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Title:Effects of photoperiod on weight maintenance in adult neutered male cats
Author(s):Kappen, Kelly
Advisor(s):Swanson, Kelly S.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
resting metabolic rate
energy requirement
Abstract:With the continued rise of obesity in humans and companion animals, novel weight management strategies are needed. To date, most strategies have focused on dietary intervention. Strategies aimed at altering physical activity, an important factor in weight maintenance, have been lacking. Due to the drastic decrease in physical activity level noted after gonadectomy, neutered animals are targets for activity-related weight management strategies. Photoperiod is known to cause physiological changes in seasonal mammals, including changes in body weight (BW) and reproductive status. Thus, our objective was to determine the effect of increased photoperiod (longer days) on voluntary physical activity levels, resting metabolic rate (RMR), food intake required to maintain BW, and fasting serum leptin and ghrelin concentrations in adult cats. Eleven healthy, adult, neutered, male domestic shorthair cats were used in a randomized crossover design study. During two 12-wk periods, cats were exposed to either a short day (SD) photoperiod of 8 hr light: 16 hr dark or a long day (LD) photoperiod of 16 hr light: 8 hr dark. Cats were fed a commercial diet to maintain baseline BW. In addition to daily food intake and twice-weekly BW, RMR (via indirect calorimetry), body composition [via dual-energy X-ray absorptiometry (DEXA)], and physical activity (via Actical activity monitors) were measured at wk 0 and 12 of each period, and fasted serum leptin and ghrelin concentrations were measured at wk 0, 6, and 12 of each period. Average hourly physical activity was greater (P=0.008) in LD vs. SD cats (3770 vs. 3129 activity counts/hr), which was primarily due to an increase (P<0.001) in dark period activity (1188 vs. 710 activity counts/hr). This corresponded to a higher (P<0.0001) daily ME intake (mean over 12-wk period: 207 vs. 197 kcal/d), and an increased (P=0.048) RMR in LD cats (9.02 vs. 8.37 kcal/h). Body composition, serum leptin, and serum ghrelin were not altered by photoperiod. More research is needed to determine potential mechanisms by which these physiological changes occurred and how they may apply to weight management strategies.
Issue Date:2012-09-18
Rights Information:Copyright 2012 Kelly Kappen
Date Available in IDEALS:2012-09-18
Date Deposited:2012-08

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