| By studying the effect of cold and hot stimulus on physiological and behavioral regulation and performance, evaluate thermal neutral temperature in 5~6 weeks of broilers. Research on the following two aspects:Trial 1.Behavior spent time length and space distribution in hot and cold temperature stimulation in broilers. Using infrared camera video in broilers test 1, 7 and 14 days, at 10:00 began video, and continuous shooting 20 min, by recording the spent time of posture and space position distribution behavior in broilers. Finding that more time was spent showing aggression and standing at 10°C and 14°C than other groups(P < 0.01) as trial first day, Test 7 and 14 days, time spent aggression and standing at 10 ℃ were significantly higher than other groups(excluding the 14 th day of aggression behavior)(P < 0.01).2. Test 1 day, at 30 ℃the more time the broilers spent stretching(P < 0.01). Test 14 days, more time was spent showing prostrating at 26°C and 30°C than other groups(P < 0.01).3. Hot and cold temperature stimulation 14 d, broilers had significant difference at the edge of the cage(P < 0.05), and did not significantly differ at other location(P>0.05). In 26 ℃ and 30 ℃, broilers at edge rest time was significantly higher than at other location(P < 0.05), while in 10 ~ 18 ℃ the value was not significant difference(P > 0.05). Indicating that hot and cold temperature stimulation after 14 d, under the condition of cold temperature stimulation broilers posture behavior and space distribution could not be relatively sensitive, under the condition of the hot temperature stimulation broilers rest behavior and spatial distribution had significantly change, when the temperature is above 26 ℃, time spent of prostrating and rest at the edge of the cage wall were significantly increased(P < 0.05).Trial 2. Influence of thermal stimulation on thermoregulation and performance in broilers. Thermal stimulated 14 d, and measured the rest behavior, physiology, endocrine, and performance in broilers. The results showed that, temperature treatments for 14 d, compared with 26 °C and 30 °C, percentage of time spent of sitting rest was distinctly increased at 18 °C and 22 °C(rule out the value at 18 ℃ and 26 ℃ on test 1 day)(P<0.05), compared with 18°C and 22 °C, percentage of time spent of prostrating rest was distinctly increased at 26 °C and 30 °C(P<0.05).2. Thermal stimulated 1 d, hypothalamus heat shock protein(HSP) 70 concentration was no significantly different at 26 °C and 30 °C(P>0.05). Temperature treatments for 3 and 10 days, hypothalamus HSP70 concentration had significantly different(26 °C versus 22 °C, 30 °C versus 22 °C: P<0.05). Temperature treatments for 1, 3 and 10 days, body core temperature, plasma corticosterone(CORT) and Triiodothyronine(T3) concentration did not differ(26 °C versus 22 °C: P>0.05), body core temperature was significantly increased at 30 °C. Temperature treatments for one to seven days and seven to fourteen days, average daily feed intake(ADFI) were significantly decreased(26 °C versus 22 °C, 30 °C versus 22 °C: P<0.05). Temperature treatments for two weeks, ADFI and average daily gain(ADG) of broilers distinctly decreased compared(26 °C versus 22 °C, 30 °C versus 22 °C: P<0.05). Consequently, when housing temperature reached 26 °C thermal stimulation, percentages of time spent of sitting rest posture and performance had distinct decrease, percentages of time spent of prostrating rest posture and hypothalamus HSP70 concentration were significantly increased in 29~42 days of broilers.Comprehensive the above results, 1. Under the cold temperature stimulation, 5~6 weeks of broilers activities posture behavior of spent time had signigicant changes, spent time of standing and aggression had distinct increase. 2. Thermal stimulated 14 d, 5~6 weeks of broilers resting behavior and the concentration of the hypothalamus HSP70 changed significantly, the percentage of spent time of prostrating and rest at the edge could be used to early evaluate thermal comfort of broiler. 3. From the physiological and behavioral regulation and performance indicators comprehensive consideration, 5~6 weeks broilers thermal neutral temperature was 18~22 ℃. |
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