Effect of temporal synergism of neural oscillators on gonadal development, egg production and hatchability of Japanese quail (Coturnix coturnix japonica)

To study the effect of temporal synergism of neural oscillators (serotonergic and dopaminergic) on gonadal development, egg production and hatchability, three weeks old sexually immature Japanese quail were divided into three groups. First group quail received two daily injections of normal saline (control), second group quail received serotonin precursor (5-Hydroxytryptophan-5-HTP, 5 mg/100gm body weight) at 5.00 A.M. and dopamine precursor (L-dihydroxyphenylalanine-L-DOPA, 5mg/l00gm body weight) at 1.00 P.M. (8-hr) and third group quail received above two injections at the interval of 12 hour i.e. at 5.00 A.M. and 5.00 P.M. respectively (12-hr). Each group contained colony of male and female quail (1:2 ratio). After 11 days of treatment, given in continuous condition of light (LL), quail were transferred to long day length condition (LD 16:8) and biweekly observations were taken. The 12-hr quail showed significant increase in the rate and degree of development of cloacal gland and testicular size, whereas in 8-hr group suppression of reproductive development was seen compared to control. Female quail also showed similar trend in follicular diameter and ovarian weight. Onset of egg laying was observed by 5th week in 12-hr quail, by 7th week in control and no egg laying was noted in 8-hr quail. Moreover, rate of egg production, egg size and hatchability rate was remarkably high in 12-hr quail compared to control. It is obvious that 12-hr relation induced precocious sexual maturity and increased the rate of tertility. These observations suggest that injections of serotonergic and dopaminergic precursor drugs (5-HTP and L-DOPA) given at specific time interval had significant intluence on the maturation of neuroendocrine gonadal axis as well as rate of reproduction.