Author/Editor		Mugaas, John N
Title		Effect of changing photoperiod on body weight, food consumption, and glucose tolerance of the white-eared opussum, Didelphis albiventris, in Brazil
Type		članek
Source		In: Hočevar A, Črepinšek Z, Kajfež-Bogataj L, editors. Biometeorology 14. Proceedings of the 14th international congress of biometeorology. Part 2. (Vol 2); 1996 Sep 1-8; Ljubljana. Ljubljana: Slovenian meteorological society,
Publication year		1996
Volume		str. 292-302
Language		eng
Abstract		The Virginia opossum, Didelphis virginiana, increases food consumption, and fattens when exposed to summer and autumn photoperiods; a metabolic response that enhances its winter survival in hash temperature climates. This study was conducted to determine if the tropical white-eared opossum, Didelphis albiventirs, would respond to an autumn photoperiod in the same way. In early, July, eight white-eared opossums were captured on the UNESP campus at Jaboticabal, S.P., Brazil, and divided into control, and experimental groups of equal size. The control group was exposed to a light/dark pattern that matched the winter and spring photoperiod at Jaboticabal (21 degrees S). The experimental animals were exposed to an eight week long photoperiod regimen designed to phase-shift their internal clocks from winter to the autumnal equinox. They were then exposed for 40 days to an autumn photoperiod. All animals received food and water ad libitum. Their food consuption, and body weight was measured periodically. Oral glucose tolerance tests were conducted on all the animals at the end of weeks, 5, 10, and 14; blood samples were assayed for glucose and insulin. Both groups displayed similar changes in body weight (fat content), and food consumption, but because they were exposed to different light/dark schedules, the timing of these changes was different in each group. In both groups, body weight (body fat) increased in response to an increase in the hours of daylinght. Food consumption in both groups was highest during the early period of weight gain. Insulin release was greatest for both groups during exposure to equinox photoperiods, which also corresponded with the time that each group reached its highest body weight.(Abstract truncated at 2000 characters.)
Descriptors		PHOTOPERIOD BODY WEIGHT EATING GLUCOSE TOLERANCE TEST OPOSSUMS BRAZIL