Thermographic evaluation of climatic conditions on lambs from different genetic groups

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of the Temperature and Maturation Stages on the Germination of Roystonea regia Seeds

Roystonea regia (Kunth) O.F. Cook is largely used as ornamental. The propagation is done almost exclusively by seeds; however, there is a great variation in the germination process influenced by many factors. The objective of this work was to study the effects of the temperature and maturation stages on the germination of R. regia seeds. The experimental design was entirely randomized in a factorial arrangement 6x3 (six temperatures: constant at 20, 25, 30 and 35 degrees C and alternated at 20-30 and 25-35 degrees C, with a photoperiod of 12 hours; and three fruit maturation stages: brown, yellow and black), with four replications of 25 disseminules (seed with stucked endocarp) each. The disseminules had their mesocarp and exocarp were removed and shade dried. Their moisture content was determined, and then they were placed in plastic boxes (gerbox type) containing vermiculite. The disseminules, with the germinative intumescence, were daily noted until germination was steady. The germination rate and the germination speed index were calculated, and the data were submitted to the variance analysis. The means were compared by the Tukey test. It was concluded that the highest germination rate (99.7%) and germination speed were obtained by seeds from mature (black) fruits at the temperature of 35 degrees C.

Scrotal Thermography and Doppler Ultrasonography of the Testicular Artery of Buffaloes Subjected to Environmental Heat Stress

The process of spermatic division and differentiation (spermatogenesis) occurs with intratesticular temperature lower that the corporal temperature and for that is essential that the testicular thermoregulation mechanism occurs properly. For evaluation of the scrotal surface temperature can be used the infrared thermography or testicular sensors, besides that, can be evaluated the blood flux in the spermatic cord through the Doppler ultrasonography. Therefore the objective of this study was the evaluation of the scrotal thermography and Doppler flowmetry of the testicular artery of buffaloes subjected to environmental heat stress. For that were used seven healthy buffaloes, with age of 3 and 4 years, of the Murrah breed. For the surface scrotal temperature measurement (SST, degrees C) and superficial neck temperature (SNT, degrees C) was used the infrared termography (Infra Cam (TM) of the brand FLIR Systems Inc.), then Doppler flowmetry of the testicular artery in the region of the spermatic cord through the ultrasonography (Mylab 5, Esaote (R)) and measurement of the rectal temperature (RT, degrees C). The evaluations were done in two moments: moment 1 (M1) with all the animals in the shade (Temperature=32,2 degrees C) and moment 2 (M2) after 3 hours of exposure of animals to the sun (Temperature=38,7 degrees C To calculate the resistivity index (RI) and pulsatility index (PI), spectra were obtained from pulsed Doppler in three random regions of the testicular artery in the spermatic cord. Data were subjected to analysis of variance (ANOVA) followed by T test, using a significance level of 5%. There was an increase (p<0,05) of RT (37,4 +/- 0,4(a) vs 39,0 +/- 0,3(b); M1 and M2 respectively), SST (30,6 +/- 1,4(a) vs 35,2,0 +/- 1,0(b); M1 and M2 respectively) and SNT (33,1 +/- 2,5(a) vs 38,5,0 +/- 0,3(b); M1 e M2 respectively) e RI (0,67 +/- 0,1(a) vs 0,74 +/- 0,1(b); M1 e M2 respectively) in M2. Increasing trend was observed (0,05>p>0,01) in PI (1,10 +/- 0,4(a) vs 1,23 +/- 0,2(b); M1 and M2 respectively) in M2. The results of the present study allow us to conclude the healthy buffaloes have the scrotal average surface temperature 3 degrees C lower that the body temperature and that the exposure of 3 hours to sun in healthy buffaloes causes thermal stress to the animals and changes in its surface scrotal temperature, and the Doppler flowmetry of the testicular artery demonstrating the importance of thermal management for breeding buffaloes. Besides that, the thermography and the Doppler ultrasonography presented great potential to detect changes of testicular perfusion, being a promising additional test in the buffalo andrological evaluation.

Temperature and storage period over spermatic parameters of jundia, Rhamdia quelen (Quoy & Gaimard, 1824)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

New insights into the structural characteristics of irradiated crotamine

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermoregulatory responses of goats in hot environments

Notwithstanding the solar radiation is recognized as a detrimental factor to the thermal balance and responses of animals on the range in tropical conditions, studies on the amount of thermal radiation absorbed by goats therein associated with data on their production and heat exchange are still lacking. Metabolic heat production and the heat exchange of goats in the sun and in the shade were measured simultaneously, aiming to observe its thermal equilibrium. The results showed that black goats absorb twice as much as the white goats under intense solar radiation (higher than 800 W m(-2)). This observation leads to a higher surface temperature of black goats, but it must not be seen as a disadvantage, because they increase their sensible heat flow in the coat-air interface, especially the convection heat flow at high wind speeds. In the shade, no difference between the coat colours was observed and both presented a lower absorption of heat and a lower sensible heat flow gain. When solar radiation levels increases from 300 to 1000 W m(-2), we observed an increase of the heat losses through latent flow in both respiratory and cutaneous surface. Cutaneous evaporation was responsible for almost 90 % of the latent heat losses, independently of the coat colour. Goats decrease the metabolic heat production under solar radiation levels up to 800 W m(-2), and increase in levels higher than this, because there is an increase of the respiratory rate and of the respiratory flow, but the fractions of consumed oxygen and produced carbon dioxide are maintained stable. The respiratory rate of black goats was higher than the white ones, under 300 W m(-2) (55 and 45 resp min(-1)) and 1000 W m(-2) (120 and 95 resp min(-1), respectively). It was concluded that shade or any protection against solar radiation levels above 800 Wm(-2) is critical to guarantee goat's thermal equilibrium. Strategies concerning the grazing period in accordance with the time of the day alone are not appropriate, because the levels of radiation depend on the latitude of the location.

The effects of temperature and busulfan (Myleran) on the yellowtail tetra Astyanax altiparanae (Pisces, Characiformes) spermatogenesis

We aimed to standardize a protocol to suppress spermatogenesis in the characiform fish, Astyanax altiparanae, for future use as a host in germ cell transplant research, opening opportunities for a range of studies, such as spermatogenesis analyses and transgenesis because this species presents livestock characteristics to be used as a biological model. The effects of the chemotherapeutic busulfan (formulated as Myleran), which is used as medicine, therefore not as toxic to humans manipulation as analytical grade busulfan (Fluka) used in previous studies, were evaluated at physiological temperature of 28 °C, ideal for growth and reproduction of A altiparanae, and also at increased temperature 35 °C. The temperature groups were divided into three treatment groups: busulfan, DMSO only, and an untreated control. Macroscopic, histologic, stereological, and ultrastructure analysis showed that, at 28 °C, busulfan did not cause depletion of germ cells in A altiparanae. However, at 35 °C, sterilization was observed 3 weeks after the initial application. Similar results were obtained with maintenance of fish at 35 °C for a longer period with no accompanying Myleran treatment. This procedure allows reduction in stress and lower mortality resulting from manipulation during busulfan injection and is also suitable for mass treatment because large numbers of fish can be incubated in warm water.

Assessment of broiler surface temperature variation when exposed to different air temperatures

This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST) of 7-to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb(R) broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 degrees C) to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05) from the values obtained by the equations. MST values significantly increased (p < 0.05) when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

Regulation of the abundance and turnover of copepod species by temperature, turbidity and habitat type in a large river basin

Freshwater copepods were sampled in the La Plata River basin to identify the processes that affect beta diversity and to determine the main factors influencing their geographical distribution and patterns of endemism. Beta diversity patterns exhibited strong dissimilarity between locations; the turnover process was predominant and indicated a replacement of species along the basin. Redundancy analysis indicated the presence of two large sets of species separated geographically by a boundary zone, with several associated variables. Northern species were associated with water transparency and temperature, mean air temperature, mean air temperature during winter and minimum air temperature of coldest month, indicating that these species are not tolerant to low temperatures and are abundant in reservoirs that are common in the upper stretch of the Paraná River basin. Southern species were related with amplitude of air temperature, turbidity, total phosphorus and total suspended matter, indicating that these species are polythermic and have adapted to live in river stretches. From 20 environmental variables analyzed in our study, partial least squares analysis indicated four variables with increased retention of effects on copepod abundance: air temperature, minimum temperature of coldest month, turbidity and transparency. Because almost all of the species found in this study occurred across a wide range of habitat types, the cause of the separation between river and reservoir species could be considered to be more anthropogenic than natural, and it primarily affected species abundance. For certain members of the northern group of copepod species, distribution was dependent on high temperatures, whereas the distribution of the southern group indicated that the species were polythermic.