Tung R S, Kung L
Department of Animal Science and Agricultural Biochemistry, College of Agricultural Sciences, University of Delaware, Newark 19717-1303.
J Dairy Sci. 1993 Apr;76(4):1083-90. doi: 10.3168/jds.S0022-0302(93)77437-8.
Using a purified diet and a mixed culture of ruminal microorganisms, we studied the in vitro effects of a sulfur-containing peptide (A10255) and monensin on ruminal VFA and lactic acid concentrations. After 22 h of fermentation, total VFA concentration was greater in cultures with A10255 and monensin (2.5 ppm each) than in untreated controls (84.1, 91.9, and 65.2 mM for cultures with A10255, monensin, and control, respectively). The molar proportions of propionate were more than 40% greater, and the molar proportions of acetate were about 15% less, in treated than in untreated cultures. The molar proportions of the remaining VFA were lowest in monensin-treated cultures, intermediate in A10255-treated cultures, and greatest in untreated cultures. Addition of A10255 or monensin also prevented the accumulation of lactate and maintained higher pH than in untreated cultures. In pure culture, growth of Streptococcus bovis was slowed by A10255 at pH 5.5 and 6.5. Growth of S. bovis was reduced markedly with addition of monensin at pH 6.5 and inhibited at pH 5.5. Growth of Lactobacillus acidophilus was inhibited more at pH 5.5 than 6.5 with monensin but was unaffected by A10255. The thiopeptide A10255 and monensin inhibited ruminal lactate production, but sensitivities of lactate-producing bacteria differed between compounds.
我们使用纯化日粮和瘤胃微生物混合培养物，研究了一种含硫肽（A10255）和莫能菌素对瘤胃挥发性脂肪酸（VFA）和乳酸浓度的体外影响。发酵22小时后，添加A10255和莫能菌素（各2.5 ppm）的培养物中总VFA浓度高于未处理的对照（添加A10255、莫能菌素和对照的培养物中分别为84.1、91.9和65.2 mM）。处理后的培养物中，丙酸的摩尔比例增加超过40%，乙酸的摩尔比例减少约15%。其余VFA的摩尔比例在莫能菌素处理的培养物中最低，在A10255处理的培养物中居中，在未处理的培养物中最高。添加A10255或莫能菌素还可防止乳酸积累，并维持比未处理培养物更高的pH值。在纯培养中，A10255在pH 5.5和6.5时减缓了牛链球菌的生长。在pH 6.5时添加莫能菌素显著降低了牛链球菌的生长，在pH 5.5时抑制了其生长。莫能菌素在pH 5.5时比在pH 6.5时更能抑制嗜酸乳杆菌的生长，但A10255对其无影响。硫肽A10255和莫能菌素均抑制瘤胃乳酸生成，但两种化合物对产乳酸细菌的敏感性不同。
