EFFECT OF CARBONATED DRINKING-WATER ON PRODUCTION PERFORMANCE AND BONE CHARACTERISTICS OF LAYING HENS EXPOSED TO HIGH ENVIRONMENTAL TEMPERATURES

An experiment was conducted to determine the effects of providing heat-stressed laying hens with carbonated drinking water on production performance and tibia bone breaking strength. A total of 32 commercial laying hens (89 wk of age) were housed in an environmental chamber and exposed to 1 wk of a constant thermoneutral temperature (21 C), followed by 6 wk of a daily heat stress temperature cycle (34 C for 8 h; 21 C for 16 h). One half of the hens received tap water and the other half were provided carbonated water immediately after housing. Following 6 wk of heat stress temperature exposure, all hens were killed by cervical dislocation and left tibia bone strength measurements were taken. Hen-day egg production, egg weight, egg yield, feed consumption, and feed efficiency did not differ between water treatments; however, egg specific gravity was depressed for hens provided carbonated versus tap drinking water. Left tibia bone breaking strength per 100 g body weight was improved (P less-than-or-equal-to .05) for hens provided with carbonated drinking water during exposure to heat stress temperatures. These results suggest that carbonated drinking water may enhance bone integrity by increasing tibia bone breaking strength of older laying hens exposed to a short-term heat stress period.