McAllister T A, Phillippe R C, Rode L M, Cheng K J
Research Station, Agriculture Canada, Lethbridge, Alberta.
J Anim Sci. 1993 Jan;71(1):205-12. doi: 10.2527/1993.711205x.
Experiments were conducted to investigate the role of the protein matrix in the digestion of barley and corn by ruminal microorganisms. Grains, ground and collected on sieves as two particle fractions .25 to .89 mm (small particles) and 2.00 to 3.00 mm (large particles), as well as isolated barley and corn starch granules, were incubated with ruminal inocula. For both grains, digestion of starch in small particles was greater (P < .001) than that of large particles. At 16 and 24 h starch digestion was greater (P < .01) in barley than in corn, for small and large particles. Digestion of barley starch granules did not differ (P > .05) from that of corn starch granules at any incubation time. A 4-h preincubation of small-particle corn and barley with protease increased (P < .001) microbial digestion of starch in corn at 16 h but did not affect digestion of barley. When four ruminally cannulated steers were fed diets containing 80% barley, corn, or wheat or 100% alfalfa hay in a 4 x 4 Latin square experiment, amylolytic activity of ruminal inoculum was higher for steers fed grains than for those fed alfalfa. However, when standardized for total viable counts of bacteria, ruminal amylolytic activity did not differ (P > .05) among diet treatments, but proteolytic activity of ruminal inoculum for steers fed alfalfa was higher (P < .01) than that for steers fed cereal grains. Activity of serine proteases in ruminal inoculum was higher (P < .05) for steers fed alfalfa than for steers fed grains.(ABSTRACT TRUNCATED AT 250 WORDS)
开展了实验以研究蛋白质基质在瘤胃微生物对大麦和玉米消化过程中的作用。谷物经研磨后通过筛网收集为两个颗粒级分，即0.25至0.89毫米（小颗粒）和2.00至3.00毫米（大颗粒），以及分离出的大麦和玉米淀粉颗粒，与瘤胃液接种物一起培养。对于两种谷物，小颗粒淀粉的消化率均高于大颗粒（P < 0.001）。在16小时和24小时时，无论大小颗粒，大麦淀粉的消化率均高于玉米（P < 0.01）。在任何培养时间，大麦淀粉颗粒的消化率与玉米淀粉颗粒均无差异（P > 0.05）。小颗粒玉米和大麦与蛋白酶进行4小时预培养后，16小时时玉米淀粉的微生物消化率增加（P < 0.001），但对大麦消化率无影响。在一项4×4拉丁方实验中，给4头安装了瘤胃瘘管的阉牛饲喂含80%大麦、玉米或小麦或100%苜蓿干草的日粮，饲喂谷物的阉牛瘤胃液接种物的淀粉酶活性高于饲喂苜蓿的阉牛。然而，以细菌总活菌数进行标准化后，日粮处理间瘤胃淀粉酶活性无差异（P > 0.05），但饲喂苜蓿的阉牛瘤胃液接种物的蛋白水解活性高于饲喂谷物的阉牛（P < 0.01）。饲喂苜蓿的阉牛瘤胃液接种物中丝氨酸蛋白酶的活性高于饲喂谷物的阉牛（P < 0.05）。（摘要截短于250词）
