Effects of glucose in drinking water on feed intake, rectal temperature, plasma glucose, free fatty acid and mortality of broilers during high temperature exposure

This study was conducted to evaluate the effects of drinking glucose water and ambient temperatures on feed intake, rectal temperature, plasma glucose and free fatty acid concentrations, and mortality of male commer-cial broilers from 48 to 54 days of age. Two groups (8 birds/group), which were available to access 4% glucose water solution (Group G) and tap water (Group W) ad libitum, respectively, were subjected to the following temperature treatments. A diurnal temperature cycles (12h : 12h) of 17 : 25 degrees C was performed from 48 to 50-d-old, then 25 : 33 degrees C (12h : 12h) from 51 to 53-d-old, finally a constant temperature of 12h at 38 degrees C at 54-d-old. The average feed intakes during 25 and 33 degrees C wee significantly smaller in Group G than in Group W, while water and ME intakes significantly greater. No marked difference in rectal temperature was found between the two groups under the ambient temperature of 17, 25 and 33 degrees C. However, at 38 degrees C, rectal temperature was enhanced quickly after exposure for 2h in Group W, while its slow increase was found in Group G. The survival time of broilers were prolonged obviously by drinking glucose water during exposure to 38 degrees C. Plasma glucose was significantly higher in Group G than in Group W after exposure to 38 degrees C for 8h, while plasma free fatty acid was significantly lower. These results indicate that glucose intake alleviates the influence of heat stress which may be related to