板栗总苞多酚对AA肉鸡生长、抗氧化性能影响

【目的】氧化应激在畜牧业生产中普遍存在，诱发氧化应激的因素很多，热应激是诱发氧化应激反应的重要因素之一，氧化应激能够影响动物生长性能，甚至造成动物死亡，带来严重的经济损失。近年来，植物多酚因其具有多种生物学功效日益而受到关注。故研究不同剂量板栗总苞多酚对常温和高温热应激条件下肉鸡生长、抗氧化性能的影响。【方法】研究包括两个试验。试验一：将400只1日龄健康爱拔益加（AA）雄性雏鸡随机分成5组，每组4个重复，每个重复20只鸡：Ⅰ组为空白对照组，饲喂基础日粮；Ⅱ组为阳性对照组，饲喂日粮为基础日粮中添加0.15% 2,6-二叔丁基对甲苯酚(BHT)添加剂预混料（其中BHT含量0.015%）；Ⅲ-Ⅴ组为板栗总苞多酚试验组，饲喂日粮为基础日粮中分别添加0.2%、0.3%和0.4%板栗总苞多酚提取物。试验一：常温条件下饲养42d，根据AA肉鸡饲养程序和免疫程序进行饲养管理。每周末称体重和采食饲料重，测定各组AA肉鸡不同阶段生长性能指标。试验二：将400只28日龄的AA雄性肉鸡按试验一分组，在常温下适应一周后，开始连续7d的高温热应激。高温3d、7d称重、屠宰、取样。测定高温热应激条件下，板栗总苞多酚对AA肉鸡生长性能、屠宰指标和血清抗氧化指标的影响。【结果】试验一结果表明，常温条件下，板栗总苞多酚对肉鸡生长性能无显著影响（P＞0.05）。试验二表明，在初始体重相同的情况下，热应激一周后，Ⅳ、Ⅴ组体重显著高于Ⅰ组（P＜0.05）；Ⅳ组平均日增重（ADG）和平均日采食量（ADFI）均显著高于Ⅰ组、Ⅱ组和Ⅲ组（P＜0.05）；Ⅳ和Ⅴ组料重比（F/G）显著低于Ⅰ组（P＜0.05）；各组间死亡率差异趋于显著（P=0.059)并以V组最低。板栗总苞多酚对AA肉鸡屠宰指标无显著差异（P＞0.05）。高温热应激3d的肉鸡，各试验组血清总抗氧化能力（T-AOC）含量虽有波动，但是差异均不显著(P＞0.05)；Ⅳ组血清的总超氧化物歧化酶（T-SOD）活力显著高于Ⅰ组(P＜0.05)；Ⅲ、Ⅳ、Ⅴ组丙二醛（MDA）含量显著低于Ⅰ组(P＜0.05)，Ⅱ组居中间，和所有的组相比都不显著(P＞0.05)；相对于Ⅰ组，Ⅱ-Ⅴ组谷胱甘肽过氧化物酶(GSH-Px)活力均显著升高(P＜0.05)。高温热应激7d时，Ⅳ组血清T-AOC显著高于Ⅰ组和Ⅱ组，Ⅲ组显著高于Ⅱ组(P＜0.05)；相对于Ⅰ组，其他各组血清中T-SOD活力均显著增高，Ⅱ组效果最好，显著高于IV和V组(P＜0.05)；而对于血清MDA各组之间差异均不显著(P＞0.05)；GSH-Px活力在各组间变异较小，只有Ⅲ组显著高于Ⅴ组(P＜0.05)。【结论】日粮中添加板栗总苞多酚在常温饲养条件良好的情况下对肉鸡生长性能无显著影响，但在高温热应激条件下，添加0.3%的板栗总苞多酚能够显著提高肉鸡抗氧化能力、缓解高温热应激造成的影响。

Effect of Chestnut Involucres Polyphenols on Growth Performance and Antioxidant Properties of AA Broilers

【Objective】Oxidative stress is widespread in livestock production. Lot of factors can induce oxidative stress, among which heat stress is an important factor. Oxidative stress can influence animal growth performance and even cause death, leading to serious economic losses. Recently, plant polyphenols are getting ever growing attention for their biological functions. The aims of this study were to investigate the effects of different doses of polyphenolic extract from involucres of Castanea mollissima Blume (PICB) on broiler growth performance and antioxidant properties. 【Method】 The experiments were divided into two trials: in trial 1, 400 one-day-old male Abor Aerec (AA) broilers were randomly assigned into 5 groups (4 replicates / group, 20 chicks / replicate): Group I was used as normal control group and the broilers were fed with basic ration; broilers in group II were fed with basic ration with a supplementation of 0.15% 2,6-Ditert butyl-4 methyl phenol (BHT) premix (containing 0.015% effective BHT); broilers in group III-V were fed with the basic ration with an addition of 0.2%,0.3% and 0.4% of PICB, respectively. Intrial 1, The trial lasted for 42 days under normal temperature condition. The broilers were reared according to the AA boilers feeding and immunity programs. The body weights and feed intake were measured every week for monitoring broilers growth performance. In trial 2, 400 28-day-old male AA chicks were randomly assigned into groups described in trial 1. After one week’s adaptation under normal temperature condition, heat stress was applied for 7 consecutive days for all groups. On 3rd and 7th day of heat stress, the chicks were slaughtered and sampled. Growth performance, slaughtering parameters and anti-oxidative parameters were measured to evaluate the effects of PICB on broilers under heat stress condition. 【Result】 Trial 1 showed that under normal temperature conditions, the supplementation of PCIB had no significant effects on chick growth performance (P＞0.05). In Trial 2, the body weights of groups Ⅳ and Ⅴ were significantly higher than that of group I under heat stress condition. Compared with groups I, II, and III, group IV had significantly improved average daily gain and average daily feed intake (P＜0.05). Feed conversion ratio of groups IV and V was significantly lower than that of group I (P＜0.05). The mortality among groups tended (P=0.059) to be significant and that of group V was the lowest. The slaughtering parameters had no significant differences among groups. For broilers heat stressed after three days, total antioxidant capacity (T-AOC) in serum was not significantly different among groups even though there were some oscillations. Total superoxide dismutase (T-SOD) of group IV was significantly higher than that of group I (P＜0.05). Serum malondialdehyde (MDA) contents of different groups were significantly different. The similar situation was also for GSH-Px except for group III significantly higher than group V (P＜0.05). 【Conclusion】 Dietary PICB supplementation had no effect on growth performance of AA broilers under normal temperature condition. While under heat stress conditions 0.3% PCIB addition can significantly improve the antioxidant capacity and growth performance of broilers and mitigate the adverse effects of heat stress.