Sindt J J, Drouillard J S, Thippareddi H, Phebus R K, Coetzer C M, Kerr K D, Lambert D L, Farran T B, Montgomery S P, LaBrune H J
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-1600, USA.
J Anim Sci. 2004 Apr;82(4):1170-6. doi: 10.2527/2004.8241170x.
Six ruminally cannulated Angus-cross steers (362 kg) were used in a replicated 3 x 3 Latin square design to determine effects of supplementing Maillard reaction products (MRP) on acid-resistant E. coli and coliform populations. Steers were fed roughage-based diets supplemented (DM basis) with either 10% soybean meal (SBM), 10% nonenzymatically browned SBM (NESBM), or 10% SBM top-dressed with 45 g of a lysine-dextrose Maillard reaction product (LD-MRP). Equal weights of dextrose, lysine hydrochloride, and deionized water were refluxed to produce the LD-MRP. The NESBM was manufactured by treating SBM with invertase enzyme, followed by heating to induce nonenzymatic browning. Steers were allowed slightly less than ad libitum access to diets fed twice daily and were adapted to their respective treatments within 10 d. On d 11, ruminal and fecal samples were collected at 0, 2, 4, 6, 8, and 12 h after feeding from each of the steers and transported to the laboratory for microbial analysis. Ruminal samples and feces were analyzed for pH and VFA, and both ruminal fluid and feces were tested for acid-resistant E. coli and total coliforms by incubating samples in tryptic soy broth adjusted to pH 2, 4, and 7. Ruminal pH and total VFA concentrations did not differ among treatments. The molar proportion of ruminal acetate was higher (P < 0.05) for steers receiving NESBM than for steers receiving SBM and LD-MRP. At pH 4, steers that received NESBM had lower (P < 0.05) ruminal populations of E. coli and total coliforms than steers that received SBM. No differences were observed for ruminal E. coli and total coliforms at pH 2 and 7. Fecal pH was lower (P < 0.05) for steers fed NESBM than for steers fed SBM or LD-MRP. Molar proportions of fecal acetate were lower (P < 0.05) and proportions of butyrate and isovalerate were higher (P < 0.05) for steers fed NESBM compared with steers fed SBM. Fecal E. coli at pH 4 was lower (P < 0.05) for steers fed NESBM than for steers fed LD-MRP. Fecal E. coli and total coliforms at pH 2 and 7 did not differ among treatments. Dietary MRP had limited effectiveness at decreasing acid-resistant coliforms in the rumen and feces of cattle. Acid resistance in coliforms may depend on protein availability.
选用6头装有瘤胃瘘管的安格斯杂交阉牛（体重362千克），采用重复3×3拉丁方设计，以确定补充美拉德反应产物（MRP）对耐酸大肠杆菌和大肠菌群数量的影响。给阉牛饲喂以粗饲料为基础的日粮，按干物质计，分别添加10%豆粕（SBM）、10%非酶褐化豆粕（NESBM）或10%豆粕并额外添加45克赖氨酸 - 葡萄糖美拉德反应产物（LD - MRP）。将等量的葡萄糖、盐酸赖氨酸和去离子水回流以制备LD - MRP。NESBM是通过用转化酶处理豆粕，然后加热诱导非酶褐化来制备的。让阉牛每天采食略低于随意采食量的日粮，每天饲喂两次，并在10天内适应各自的处理。在第11天，在饲喂后0、2、4、6、8和12小时从每头阉牛采集瘤胃和粪便样本，并运至实验室进行微生物分析。分析瘤胃样本和粪便的pH值和挥发性脂肪酸（VFA），并通过将样本在调整至pH 2、4和7的胰蛋白胨大豆肉汤中培养，检测瘤胃液和粪便中的耐酸大肠杆菌和总大肠菌群。各处理间瘤胃pH值和总VFA浓度无差异。采食NESBM的阉牛瘤胃乙酸摩尔比例高于采食SBM和LD - MRP的阉牛（P < 0.05）。在pH 4时，采食NESBM的阉牛瘤胃大肠杆菌和总大肠菌群数量低于采食SBM的阉牛（P < 0.05）。在pH 2和7时，瘤胃大肠杆菌和总大肠菌群数量无差异。采食NESBM的阉牛粪便pH值低于采食SBM或LD - MRP 的阉牛（P < 0.05）。与采食SBM的阉牛相比，采食NESBM的阉牛粪便乙酸摩尔比例较低（P < 0.05），丁酸和异戊酸比例较高（P < 0.05）。在pH 4时，采食NESBM的阉牛粪便大肠杆菌数量低于采食LD - MRP的阉牛（P < 0.05）。在pH 2和7时，各处理间粪便大肠杆菌和总大肠菌群数量无差异。日粮MRP在降低牛瘤胃和粪便中耐酸大肠菌群数量方面效果有限。大肠菌群的耐酸性可能取决于蛋白质的可利用性。
