本试验旨在探究饲养密度与活动空间对肉鸡免疫和应激指标的影响。试验选用1日龄爱拔益加（AA）肉鸡756只，采用3×2因子设计，随机分成6个处理，每个处理6个重复。活动空间分大、小2种：2.88（2.4 m×1.2 m）和1.44 m²（2.4 m×0.6 m），密度分高、中、低3种：14、10、6只/m²。试验期42 d。结果表明：1）21日龄时，饲养密度与活动空间对平均日增重、平均体重的交互作用显著（P<0.05），大空间中密度组平均日增重、平均体重显著高于小空间中、高密度组（P<0.05）。饲养密度与活动空间对血清游离脂肪酸（FFA）含量有极显著影响（P<0.01），中密度组显著低于高、低密度组（P<0.05），并且交互作用极显著（P<0.01）。饲养密度对血清白细胞介素-1β（IL-1β）和白细胞介素-6（IL-6）含量分别有极显著和显著影响（P<0.01和P<0.05）。饲养密度对血清总抗氧化能力（T-AOC）有显著影响（P<0.05）；饲养密度与活动空间对血清谷胱甘肽过氧化物酶（GSH-Px）活性的交互作用显著（P<0.05）。2）42日龄时，饲养密度与活动空间对平均日增重、料重比、平均体重的交互作用极显著（P<0.01）。大空间中、低密度组和小空间低密度组的平均日增重、平均体重显著高于其他各组（P<0.05），高密度组平均日采食量、平均日增重、平均体重显著低于中、低密度组（P<0.05），大空间组平均体重显著高于小空间组（P<0.05），大空间组平均日采食量显著低于小空间组（P<0.05），大空间中、高密度组料重比显著低于小空间中、高密度组（P<0.05）。高密度组的血清葡萄糖含量显著高于中、低密度组（P<0.05）。中密度组血清IL-1β含量显著低于高、低密度组（P<0.05）。由此可见，饲养密度与活动空间对平均日采食重、平均日增重、料重比、平均体重及血清FFA、IL-1β及IL-6含量产生了一定影响，可引起肉鸡的应激免疫反应。其中，中密度大空间组（10只/m²、2.88 m²）免疫应激最小，更适宜肉鸡生长。

The influence of breeding density and space allowance on immune and stress indexes of broilers were investigated in this experiment. Using a 3×2 factors completely randomized design, a total of 756 one-day-old Arbor Acres (AA) broilers were randomly allotted into 6 groups with 6 replicates per group. Two kinds of space allowance were designed as 2.88 (2.4 m×1.2 m) and 1.44 m² (2.4 m×0.6 m), three breeding densities were designed as high density (14 birds/m²), medium density (10 birds/m²) and low density (6 birds/m²). The experiment lasted for 42 day. The results showed as follows: 1) at 21 days of age, breeding density and space allowance had a significant interaction on average daily gain (ADG) and average body weight (ABW) (P<0.05). The ADG and ABW of broilers in the medium density with large space allowance group were significantly higher than those in the medium density with small space allowance group and the high density with small space allowance group (P<0.05). Breeding density and space allowance had significant effects on serum free fatty acids (FFA) content (P<0.01), also had a significant interaction (P<0.01), the serum FFA content in medium density group was significantly lower than that of high and low density groups (P<0.05). Breeding density had significant effects on the contents of interleukin-1β (IL-1β) and interleukin-6 (IL-6) in serum (P<0.01 and P<0.05). Breeding density had significant effect on serum total antioxidant capacity (T-AOC) (P<0.05). Breeding density and space allowance had a significant interaction on serum glutathione peroxidase (GSH-Px) activity (P<0.05). 2) At 42 days of age, breeding density and space allowance had a significant interaction on ADG, feed to gain (F/G) and ABW (P<0.05). The ADG and ABW of broilers in medium and low density with large space allowance group and low density with small space allowance group were significantly higher than those in other groups (P<0.05), the average daily feed intake (ADFI), ADG and ABW of broilers in high density were significantly lower than those in medium and low density group (P<0.05), the ABW of broilers in large space allowance group was significantly higher than that in small space allowance group (P<0.05), the ADFI of broilers in large space allowance group was significantly lower than that in small space allowance group (P<0.05), the F/G of broilers in medium and high density with large space allowance group was significantly lower than that in medium and high density with small space allowance group (P<0.05). The serum glucose content in high density group was significantly higher than that in medium and low density group (P<0.05). The serum IL-1β content in medium density group was significantly lower than that in high and low density group (P<0.05). In summary, breeding density and space allowance have a certain influences on ADFI, ADG, F/G, ABW and contents of FFA, Il-1β and IL-6 in serum, and cause chicken's stress and immune response. This experiment can preliminary draw the conclusion that the medium density (10 birds/m²) with large space allowance (2.88 m²) has lowest immunological stress, which is more suitable for the growth of broilers.