RESUMO
ABSTRACT: This study aimed to evaluate the influence of replacing soybean oil with extra virgin coconut oil in normolipidic and hyperlipidic diets, on the lipid metabolism of Wistar rats. In the first stage of the experiment (30 days), 36 rats were divided into 2 groups and fed with a control or a hyperlipidic diet. Six animals from each group were then killed, and the remaining rats were redistributed into 4 new groups: 2 groups remained on the control and hyperlipidic diets, and in the diets of the other 2 groups, the soybean oil was replaced with coconut oil (30 days). At the end of the assay, the biological models were decapitated for blood collection and removal of organs and peritoneal fat. Although the diet intake differed among groups during both stages of the experiment, no differences were noted with regard to weight gain and peritoneal fat. Replacing soybean oil with coconut oil in the rat diet lowered triglyceride and low-density lipoprotein serum concentrations in both groups. Liver parameters, namely, total cholesterol and triacylglycerols, increased with the substitution of soybean oil by coconut oil in the normolipidic diet and decreased in the hyperlipidic diet. Thus, replacing soybean oil by coconut oil may improve serum and liver lipid levels in Wistar rats.
RESUMO: O estudo teve como objetivo avaliar a influência da substituição do óleo de soja por óleo de coco extravirgem em dietas normolipídicas e hiperlipídicas, sobre o metabolismo lipídico de ratos Wistar. Na primeira fase do experimento, 30 dias, 36 ratos foram distribuídos em dois grupos, receberam dieta controle e dieta hiperlipídica. Após eutanásia de seis animais por grupo, os ratos de ambos os grupos foram redistribuídos em quatro novos grupos, dois permaneceram com as dietas controle e hiperlipídica e nos outros dois houve substituição do óleo de soja por óleo de coco (30 dias). Ao final do ensaio, os modelos biológicos foram decapitados, para coleta de sangue, retirada de órgãos e gordura peritoneal. O consumo de dieta foi diferente entre os grupos durante as duas fases do experimento, porém sem diferença no ganho de peso e gordura peritoneal. A substituição, na dieta, do óleo de soja por óleo de coco diminuiu as concentrações séricas de triacilgliceróis e de lipoproteínas de baixa densidade, em ambos os grupos. Os parâmetros hepáticos colesterol total e triacilgliceróis aumentaram com a substituição do óleo de soja por óleo de coco em dieta normolipídica e diminuíram na dieta hiperlipídica. A substituição do óleo de soja por óleo de coco pode ter benefícios com relação aos lipídeos séricos e hepáticos em ratos Wistar.
RESUMO
Hypercholesterolemia is a major risk factor for cardiovascular disease. Supplements containing the vitamins niacin (B3) and pyridoxine (B6) can promote the reduction of total cholesterol and an increase in HDL cholesterol. In this study, the effects of diets supplemented with niacin (B3) and pyridoxine (B6) on the hepatic and serum lipid profiles of Wistar rats were assessed. The diets were prepared with combinations of three concentrations of niacin (3, 4 and 5 g/kg) and pyridoxine (6, 12 and 18 mg/kg) and one with neither vitamin. The animals were divided into eleven experimental groups of six animals per group, and nine groups were fed on a standard diet with 7.5% fat and vitamin supplementation. Another group was fed with 7.5% fat without vitamin supplements. A control group received the standard diet (AIN-93M) without modifications (4% fat). The weight gain, food intake, serum and hepatic total cholesterol, serum cholesterol fractions (HDL, LDL, and VLDL), serum and hepatic triacylglycerols and hepatic and fecal lipid contents were measured after 30 days. The diet with the highest concentration of niacin and lowest concentration of pyridoxine had the lowest level of total hepatic cholesterol. Hepatic triacylglycerols were reduced by the highest concentration of niacin (5 g/kg), and this reduction was enhanced by increasing the pyridoxine concentration. The diets supplemented with niacin and pyridoxine reduced the levels of serum total cholesterol, LDL, VLDL, triacylglycerols and hepatic lipids. These effects on the lipid profile varied with the concentrations of the two vitamins and the interactions between them.