• The long-term reproductive consequences of neonatal immune challenges are not fully understood.

Purpose of the Study:

• To investigate the lasting effects of early-life lipopolysaccharide (LPS) administration on reproductive physiology, social behavior, and reproductive success in Siberian hamsters.
• To determine if physiological changes due to neonatal immune challenge affect ultimate reproductive outcomes.

Main Methods:

• Siberian hamster pups (male and female) were administered LPS or saline on postnatal days 3 and 5.
• Adult hamsters were assessed for same-sex social behaviors (investigation, aggression).
• Reproductive function was evaluated through mating trials and assessment of fecundity.

Main Results:

• LPS-treated females exhibited smaller ovaries and abnormal estrous cycles in adulthood.
• No significant differences in same-sex social behavior were observed between LPS-treated and control groups.
• Mating success and fecundity were not significantly affected by early-life LPS exposure in either sex.

Conclusions:

• Neonatal immune challenge can cause persistent physiological changes but may not compromise reproductive success in a controlled setting.
• Siberian hamsters may compensate for early-life stress-induced physiological alterations to maintain reproductive function.
• These findings highlight the complex interplay between early-life adversity, physiology, and behavior in determining long-term survival and reproduction.