真空冷冻干燥法制备微生态制剂及其对肉牛养分表观消化率的影响

Preparing probiotics by vacuum freeze-drying method and its effect on nutrient apparent digestibility of beef cattle

试验旨在研究真空冷冻干燥法制备微生态制剂及其对肉牛养分表观消化率影响。方法1微生态制剂的制备试验:选取地衣芽孢杆菌(Bacillus licheniformis,BL)、枯草芽孢杆菌(Bacillus subtilis,BS)和植物乳酸杆菌(Lactobacillus plantarum,LP)为本验主要菌种,经过菌种活化、传代、扩繁和二级菌液浓缩、与保护剂混合等预处理后,采取真空冷冻干燥法制成冻干菌粉,将计数后的BS、BL和LP菌粉按2.2.1比例混合,制成供试验用的微生态制剂。结果显示:真空冷冻干燥法制备微生态制剂的活菌量≥1.35×10^(10)CFU/g;方法2表观消化率测定试验:随机选取健康、月龄和体重[(284±19.33)kg]相近的本地牛和伊犁褐牛杂交代公肉牛20头,随机分为对照组和试验组(每组10头),对照组(CG)饲喂全混合日粮(TMR)和试验组(TG)饲喂TMR+微生态制剂。微生态制剂在晨饲时先与少量的TMR均匀混合后单槽饲喂,每天一次,一次性喂完后,再饲喂不加微生态制剂的TMR,保证每头牛食入益生菌总数为5×1010CFU/(头·d),预试期7 d,正试期30 d。在正试期内最后5 d,采集饲粮样和粪样,用酸不溶灰分(AIA)作为内源指示剂进行肉牛养分表观消化率的测定。结果表明:饲粮中添加活菌量为5×10^(10)CFU/(头·d)的微生态制剂,可以显著提高肉牛DM表观消化率(P<0.05)和改善CP、EE、NDF和ADF的消化能力。

This experiment was conducted to study preparing probiotics by vacuum freeze-drying and the effect of probiotics on the nutrient apparent digestibility of beef cattle. Method 1： Preparation test of probiotics： Bacillus licbeniformis （BL）, Bacillus subtilis （BS） and Lactobacillts plantarum （LP） were selected as the main strains of this experiment. After strain activation, passage, propagation and secondary bacterial solution＇s concentration, and protective agent mixing etc., freeze-dried powder was made by vacuum freeze-drying method. The counted BS, BL and LP powder with 2 ： 2 ： 1 ratio of mixing, which was made of the probiotics used in this test. The results showed that the viable count of probiotics prepared by vacuum freeze-drying was ≥1.35×10^10 CFU/g. Method 2： Test of apparent digestibility： the experiment was designed using single factor complete randomized trial.Twenty healthy male beef cattle of Native and Yili brown with a similar age of months and body weight [（284±19.33） kg], were randomly divided into two groups （10 in each group）. Control group（CG） were fed with Total Mixed Ration（TMR） and test group（TG） were fed with TMR ＋ probiotics respectively. Once a day, one-time feeding was fed to ensure that the total number of probiotics into each cow was 5×10^10 CFU/（head·d）. The adaption period lasted for 7 days and the formal trial period lasted for 30 days. In the last 5 days of the trial period, feed and fecal samples were collected, and the apparent digestibility of beef cattle was determined by using acid-insoluble ash（AIA） as the endogenous indicator. The results showed that adding probiotics with 5×10^10 CFU/（head· d） could significantly improve DM apparent digestibility （P〈0.05） and improve the digestibility of CP, EE, NDF and ADF ability.