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M Mañas

Publications and source records attributed to M Mañas.

At least 37 records · Page 2Linked to original sources
PubMed1996

Taurine- and glycine-conjugated bile acids in the preruminant goat: identification by high performance liquid chromatography.

A reversed-phase high performance liquid chromatography technique has been developed for the identification of taurine- and glycine-conjugated bile acids in the bile of preruminant goats. The mobile phase consisted of two solvents: acetonitrile (A) and 5 mM potassium phosphate buffer (pH 4.5) (B). Samples (10 microliters) were eluted with a linear gradient in which acetonitrile was increased from 25 to 35%, and from 35 to 45%, at 10 min intervals. Flow rate was 1.0 ml min-1, and bile acids were detected at 200 nm. This sample high resolution technique was highly reproducible, involved a minimum of straightforward sample treatment, and required a short chromatographic development time. The technique will be of use in the systematic identifications of bile acids in preruminants.

Acetonitriles↗
PubMed1996

Long-term effects on lipid metabolism in miniature swine (Sus scrofa) of diets enriched in saturated, monounsaturated and polyunsaturated (N-6 and N-3) fatty acids.

In this paper we study the effect of long-term adaptation (twelve months) of lipidic parameters of miniature swine to diets enriched in saturated (lard; L-group), monounsaturated (olive-oil; O-group) and polyunsaturated (sunflower and fish-oil; S- and F-groups respectively). The experimental group with the highest level of total cholesterol, free cholesterol and phospholipids was the S-group. This group had as well levels of HDL-C and LDL-C significantly higher when compared with the remaining groups. The L-group had the lowest value of HDL-C. In spite of that, the index of artherogenicity (HDL/LDL+VLDL) was significantly higher in the L-group, followed by the O-, F- and S-group respectively. On the other hand, after 12 months adaptation we observed that the fatty acid composition of serum lipids clearly reflects the quality of the dietary fats. The O-group had significantly higher serum oleic acid levels than all the other groups, and its content in saturated fatty acids was the lowest. The same happens with red blood cell (Rbcs) membranes fatty acids but the effect is less marked. Membranes of the L-group were found to have the highest saturation index (SI) in Rbcs membranes, while the F-group had the highest unsaturation index (UI), followed by the O-group. Taken together, our findings show that the diet enriched in olive oil produces a lipid pattern intermediate between that obtained with the fish-oil-diet and the sunflower-oil-diet but with the advantage of Rbcs membranes with a lower amount of PUFAS. As it is known, membranes with high percentages of PUFAS are more accessible for peroxidation, and the degree of peroxidation of lipids is directly related with changes in the membranes functionality.

Adaptation, Physiological↗
PubMed1996

Biliary secretion in suckling goats: the effect of maternal milk and of a lamb milk replacer.

A total of 45 preruminant goats were fed either goat milk or a milk substitute. The postnatal development of bile secretion and biliary lipids composition of suckling goats and the influence upon these parameters of maternal milk substitution were studied during the first month of life. Samples of hepatic and gallbladder bile were obtained from kids of 1, 7, 14, 21 and 28 day-old. Bile flow rate, cholesterol, total bile salts and phospholipids were measured. Our results show that the quality of the protein and fat used in the elaboration of the milk replacer, affects the evolution of both hepatic bile flow and biliary lipids composition. Differences between gallbladder and hepatic bile composition show a scarce concentration capacity of the gallbladder with both diets and at all ages studied.

Animals↗
PubMed1996

Conjugated bile acids and intestinal flora during the preruminant stage in goat. Influence of a lamb milk replacer.

A total of 45 preruminant goats were fed either goat milk or a milk substitute to compare the evolution of taurine and glycine conjugated bile acids and the evolution of the intestinal flora during the first month of life. Samples of hepatic bile were obtained from kids of 1, 7, 14, 21, and 28 days old and conjugated bile acids were measured by high performance liquid chromatography. Bacterial flora were determined in 14 and 28 day old animals. Ours results show that under our experimental conditions tauroconjugated bile acids clearly predominated over the conjugated with glycine. This pattern of preferential tauroconjugation persisted at all ages tested and in both groups studied. On the other hand, it seems that the quality of the protein and fat used in the elaboration of the milk replacer affects the intestinal flora and the postnatal evolution of conjugated bile acids.

Animals↗
PubMed1996

Absence of rapid adaptation of the exocrine pancreas of conscious dogs to diets enriched in fat or carbohydrates.

Adult mongrel dogs were fed during 8 days on one of two diets, one rich in fat (FR) and the other rich in carbohydrates (CR), in order to compare the exocrine pancreatic secretion in the basal period and in response to food. Under resting conditions, mean pancreatic juice flow and mean values of protein content, amylase and lipase activity and production were similar in both experimental groups, suggesting that the period of adaptation used did not produce any influence on the measured parameters. No significant difference between the two dietary groups was found in postprandial volume of pancreatic juice. The peak of pancreatic juice flow in FR-group was smaller but remained elevated until the end of the 5th h, possibly due to the fact of delayed gastric emptying when animals are fed with a high fat diet. No significant differences were found between the groups in neither postprandial amylase activity and secretion nor lipase activity. On the other hand, lipase output was significantly higher in FR-group but only during the 5 postprandial h. This fact may be related to some intestinal factor stimulated by the hydrolysis products of fat. Finally, our findings show that no rapid adaptation of exocrine pancreatic secretion exist to the diet, at least in our experimental conditions. Of course, this does not exclude that the phenomenon of adaptation may appear in the dog under long-term adaptation to the diet.

Adaptation, Physiological↗
PubMed1996

Long-term influence of dietary fat (sunflower oil, olive oil, lard and fish oil) in the serum fatty acid composition and in the different lipidic fractions, in miniature swine.

A total of 24 miniature swine (sus scrofa) was fed with four diets of 9% fat content, differing only in the quality of the fat source (sunflower oil, olive oil, lard fat and fish oil) for a 12 months period. After the experimental period, the influence of the dietary fat on the serum fatty acid composition, and the distribution of those fatty acids in the different serum lipidic fractions was studied. The olive oil group had the lowest SI value (total sum of saturated fatty acids) and the highest MUFA value (total sum of monounsaturated fatty acids) in serum. The sunflower group had higher proportions of n6 polyunsaturated fatty acids in serum, when compared with the remaining groups. The lard group and the fish oil group had both the highest values of SI and n3 polyunsaturated fatty acids. The results show that fatty acid composition in serum reflected, but not in all cases, the fatty acid composition of the diet. The highest correspondence was found with sunflower oil and olive oil diets. The existence of interactions between the different fatty acid series was evident, especially with the lard and the fish oil diets, as well as endogenous synthesis mechanisms. In lipidic fractions, higher correspondence with diet was found in EC fraction, but, as well as in serum, the existence of interactions between fatty acid series was evident, and especially activity and biosynthesis of desaturases may have been affected.

Analysis of Variance↗
PubMed1996

Blood platelet function in healthy individuals of different ages. Effects of exercise and exercise conditioning.

The influence of age, physical conditioning and physical exercise on platelet function on human being is still controversial. The aim of our study were to evaluate the effect of physical exercise on platelet activation measured by beta-thromboglobulin (beta-TG) levels and the number of platelets in sedentary and athlete subjects of different ages, and also to investigate the response of these parameters during the period of recover immediately after a bicycle exercise test. Our results show differences in platelet count and beta-TG levels among the experimental groups studied, in basal conditions, in response to the exercise test and during postexercise period. These results seem to indicate that regardless age, regular physical exercise diminish age negative effects on platelet aggregation.

Adult↗
PubMed1996

Dietary intake and anthropometric measures in a Spanish students group.

Two four-day diet records were used to estimate usual energy and nutrient intake, eating patterns (habits) and contribution of meals to total energy intake, in a group of 92 biology students from the Granada University. At the same time, a series of anthropometric measures was taken from each subject (weight, height, skin pleats and arm measurement). Comparison of real intakes with those recommended was carried out using the 1980 Spanish recommendations and the 1992 European Community recommendations. For men (n = 42) mean intakes for most nutrients were similar to the recommended levels and the proportion with intakes of vitamins and minerals below 80% of the recommended intakes was also minimal. Among women (n = 50) mean intake of zinc was below 80% of the Spanish recommendation. However, there was a wide range of intakes of minerals and vitamins within both groups; therefore, we found a high percentage of subjects with intakes of some vitamins or minerals below 80% of the recommended intakes. Finally, anthropometric measures showed normal body weight, height, and body composition among the students.

Adult↗
PubMed1995

The influence of dietary fat source (sunflower oil or olive oil) on LDL composition and serum lipid levels in miniature swine (Sus scrofa).

A total of 24 miniature swine (Sus scrofa) were fed with two diets of 9% fat content, differing only in the quality of the fat source (sunflower oil and olive oil). Two groups of animals were fed for a 12-week period, and the other two groups were fed for a 50-week period. After the two experimental periods, the influence of the dietary fat on serum lipids and protein and fatty acid composition of isolated LDLs was studied. In the short term, the serum cholesterol level was slightly higher in the olive oil group but, with the time of adaptation to the diet, serum levels of TC, FC and PL increased significantly in the sunflower group. In the long term, LDL and HDL were also significantly higher in the sunflower group when compared to the monounsaturated diet. In the sunflower group, PROT/TC and PROT/LIP ratios decreased significantly with the experimental period, while in the olive oil group they increased, due to the decrease in EC and TG fractions. The LDL particle in the olive group contained fewer saturated fatty acids and more monounsaturated fatty acids, specially oleic acid, than the LDL in the sunflower group. The changes found in chemical and fatty acid compositions of LDL, according to the saturation degree of the predominant fat of the diet, could alter its cellular metabolism.

Animals↗
PubMed1995

Effects of adaptation to dietary fat on fatty acid composition of serum and serum lipids in miniature swine.

The influence of dietary fat on the serum fatty acid composition and distribution in different serum lipids was studied in 24 miniature swine (Sus scrofa) divided into 4 groups. Three groups were fed a low-fat chow with different kind of fats added (sunflower oil, olive oil and bovine lard) and the other group was fed a control diet with no fat added. The animals were fed the four diets for an experimental period of 12 weeks. Afterwards blood samples were taken to obtain serum, and the serum lipids were separated into the following fractions: phospholipids, triglycerides, and esterified cholesterol. The fatty acid composition of the serum and fractions was analyzed by gas chromatography. Under our experimental conditions, the fatty acid composition of the diets was reflected in serum, but not in all cases. In the triglyceride fraction the fatty acid composition was more evident. Our results show the interaction of the fatty acids in the different series and even within a single series, along with the endogenous synthesis processes.

Animals↗
PubMed1994

Peroxidative extent and coenzyme Q levels in the rat: influence of physical training and dietary fats.

Sport practice is widely recognized as capable of producing peroxidative damages, even of severe intensity. Dietary manipulations can also modify membrane susceptibility to peroxidation. In previous experiments we found that, while dietary virgin olive oil successfully protects mitochondrial and microsomal membranes from endogenous, xenobiotics-induced peroxidation, dietary polyunsaturated oils lead to increased peroxidative levels. In the latter conditions, cell machinery tries to counteract the structural and functional changes which have occurred, by modulating enzyme activities and concentrations, by increasing biosynthesis of coenzyme Q and by mobilizing cholesterol. In the present study we hypothesized that combining these two aspects could give useful information on the membrane response to peroxidation phenomena that daily occur throughout the lifespan. Rats fed different dietary oils as only fat source underwent a carefully designed training program and were killed at different times following acute or chronic exercise. Results show that peroxidation related to chronic training and to an acute bout of exercise sum up with peroxidative effects induced by dietary factors. The above mentioned phenomena occurred simultaneously with increased tissue levels of coenzyme Q, possibly triggered within a physiological reactive antioxidant strategy.

Aging↗
PubMed1993

Role of vasoactive intestinal polypeptide (VIP), secretin and gastrin in the genesis of the late exocrine pancreatic hypersecretion, food intake dependent in conscious dogs.

Plasma levels of vasoactive intestinal polypeptide (VIP), secretin and gastrin were studied in four saphenous vein-catheterized dogs during the first 12 h after ingestion of a standard solid meal. Under these conditions we found significant postprandial increases in secretion only, which rose from a basal value of 219 +/- 27 pg/ml to 449 +/- 66 pg/ml 60 min postprandial (p < 0.001), and remained elevated until 4 h after food intake. However, no increase was seen from 8 to 12 h in any of the hormones studied, indicating that they are not directly involved in the enhancement of exocrine pancreatic secretion during this period.

Animals↗
PubMed1992

Adaptation of biliary response to dietary olive oil and sunflower-seed oil in dogs.

The effects of adaptation to dietary fat of different degrees of unsaturation (olive oil and sunflower oil) on bile secretion were studied in dogs at rest and after food intake. The animals were prepared with a bidirectional biliary cannula and a duodenal cannula to provide bile return. The two experimental groups were fed on diets containing 150 g fat/kg in the form of either olive oil (O) or sunflower-seed oil (S). The flow-rate under resting conditions and the patterns of response to food were similar in both experimental groups, although postprandial hypersection were significantly greater in volume and more prolonged in group O. No appreciable differences in concentration and output of biliary cholesterol or phospholipids were noted between the two groups. In contrast, the concentration and output of bile acids differed significantly both at rest and after food: concentration and output of bile acids were greater at rest in group S. However, after food intake, these responses were increased only in group O. The results suggest that the type of dietary fat affects biliary response to food, probably through differences in the contribution of the gall bladder in the two experimental groups.

Adaptation, Physiological↗
PubMed1992

Comparative effect of truncal vagotomy and pirenzepine on postprandial secretory response of exocrine pancreas in dogs.

The comparative effect of truncal vagotomy and associated pyloroplasty and orally administrated pirenzepine (75 mg, 1 h before food intake) on the exocrine pancreatic secretory response to food was studied in conscious dogs. Both pirenzepine administration and truncal vagotomy totally abolished the pancreatic hydromineral and organic secretory response to food intake while postprandial pH of intraduodenal content remained above 6. From the results of our study we conclude that the vago nerve must not be altered in order to assure a pancreatic response to food intake and that pirenzepine is as strong as truncal vagotomy in maintaining pH in postprandial intraduodenal content over 6.

Amylases↗
PubMed1991

Protein digestibility in dog. Effect of the quantity and quality of dietary fat (virgin olive oil and sunflower oil).

Protein digestibility has been estimated in dog when fed on two similar diets except their lipid quality (virgin olive oil and sunflower oil) from weaning up to 6 months of life. Experiments were carried out at 60, 105 and 150 days of adaptation to either diet. In dog, age does not seem to affect the protein digestive and metabolic utilization when fed on a high lipid content diet. A higher dietary fat percentage led to an increase of the mentioned parameters which could be caused to a delayed gastric emptying due to fat. As far as the fat quality is concerned, an improved protein digestive and metabolic utilization was evidenced in adult animals fed on olive oil. On the other hand, the weight progress was normal in both experimental groups. These results suggest that olive oil may have beneficial effects on protein digestibility as compared to sunflower oil.

Age Factors↗
PubMed1991

Effect of dietary fat on biliary lipids composition of gallbladder bile in miniature swine (Sus scrofa).

1. Weaning animals (34 days old) were fed for 6 months with four diets that differed only in the quantity and quality of fat sources (control group 3.2% (w/w), lard-fed group 7.6% (w/w), olive-oil-fed group 10.4% (w/w), and sunflower-oil-fed group 10.5% (w/w). Samples were collected and assessed after animals were killed at 6 months of age. 2. Our results show that the quality of fat did not alter biliary lipids composition of the gallbladder bile composition in miniature swine after 6 months adaptation to the diet, except for a significant increase of the phospholipid concentration in the lard-fed group with regard to the control group. 3. The highest and lowest bile cholesterol saturation indices were observed in sunflower and lard-fed groups, respectively showing in all cases saturation indices far from the saturation point.

Adaptation, Physiological↗
PubMed1991

Postprandial modifications of plasma secretin levels during pancreatic secretion in dogs.

In dogs with a direct pancreatic fistula, a duodenal cannula and a catheter in a saphenous vein, plasma secretin levels, changes in the flow, bicarbonate and chloride concentrations of the exocrine pancreatic secretion as well as in the pH of intraduodenal content have been studied 12 hours after the ingestion of a standard diet. Under these conditions the pancreatic secretion showed a biphasic response with a maximum flow and bicarbonate concentration during the 0-4 and 8-12 h postprandial periods. This coincided with a marked decrease of pH in the intraduodenal content, with values close to 4.5. On the other hand, during the first postprandial hour, plasma secretin values increased from basal ones (218.66 +/- 27 pg/ml) to 448.94 +/- 66 pg/ml, remaining elevated for four hours after the meal ingestion. However, no increase occurred between 8-12 h when intraduodenal pH reached values below 4.5. This study indicated that: 1) plasma secretin levels increased significantly (P less than 0.05) after the ingestion of a standard solid diet, and 2) determinants liberating secretin were not only the presence of a duodenal pH below 4.5, but probably the presence of some macronutrients from the meal.

Animals↗