本试验旨在研究发酵前包被微囊化乳酸乳球菌的生物学特性及其对肉仔鸡生长性能的影响.试验首先从健康爱拔益加(AA)肉仔鸡的小肠中分离菌株,经病原茵抑制能力、生长性能、产酸能力及逆性环境耐受力等益生特性筛选得到益生茵,同时进行16S rRNA基因和Biolog自动微生物分析系统鉴定;然后选用1日龄健康AA肉仔鸡180只,分为3组(对照组;微囊化茵包被组:微胶囊组;菌液-不包被组:茵液组),每组6个重复,每个重复10只鸡,分别饲喂同一基础配方的添加不同形式或不添加益生茵的3种饲粮.试验期42 d.结果表明,经筛选得到菌株GJ0007,鉴定为乳酸乳球茵;其生长速度快(代时＜30 main)、延滞期短、产L-乳酸能力(5.6g/L)强、抑制病原菌(大肠杆菌K88和K99、金黄色葡萄球茵、沙门氏茵、巴氏杆菌)生长、逆性环境(模拟胃液、肠液、H2O2)耐受力强等.饲养全期(1～42 d),与对照组和茵液组相比,微胶囊组肉仔鸡平均日增重分别提高了16.94%(P＜0.05)和11.25%(P＜0.05);料重比分别降低了16.13%(P＜0.05)和6.19%(P＞0.05).42日龄时微胶囊组与对照组和菌液组相比较,肉仔鸡的胸腺相对重量分别提高了46.56%(P＜0.05)和18.38%(P＜0.05),法氏囊相对重量分别提高了16.67%(P＜0.05)和5.66%(P＞0.05).由此可知,乳酸乳球菌GJ0007经微囊化包被后饲喂肉仔鸡,可改善肉仔鸡的平均日增重、料重比和胸腺与法氏囊的相对重量.%This experiment was conducted to study the biological characteristics and effects of pre-fermentation microcapsulated Lactococcus lactiss on growth performance of broilers. The Lactococcus lactiss strain was selected by the growth performance, lactic acid yield, inhibition of pathogen and resistance to adversity, and identified by Biolog automatic micro-analysis system and 16S rRNA gene. Then, a total of 180 one-day-old AA broilers were randomly assigned to three groups (the control group, broth group, microcapsules group) with 6 replicates per group and 10 broilers per replicate. The experiment lasted for 42 d. The results showed as follows: by Biolog automatic micro-analysis system and 16S rRNA gene comparing with GenBank, the strain GJ0007 was primarily identified as Lactococcus lactis ss lactis. Other experiments on biological characteristics showed that GJ0007 has fast growth (time per generation ＜30 rnin), short lag phase, high L-lactic yield (5. 6 g/L), and high tolerance of reverse environment ( including H202, artificial gastric juice and intestinal juice), and it can inhibit pathogenic bacteria (E. coli K88 and K99, Staphylococcus aures, Salmonnella pullorum, and Pasteurella sp. ), etc.During the whole feeding period ( 1 to 42 d), comparing with the control group and broth group, average daily gain (ADG) of broilers fed with microcapsulated GJ0007 was increased by 16. 94％ (P ＜0. 05) and 1125％( P ＜0. 05), while the ratio of feed to gain (F/G) was decreased by 16. 13％ ( P ＜ 0. 05 ) and 6. 19％ ( P ＞0. 05) , and the relative weight of thymus and bursa of Fabricius of 42-day-old broilers was increased by 46. 56％ (P ＜ 0. 05, thymus), 18. 38％ ( P ＜ 0. 05, thymus), 16. 67％ ( P ＜ 0. 05, bursa of Fabricius) and 5. 66％ (P ＞0. 05, bursa of Fabricius). These results indicate that microcapsulated Lactococcus lactis can increase ADG and decrease F/G, and increase the relative weight of thymus and bursa of Fabricius of broilers.[ Chinese Journal of Animal Nutrition ,2011,23(4) :631-639]
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