RESUMO
Sunflower oil is one of the most commonly used fat sources in Argentina, and deep-fat frying is the popular food preparation process. The liver response of feeding a diet containing fried sunflower oil (SFOx) on growing rats was studied. Thirty-nine male weanling Wistar rats were randomly assigned to one of three diets for 8 wks: control (C), sunflower oil (SFO), and a diet containing SFOx, both of the sunflower diets were mixed with a commercial rat chow at weight ratio of 13% (w/w). Body weight and food consumption were recorded weekly. At t=8 wk, lipid profile and glycemia were measured. Visceral adiposity was registered. Liver was weighed and preserved for histological analysis, relative fatty acid profile, fibrosis markers and oxidative status. The three diets did not alter body weights; however, the SFOx fed rats showed increased energy intake and visceral fat; therefore, in liver saturated fat content, trans fatty acids, plus other unidentified minor components, such as hydroperoxides, hydroxides, epidioxides, hydroperoxy epidioxides, hydroxylepidioxides, and epoxides, were detected. The hepatosomatic index of SFOx rats was altered and showed hepatic steatosis. SFOx rats exhibited increased liver dichlorodihydrofluorescein-diacetate and thiobarbituric acid substance levels and oxidized-proteins content. Their livers had lower relative levels of monounsaturated, polyunsaturated fatty acids and catalase activity, but matrix metalloproteinase-9 activity was unchanged. Consumption of a diet rich in fried oil during growth could induce liver damage due to steatosis, excessive lipid toxicity and the accumulation of reactive oxygen species. Further progression could lead to hepatic fibrosis.
RESUMO
Introducción: Los GOS son prebióticos naturales presentes en la leche materna que pue-den obtenerse enzimáticamente a partir de la lactosa de leche de vaca durante la fabricación de yogur. El producto lácteo resultante será reducido en lactosa y contendrá prebióticos y bacterias potencialmente probióticas. Sin embargo, mantendrá la baja relación Ca/Pi que aporta la leche de vaca, lo que podría alterar el remodelamiento óseo y la mineralización. Objetivo: comparar si un yogur reducido en lactosa que contiene GOS (YE) ofrece ventajas adicionales respecto de un yogur regular sin GOS (YR) sobre las absorciones (Abs) de Ca y Pi, retención y calidad ósea durante el crecimiento normal. Al destete, ratas machos fueron divididas en 3 grupos alimentados con AIN Ì93-G (C), YE o YR durante 28 días. Resultados: YE mostró el mayor aumento de lactobacilos fecales; producción de ácidos grasos de cadena corta especialmente p, profundidad de las criptas colónicas y menor pH cecal. El %AbsCa y %AbsPi aumentó en el siguiente órden: YE> YR> C (p < 0,05). El contenido de Ca y Pi en fémur, la densidad y contenido mineral óseos y los parámetros biomecánicos fueron similares en YE y C, mientras que YR mostró valores significativa-mente menores (p < 0,05). Conclusiones: YE aumentó las Abs y biodisponibilidad de minerales, alcanzando la retención y calidad ósea de C. El aumento en las Abs observado en YR no logró obtener la retención y calidad ósea de C. Conclusión: YE habría contrarrestado el efecto negativo del mayor aporte de Pi de la leche de vaca y sería una buena estrategia para lograr el pico de masa ósea y calidad del hueso adecuados, especialmente en individuos intolerantes a la lactosa. (AU)
Breast milk contains an optimal calcium/phosphate (Ca/Pi) ratio and GOS. These natural prebiotics can be enzymatically produced via cow's milk lactose inyogurt manufacture. This milk product is low in lactose and contains prebiotics and potentially probiotic bacteria but maintains a low Ca/Pi ratio that could alter bone remodeling and mineralization. We evaluated if a lactose-reduced yogurt containing GOS (YE) offers additional advantages over regular yogurt without GOS (YR) on Ca and Pi absorption (Abs), bone retention and quality during normal growth. Weaning male rats were divided into 3 groups fed AIN'93-G (C), YE or YR for 28 days. Results: YE showed the highest increase in fecal lactobacilli; short-chain fatty acids production, especially propionate and butyrate; intestine crypt depth, and the lowest cecal pH. AbsCa% and AbsPi% increased in this order: YE> YR> C (p <0.05). Ca and Pi content in femur, bone density and mineral content, and biomechanical parameters were similar in YE and C, while YR showed the significantly lowest value (p < 0.05). Conclusions: YE increased mineral Abs reaching the retention and bone quality of C. Although YR increased Abs, bone retention and quality did not achieve C values. Seemingly, YE compensated for the negative effect of the higher Pi supply and would be a good strategy to achieve adequate peak bone mass and bone quality, especially in lactose intolerant individuals. (AU)
Assuntos
Animais , Ratos , Oligossacarídeos/metabolismo , Osteogênese/fisiologia , Cálcio da Dieta/farmacocinética , Fósforo na Dieta/farmacocinética , Absorção Intestinal/fisiologia , Lactose/metabolismo , Magnésio/farmacocinética , Tíbia/anatomia & histologia , Iogurte/análise , Cálcio da Dieta/metabolismo , Absorciometria de Fóton , Densidade Óssea , Interpretação Estatística de Dados , Fósforo na Dieta/metabolismo , beta-Galactosidase/síntese química , Ratos Wistar , Lactobacillus delbrueckii/isolamento & purificação , Fêmur/anatomia & histologia , Intestino Grosso/anatomia & histologia , Magnésio/metabolismo , Valor NutritivoRESUMO
Compared with the extensor digitorum longus (EDL) muscle of control rats (C), the EDL muscle of rats fed a low-protein, high-carbohydrate diet (LPHC) showed a 36% reduction in mass. Muscle mass is determined by the balance between protein synthesis and proteolysis; thus, the aim of this work was to evaluate the components involved in these processes. Compared with the muscle from C rats, the EDL muscle from LPHC diet-fed rats showed a reduction (34%) in the in vitro basal protein synthesis and a 22% reduction in the in vitro basal proteolysis suggesting that the reduction in the mass can be associated with a change in the rate of the two processes. Soon after euthanasia, in the EDL muscles of the rats fed the LPHC diet for 15days, the activity of caspase-3 and that of components of the ubiquitin-proteasome system (atrogin-1 content and chymotrypsin-like activity) were decreased. The phosphorylation of p70(S6K) and 4E-BP1, proteins involved in protein synthesis, was also decreased. We observed an increase in the insulin-stimulated protein content of p-Akt. Thus, the higher insulin sensitivity in the EDL muscle of LPHC rats seemed to contribute to the lower proteolysis in LPHC rats. However, even with the higher insulin sensitivity, the reduction in p-E4-BP1 and p70(S6K) indicates a reduction in protein synthesis, showing that factors other than insulin can have a greater effect on the control of protein synthesis.
Assuntos
Caspase 3/metabolismo , Dieta da Carga de Carboidratos/efeitos adversos , Dieta com Restrição de Proteínas/efeitos adversos , Regulação para Baixo , Resistência à Insulina , Músculo Esquelético/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Pé , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Desenvolvimento Muscular , Músculo Esquelético/enzimologia , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/metabolismo , Proteólise , Distribuição Aleatória , Ratos Wistar , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , UbiquitinaçãoRESUMO
The our objective was to investigate the adaptations induced by a low-protein, high-carbohydrate (LPHC) diet in growing rats, which by comparison with the rats fed a control (C) diet at displayed lower fasting glycemia and similar fasting insulinemia, despite impairment in insulin signaling in adipose tissues. In the insulin tolerance test the LPHC rats showed higher rates of glucose disappearance (30%) and higher tolerance to overload of glucose than C rats. The glucose uptake by the soleus muscle, evaluated in vivo by administration of 2-deoxy-[(14)C]glucose, increased by 81%. The phosphoenolpyruvate carboxykinase content and the incorporation of [1-(14)C]pyruvate into glucose was also higher in the slices of liver from the LPHC rats than in those from C rats. The LPHC rats showed increases in l-lactate as well as in other gluconeogenic precursors in the blood. These rats also had a higher hepatic production of glucose, evaluated by in situ perfusion. The data obtained indicate that the main substrates for gluconeogenesis in the LPHC rats are l-lactate and glycerol. Thus, we concluded that the fasting glycemia in the LPHC animals was maintained mainly by increases in the hepatic gluconeogenesis from glycerol and l-lactate, compensating, at least in part, for the higher glucose uptake by the tissues.