Biomedical subjects

J Boza

Publications and source records attributed to J Boza.

At least 19 recordsLinked to original sources

PubMed2006

Identification and characterization of novel angiotensin-converting enzyme inhibitors obtained from goat milk.

The aim of the present study was to identify and characterize new inhibitory peptides of angiotensin I-converting enzyme (ACE) from goat milk and to analyze the effect of long-term intake of a goat milk hydrolysate-supplemented (GP-hyd) diet on the development of hypertension in spontaneously hypertensive rats (SHR). Three new inhibitory peptides for ACE (TGPIPN, SLPQ, and SQPK) were isolated. The inhibitory concentration 50% (IC50) values of individual peptides were 316, 330, and 354 micromol/L, respectively. Only TGPIPN was found to pass intact a monolayer of Caco-2 cells in small amounts. The SHR fed for 12 wk a diet (GP-hyd) enriched in a hydrolysate containing these peptides (estimated intake of TGPIPN was 230 mg/kg per d) showed lower (approximately 15 mmHg) systolic blood pressure than animals fed a control diet. The ACE activities in the aorta, left ventricle, and kidney were significantly decreased in the GP-hyd group compared with those of the control group and were similar to those found in SHR fed captopril (130 mg/kg per d). Impaired endothelium-dependent relaxation to acetylcholine by aortic rings from SHR was improved in those fed the GP-hyd diet. The left ventricle weight and kidney weight index were significantly reduced in the GP-hyd group and captopril groups. Moreover, long-term treatment of SHR with a diet enriched in goat milk hydrolysate, or captopril, attenuated the development of hypertension, cardiac and renal hypertrophy, and endothelial dysfunction. These effects might be related to the in vivo inhibitory effects of the hydrolysate on tissue ACE activity.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2004

The chronic colitis developed by HLA-B27 transgenic rats is associated with altered in vivo mucin synthesis.

HLA-B27 transgenic rats spontaneously developing a chronic inflammation mainly involving the colon are recognized as a powerful animal model for IBD. We investigated the mucin production in 6-month-old HLA-B27 rats by measuring in vivo fractional synthesis rate (FSR) and expression of mucins. In the inflamed colon of HLA-B27 rats, the mucin FSR was stimulated by 75% compared to F-344 controls, while MUC2,3 mRNA expression was unchanged. A local depletion in mucus-containing goblet cells was observed, suggesting a rapid mucin production/release and/or a real global decrease in goblet cell number. In the noninflamed jejunum of HLA-B27 rats, the mucin FSR was reduced by 35% compared to controls, while MUC2,3 mRNA expression was unchanged. Different alterations in mucin metabolism and expression are observed between HLA-B27 rats and a model of chemically induced chronic colitis (DSS-treated rats), suggesting that mucin alterations may be dependent on the animal model and colitis underlying mechanism.

Amino Acids↗

PubMed2004

Dietary supplements for lactating goats by polyunsaturated fatty acid-rich protected fat. Effects after supplement withdrawal.

The objective of this study was to investigate the persistence of the effects of supplements after they were withdrawn. Two groups of 12 goats were maintained under semiextensive breeding conditions; they were fed indoors with a concentrate with alfalfa hay and olivetree leaves. Goats were in their sixth month of lactation at initiation of the study. During the first month of the trials, the concentrate supplied to the goats was either nonsupplemented (group 1) or supplemented with 9% polyunsaturated fatty acids (PUFA)-rich protected fat (group 2). After this period, the 2 groups were given the nonsupplemented until the average daily production of milk per animal within each group had decreased to 300 g or less. The fat supplementation supplied increased milk production and also improved fat and protein yield. These effects persisted after the supplement was withdrawn. The supplement, moreover, produced noticeable changes in the fatty acids profile of the milk fat, namely a reduction in the concentration of saturated fatty acids and an increase in that of PUFA. In contrast to the effects on milk production and on the yield of its main constituents, the effects on fat composition disappeared when the supplement was withdrawn.

Animal Feed↗

PubMed2003

Glutamine supplementation further enhances exercise-induced plasma IL-6.

Exercise stimulates the production and release of interleukin-6 (IL-6) from skeletal muscle. Glutamine is also synthesized in skeletal muscle and is involved in protein synthesis within this tissue. During exercise, plasma levels of glutamine decline, and this may affect the concentration of plasma IL-6 via a decrease in IL-6 synthesis and release from muscle. We hypothesized that glutamine supplementation would attenuate the exercise-induced decrease in plasma glutamine concentration and, thus, further enhance levels of plasma IL-6. Eight healthy men participated in a randomized, double-blind, crossover study in which they performed 2 h of cycle ergometry at 75% of peak O2 uptake. They received glutamine, glutamine-rich protein, or placebo supplementation at intervals during and 2 h after exercise. Exercise induced an 11-fold increase in plasma IL-6, which was further enhanced by glutamine (18-fold) and glutamine-rich protein (14-fold) supplementation, administered at doses that attenuated the exercise-induced decrease in plasma glutamine concentration.

Adult↗

PubMed2003

Mucin production and composition is altered in dextran sulfate sodium-induced colitis in rats.

We evaluated the small and large intestinal mucin production in a rat model of human ulcerative colitis by measuring the in vivo fractional synthesis rate (FSR) and the expression of mucins. A chronic colitis was induced by oral administration of 5% dextran sulfate sodium (DSS) for 9 days followed by 2% DSS for 18 days. DSS-treated rats showed increased colonic MUC2,3 mRNA levels compared pair-fed controls. The mucin FSR was unaffected while mucin-containing goblet cells were depleted in the vicinity of lesions. In the small intestine, no inflammatory lesions were observed but ileal MUC2 mRNA levels and mucin FSR were decreased by 46% and 21%, respectively. Finally, DSS-treated rats showed a marked decrease in mucin's threonine + serine content all along the gut, which may lead to a reduction of potential O-glycosylation sites. Our data indicate that the chronic colitis may impair the mucus layer protective function all along the gut.

Animals↗

PubMed2001

Effect of glutamine supplementation on exercise-induced changes in lymphocyte function.

The purpose of this study was to investigate the possible role of glutamine in exercise-induced impairment of lymphocyte function. Ten male athletes participated in a randomized, placebo-controlled, double-blind crossover study. Each athlete performed bicycle exercise for 2 h at 75% of maximum O(2) consumption on 2 separate days. Glutamine or placebo supplements were given orally during and up to 2 h postexercise. The trial induced postexercise neutrocytosis that lasted at least 2 h. The total lymphocyte count increased by the end of exercise due to increase of both CD3(+)TCR alpha beta(+) and CD3(+)TCR gamma delta(+) T cells as well as CD3(-)CD16(+)CD56(+) natural killer (NK) cells. Concentrations of CD8(+) and CD4(+) T cells lacking CD28 and CD95 on their surface increased more than those of cells expressing these receptors. Within the CD4(+) cells, only CD45RA(-) memory cells, but not CD45RA(+) naive cells, increased in response to exercise. Most lymphocyte subpopulations decreased 2 h after exercise. Glutamine supplementation abolished the postexercise decline in plasma glutamine concentration but had no effect on lymphocyte trafficking, NK and lymphokine-activated killer cell activities, T cell proliferation, catecholamines, growth hormone, insulin, or glucose. Neutrocytosis was less pronounced in the glutamine-supplemented group, but it is unlikely that this finding is of any clinical significance. This study does not support the idea that glutamine plays a mechanistic role in exercise-induced immune changes.

Adult↗

PubMed2001

Effect of glutamine and protein supplementation on exercise-induced decreases in salivary IgA.

Postexercise immune impairment has been linked to exercise-induced decrease in plasma glutamine concentration. This study examined the possibility of abolishing the exercise-induced decrease in salivary IgA through glutamine supplementation during and after intense exercise. Eleven athletes performed cycle ergometer exercise for 2 h at 75% of maximal oxygen uptake on 3 separate days. Glutamine (a total of 17.5 g), protein (a total of 68.5 g/6.2 g protein-bound glutamine), and placebo supplements were given during and up to 2 h after exercise. Unstimulated, timed saliva samples were obtained before exercise and 20 min, 140 min, 4 h, and 22 h postexercise. The exercise protocol induced a decrease in salivary IgA (IgA concentration, IgA output, and IgA relative to total protein). The plasma concentration of glutamine was decreased by 15% 2 h postexercise in the placebo group, whereas this decline was abolished by both glutamine and protein supplements. None of the supplements, however, was able to abolish the decline in salivary IgA. This study does not support that postexercise decrease in salivary IgA is related to plasma glutamine concentrations.

Adult↗

PubMed2000

Social hierarchy in the domestic goat: effect on food habits and production.

Outside the scientific world, the effect of social behaviour on production is little taken into account, but the importance of this relationship has been sufficiently proven in some animal species. Nevertheless, there are scarce works that emphasise the importance of behaviour in the production of the goat. The main objective of this paper is to determine if there is a stable hierarchy of dominance in a flock of goats fed in pasture, and if this hierarchy influences somehow the diet selected in the pasture and in its production of milk and meat. The study was carried out in a flock of goats in semi-extensive grazing management. The interactions observed in the pasture during the supplementary feeding and during the milking were written down. This allowed us to determine the dominance rank. The diet was determined in the pasture by the direct observation method. The production of milk was measured daily. The meat production consisted on the weight of the kids in their first day of life and after a month. Among the most prominent results, the following should be indicated: (a) Within the herd, a clearly established, quite stable and linear hierarchic order exists. (b) The most aggressive animals are those that occupy the highest positions within the social hierarchy. (c) Age, large size and horns seem to be the physical factors that most favor dominance. (d) When more forage becomes available, differences appear in the diet chosen by dominant and subordinate animals, that is, they become more selective. In the months of greater shortage, these differences in feeding disappear, and they become more generalist. (e) The production of animals is affected by dominance. However, contrary to what might otherwise be thought, it is the middle range of goats that are the most productive.

Journal Article↗

PubMed2000

Physiological responses of pre-ruminant kid goats and lambs to different environmental temperatures.

The purpose of this study was to establish the metabolic behaviour of both preruminant kid goats and lambs, when they are kept at different environmental temperatures (12, 24 and 30 degrees C). The animals were fed ad libitum with a milk replacer for the first two months of life. Blood samples were taken from all the animals on days 30, 40, 50 and 60 post partum, to determine serum levels of glucose, insulin, free fatty acids, triiodothyronine (T3) and thyroxine (T4), both when fasting and 4 hours after starting feeding. The high sensitivity of both kinds of animal to the lowest of the environmental temperatures used, particularly for the first periods of life here considered, was established from the glucose/insulin and T3/T4 molar ratios and from the concentrations of free fatty acids. The results obtained by species were also evidence of metabolic behaviour typical of leanner animals in kids.

Adaptation, Physiological↗

PubMed2000

Production of healthier goat milk. Use of a concentrate supplemented with a "protected" fat rich in PUFA.

In order to obtain healthier goat milk as far as its fat composition is concerned, milk production and composition trials were carried out with Granadina goats kept in semi-extensive breeding conditions. The animals were feeding indoors with a concentrate supplemented or not with 7% of fat conveniently protected against the action of rumen, which had 35% of polyunsaturated fatty acids (PUFA). The amount of milk produced was higher (p < 0.05) with consumption of the fat supplemented concentrate. At the same time, and although there was no difference in the milk concentration of fat and protein nitrogen (p > 0.05), the corresponding yields were higher for consumption of the fat supplemented concentrate. As for the composition of milk fat, the use of the supplemented concentrate resulted in fat with a higher (p < 0.05) concentration of PUFA and a lower (p < 0.05) concentration of stearic acid. At the same time, the concentration of medium chain triglycerides, which is the specific nutritional value particular to goats' milk, was the same whichever concentrate was consumed.

Animal Nutritional Physiological Phenomena↗

PubMed1999

Use of different dietary protein sources for lactating goats: milk production and composition as functions of protein degradability and amino acid composition.

To establish the effect of the nature of four different protein sources [fababeans, 27.8% crude protein (CP); sunflower meal, 41.7% CP; corn gluten feed, 18.8% CP; and cottonseed, 18.3% CP] on milk protein production by goats, the ruminal degradation of these feeds was studied as was the amino acid (AA) composition of the original material and that of the undegradable fractions of the protein sources. Four diets were designed; 20% of their protein was supplied by each of the different sources. Four groups of 5 Granadina goats were used to study the utilization of these diets for milk production. No significant differences were observed in dry matter intake or milk production. The milk produced by goats fed the diet containing sunflower meal had the lowest protein concentration; the highest milk protein concentration was observed for goats fed the diet containing corn gluten feed. From a multivariate analysis, it was deduced that the quickly degradable protein fraction in the rumen and the ruminally undegradable protein fraction were the components of the protein sources most directly related to the milk protein produced. Given the similar AA profiles of the undegradable fractions of the different protein sources, the possible supplementation achieved from these ruminally undegradable fractions must be established by the amount of protein supplied regardless of AA composition.

Amino Acids↗

PubMed1998

Forage of different physical forms in the diets of lactating Granadina goats: nutrient digestibility and milk production and composition.

To determine whether the energy balance of goats or characteristics of the diet consumed were the principal factors that determined milk production, feeding and digestion trials were carried out using two groups of 5 Granadina goats. The concentrate fraction of both diets was the same, but the forage fraction of the diets differed. In diet 1, the forage was in the form of long alfalfa hay, and, in diet 2, forage was in the form of pelleted alfalfa. Intake and the forage to concentrate ratio of the two diets were not significantly different, although diet 2 was more digestible. The amount of fat and protein in the milk depended on energy intake and not on dietary treatment. The milk protein of goats fed diet 2 was higher in casein. No sensible differences were noted in the fatty acid composition of the milk. Nitrogen and metabolizable energy utilization for milk production was greater for goats fed diet 2. According to the results obtained, it would seem advantageous to use pelleted alfalfa rather than alfalfa hay in the diets of goats.

Animal Nutritional Physiological Phenomena↗

PubMed1996

Effects of native and hydrolyzed whey protein on intestinal repair of severely starved rats at weaning.

The aim of this study was to evaluate the effect of two sources of dietary nitrogen (isolated whey protein and hydrolyzed whey protein) on the intestinal repair of malnourished rats at weaning. The malnutrition was achieved by a 3 days' starvation period. Normally fed male Wistar rats were used as controls. Intestinal repair was studied after a refeeding period of 4 days. The parameters studied included nitrogen balance, lactase, sucrase, isomaltase, and maltase activities of the jejunum; liver acetylcholinesterase and glutamate dehydrogenase activities; and the serum amino acid profile. In addition, tests of intestinal permeability to macromolecules were performed by measurement of ovalbumin and beta-lactoglobulin in serum. Both diets of led to the recovery of the severely starved rats, in terms of the values of all the parameters evaluated. The serum beta-lactoglobulin was the only exception, because its concentration was significantly lower in the normally fed animals. This study suggests that the intestinal mucosal barrier is not completely repaired, even after a 4-day refeeding period, to the point of being suitable to accept an increase in the uptake of antigens.

Acetylcholinesterase↗

PubMed1995

Dietary factors affecting the maximum feed intake and the body composition of pre-ruminant kid goats of the Granadina breed.

An experiment was carried out with kid goats of the Granadina breed to identify the dietary factors affecting voluntary feed intake of the kid goat and those that additively could determine its body composition. The animals used were from birth to 61 d of age, fed ad lib. on different milk replacers containing 200, 240 and 280 g crude protein/kg DM and 200, 240 and 280 g fat/kg DM, thus giving nine dietary treatments. The utilization of the milk replacers and the animals' body composition were determined by balance and slaughter trials. There were significant positive effects of protein concentration of the milk replacers on component digestibilities, energy metabolizability, feed intake, empty-body weights, empty-body composition and protein and fat retention. The concentration of fat in the milk replacers also had a significant positive effect on the digestible and metabolizable energy concentration of the diets and on fat retention. The relationships existing between feed intake and diet composition (concentration of digestible protein, metabolizable energy and digestible protein:metabolizable energy ratio) as well as between empty-body composition or protein and fat retention and diet composition, were examined. From these it was deduced that feed intake was significantly influenced by the digestible protein concentration of the diets. The higher the digestible protein concentration the higher the feed intake up to a maximum digestible protein concentration value. As the digestible protein concentration of the diets was the dietary factor which significantly influenced feed intake, this also significantly influences the body composition and the protein and fat retention. The protein concentration of the feed at which metabolizable energy intake in these animals would be greatest was estimated to be 347 g/kg DM.

Analysis of Variance↗

PubMed1992

Changes in liver microsome lipids and plasma fatty acids induced by dietary orotate in the weanling rat.

1. Dietary orotate produced a decrease in total plasma fatty acids which was reflected in low values of saturated, monounsaturated and polyunsaturated fatty acids longer than 18 carbon atoms of the n-6 series. The relative content of saturated fatty acids in microsomes of animals fed orotate was also decreased. 2. Rat liver delta-9 desaturase activity was lower in the group fed orotate. However, delta-6 desaturase activity did not show significant differences between the groups. 3. Microsomal cholesterol content was lower in rats fed orotate than in controls but phospholipid phosphorus contents were similar. These results suggest a direct effect of dietary orotate on the key enzymes which regulates cholesterol liver metabolism.

Animals↗

PubMed1992

Changes in fatty acid profiles of red blood cell membranes mediated by dietary nucleotides in weanling rats.

Dietary nucleotides have been described to play multiple physiological roles. We examined the effect of feeding, for 4 weeks, nucleotide-supplemented diets (N-50 and N-250) on red blood cell (RBC) membrane fatty acid composition in weanling rats. Long-chain polyunsaturated fatty acids (LC-PUFA) of the n-6 series, especially arachidonic acid, increased in total RBC phospholipids in N-50 and N-250 groups. Concentrations of LC-PUFA of the n-3 series were preserved or slightly decreased. Saturates and monoenates also decreased. Phosphatidylethanolamine and sphingomyelin followed the variations observed for total phospholipids. Phosphatidylcholine showed a different response; saturated fatty acids increased while n-6 LC-PUFA decreased. Dietary nucleotides seem to affect the conversion of essential fatty acids to their long-chain derivatives in weanling rats in a similar way to that occurring in newborn infants during early life. These results show that the rat may be a valid model with which to study the biochemical mechanisms by which dietary nucleotides affect fatty acid desaturation.

Analysis of Variance↗

PubMed1991

Effect of dietary nucleotides and orotate on the blood levels of prostacyclin (PGI2) and thromboxane (TXA2) in the weanling rat.

Dietary nucleotides affect the maintenance of immune responses, tissue repair and polyunsaturated fatty acid metabolism. Orotate, a pyrimidine nucleotide precursor, induces fatty livers by impairing VLDL hepatic secretion. The aim of this study was to evaluate the changes in the blood levels of fatty acids and prostacyclin (PGI2) and thromboxane (TXA2) in the weanling rat caused by the dietary intake of nucleotides and orotate. Three groups of rats at weaning were fed a control diet, an orotate supplemented diet (O-50) and a nucleotide supplemented diet (N-50) during 4 weeks, respectively. Absolute values of plasma polyunsaturated fatty acids greater than 18 carbon atoms of the n-6 and n-3 series were increased in the N-50 group and decreased in O-50 with regard to the control. However, the relative fatty acid composition of plasma lipid fractions was mostly unaffected. Plasma 6-keto-PGF1 alpha showed a trend to be increased in N-50 and serum TXB2 was significantly increased in that group. Both eicosanoids were unchanged by dietary orotate intake. These results may be explained because of the increased plasma 20:4n-6 found in rats fed a supplemented nucleotide diet. Thus, nucleotides present in foods appear to modulate PUFA conversion and eicosanoids synthesis in early life.

6-Ketoprostaglandin F1 alpha↗

PubMed1991

[Comparative cytotaxonomy of 3 species of Cichlasoma (Pisces: Cichlidae) native of Costa Rica].

The karyotype of three species of Cichlasoma: C. dovii, C. managuense and C. friedrichstali were studied. The number of diploid chromosomes is 2n = 48 in the first two species. Their karyotypes are composed of four pairs of meta-submetacentric chromosomes. The arms fundamental number (NF) is 56. C. friedrichstali has three pairs of meta-submetacentric chromosomes and 21 pairs of subtelocentric-telocentric chromosomes. This species presents two different diploid numbers, 2n = 48 and 2n = 47.

Animals↗