ABSTRACT

1. The aim of this study was to evaluate the effect of graded levels of the microbially derived feed lysozyme, muramidase (MUR) on feed intake (FI), weight gain (WG), feed conversion ratio (FCR), European Performance Index (EPI), dietary N-corrected apparent metabolisable energy (AMEn), footpad dermatitis score (FPD) and other welfare variables, when fed to broilers from 0 to 42d age.

2. A four-phase dietary programme and four experimental pelleted diets were used; a control diet (following breeder recommendations without MUR supplementation), and three diets based on the control diet supplemented with 25,000, 35,000 and 45,000 LSU (F)/kg of MUR, respectively. In addition, all experimental diets contained exogenous xylanase, phytase and a coccidiostat. Each diet was fed to birds in 24 pens (20 male Ross 308 chicks in each pen) following randomisation. Dietary AMEn was determined at 21 d of age, and FPD was evaluated at the end of the study. Data were analysed by ANOVA, using orthogonal polynomials for assessing linear and quadratic responses to MUR activity.

3. The inclusion of MUR did not change FI (P > 0.05), but increased WG in a linear manner (P < 0.05) and reduced FCR in a quadratic manner, with optimum WG and FCR observed in birds fed approximately 35 000 LSU (F)/kg. In accordance with the improvement in FCR, 35 000 LSU (F)/kg MUR supplementation produced the highest EPI (P < 0.05). FPD score was linearly decreased with increased addition of MUR (P < 0.05). Dietary AMEn responded in a quadratic fashion to the MUR inclusion, as the highest values were obtained with the highest inclusion rate (P < 0.05).

4. In conclusion, the results showed that inclusion of MUR improved feed efficiency and the foot health of birds.

摘要

1. 本研究的目的是评估微生物来源的饲料溶菌酶、胞壁质酶 (MUR) 的分级水平对采食量 (FI)、增重 (WG)、饲料转化率 (FCR)、欧洲性能指数 ( EPI)、日粮 N 校正表观代谢能 (AMEn)、足垫皮炎评分 (FPD) 和其他福利变量，当饲喂 0 至 42 日龄的肉鸡时。

2. 使用四阶段膳食计划和四种实验性颗粒饲料；一种对照日粮（按照饲养员的建议，不添加 MUR），以及三种基于对照日粮的日粮，分别补充 25,000、35,000 和 45,000 LSU (F)/kg MUR。此外，所有实验日粮都含有外源木聚糖酶、植酸酶和抗球虫剂。随机分组后，将每种饮食喂给 24 个围栏中的鸟类（每个围栏中有 20 只雄性罗斯 308 只小鸡）。在 21 日龄时测定膳食 AMEn，并在研究结束时评估 FPD。通过方差分析分析数据，使用正交多项式评估对 MUR 活动的线性和二次响应。

3. 加入 MUR 并没有改变 FI（P > 0.05），但以线性方式增加 WG（P < 0.05）并以​​二次方式降低 FCR，在喂食约 35 000 LSU 的鸡群中观察到最佳 WG 和 FCR（ F)/公斤。根据 FCR 的改善，补充 35 000 LSU (F)/kg MUR 产生最高的 EPI (P < 0.05)。FPD 评分随着 MUR 的增加而线性下降（P < 0.05）。膳食 AMen 对 MUR 的包含以二次方的方式响应，因为最高值与最高的包含率 (P < 0.05)。

4. 总之，结果表明添加 MUR 可以提高饲料效率和鸡的足部健康。