This study was designed to test whether Mucuna pruriens, a natural source of L-dihydroxyphenylalanine (L-DOPA, a dopamine precursor) feeding, can influence development and reproductive conditions in the high food value bird, Japanese quail, Coturnix coturnix japonica. Experiments were performed in both male and female Japanese quail. One-week-old quail chicks were divided into three groups of 36 birds each. Group I was provided with normal diet and served as control. Group II was provided with food mixed with L-DOPA (50 mg/15 g food) and Group III was provided with food mixed with M. pruriens seed powder (480 g/kg food). At the age of 3 weeks (when birds were sexually distinguished) Group I was divided into two subgroups IA (male) and IB (female) of six birds each. Similarly, Groups II and III were sub-divided into IIA (male), IIB (female) and IIIA (male), IIIB (female), respectively, of six birds each. Observations were made up to the age of 5 weeks. Male experimental groups (IIA and IIIA) showed significantly increased testicular activity, cloacal gland volume, body weight (BW), plasma testosterone and LH level in comparison to control (IA). Similarly female experimental groups (IIB and IIIB) showed significantly greater weight of reproductive organs (uterus, ovary, oviduct and ovarian follicle), BW, egg weight and size and number of follicles. On the other hand, plasma prolactin level was significantly low in comparison to control (IB). Results suggest that M. pruriens is a rich natural source of L-DOPA and the development and reproduction in Japanese quail might be associated with the dopaminergic system of the brain.Keywords: reproduction, Mucuna pruriens, L-DOPA, nutrition, Japanese quail
IntroductionAccording to our present knowledge, neuropeptides and biogenic amines are the most important secretions of neuroendocrine cells. The role of the central nervous system (CNS) neurotransmitters, which appear to be the mediator of many control mechanisms in mammals (Weiner and Ganong, 1978), is little understood in other vertebrate groups except for mammals. The neuroendocrine system is an integral component of the neuronal apparatus of the brain, a major portion of which is concentrated in the hypothalamus. The hypothalamic monoamines dopamine (3,4-dihydroxyphenylalanine), noradrenalin and serotonin have profound effects on the release of mammalian pituitary hormones, presumably in most cases by modulating the release of the hypothalamic hormone . The hypothalamus is of paramount importance as an 'integration center' for the various influences on pituitary function. The hypothalamus apparently responds to the exteroceptive and interoceptive stimuli by altering the secretion of certain neurotransmitters and release hormones. Ideally, a study of the control of pituitary function should not only show the effects of any particular influence on hormone secretion but also demonstrate the changes in the metabolism of neurotransmitters and release of inhibiting hormones. Dopamine (DA) is reported to be synthesized large...
