关键词: 湿度, 抗氧化能力, 细胞因子, 生产性能, 肉鸡

Abstract:

【Objective】 The aim of this study was to investigate the effect of relative humidity on growth performance, antioxidant capacity and immune function of broiler chickens by simulates high, medium and low humidity, and to provide data support for the reasonable regulation of humidity in poultry house, and promote the development of healthy cultivation of broiler chickens. 【Method】 The trial adopted single factor completely random design. A total of 270 healthy AA broilers with similar initial body weight of 1 day old were randomly divided into 3 groups: normal humidity group (control group, 60% RH), low-humidity group (30% RH) and high-humidity group (90% RH), with 6 replications per group and 15 chickens in each replicate. The experiment was conducted in the artificial climate chamber of Changping Base, the State Key Laboratory of Animal Nutrition from February to April in 2006. The cabin was equipped with humidity sensors to continuously monitor the humidity in the cabin for 24 hours, and the humidity was adjusted according to the real-time monitoring values. And the test period was 42d, the starter phase was 1-21 d, and the later phase was 22-42 d. Broilers were reared in flat cages and provided ad libitum access to feed and water, and a 24 h lighting programme was applied during the experiment. They were routinely managed according to the AA broiler feeding manual and immunized according to routine procedures. The growth performance of broiler chickens were measured per pen and blood samples (2 randomly selected from each replicate) were obtained from wing vein of broilers and then slaughtered at 21 and 42 days of age, respectively. The antioxidant capacity, cytokines contents and viscera index of broilers were determined.【Result】 The results showed that: 1) Growth performance: compared to the control group with normal humidity, low-humidity treatment significantly reduced the body weight of 21 and 42 days of age broilers, and significantly reduced average daily gain of broilers (P＜0.05). 2) Antioxidant ability: the serum SOD activity and total antioxidant capacity of broilers in low-humidity group were significantly lower than those in control group at 21 and 42 days of age (P＜0.05). At 42 days of age, the content of malondialdehyde in low-humidity group was significantly higher than that in control group (P＜0.05); total antioxidant capacity in high-humidity group was significantly lower than that of the control group (P＜0.05). 3) Immune function: compared with control group, high-humidity treatment significantly increased the content of inflammatory cytokine IFN-γ and TNF-α in serum of 21 day old broilers (P＜0.05), while the contents of serum cytokines in 42-day-old broilers were not significantly affected by humidity (P＞0.05). 4) Visceral index: the lung index of 42-day-old broilers in the high-humidity group was significantly lower than that in the control group (P＜0.05). In addition, the 42-day-old liver index in the low-humidity group was significantly higher than that in the high-humidity group (P＜0.05). 【Conclusion】 It could be seen that long-term low humidity and high humidity environment reduced the growth performance, antioxidant capacity and immune function of broilers, which was not conducive to the healthy growth of broilers. In the process of broiler breeding, humidification or dehumidification could be used to regulate the humidity in the house in time to promote the healthy growth of broilers.

Key words: humidity, antioxidant capacity, cytokine, production performance, broiler