Maternal photoperiodic exposures alter the neonatal growth, pineal functions and sexual development of the Indian palm squirrel F. pennanti

Summary.

The phenomenon of maternal transfer of photic information to their young ones is still an enigma. Existing reports in some rodents of temperate zone suggest that photoperiodic condition experienced by mother during their gestation period influences the pineal physiology of fetus, but nothing has been reported about the growth and sexual development of pups. Present experiment for the first time explains the effect of gestational photoperiod on the growth and sexual development of pups from a seasonally breeding tropical rodent F. pennanti. The results suggest that, constant light (LL; 24L: 0D) and long day length (LDL; 14L: 10D) experiencing mother conveyed the photic information to young ones to inhibit the pineal function, while short day length (SDL; 10L: 14D) stimulated the pineal function in pups. Altered pineal functions of pups ultimately interfered with their growth and sexual maturation. Most interestingly, the pups delivered by DD experiencing mothers and then reared under same condition, at the age of 40 days attained a level of growth and sexual maturity equivalent to the growth and sexual maturation of 60 days old pups under natural day length (NDL) condition. Therefore, we may suggest that the photic information perceived by the mother alter her normal melatonin level, hence, passing through placenta melatonin influences the growth and sexual maturation of the young ones.