Feeding patterns of s. crassicaudata (marsupialia: dasyuridae): the
role of gender, photoperiod and fat stores.
Hope, Perdita J., Gary A. Wittert, Michael Horowitz, John E. Morley.
Department of Medicine, University of Adelaide, Royal Adelaide
Hospital, North Terrace, Adelaide, South Australia 5000 Australia and
Division of Geriatrics, St Louis University, St Louis Mo
APStracts 3:0246R, 1996.
Little is known about feeding regulation in marsupials. Sminthopsis
crassicaudata is a small nocturnal marsupial, whose tails contain
approximately 25% of total body fat. We have characterised the effect
of gender, photoperiod, food deprivation and tail removal (lipectomy)
on food intake in S. crassicaudata. Males and females maintained in
captivity on long day (16 hour light, 8 hour dark) and short day (9
hour light, 15 hour dark) light regimes were studied. Feeding
patterns under long day and short day photoperiods were initially
measured under conditions of ad libitum food supply and then in
groups of animals exposed to 24 and 36 hour periods of food
deprivation. Feeding occurred predominantly in the dark. Females
maintained on short day photoperiods for 5 weeks ate less (P <
0.005) than females on long days or males on either short or long
days, but this reduction in food intake was not associated with
either a decrease in body weight or tail width. Following both 24 and
36 hour fasts, total food intake in the subsequent 24 hours increased
(P < 0.001) by up to 100% in all groups, with no gender or
photoperiod effect. SD females however ate less (P < 0.05) than
LD females in the first 6 hours after re-feeding. Tail width
decreased (P < 0.05) in all groups of animals after the 36 hour
fast, but only in LD animals after the 24 hour fast (P < 0.05).
Body weight decreased similarly in all groups of animals following
fasting. The effect of tail removal was studied in LD males. The
procedure, which was well tolerated, resulted in an initial fall in
body weight (P < 0.005), which recovered within 3 weeks. On day
45 in the animals who had their tails removed body fat was about 30%
greater than body fat of controls (P < 0.02). No significant
increase in food intake occurred after tail removal. These data
demonstrate in Sminthopsis crassicaudata (i) a photoperiod and gender
dependent effect on food intake, (ii) the ability to regulate the
amount and distribution of total body fat and (iii) a dissociation
between the regulation of food intake and changes in body fat stores,
which suggest alterations in energy expenditure.
Received 21 March 1996; accepted in final form 12 June 1996.
APS Manuscript Number R174-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 July 96