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Effects of a high‐fat diet on spontaneous locomotor activity and blood metabolic biomarkers in Sprague Dawley rats
Author(s) -
ChiaYing Wu,
Yang YanTing,
Chen ChingHan,
Chang JuiChou,
Tsai ShiowChwen,
Chen ChungYu,
Chen ChiaoNan,
Bernard Jeffrey R.,
Liao YiHung
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.643.17
Subject(s) - endocrinology , medicine , leptin , adiponectin , insulin , obesity , glucose tolerance test , insulin tolerance test , carbohydrate metabolism , insulin resistance , insulin sensitivity
Purpose Obesity commonly results from the combination of excessive caloric intake and lack of physical activity. However, it is not well known if a chronic high‐fat diet leads to negative changes in resting physical activity level, which would be expected to accelerate the development of obesity. Therefore, the purpose of this study was to investigate whether a 10‐week high‐fat diet would suppress spontaneous locomotor activity in Sprague Dawley rats. Methods Sixteen male Sprague Dawley rats were randomly assigned into one of two treatment groups: 1) standard diet (SD: 10% fat, 20% protein and 70% carbohydrate) or 2) high‐fat diet (HFD: 45% fat, 20% protein and 35% carbohydrate). After one‐week acclimation, rats were fed either the SD or HFD for 10‐weeks. Throughout the dietary intervention period, body weight, water and food intake were recorded on a weekly basis. In addition, body composition (via DEXA) and spontaneous locomotor activity (via image analysis) were measured at the 9‐week time point. Immediately following the completion of the dietary intervention fasting blood glucose, plasma insulin, HbA1c and the hormones leptin and adiponectin were assess. Thereafter, an intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) were performed at two‐day intervals in order to evaluate whole‐body glucose metabolism. All results were analyzed using a t‐Test. Significance was set at p ≤0.05. Results Spontaneous locomotor activity (inactive time, standing frequency, movement distance, and movement velocity) were not different between SD and HFD treatment groups. Consumption of the high‐fat diet significantly increased weight gain and increased fat accumulation (whole body and visceral part), while significantly decreasing muscle mass compared to the control diet ( p <0.05). In addition, rats fed the high‐fat diet showed a significant increase (by ~310%) in circulating leptin levels compared to rats fed the standard diet ( p <0.05), whereas the adiponectin levels were not different between treatment groups. However, blood glucose, HbA1c and the homeostatic model assessment (HOMA) were all significantly elevated for HFD compared to SD ( p <0.05). In addition, the area under the curve (AUC) for the ITT and IPGTT tests were also significantly greater for the HFD treatment group ( p <0.05). Conclusion This investigation demonstrates that despite negative changes in body composition, impaired whole‐body glycemic control, and spontaneous locomotor activity were not affected by a high‐fat diet in Sprague Dawley rats. Thus, these results suggest that excessive caloric intake may play a more critical role in the development of obesity rather than the lack of spontaneous locomotor activity.