86 resultados para Lower temperatures
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Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits. © 2012 The Animal Consortium.
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The present study was developed in Departamentos de Engenharia Rural e Morfologia e Fisiologia Animal da FCAV/Unesp. The objective of evaluating different roof slopes and exposure in three types of coverage in models of animal installations. Project 48 built reduced models of wood were used with dimensions of 1,00 x 1,00 x 0,50 meters. The covering was one water, lateral and wood floor, disposed in the exhibitions North-south, being 24 prototypes in the north exhibition and 24 in the south. Were used in the covering roofs of ceramic type, galvanized steel and asbestos. The slopes varied of 20, 30, 40 and 50% for ceramic tile and 10, 30, 40 and 50% for the others and with two repetitions for slope. Inside the reduced models temperature readings were accomplished, of hour in hour during one year, for the system of acquisition of Data Logger Campbell Scientific-Ínc and externally the temperature of the air, incident radiation global solar, precipitation, speed and relative humidity of the air were measured. The results obtained during the experimental period of one year were appraised statistically for the statistical package SAS in the factorial outline, where three factors were considered: tile type, slope degree and exposure. The obtained averages were compared through the test of Tukey to 5% of probability. After analyzing the data we found that with increasing slope, there was a decrease in inside temperature in the cover prototypes, therefore, using steeper slopes with 50% of tipping ceramics and asbestos, with greater coverage on display South, we have lower temperatures in poultry houses in the geographic coordinates of the city of Jaboticabal.
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This study was performed in order to determine the effect of the addition of different concentrations of glycerol and ethanol over functional and structural properties of zein-oleic acid films. Films were prepared from zein and oleic acid formulations, containing: 0, 10, 20 and 30% (w/w) of glycerol as plasticizer and 75, 80, 85, 90 and 95% (v/v) of ethanol as zein solvent. Water vapor permeability (WVP) at 4 and 24 C, opacity, water solubility and structural behavior of the film were assessed. The film water barrier properties, WVP and water solubility, were increased when higher ethanol concentration and lower glycerol concentration were used. Furthermore, WVP at 4 C was lower than WVP at 24 C due to the crystalline solid state of oleic acid at lower temperatures. Likewise, opacity, homogeneity and structure of the composite film were improved as ethanol increased and glycerol lowered. © 2013 Elsevier B.V. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Química - IQ
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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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In Southern Brazil, Aegla parana Schmitt, 1942 is characterized by a broad distribution throughout the Iguacu River basin, particularly between the southern state of Parana and the northern state of Santa Catarina, preferentially inhabiting streams with rocky substrates. Although there has been an increase in the number of studies about the population biology of Aeglidae, many aspects about the reproductive biology of A. parana are still unknown. Therefore, the present study aimed to investigate the size at sexual maturity, reproductive seasonality and recruitment of A. parana from November, 2008 to December, 2009, in a tributary of the Iguacu River located in Uniao da Vitoria, Parana, Brazil. Basic environmental factors were investigated to determine their influence on the reproductive cycle of this species. Gonadal stages were characterized macroscopically, and the presence or absence of embryos in females (ovigerous females) from monthly samples was recorded. The entire sample was composed of 436 males and 211 females. Although the smallest ovigerous female was 16.2 mm, the average size (carapace length, CL) at sexual maturity (CL50%) was calculated at 17.4 mm. The greatest percentage of females with developed (mature, near spawning) gonads stage was observed from January to June, 2009, while ovigerous females were recorded from April to July, 2009, after which the reproductive period ended. Recruitment occurred from October to December, 2009. The presence of ovigerous females was negatively correlated with temperature (Spearman, p < 0.05). Females carrying embryos were generally collected during periods of lower temperatures, whereas recruits entered the population during periods of higher temperatures, when food for them is more abundant in the region studied.
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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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Pós-graduação em Medicina Veterinária - FMVZ