Effect of rice parboiling on performance and metabolic responses in rats.

This research is aimed at evaluating the effect of rice grains submitted to different processing (white or parboiling) on performance and biological responses in rat. Male Wistar rats were fed with diets containing white or parboiled rice grains of the cultivar IRGA 417. Wet and dry faecal production, fasting serum glucose concentration, serum total protein and organs' weights as liver, kidney and epididymal fat pads were not affected by processing. The animals in the treatment with parboiled rice showed higher body weight gain, feed intake, nitrogen excretion, serum triglycerides, uric acid levels and pancreas weight and lower feed conversion, faecal pH, albumin and serum HDL cholesterol, when compared with the treatment with white rice. The results obtained in this work allow the conclusion that structural change of rice components caused by parboiling results in variations in different essential body metabolic parameters, such as body weight gain, gastrointestinal function and glycaemic control.

The effects of hypercaloric diets on glucose homeostasis in the rat: influence of saturated and monounsaturated dietary lipids.

Consumption of energy-dense/high-fat diets is strongly and positively associated with overweight and obesity, which are associated with increase in the prevalence of certain chronic diseases. We evaluated the effect of hypercaloric/fat or normocaloric diets on some biochemical parameters in rats. Seventy-two rats were divided into four groups that were fed for 16 weeks with diets: normocaloric [9.12% soy oil, normocaloric soy oil (NSO)], hypercaloric olive oil [43.8% olive oil, hypercaloric olive oil (HOO)], hypercaloric saturated fat [43.8% saturated fat, hypercaloric saturated fat (HSF)] and normocaloric saturated fat [43.8% saturated fat, normocaloric saturated fat (NSF)]. HSF rats consumed more calories daily than the others and gained more retroperitoneal fat, although HSF and HOO rats had higher body weight. In liver, glycogen synthesis and concentration were higher in rats HSF and NSF. In plasma, total cholesterol (TC) levels were higher in HSF rats than in the others, and triacylglycerol (TAG) levels were lower in HOO and higher in HSF rats in relation to the others. In liver, TC and TAG were elevated in HSF, NSF and HOO rats. Paraoxonase 1 activity, which is related to high-density lipoprotein cholesterol and has anti-atherogenic role was lower in rats HSF. In HOO rats, glucose tolerance test was altered, but insulin tolerance test was normal. These results suggest that consumption of energy-dense/high-fat diets, both saturated or monounsaturated, causes damaging effects. However, more studies are necessary to understand the mechanisms by which these diets cause the metabolic alterations observed.