Light colour and intensity alters reproductive/seasonal responses in Japanese quail.
An extensive literature is available on the photoperiodic responses of avian species but studies on light colour and wavelength from light emitting diode (LED) sources on reproduction are limited. Hence, an experiment was designed to study the effect of different colours and intensities of light on the reproductive responses of Japanese quail. Three-week old quail were exposed to five different light conditions with a long photoperiod (LD 16:8): WT (white fluorescent light 100 lux as control), W LED (white light emitting diode, 30 lux), B LED (blue LED, 30 lux), G LED (green LED, 30 lux) and R-LED (red LED, 30 lux). The cloacal gland size, an indicator of androgenic activity, was monitored weekly. The results indicated an early initiation of gonadal growth in WT quail which continued and maintained a plateau throughout the period of study. On the other hand, in general low intensity light, there was a decreased amplitude of the reproductive cycle and the quail exposed to different colour lights (green, red and blue lights) used different incubation times to initiate their gonadal growth and exhibited a gonadal cycle of a different duration up to 15.5 weeks. Thereafter, the gonad of quail of all the LED groups started developing again (including the blue LED exposed quail which remained undeveloped until this age) and attained the increased degree of growth until 26.5 weeks of age. During the second cycle, gonads of green and red light exposed quail continued to increase and maintained a plateau of development similar to WT exposed control while white and blue LED exposed quail exhibited spontaneous regression and attained complete sexual quiescence. Based on our study, it is suggested that long term exposure to blue LED light of low intensity may induce gonadal regression even under long-day conditions (LD 16:8), while exposure to green and red lights appears to maintain a constant photosensitivity after one complete gonadal cycle.
Department of Zoology, Banaras Hindu University, Varanasi 221 005, India. Electronic address: suneeta17bhu@gmail.com.
Suneeta
S
Yadav
Department of Zoology, Banaras Hindu University, Varanasi 221 005, India. Electronic address: cmcbhu@gmail.com.
Chandra Mohini
CM
Chaturvedi
D000818:Animals; D002940:Circadian Rhythm / Q000528:radiation effects*; D003116:Color; D003118:Color Perception / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology; D008027:Light; D008297:Male; D009929:Organ Size / Q000528:radiation effects; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D011784:Quail; D012098:Reproduction / Q000528:radiation effects*; D012621:Seasons; D013737:Testis / Q000033:anatomy & histology; D013739:Testosterone / Q000097:blood; D013997:Time Factors
D013739:Testosterone
Cloacal gland; Gonad; LED; Light colours; Light intensity