Desempenho e termorregulação de porcas lactantes alojadas em diferentes localizações no interior de um galpão com sistema de resfriamento evaporativo em ambiente tropical / Performance and thermoregulation of lactating sows housed in different locations inside a shed with an evaporative cooling system in a tropical environment

The effects of housing lactating sows at different locations in a shed with evaporative cooling system (ECS) on their thermoregulation and reproductive and productive performance of the sow and the litter in summer were determined. 34 females were used in the three lines of cages at these locations: near the pad cooling; in the middle of the shed and near the exhaust fans. The air temperature and the temperature and humidity index (THI) were lower near the pad cooling (22.38ºC, 71.84) than the middle (24.56ºC, 74.82) and near the exhaust fans (25.00°C, 75.62). Respiratory rate, rectal and surface temperatures were lower in sows near the pad cooling (43.67 breaths.min -1 , 38.40°C; 29.51°C) than in the center (52.04 breaths.min -1 ; 38.48ºC; 32.02ºC) and near the exhaust fans (56.38 breaths.min-1, 38.93ºC; 32.52ºC). The backfat thickness, the weaning-estrus interval and daily average consumption of the sows, number of weaning piglets, corporal mass and daily average gain of the piglets were not influenced by the location of housing in the shed. Lactating sows housed in the middle and near the exhaust fans in the ECS presented increased thermoregulation physiological variables, however, this did not impair the performance.(AU)

Aquatic Exercise at Thermoneutral Water Temperature Enhances Antitumor Immune Responses

Despite the broad rehabilitative potential of aquatic exercises, the relationship between aquatic exercise and the immune system has not been fully elucidated to date. In particular, there are few specific and delicate immunological approaches to the effect of water temperature on immunity. Thus, we examined the effect of water temperature on immunity during aquatic exercise. The animal tumor model was adopted to examine the impact of aquatic exercise at thermoneutral temperature (TT; 29°C) on immunity compared with aquatic exercise at body temperature (BT; 36°C). Tumor-bearing mice were made to swim in TT water or in BT water for 3 wk and immune cells and their functional activity were analyzed using FACS. Tumor growth was significantly suppressed in mice that exercised in TT than in BT water. The tumor control correlated with the increased number of NK (2-fold), γδT cells (2.5-fold), NKT (2.5-fold), and cytotoxic CD8⁺ T cells (1.6-fold), which play a critical role in anti-tumor immune responses. Furthermore, the functional activity was dramatically improved in the TT group, showing enhanced production of IFNγ in CD8⁺ T cells compared with the BT group. This study demonstrates that aquatic exercise in TT water may improve protective immune responses more effectively than in BT water. Although the effects of water temperature on immune function need further verification in humans, this study suggests that water temperature in human hydrotherapy may be important for improving immune function.

Heart Rate Variability during the Bathing in Still Water and Flowing Water / 日本温泉気候物理医学会雑誌

This study was conducted to assess the effects of bathing in still water and in flowing water on the heart rate variability. Eight healthy young males (age 20 to 28) bathed in still water at temperatures of 34°C, 38°C, and 41°C for 20 minutes each. The other eight healthy young males (age 22 to 28) bathed in flowing water at a temperature of 36°C for 30 minutes. Electrocardiograms were recorded before, during, and after the bathing. Subjects sat still for 20 minutes before bathing, and then bathed in water to the axilla in a sitting position. Subjects breathed freely during the experiment. Heart rate variability was estimated with the power spectral analysis using FFT. The power densities in the high frequency (0.15 to 0.50Hz) and low frequency (0.04 to 0.15Hz) areas as obtained from this frequency analysis (HF and LF) as well as the ratio of LF/HF were calculated, and HF was used as index of cardiac parasympathetic activity, LF as index of sympathetic activity with parasympathetic modulation, and LF/HF as index of sympathetic activity.<br>During bathing in still water at 34°C and 36°C, no significant change from the value before the bathing was found in heart rate, HF, LF, or LF/HF. HF and LF significantly decreased during the bathing in still water at 38°C and 41°C, LF/HF significantly increased during the bathing in still water at 38°C, During the bathing in still water at 41°C, we could not calculate LF/HF for many subjects because HF disappeared. During the bathing in water flowing at a moderate speed (1.0m/sec), LF/HF increased significantly. During the bathing in water flowing at a high speed (2.0m/sec), heart rate and LF/HF increased significantly while LF decreased significantly.<br>These results suggest that parasympathetic nervous activities are suppressed and sympathetic nervous activities are enhanced during bathing in still water at temperatures higher than the neutral temperature (34°C), and sympathetic nervous activity is enhanced during the bathing in flowing water at 36°C, However, the effects of respiration rate and tidal-volume on HF, and the validity of the HR variabilities as an index of autonomic nervous activities should be examined in further detail.