AB Vista, Marlborough Wiltshire United Kingdom.
Harper Adams University, Shropshire, United Kingdom.
Poult Sci. 2018 Jun 1;97(6):2123-2138. doi: 10.3382/ps/pey080.
Three experiments were conducted to evaluate eight neutral and six acid proteases on growth performance and apparent ileal amino acid digestibility (AID) of poults (Experiment 1) or chicks (Experiments 2 and 3). Two basal diets were formulated: a nutrient adequate positive control (PC), which met or exceeded the nutrient requirements for poults (Experiment 1) or chicks (Experiments 2 and 3) and a negative control (NC) formulated to achieve 85% (Experiments 1 and 2) or 80% (Experiments 3) of the requirement for protein and amino acids. Phytase was included in all diets to provide 500 phytase units (FTU)/kg and xylanase was included in all diets to provide 10,000 (Experiments 1 and 2) or 16,000 (Experiments 3) xylanase units (BXU)/kg. Proteases were supplemented in the NC diet at an equivalent amount of enzyme protein to create 16 experimental diets. There were five birds/pen and 10 replicate pens per treatment in each experiment. In experiment 1, birds fed the PC diet gained more (P < 0.05) than birds fed the NC. There were no differences in growth performance in birds fed the PC or NC in experiments 2 or 3. In all three experiments, birds fed the NC supplemented with neutral protease 1 had reduced (P < 0.05) feed intake (FI) or body weight gain (BWG) and increased (P < 0.05) feed conversion ratio (FCR) compared with birds fed the NC. Birds fed the NC diet supplemented with neutral protease 3, 7 (Experiment 1), or acid protease 4 (Experiment 3) had increased (P < 0.05) FCR and birds fed neutral protease 6 (Experiment 2) had reduced (P < 0.05) BWG compared with birds fed the NC. Apparent ileal amino acid digestibility was improved (P < 0.05) with protease supplementation to the NC diets (Experiment 1 or 3), but this was dependent on the protease and the amino acid. In conclusion, novel protease supplementation improved AID of amino acids but this was not reflected in improvements in growth performance of poults or chicks.
进行了三项实验，以评估八种中性和六种酸性蛋白酶对雏鸡（实验 1）或小鸡（实验 2 和 3）的生长性能和表观回肠氨基酸消化率（AID）的影响。配制了两种基础日粮：一种是营养充足的阳性对照（PC），其满足或超过了雏鸡（实验 1）或小鸡（实验 2 和 3）的营养需求，另一种是负对照（NC），其配制目的是达到蛋白质和氨基酸需求的 85%（实验 1 和 2）或 80%（实验 3）。所有日粮都添加植酸酶以提供 500 植酸酶单位（FTU）/kg，所有日粮都添加木聚糖酶以提供 10,000（实验 1 和 2）或 16,000（实验 3）木聚糖酶单位（BXU）/kg。蛋白酶以与酶蛋白等量的量添加到 NC 日粮中，共创建了 16 种实验日粮。每个实验每个处理有 5 只鸡/笼，有 10 个重复笼。在实验 1 中，饲喂 PC 日粮的鸡比饲喂 NC 日粮的鸡生长更好（P<0.05）。在实验 2 或 3 中，饲喂 PC 或 NC 的鸡在生长性能方面没有差异。在所有三个实验中，与饲喂 NC 的鸡相比，饲喂 NC 并补充中性蛋白酶 1 的鸡的采食量（FI）或体重增加（BWG）减少（P<0.05），饲料转化率（FCR）增加（P<0.05）。与饲喂 NC 的鸡相比，饲喂 NC 日粮并补充中性蛋白酶 3、7（实验 1）或酸性蛋白酶 4（实验 3）的鸡的 FCR 增加（P<0.05），而饲喂中性蛋白酶 6（实验 2）的鸡的 BWG 减少（P<0.05）。蛋白酶补充到 NC 日粮中提高了（P<0.05）氨基酸的表观回肠消化率（实验 1 或 3），但这取决于蛋白酶和氨基酸。总之，新型蛋白酶补充剂提高了氨基酸的 AID，但这并没有反映在雏鸡或小鸡的生长性能的改善上。
