147 resultados para heat shock protein


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This study was carried out with the objective of evaluating the effect of heat (38.8 degreesC) or cold (35.8 degreesC) stress on chicken embryo development and tissues Hsp70 levels, after the 13th day of incubation. Embryo weight (percent egg weight), organ weight (percent embryo weight) and Hsp70 levels (ng Hsp70 mug(-1) total protein) in different tissues (liver, breast muscle, heart, lungs, brain and kidney) were studied at the end of incubation. Cold stress induced a lower embryo weight and lower kidney and lungs weights, whereas heart and liver were lighter in heat-stressed embryos. An interaction between temperature and age was obtained only for Hsp70 levels in kidney and heart. Cold-stressed embryos showed higher Hsp70 levels in the brain, lungs and liver; a decrease in brain and breast muscle Hsp70 levels was seen from the 19th to 20th days in control embryos. Hsp70 levels increased with age in kidneys of control embryos and in heart of heat- and cold-stressed embryos. In conclusion, this study showed that chicken embryo organ weights are affected by incubation temperature, and that Hsp70 expression is tissue dependent (higher levels being seen in the brain) being cold-stress more effective in increasing Hsp70 levels in most studied tissues.

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The aim of this study was to isolate the protein fractions from chickpea, var. IAC-Marrocos, as well as to evaluate its in vivo nutritional protein quality. Among the proteins, albumins showed better nutritional value in the in vivo assays and amino acid contents, despite their higher trypsin inhibitor contents. Trypsin inhibitors were found to be heat labile in all samples, but the digestibility results for unheated and heated flour and albumins suggest that their contents are not very decisive. The PER values for casein (not supplemented) were very similar to those of heated flour and unheated or heated albumin and total globulins. The albumin and glutelin fractions showed the best results for PDCAAS, however, lower than those of casein. Despite the high digestibility of the globulin the very low essential amino acid content lowered its PDCAAS, and it had the lowest values.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The albumin and globulin fractions from lentil seeds were isolated and characterised by gel filtration. The latter was shown to be homogeneous and the former heterogeneous on PAGE. The aminoacid analysis revealed high values of amidic amino acids for both fractions with great differences in the sulphur-containing amino acids. Native albumin, globulin and salt-soluble proteins were markedly resistant to trypsin hydrolysis compared to casein. The SDS-PAGE of native salt-soluble proteins indicated that the globulin fragments (20 to 30 kD) were slowly digested in the presence of albumin. The heating increased the hydrolysis of the proteins in the order: salt-soluble, albumin and globulin. The facilitated hydrolysis of the heated salt-soluble fraction seemed to be due to protein-protein interactions induced by heat.

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The objective of this work was to evaluate the total endogenous N losses, and protein and energy net requirements for maintenance in growing lambs. Thirty-four castrated lambs, 17 F1 Ideal X Ile de France wool and 17 Santa Inas hair lambs, averaging 20 +/- 0.14 kg BW, were used in the experiment. Five animals from each genotype were slaughtered at the beginning of the experiment and taken as controls. Diets (D) were composed of concentrate mix (C) and Cynodon sp. c.v. Tifton 85 hay (R), combined in three different ratios: D1 = 60C:40R; D2 = 40C:60R and D3 = 20C:80R. Animals of each group of three lambs, that showed BW of 20 kg at the beginning of the dietary regimen, were slaughtered when one of them reached 35 kg, what always happened to be the one fed with D1. Total endogenous N losses estimated for wool lambs were 250 mg N/kg BW0.75. For hair lambs, total endogenous N losses reached 324 mg N/kg BW0.75 . Hair lambs showed higher (P < 0.01) (29.9%) net requirements of protein for maintenance than wool lambs. In contrast, net energy (NE) requirement for maintenance was similar (P > 0.05) for both genotypes (74.27 kcal/kg BW0.75 per day), the average of the antilog of the two intercept values obtained from the estimated regression equations of heat production for zero metabolizable energy (ME) consumption. Further studies should be done to check if this trend is also true for metabolizable energy and protein in animals exhibiting BW gains in tropical region. (C) 2003 Elsevier B.V. B.V. All rights reserved.

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The objective of the present study was to investigate the effects of dietary macronutrient ratio on energy metabolism and on skeletal muscle mRNA expression of avian uncoupling protein (UCP), thought to be implicated in thermogenesis in birds. Broiler chickens from 2 to 6 weeks of age received one of three isoenergetic diets containing different macronutrient ratios (low-lipid (LL) 30 v. 77 g lipid/kg-, low-protein (LP) 125 v. 197 g crude protein (N X 6.25)/kg; low-carbohydrate (LC) 440 v. 520 g carbohydrate/kg). LP chickens were characterised by significantly lower body weights and food intakes compared with LL and LC chickens (-47 and -38% respectively) but similar heat production/kg metabolic body weight, as measured by indirect calorimetry, in the three groups. However, heat production/g food ingested was higher in animals receiving the LP diet (+41%, P<0.05). These chickens also deposited 57% less energy as protein (P<0.05) and 33% more as fat. No significant differences in energy and N balances were detected between LL and LC chickens. The diets with the higher fat contents (i.e. The LP and LC diets) induced slightly but significantly higher relative expressions of avian UCP mRNA in gastrocnemius muscle, measured by reverse transcription-polymerase chain reaction, than the LL diet (88 and 90 v. 78% glyceraldehyde-3-phosphate dehydrogenase respectively, P<0.05). Our present results are consistent with the recent view that UCP homologues could be involved in the regulation of lipid utilisation as fuel substrate and provide evidence that the macronutrient content of the diet regulates energy metabolism and especially protein and fat deposition.

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In order to determine the net energy, protein and macrominerals requirements of 70 to 120 day old, 52 female White New Zealand rabbits, weighing 1900g +/- 40g were used. At the beginning of the experimental period, 14 of the 52 young does were slaughtered and the 38 remaining animals were kept under two dietary management: ad libitum and restricted feeding. Slaughters were performed to determine each nutrient body content. The weight gain nutrient requirements depicted by the quantities of each nutrient stored into the body were obtained by applying the regression equation, which estimate the empty body nutrient content logarithm as a function of the empty body weight logarithm, as described by ARC (1980). By determining the heat production logarithm at the zero level of metabolizable energy intake, the maintenance net energy requirement was estimated to be 45.31 Kcal/day/Kg(0.75) the mean net energy. protein, calcium, phosphorous, sodium, magnesium and potassium requirements for each gram of weight gain per day were estimated to be, 2.51 Kcal, 0.21g, 0.02g, 0.005g, 0.001g, 0.0004g and 0.002g, respectively.

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Meat production by goats has become an important livestock enterprise in several parts of the world. Nonetheless, energy and protein requirements of meat goats have not been defined thoroughly. The objective of this study was to determine the energy and protein requirements for maintenance and growth of 34 3/4 Boer x 1/4 Saanen crossbred, intact male kids (20.5 +/- 0.24 kg of initial BW). The baseline group was 7 randomly selected kids, averaging 21.2 +/- 0.36 kg of BW. An intermediate group consisted of 6 randomly selected kids, fed for ad libitum intake, that were slaughtered when they reached an average BW of 28.2 +/- 0.39 kg. The remaining kids (n = 21) were allocated randomly on d 0 to 3 levels of DMI (treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 kid from each treatment, and kids were slaughtered when the ad libitum treatment kid reached 35 kg of BW. Individual body components (head plus feet, hide, internal organs plus blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Initial body composition was determined using equations developed from the composition of the baseline kids. The calculated daily maintenance requirement for NE was 77.3 +/- 1.05 kcal/kg(0.75) of empty BW (EBW) or 67.4 +/- 1.04 kcal/kg(0.75) of shrunk BW. The daily ME requirement for maintenance (118.1 kcal/g(0.75) of EBW or 103.0 kcal/kg(0.75) of shrunk BW) was calculated by iteration, assuming that the heat produced was equal to the ME intake at maintenance. The partial efficiency of use of ME for NE below maintenance was 0.65. A value of 2.44 +/- 0.4 g of net protein/kg(0.75) of EBW for daily maintenance was determined. Net energy requirements for growth ranged from 2.55 to 3.0 Mcal/kg of EBW gain at 20 and 35 kg of BW, and net protein requirements for growth ranged from 178.8 to 185.2 g/kg of EBW gain. These results suggest that NE and net protein requirements for growing meat goats exceed the requirements previously published for dairy goats. Moreover, results from this study suggest that the N requirement for maintenance for growing goats is greater than the established recommendations.

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This work investigates some factors affecting the inactivation of common bean trypsin inhibitor and phytohemagglutin. Trypsin inhibitor activity was totally stable to heat treatment (30 min, 97C) in the total protein extract, albumin or globulin fraction. Heat treatment of the whole beans easily inactivated the inhibitor. Heat resistance of trypsin inhibitor was intermediate in the bean flour which received the same heat treatment. Independent of sample, the inhibitor was very stable to heat treatment at neutral and acidic pH and labile under strong alkaline conditions. Heating for 30 min in boiling water at pH 12 resulted in complete inactivation of the trypsin inhibitor. Autoclaving (121C) soaked whole beans and flour for 5 min inactivated 55% of the trypsin inhibitor activity in the soaked flour and 75% in the whole beans. After autoclaving 20 min, inactivation of trypsin inhibitor was about 65% in the flour and 80% in the whole beans. The phytohemagglutinin (lectin) activity was totally destroyed in the autoclaved beans after 5 min and in the flour after 15 min.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)