Vc对肉鸡腹水综合征发病率、右心肥大和肺微细动脉肌型化的作用

Effect of Vitamin C Supplementation on Ascites Incidence and Muscularization of Pulmonary Arterioles in Broilers

350只AA商品内鸡随机分为A、B、C、D和E组，常规饲养。14日龄后，A组鸡正常对照，B、C、D和E组鸡舍温按每日1～2C由25C逐步降至12C，同时D和E组在日粮中按1．5mg／kg的剂量添加甲状腺素T3以诱发内鸡腹水综合征（AS）；C和E组在日粮中以500mg／kg的剂量添加雏生素C（Vc）以观察其效果。结果表明，低温和T3能显著增加AS发病率、红细胞压积（PCV）值和肺厚壁末梢血管百分率（P〈0．01），显著抑制内鸡的增重（P〈0．05），低温显著增加采食量，而T3则显著抑制采食量（P〈0．01）；同时，分别在低温或低温加T3的条件下，添加Vc能显著抑制AS发病率和肺厚壁末梢血管百分率的上升（P〈0．01），但未能改变内鸡的PCV值、增重、采食量和饲料转换率（P〉0．05），从而提示Vc对低温和T3诱发的内鸡AS和肺微细血管肌型化有预防作用。

Three hundred and fifty 1-day-old AA commercial broilers were divided randomly into control （Group A） and four experimental groups（B,C,D and E）. Broilers in different experimental groups and group A were fed a normal diet before 14 days of age. In different experimental groups,broilers were subjected to a change of temperature by lowering 1-2C per day from 25C （day 14） down to 12 C ,and then maintained at this ambient temperature until 7 weeks of age. At the same time,1.5 mg/kg 3,3,5-triiodothyronine （T3） in the diet was added to in groups D and E in order to induce ascites syndrome （AS）,and 500 mg/kg ascorbic acid（Vitamin C） in the diet was added to in groups C and E with the purpose of decreasing the incidence of AS. The result indicated that the lower ambient temperature and dietary T3 significantly increased AS incidence,packed cell volume （PCV） and the percentage of thick-walled peripheral lung vessels （%TWPV）（P〈0. 01）,and significantly decreased body weight gain（P〈0. 05）. The lower ambient temperature significantly increased the feed intake （P〈0. 01）,however dietary T3 significantly decreased it （P〈0. 01 ）. In the same times,vitamin C supplementation,in the cool environmental temperature or dietary T3,significantly reduced AS incidence and %TWPV（P〈0. 01）,but didn＇t change PCV,body weight gain,feed intake and food conversion rate（P〉0. 05）. It might be concluded that vitamin C supplementation could prevent broiler AS induced by cool or dietary T3 and muscularization of pulmonary arterioles in broilers.