添加不同种类二糖对奶牛体外瘤胃发酵与微生物蛋白合成的影响

Effects of different disaccharide additions on rumen fermentation and microbial synthesis in vitro

本试验旨在研究不同种类二糖对苜蓿瘤胃发酵与微生物蛋白合成的影响。试验选用3头健康的,装有永久性瘤胃瘘管的中国荷斯坦奶牛作为瘤胃液供体动物（600 kg左右）,利用体外批次培养方法,以苜蓿和玉米为饲料源做体外发酵基质,然后添加蔗糖、乳糖以及异麦芽糖（添加水平分别为0%、0. 5%、1. 5%、3. 0%）。结果表明：随着三种二糖添加水平的提高,瘤胃体外潜在产气量显著增加（P〈0. 05）、慢速降解部分极显著增加（P〈0. 01）;瘤胃总挥发性脂肪酸浓度、乙酸/丙酸值极显著增加（P〈0. 01）、氨态氮浓度极显著降低（P〈0. 01）;乳酸有降低的趋势;瘤胃微生物蛋白极显著增加（P〈0. 01）,微生物蛋白合成效率极显著提高（P〈0. 01）。二糖种类与添加水平对潜在产气量、慢速降解部分、总挥发酸浓度、氨态氮浓度存在显著互作影响（P〈0. 05）,对瘤胃微生物蛋白合成、乳酸浓度不存在显著互作影响（P〉0. 05）。综上,添加乳糖对瘤胃发酵功能的微生物蛋白质合成影响最显著。

The purpose of this experiment was to investigate the effects of disaccharide from different sources on ruminal fermentation and microbial protein synthesis in vitro. Three healthy China Holstein dairy cows having a body weight of about 600 kg and equipped with the per- manent fistula were used as rumen fluid donors. A batch culture method in vitro was used, alfalfa and corn were used as feed source for fer- mentation matrix in vitro, and then three disaccharides, sucrose, lactose and maltose, were added at 0%, 0. 5%, 1.5%, 3.0%, respective- ly. The results showed that as the addition levels of the three disaccharides increased, the amount of potential gas production （P〈0. 05） and the slowly degraded fraction （P〈0. 01 ） were both significantly increased, the content of rumen total volatile fatty acids and acetic acid/pro- pionic acid were significantly increased （P〈0. 01 ）, the content of ammonia nitrogen was very significantly reduced （ P〈O. 01 ）, the lactate showed a decreasing trend, and the amount of microbial protein in the rnmen and the synthesis rate of microbial protein were increased signif- icantly （P〈0. 01 ）. To sum up, the different kinds and addition levels of disaccharides had significant interactive influences on the amount of potential gas production, the slowly degraded fraction, the content of rumen total volatile fatty acids and the content of ammonia nitrogen （ P〈 0. 05）, but not on the synthesis of rumen microbial protein and the content of lactate.