961 resultados para PHYSIOLOGICAL PH CONDITIONS


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The relationships between physiological variables and sugarcane productivity under water deficit conditions were investigated in field studies during 2005 and 2006 in Weslaco, Texas, USA. A total of 78 genotypes and two commercial varieties were studied, one of which was drought-tolerant (TCP93-4245) and the other drought-sensitive (TCP87-3388). All genotypes were subjected to two irrigation regimes: a control well-watered treatment (wet) and a moderate water-deficit stress (dry) treatment for a period of 90 days. Maximum quantum efficiency of photosystem II (F (v)/F (m)), estimated chlorophyll content (SPAD index), leaf temperature (LT), leaf relative water content (RWC) and productivity were measured. The productivity of all genotypes was, on average, affected negatively; however, certain genotypes did not suffer significant reduction. Under water deficit, the productivity of the genotypes was positively and significantly correlated with F (v)/F (m), SPAD index and RWC, while LT had a negative correlation. These findings suggest that genotypes exhibiting traits of high RWC values, high chlorophyll contents and high photosynthetic radiation use efficiency under low moisture availability should be targeted for selection and variety development in programmes aimed at improving sugarcane for drought prone environments.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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The aim of this work was to determine the adaptability of Saanen and A1/2Saanen x A1/2Anglo-Nubian (A1/2SA1/2AN) goats bred in tropical climates. The study included 30 goats, 15 Saanen and 15 A1/2SA1/2AN. The data was collected during the rainy and dry seasons. During the whole experimental period, the environment variables were recorded, as well as rectal temperature (RT), superficial temperature (ST), respiratory rate (RR) and heart rate (HR) and milk production (MP). The adaptability coefficient (AC) was calculated for both genotypes. The averages were evaluated by ANOVA at 5 % probability. There was a genotype and period of year effect, as well as the interaction genotype x period of year. Pearson's simple correlation analysis was then carried out between milk production and physiological and environment variables. There was a statistical difference (p < 0.05) between the seasons for RT, ST and RR. RT, RR and HR were lower for A1/2SA1/2AN than Saanen goats, regardless of the season. MP was greater in the dry season (p < 0.05) (2.52 A +/- 0.50 kg/day for A1/2SA1/2AN and 2.41 A +/- 0.38 kg/day for Saanen) than the rainy season (2.17 A +/- 0.27 kg/day for A1/2SA1/2AN and 2.28 A +/- 0.53 kg/day for Saanen). The MP correlations were very significant (p < 0.05), however low and negative, where it was higher when correlated with RR in Saanen goats. Under the conditions of the present study, it is concluded that the goats were influenced by climatic factors, where the rainy period was more likely to cause thermal stress in the animals.

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Feeding strategies that reduce feed and promote compensatory growth could be an interesting tool to reduce costs in the fish production. However, fish health must be monitored to evaluate if their physiological response to adverse conditions, such as parasite infection, does not become compromised. A 12-wk growth trial was conducted to determine the physiological responses of pacu, Piaractus mesopotamicus, that were subjected to different fasting/refeeding cycles and infected with the Dolops carvalhoi. The schemes were: (i) control group fish (FD), (ii) food-restricted and controlled refeeding group (FR/Rc), and (iii) food-restricted and refeeding to satiation group (FR/Rs). After 84 d, the fish were exposed to D. carvalhoi for 30 h. The fish subjected to food restriction did not exhibit compensatory growth. Cortisol levels decreased in all groups within 30 h after infection. Glucose levels increased 6 h after the D. carvalhoi in the FR/Rs and 30 h after infection in the FD. In all of the fish groups, the hematocrit values were reduced after infection, and it was associated with a reduction in the mean corpuscular volume and erythrocytes. At 30 h after infection, the number of erythroblasts increased. The use of the feeding schemes does not indicate a failure of the pacu physiological responses.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Zagatto, AM, Padulo, J, Muller, PTG, Miyagi, WE, Malta, ES, and Papoti, M. Hyperlactemia induction modes affect the lactate minimum power and physiological responses in cycling. J Strength Cond Res 28(10): 2927-2934, 2014The aim of this study was to verify the influence of hyperlactemia and blood acidosis induction on lactate minimum intensity (LMI). Twenty recreationally trained males who were experienced in cycling (15 cyclists and 5 triathletes) participated in this study. The athletes underwent 3 lactate minimum tests on an electromagnetic cycle ergometer. The hyperlactemia induction methods used were graded exercise test (GXT), Wingate test (WAnT), and 2 consecutive Wingate tests (2 x WAnTs). The LMI at 2 x WAnTs (200.3 +/- 25.8 W) was statistically higher than the LMI at GXT (187.3 +/- 31.9 W) and WAnT (189.8 +/- 26.0 W), with similar findings for blood lactate, oxygen uptake, and pulmonary ventilation at LMI. The venous pH after 2 x WAnTs was lower (7.04 +/- 0.24) than in (p <= 0.05) the GXT (7.19 +/- 0.05) and WAnT (7.19 +/- 0.05), whereas the blood lactate response was higher. In addition, similar findings were observed for bicarbonate concentration [HCO3] (2 x WAnTs lower than WAnT; 15.3 +/- 2.6 mmol center dot L-1 and 18.2 +/- 2.7 mmol center dot L(-)1, respectively) (p <= 0.05). However, the maximal aerobic power and total time measured during the incremental phase also did not differ. Therefore, we can conclude that the induction mode significantly affects pH, blood lactate, and [HCO3] and consequently they alter the LMI and physiological parameters at LMI.

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The jambu belongs to the family Asteraceae, tropical crop, nowadays, this plant has been considered as a promising vegetable crop, because to its pharmacological properties. Despite this novelty, the vegetable remains invisible in the statistics of production and market in the state of Para, Brazil. This research was carried out with the aim of comparing the economic productivity and phenological development by the morpho-physiological growth indexes of two cultivars of jambu organic manure and mineral fertilizers. The experiment was carried out at the Sao Manuel Experimental Farm (Sao Manuel-SP), which belongs to the Faculdade de Ciencias Agronomicas - UNESP, campus Botucatu. The experimental design was a factorial randomized blocks (2 x 2) with two fertilization (organic and mineral) and two cultivars (Jambuarana and Nazareth), with six replications, two fertilization (organic and mineral) and two cultivars (Jambuarana and Nazareth). The following characteristics were evaluated: Plant height (cm), Leaf area (cm(2)), Fresh mass (g), Dry mass (g), Leaf area index (LAI), Leaf area ratio (LAR), Specific leaf Area (SLA), Leaf Weight Ratio (LWR), Amount of water in the plant (QAPA) (g per plant set), Leaf specific weight (LSW) (g cm(-2) per plant set) and Economic productivity. All data were statistically analyzed by analysis of variance and the Tukey test (1%) for mean comparison, with the software SISVAR. In the conditions of this experiment was carried out, it was possible to verify that the cultivar Jamburana had not only a good agronomic development and economic productivity under organic fertilization but also the best morpho-physiological indexes, showing that this kind of fertilization increases the agronomic effectiveness of this cultivar.

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

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

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The objective of this experiment was to determine if frequency of protein supplementation impacts physiological responses associated with reproduction in beef cows. Fourteen nonpregnant, nonlactating beef cows were ranked by age and BW and allocated to 3 groups. Groups were assigned to a 3 x 3 Latin square design, containing 3 periods of 21 d and the following treatments: 1) soybean meal supplementation daily (D), 2) soybean meal supplementation 3 times/week (3WK), and 3) soybean meal supplementation once/week (1WK). Within each period, cows were assigned to an estrus synchronization protocol: 100 mu g of GnRH + controlled internal drug release device (CIDR) containing 1.38 g of progesterone (P-4) on d 1, 25 mg of PGF(2 alpha) on d 8, and CIDR removal + 100 mu g of GnRH on d 11. Grass-seed straw was offered for ad libitum consumption. Soybean meal was individually supplemented at a daily rate of 1 kg/cow (as-fed basis). Moreover, 3WK was supplemented on d 0, 2, 4, 7, 9, 11, 14, 16, and 18 whereas 1WK was supplemented on d 4, 11, and 18. Blood samples were collected from 0 (before) to 72 h after supplementation on d 11 and 18 and analyzed for plasma urea-N (PUN). Samples collected from 0 to 12 h were also analyzed for plasma glucose, insulin, and P-4 (d 18 only). Uterine flushing fluid was collected concurrently with blood sampling at 28 h for pH evaluation. Liver biopsies were performed concurrently with blood sampling at 0, 4, and 28 h and analyzed for mRNA expression of carbamoyl phosphate synthetase I (CPS-I; h 28) and CYP2C19 and CYP3A4 (h 0 and 4 on d 18). Plasma urea-N concentrations were greater (P < 0.01) for 1WK vs. 3WK from 20 to 72 h and greater (P < 0.01) for 1WK vs. D from 16 to 48 h and at 72 h after supplementation (treatment x hour interaction, P < 0.01). Moreover, PUN concentrations peaked at 28 h after supplementation for 3WK and 1WK (P < 0.01) and were greater (P < 0.01) at this time for 1WK vs. 3WK and D and for 3WK vs. D. Expression of CPS-I was greater (P < 0.01) for 1WK vs. D and 3WK. Uterine flushing pH tended (P <= 0.10) to be greater for 1WK vs. 3WK and D. No treatment effects were detected (P >= 0.15) on expression of CYP2C19 and CYP3A4, plasma glucose, and P-4 concentrations, whereas plasma insulin concentrations were greater (P <= 0.03) in D and 3WK vs. 1WK. Hence, decreasing frequency of protein supplementation did not reduce uterine flushing pH or plasma P-4 concentrations, which are known to impact reproduction in beef cows.