High Fat Diet Load Study in a Natural Obesity-Resistant Animal Model, Suncus murinus

Our previous study, demonstrated the obesity-resistant phenomenon in the House musk shrew, Suncus murinus (S. murinus). In order to go further to explore the mechanism of the phenomenon of natural obesity resistance in S. murinus, we focused on the effects of diet on fat accumulation and metabolism. In this study, four-week-old male S. murinus were assigned to 1 of 2 experimental groups (n = 6 per group) and fed either a high-fat diet (HFD) or a normal trout diet (NTD) for 24 weeks. Body weight, food ingestion, visceral fat distribution, blood biochemistry and fecal lipids were monitored and analyzed in the HFD and NTD groups. It was found no differences in the average final body weight or body fat change between the two groups. Although animals fed HFD had similar serum triglyceride concentration to animals fed NTD, they had significantly higher phospholipid and total cholesterol concentrations than the NTD group. Furthermore, fecal lipid levels in the HFD group was significantly higher than those in the NTD group, suggesting that diet composition or energy density of the diet affects blood biochemistry. Although NTD-fed S. murinus had higher food ingestion than HFD-fed S. murinus, caloric intake remained almost the same. We speculated S. murinus may suppress obesity and control fat accumulation by controlling calorie intake. These results suggest that the obesity characteristics of S. murinus are not primarily due to dietary factors but to other mechanisms of regulation. Keywords: High fat diet; Mesenteric fat; Obesity-resistant; Suncus murinus