Effects of protein malnutrition on oxidative status in rat brain.

OBJECTIVES: This study evaluated the effects of protein malnutrition on oxidative status in rat brain areas. METHODS: We investigated various parameters of oxidative status, free radical content (dichlorofluorescein formation), indexes of damage to lipid (thiobarbituric acid-reactive substances assay), and protein damage (tryptophan and tyrosine content) in addition to total antioxidant reactivity levels and antioxidant enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase in different cerebral regions (cortex, hippocampus, and cerebellum) from rats subjected to prenatal and postnatal protein malnutrition (control 25% casein and protein malnutrition 7% casein). RESULTS: Protein malnutrition altered various parameters of oxidative stress, especially damage to macromolecules. Free radical content was unchanged by protein malnutrition. There was an increase in levels of thiobarbituric acid-reactive substances, the index of lipid peroxidation, in the cerebellum and cerebral cortex (P < 0.05) from protein-malnourished rats. Moreover, significant decreases in tryptophan and tyrosine in all tested brain structures (P < 0.05) were observed. Catalase activity was significantly decreased in the cerebellum (P < 0.05). In addition, a significant decrease in total antioxidant reactivity levels (P < 0.05) was observed in the cerebral cortex from protein-malnourished rats. CONCLUSIONS: The present data indicated that protein malnutrition increased oxidative damage to lipids and proteins from the studied brain areas. These results may be an indication of an important mechanism for changes in brain development that are caused by protein malnutrition.

Serum and liver lipids in rats and chicks fed with diets containing different oils.

OBJECTIVES: Because dietary fat composition is determinant for serum cholesterol level, which is related to cardiovascular disease, we evaluated the effects of diets containing saturated (coconut oil) or polyunsaturated fatty acids (soybean oil) supplemented or not with dietary cholesterol on serum and liver lipid composition in two animal species. METHODS: Male Wistar rats (21 d old) were assigned to one of seven groups and fed with commercial diet or diets containing 5% or 20% soybean oil or 20% coconut oil with or without 1% cholesterol. Chicks were assigned to one of four groups and fed with diets containing 15% soybean oil or 15% coconut oil with or without 1% cholesterol. RESULTS: In rats, the accumulations of hepatic cholesterol and triacylglycerols were higher in the group fed 20% soybean oil and 1% cholesterol than in the group fed 20% coconut fat and 1% cholesterol. The highest serum levels of cholesterol and triacylglycerols were observed in the group fed coconut oil and cholesterol, compared with the group fed soybean oil and cholesterol. Triacylglycerol, high-density lipoprotein, and total cholesterol serum levels increased with diet containing coconut oil and cholesterol. In chicks, the highest hepatic cholesterol accumulation occurred in the group fed 15% coconut fat and 1% cholesterol. Total and high-density lipoprotein cholesterol levels increased with diet containing coconut oil and cholesterol, although none of these diets modified serum triacylglycerol levels. CONCLUSIONS: The type of experimental animal model and the diet composition influence lipid metabolism.

Effect of diet on adiponectin levels in blood.

Dietary management has been considered an alternative means of modulating adiponectin levels. The purpose of this review is to examine the scientific evidence regarding the effect of diet on adiponectin levels in blood. Clinical trials were selected from Medline until April 2010 using the following MeSH terms: adipokines OR adiponectin AND diet OR lifestyle. A total of 220 articles were identified in the initial search, and 52 studies utilizing three different methods of dietary management were included in the present review: low-calorie diets (n = 9 studies), modification of diet composition (n = 33), and diet plus exercise (n = 10). Daily intake of fish or omega-3 supplementation increased adiponectin levels by 14-60%. Weight loss achieved with a low-calorie diet plus exercise increased adiponectin levels in the range of 18-48%. A 60-115% increase in adiponectin levels was obtained with fiber supplementation. In conclusion, dietary management can be an effective therapeutic means of increasing adiponectin levels. Studies investigating different forms of adiponectin and changes in the types of adipose tissue are necessary in order to elucidate the mechanisms involved in the modulation of adiponectin levels.

Ontogenetic study of the effects of energetic nutrients on amino acid metabolism of rat cerebral cortex.

We studied the effect of various energetic nutrients on metabolism of L-[U-14C]leucine and [1-14C]glycine in cerebral cortex of rats at different ages. At gestational age, glucose and lactate stimulated protein synthesis from L-[U-14C]leucine and [1-14C]glycine and from L-[U-14C]leucine, respectively; glucose, beta-OH-butyrate and lactate stimulated lipid synthesis from L-[U-14C]leucine. At 10 days of age, glucose, mannose, and fructose stimulated protein synthesis, and glucose and mannose stimulated oxidation to CO2 as well as lipid synthesis from L-[U-14C]leucine. In adult rats, glucose, mannose, and fructose stimulated protein synthesis from L-[U-14C]leucine and [1-14C]glycine; glutamine also markedly decreased the oxidation of L-[U-14C]leucine and [1-14C]glycine in 10-day-old and adult rats.