EFFECTS OF A STRUCTURED LIPID, CAPTEX, AND A PROTEIN-BASED FAT REPLACER, SIMPLESSE, ON ENERGY-METABOLISM, BODY-WEIGHT, AND SERUM-LIPIDS IN LEAN AND OBESE ZUCKER RATS

The effects of a structured lipid, Captex 810D, and a protein based fa t replacer, Simplesse(R), on the energy metabolism of 8-week-old femal e lean and obese Zucker rats were measured for 14 days. Body weight ga in and serum lipids and glucose were also measured after 4 weeks on th e experimental diets. Zucker rats were divided into sir groups (n = 9) as follows: lean control (LC), obese control (OC), lean Captex (LX), obese Captex (OX), lean Simplesse (LS), and obese Simplesse (OS). Heat production was measured using open circuit respiration chambers (Oxym ax animal calorimeters). Average dry matter (DM) intake (g/kg(0.75)/d) during the respiration trials (two 24-hour periods) was significantly less (P < 0.05) in the OX and OC groups than in the OS group (31.9 +/ - 1.6 and 33.1 +/- 1.5 SE, respectively, vs. 40.1 +/- 4.2 SE). Gross e nergy (GE) was 5.2 and 4.7 kcal/g DM for the control and the Captex di ets, respectively. Metabolizable energy density (ME, kcal/g DM) for Si mplesse diets were significantly different from the ME in the control and Captex diets. ME density was less in the OS due to greater urine e nergy excretion (polyuria) in that group. ME intake (kcal/kg(0.75)/d) was similar for all groups (169.0 +/- 4.0 SE) wizen expressed on a met abolic body size basis, with the intake of the OX being 163.8 +/- 6.9 SE. Heat production or energy expenditure (kcal/kg(0.75)/d) of the OX group was significantly higher than the OC group (85.2 +/- 2.8 SE vs. 76.0 +/- 2.9 SE), but the OC group was not significantly different fro m the OS group(76.9 +/- 2.9 SE). Experimental diets did not affect hea t production in lean rats. A phenotypic effect was observed in serum g lucose, triglycerides, cholesterol, and high density lipoprotein (HDL) cholesterol concentrations between lean and obese rats. Obese rats co nsuming the Simplesse diet had significantly lower glucose concentrati ons than the Captex-and the cent oil control groups 116.3 +/- 3.8 vs. 20.1 +/- 4.8 and 20.7 +/- 2.1 mmol/L, respectively). Serum triglycerid es (5.61 +/- 0.55 mmol/L vs. 4.27 +/- 0.81 and 4.21 +/- 0.91 mmol/L) a nd total cholesterol concentrations (3.96 +/- 1.09 mmol/L vs. 3.18 +/- 0.49 and 3.33 +/- 0.51 mmol/L) in the obese rats on the Simplesse die t were greater than the Captex and the control groups. Obese rats had higher HDL cholesterol concentrations than the lean mts but no differe nce due to diet was observed in either rats. (C) Elsevier Science Inc. 1998.