Doutorado em Ciências Fisiológicas Multicêntrico (ICB)
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Item Manipulações alimentares em diferentes fases do desenvolvimento de bovinos(Universidade Federal de Goiás, 2019-02-22) Costa, Natália Alves; Nassar, Reginaldo Ferreira; http://lattes.cnpq.br/2555785079833283; Pansani, Aline Patrícia; Araujo Neto, Francisco Ribeiro de; Castanheira, Marlos; Santos, Fabiana Ramos dosThe objective of this study was to evaluate the physiological, biochemical and metabolic effects of milk restriction and prebiotic supplementation in suckling calves, and the same effects of supplementation of taurine in the bovine termination phase. Two experiments were executed to achieve the mentioned objectives. In the first trial it was used 20 crossbred calves with approximate initial weight of 38 kg and housed in individual pens for 56 days divided into two periods of 28 days each. The animals were allocaded in four experimental groups: animals receiving 6 L of milk in periods 1 and 2 (CON), animals with 50% milk restriction in the first period and re-alimented in the second period (RES), animals without restriction and supplemented of 5 g/day of mannanoligosaccharide (MOS) or mannan- frutoligosaccharide (MFOS). The weight gain and feed intake were verified. Serum was used to determinate glucose, lactate, creatinine, alkaline phosphatase, triglycerides, urea, toal protein and the hormones ghrelin and leptin. In the brain, in the paraventricular region of the hypothalamus, ghrelin receptor expression (GHS-R1a) was evaluated. The rumen and small intestine were used to evaluate the development of the gastrointestinal tract: rumen papilla length, villus height and intestinal crypt depth. We observed a lower weight gain of the restricted group in the first period and no difference in the weight gain among groups in the second period. It was observed that animals from the prebiotic supplemented (MOS) group showed a significant increase in jejunal villus height. Ruminal development was favored by the supplementation of mannanoligosaccharides (MOS group), which significantly increased ruminal papillae length. No difference was found for serum concentration of ghrelin and leptin among treatments in periods 1 and 2 (P> 0.05). Regarding the expression of ghrelin receptors in the paraventricular region of the hypothalamus, there was no difference between the groups evaluated. The second experiment was performed in 123 days with 80 finishing steers, mean initial weight of 507 kg and divided into groups supplemented with: 0; 0.025; 0.05; 0.075 and 0.1% taurine in the diet. Changes in performance were evaluated by weighing and control of the daily feed intake, carcass traits were evaluated after animals slaughter with data provided by the slaughter hose, and the metabolic changes were measured by plasma glucose, lactate, taurine and triglycerides values. Immediately after slaughter, a sample of Sternocephalicus ventrally muscle was collected to analyze the glycolytic potential. To complement the data from the second in vivo assay, an in vitro assay was performed using ruminal fluid cultures. Measurements included concentrations of VFA, pH, IVDMD and fermentative gas production for cultures containing 0; 0.025; 0.05; 0.075 and 0.1% taurine on the substrate. Supplementation of taurine did not affect the final characteristics of weight, HCW, DMI and carcass traits. Blood metabolites were not affected by administration of taurine. In addition, the production of in vitro gases, the concentrations of IVDMD and VFA’s were not affected by the addition of taurine. A linear response was detected for pH (P = 0.006) and with cattle consuming 0.1% taurine had the lowest pH. The compensatory gain presented by the restrictd milk animals, but did not accelerate the intestinal and ruminal development, while the supplementation of mananoligosaccharides caused an accelerated growth of the ruminal papillae and villi of the jejunum. Mannan-frutoligosaccharide supplementation did not accelerate the development of suckling calves. Taurine supplementation did not cause any change in the finishing phase of cattle, however, it caused a decrease in rumen pH.Item Contribuição dos aferentes sinoaórticos nos ajustes renais, cardiovasculares, simpáticos e ventilatórios induzidos por hiperosmolalidade aguda(Universidade Federal de Goiás, 2017-01-20) Silva, Elaine Fernanda da; Colombari, Eduardo; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4721289A2; Pedrino, Gustavo Rodrigues; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4762065Z5; Braga, Valdir de Andrade; Silveira, Nusa de Almeida; Ferreira, Patrícia Maria; Castro, Carlos Henrique de; Colombari, EduardoThe forebrain is suggested the main sensorial site for monitoring changes in plasma osmolality. In addition to the central mechanisms, it has been suggested that peripheral sensors may participate in the osmoregulation. In the present study we investigated the contribution of the sinoaortic afferents in the physiological mechanisms of regulation of the body fluids tonicity during acute hyperosmolality. In the first part of the study, we explored the participation of sinoaortic afferents in the cardiovascular, renal and autonomic responses induced by hypernatremia. Wistar rats (280-350 g) were anesthetized with halothane (2% in O2) and submitted to sinoaortic denervation (SAD), carotid body removal (CBX) or fictitious surgery, and implantation of cannula in the right femoral artery and vein to blood pressure (BP) recording and substance administration, respectively. In the next day, SAD animals were anesthetized with urethane (1.2 g/kg body weight, i.v.) and instrumentalized for renal sympathetic nerve activity (rSNA) recording. Non-anaesthetized CBX animals were used to BP recording and renal excretion test. The parameters were evaluated in response to intravenous infusion of hypertonic saline (HS) (3 mol/L NaCl, 1.8 mL/kg body weight, in 60 seconds). Renal sympathoinhibition induced by infusion of HS was abolished in SAD rats (SAD: -10.7 ± 5.5% of baseline, vs. control rats: -28.7 ± 4.8% of baseline, 60 minutes after HS, p<0.05). CBX attenuated the pressor response (CBX: 5.7 ± 2.0 mmHg, vs. control: 15.8 ± 2.0 mmHg, 12 minutes after HS; p<0.05) and sodium renal excretion (CBX: 74.9 ± 7.3%, vs. control: 99.7 ± 6.7%, 90 minutes after HS; p<0.05) to HS. These results show that the integrity of the aortic and carotid afferents are essential for autonomic, cardiovascular and renal adjustments induced by acute hypernatremia. In the second part we explored the involvement of the carotid bodies and forebrain in the autonomic and ventilatory responses induced by intra arterial infusion of HS using arterially-perfused in situ rat preparations (male Holtzman rats, 60-100 g). HS infusions (0.17; 0.3; 0.7; 1.5 and 2 mol/L NaCl; 200 µL during 20 seconds each) were performed in accumulative ascending order while thoracic sympathetic, phrenic and carotid sinus nerve activities were recorded. Intra-arterial infusion of 2 mol/L NaCl, produced a modest increase in phrenic burst frequency (5.8 ± 0.9 bpm, vs. Ringer: 0.4 ± 0.2 bpm, p<0.05) and markedly enhanced sympathetic (63.3 ± 8.4%, vs. Ringer: -0.8 ± 1.9%, p<0.05) and carotid sinus nerve activities (105.1 ± 13.2%, vs. Ringer: -0.2 ± 1.3%, p<0.05). Carotid bodies removal attenuated the sympathoexcitation (26.2 ± 4.9%, p<0.05), but not the tachypnea (3.6 ± 0.5 bpm) induced by 2 mol/L NaCl. The forebrain disconnection at the pre-collicular level, abolished the sympathoexcitation (8.4 ± 3.7%, p<0.05) and the increase in phrenic burst frequency (1.2 ± 0.4 bpm, p<0.05) in response to 2 mol/L NaCl. The results indicate the participation of forebrain in the sympathetic and ventilatory responses produced by sodium overload. Moreover, they suggest that carotid bodies may act as a sodium peripheral sensor contributing for the autonomic responses to acute hyperosmotic challenges.Item Papel da grelina e do receptor GHS-R1a no controle da função renal e hemodinâmica em animais normotensos e hipertensos(Universidade Federal de Goiás, 2019-03-14) Silva, Elder Sales da; Custódio, Carlos Henrique Xavier; http://lattes.cnpq.br/0207928273284808; Ferreira, Reginaldo Nassar; http://lattes.cnpq.br/2555785079833283; Custódio, Carlos Henrique Xavier; Ferreira, Patrícia Maria; Gomes, Rodrigo Mello; Gingozac, Marc Alexandre Duarte; Ferreira, Reginaldo NassarGhrelin (GRE) is a 28-amino acid peptide that depends on the acylation of serine at position 3 to act as a signaling molecule on growth hormone secretagogues (GHS-Rs). Its function depends on this interaction and these receptors are expressed in several tissues which may imply multisystemic actions. The objective of this research was to evaluate the responses related to renal and hemodynamic function in normotensive and hypertensive rats through administration of ghrelin and GHS-R1a agonists (MK0677) and antagonists (PF04628935). For this purpose, mice were used as experimental models being normotensive (WT) and spontaneously hypertensive (SHR). The following experimental designs were established: 1) Rats were injected subcutaneously (sc) vehicle (VEH) (NaCl 0,9%), ghrelin (GRE) (10μg / kg), GHS-R1a AT antagonist (PF04628935) (0.4mg / kg), ghrelin + PF0462893 or GHS-R1a agonist AGO (MK0677) (10μg / kg) and maintained in metabolic cages for further urinary and plasma analysis. 2- WT and SHR animals received intravenous (i.v.) injections of ghrelin (10 / kg), PF04628935 (0.4 mg / kg) or a combination of ghrelin and PF04628935 for vascular conductance record. 3 - GHS-R1a receptor expression was evaluated by Western blot in the aortic artery, renal artery, cortex and renal medulla. Metabolic parameters (renal function) revealed significant differences in relation to water and feed intake as well as urinary volumes in both the Wistar and SHR treated groups. The same was observed for free water and creatinine clearance in addition to osmolarity and urinary sodium and potassium levels. Intravenous injection of ghrelin reduced mean blood pressure in both strains without evoking significant chronotropic changes. Ghrelin increased Renal Vascular Conductivity (CVR) in SHR rats. The hypotensive and vasomotor effects (CVR) produced by ghrelin in SHR mice were reversed by the specific antagonism of GHS-R1a with PF04628935 (20 minutes after ghrelin injection), for all analyzes was determined (p <0.05). GHS-R1a receptor expression was shown to be decreased in the renal cortex of SHR animals. Thus, the data obtained suggest possible participation of ghrelin and GHR-S1a receptors in renal function and hemodynamic adjustments of normotensive and hypertensive rats.