试验选用总共132头猪（初重= 7.23kg）在21日龄断奶并喂食了7天无抗生素饲料，根据体重分成33圈，每圈4头猪（去势公猪或小母猪）。每种日粮饲喂11个圈。 日粮为玉米豆粕型基础日粮、复合酶制剂A组（每公斤日粮提供木聚糖酶4000U，β-葡聚糖酶3500U，淀粉酶A 1500U）和复合酶制剂B组（淀粉酶B 150U，其它酶制剂同A组）。所有日粮中添加植酸酶1000 U/kg。
复合酶B组显著提高了阶段一和阶段二的日增重（P＜0.05）。全期来看，复合酶B将日增重从262提高到313g，平均采食量从419提高到504g（P＜0.05）。复合酶A组将日增重提高至290g（P＜0.05），但是对采食量没有显著影响。复合酶制剂A和B对总能全肠道表观消化率无影响，但是将粗脂肪消化率从30%提高至36%、37%。复合酶制剂A不影响粪便评分，但是复合酶制剂B有降低粪便评分的趋势（P=0.09），说明其有降低腹泻的趋势。硬壁菌门是粪便中细菌最丰富的门（其相对丰度为58％至72％）。 拟杆菌和放线菌是粪便细菌的第二大和第三大门。 两种复合酶均不影响粪便细菌组成。
Growth performance, nutrient digestibility, and fecal microbial composition of weaned pigs fed multi-enzyme supplemented diets
A study determined the effects of supplementing corn-based diets for weaned pigs with multi-enzymes on growth performance, apparent total tract digestibility (ATTD) of nutrients, fecal score, and fecal microbial composition. A total of 132 pigs (initial body weight = 7.23 kg) that had been weaned at 21 d of age and fed a drug-free nursery diet for 7 d were housed in 33 pens of 4 barrows or gilts, blocked by body weight and gender, and fed 3 experimental diets at 11 pens per diet. The diets were corn-based diet without or with multi-enzyme A or B. Multi-enzyme A supplied 4,000 U of xylanase, 150 U of β-glucanase, 3,500 U of protease, and 1,500 U of amylase per kilogram of diet. Multi-enzyme B was the same as multi-enzyme A except that it supplied amylase at 150 U/kg, and that its source of amylase was different from that of multi-enzyme A. All diets contained phytase at 1,000 U/kg. The diets were fed for 35 d in 2 phases; phase 1 for the first 14 d and phase 2 for the last 21 d of the trial. Fecal score was determined daily during the first 7 d of the trial. Fecal samples were collected from rectum of 1 pig per pen on days 2, 7, 14, and 35 of the trial for determining bacterial composition. Also, fresh fecal samples were collected from each pen on days 41 and 42 to determine ATTD of nutrients. Multi-enzyme B increased (P < 0.05) average daily gain (ADG) for phases 1 and 2. For the overall study period, multi-enzyme B increased (P < 0.05) ADG from 262 to 313 g, and average daily feed intake (ADFI) from 419 to 504 g. Multi-enzyme A increased (P < 0.05) overall ADG from 262 to 290 g, but did not affect ADFI. Multi-enzyme A or B did not affect ATTD of gross energy, but increased (P < 0.05) the ATTD of ether extract from 30% to 36% or 37%, respectively. Multi-enzyme A did not affect fecal score; however, multi-enzyme B tended to decrease (P = 0.09) fecal score, implying that it tended to decrease diarrhea. Firmicutes were the most abundant phylum of fecal bacteria (its relative abundance ranged from 58% to 72%). Bacteroidetes and Actinobacteria were the 2nd and 3rd most abundant phyla of fecal bacteria. Neither multi-enzyme affected fecal bacterial composition. In conclusion, the addition of multi-enzyme A or B to phytase-supplemented corn-based diet for weaned pigs can improve their growth performance and fat digestibility. However, multi-enzyme B was more effective than multi-enzyme A in terms of improving the growth performance of weaned pigs fed corn-based diet.