Avaliação do consumo crônico de leite e kefir sobre os níveis pressóricos, parâmetros bioquímicos e renais de ratos SHR (Spontaneously Hypertensive Rats) induzidos à síndrome metabólica

• Autor(a) principal: Gontijo, Luciana Nogueira
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2799
• topic: Hipertensão; Leite fermentado - Consumo; Insuficiência renal; Hypertension; Fermented milk - Consumption; Renal failure; CNPQ::CIENCIAS DA SAUDE::NUTRICAO

Objective: To evaluate the influence of chronic consumption of milk and kefir on blood pressure levels, biochemical and renal parameters of Spontaneously Hypertensive Rats (SHR) induced the metabolic syndrome (SM). Methodology: 5 g of kefir grains were inoculated in 100 mL of pasteurized cow milk with different lipids content (5.5% and 3.5%), at 4 ° Samples were incubated at a C. controlled temperature of 25 ± 2 ° during 24 hours. In these samples were C, determined moisture, ash, protein, carbohydrates, total fat, pH and acidity. Fatty acid profile was determined by gas chromatography after extraction, saponification and esterification. The lactic acid bacteria count and total yeast was performed by surface plating method from successive decimal dilutions of samples. The assay was carried out with 35 SHR rats. Puppies of SHR male rats with two days of life underwent induction protocol of the MS. Subcutaneous injections, corresponding to a dose of 4 mg of monosodium glutamate (MSG) /g of body weight 2nd to 7th day of life. After weaning (30 days), the animals were kept in collective boxes (4 animals per cage), where now receive Nuvilab ® commercial feed and water ad libitum for a period of 12 weeks. After 12 weeks, to confirm the SM, the animals were evaluated for blood pressure, fasting glucose and weighing. Subsequently the animals were divided into 5 groups: Milk A (milk with 5.5% lipid), Kefir A (milk kefir with 5.5% lipid), Milk B (milk with 3.5% lipid), Kefir B (kefir milk with 3.5% lipid), control group (MSG + Sal). Subsequently the animals were transferred to individual cages starting to receive commercial diet and kefir (1 mL / animal) by gavage daily for 10 weeks. The body weight gain and food intake of the animals were recorded weekly. At the end of the experimental period the animals were desensitized with isoflurane and euthanized with thiopental. Blood was collected by puncturing the artery abdominal aorta and kidneys removed for analysis. Total cholesterol, HDL-cholesterol and triglycerides were determined by the enzymatic colorimetric method. Biochemical analysis of renal function were evaluated by concentrations of urea, creatinine, microalbuminuria, sodium and potassium. Enzymes catalase (CAT), superoxide dismutase (SOD) and cytosolic activities of glutathione S-transferase (GSH) were determined. For histological analysis, kidneys were subjected to the steps of fixation, dehydration, paraffin embedding, and after a microtome, stained with hematoxylin and eosin (HE). Results: Microbiological characterization of milk and kefir showed significant microbial growth in the fermentation process of approximately 5 log cycles for BAL and 2 for yeasts. The humidity of Kefir A and Kefir B was higher than that of Milk A or Milk B. The protein and lipids decreased with the fermentation process, and the levels of lactic acid elevated, which promoted pH decrease kefir. There was a reduction of 17.5% of the levels of carbohydrates for Kefir B and only 2.3% for Kefir A. The lipid profile of the samples of milk and kefir revealed the presence of 15 fatty acids. Kefir samples had higher for most fatty acids (C8: 0, C10: 0, C12: 0, C14: 0, C16: 0, C18: 0, C18: 1T, C18.1c &#969;9). The milk samples showed higher levels of C20:2, C20:4 fatty acids, as well as the essential fatty acids linoleic (&#969;6 C18.2c Milk A) and &#945;-linolenic acid (&#969;3 C18.n3 Milk B). Food intake and weight gain were similar between groups throughout the experimental period. However, the coefficient of feed efficiency was significantly higher in group Kefir B (p <0.05). At the end of the experimental period, there was a reduction in SBP in group Milk B and elevated levels of blood glucose in groups Milk A and Kefir A. The levels of total cholesterol and HDL were higher in the control group (MSG + Sal). Triglyceride levels, serum creatinine concentration and creatinine clearance did not differ significantly between groups. The concentration of plasma urea was higher in group Milk A and lower in group Milk B. There was a reduction in the concentration of urinary microalbumin in groups Milk A, Kefir A and Kefir B and increased in the control group (MSG + Sal). The consumption of kefir increased SOD activity in groups Milk B and Kefir B, but did not influence significantly the activity of CAT. The excretion of Na did not differ between the control group and those who consumed milk and kefir, but the excretion of K + was higher in the control group (MSG + Sal). Regarding the histological analysis of the kidneys, there was significant increase in glomerular area in the control group (MSG + Sal). Conclusion: The kefir has characteristics of a product fermented with probiotic potential considering its nutritional characteristics, such as low-fat, control of food intake, and body weight and blood pressure. No change in renal parameters was observed. Kefir can be considered an appropriate food for consumption as part of a healthy diet.