Circadian basis for the photoperiodic response in the male blackheaded bunting (Emberiza melanocephala)

Abstract

Short day (6 hr light in a 24 hr cycle (LO 6 : 18» inhibits growth and development of the testes in male blackheaded buntings, whereas the same (6 hr) nonstimulatory photoperiods in a 36 hr cycle (LO 6 : 30) induce complete testicular recrudescence and development. In another experiment of 24 hr cycles, using the same (6 hr) main photoperiod, testes were stimulated when the dark period was interrupted by light at 12 to 13 hr after the onset of basic photoperiod (WLD 6 : 6 : 1 : 11). The results appear to conform to the tenets of the external coincidence model.

The effects of feeding time and time-restricted feeding on the fattening traits of White Roman geese

“…Meal time affects weight gain in various animals. Among blackheaded buntings subjected to a time-restricted feeding regimen, only those fed during the first 5 h of the day gained body weight, whereas those fed during the middle or last 5 h of the day lost body weight (Kumar et al, 2001). In addition, mice fed early in the day weighed more compared with mice fed early in the night (Nelson et al, 1975).…”

“…Pigs that were fed identical meals at 12-h intervals followed a clear diurnal biorhythm in protein anabolism, exhibiting a greater amino-acid utilization and lower plasma urea response in the morning compared with the evening (Koopmans et al, 2006). Feeding experiments have shown that meal time significantly affects the weight gain of black-headed buntings (Emberiza melanocephala; Kumar et al, 2001), mice (Nelson et al, 1975), rats (Philippens et al, 1977) and catfish (Sundararaj et al, 1982;Noeske-Hallin et al, 1985), although the optimal time varies among species. In this study, we compared the fattening traits of White Roman geese fed in the morning with those fed in the afternoon in Trial I, and compared the parameters between ad libitum and time-restricted feeding regimens in Trial II.…”

The effect of duration and time of food availability on the photoperiodic response in the male house sparrow, Passer domesticus

“…This was also concluded from the experiments on blackheaded buntings. Kumar et al [20] have categorically demonstrated the effects of duration and time of food availability on the photoinduction of body fattening and subsequent gain in body mass and testis recrudescence in buntings, and the effects were dependent whether or not food was present at the beginning of the day. The importance of food at the beginning of the day can also explain why European starlings did not show any effect of food restriction [18], since food in all foodrestriction regimes was available in the morning.…”

“…Body mass was recorded using a top pan balance to an accuracy of 0.1 g. The testicular growth was recorded by laparotomy performed under local anaesthesia as per procedure described by Kumar et al [20]. Briefly, a small incision was made between the last two ribs on the left flank, and the left testis was located within the abdominal cavity with the help of a spatula.…”

“…A very clear effect of food availability has now been shown in a recent study on the migratory blackheaded bunting (Emberiza melanocephala). Kumar et al [20] showed that both the duration and the time of food availability modulated the photoperiodic induction of body fattening and subsequent weight gain, and testicular growth in the migratory blackheaded buntings. Because the blackheaded bunting is a migratory species, with breeding grounds located at ~ 40° N [21], a study on resident species will be important in determining whether the role of food availability in the photoperiodic induction can be generalized.…”