Establishment of New Evaluation System for Feed Nutritive Value

为了评价瘤胃、小肠和大肠均有消化的反刍动物的饲料营养价值，本试验采用瘤胃、十二指肠和回肠分别装瘘管的阉牛，分别饲喂不同副产物饲粮，并以大麦饲粮为对照。在实验1中，分别饲喂生米糠、加热米糠和脱脂米糠；(1)脱脂米糠提高了瘤胃液的原位降解率，降低了丙酸盐；(2)与生米糠相比，加热米糠不影响微生物合成和营养物质的消化，两种全脂米糠均抑制了瘤胃纤维的消化，小肠脂肪消化率较低；(3)所有饲粮对非结构非淀粉多糖的瘤胃消化率均小于30%。2.试验2，饲喂甜菜果肉、柑橘果肉和大豆皮时；(1)大豆壳的原位降解率低于其他品种；(2)副产物饲粮的瘤胃乙酸浓度高于对照；(3)甜菜浆和柑橘浆饲粮的微生物蛋白质合成高于对照；(4)非结构性非淀粉多糖的瘤胃消化率低于淀粉，但随副产物的不同而不同。3.试验3，饲喂不同比例的热米糠和甜菜浆高副产物饲粮时；(1)饲粮中添加高比例米糠导致瘤胃丙酸浓度升高，降低了瘤胃纤维消化率、微生物合成和DE摄入量；(2)米糠含量对脂肪和非结构性碳水化合物的消化率没有影响。4.三个试验结果表明，原位DM降解率与瘤胃消化率和微生物合成呈显著的线性关系，表明原位DM降解率可以作为一种新的饲料评价方法。

In order to evaluate feed nutritive value for ruminants with digestion in the rumen, small intestine and large intestine, steers fitted with ruminal, duodenal and ileal cannulas were used and fed various by-product diets in comparison with barley diet as a control in three experiments.1.In the experiment 1, when raw-, heated- and defatted-rice bran, or wheat bran was fed ; (1) defatted rice bran increased in situ degradability and decreased prorionate of ruminal fluids, (2) heated rice bran compared with raw rice bran did not affect microbial synthesis and nutrients digestion, and the both full-fat rice brans suppressed the ruminal fiber digestion, and showed a low fat digestibility in the small intestine, (3) the ruminal digestibility of nonstructural nonstarch polysaccharides was less than 30% for the all diets. 2.In the experiment 2, when beet pulp, citrus pulp and soybean hulls were fed ; (1) the in situ degradability for soybean hulls was less than that for the others, (2) the ruminal concentration of acetate was higher for the by-product diets than for the control, (3) the microbial protein synthesis was greater for the beet pulp and the citrus pulp diets, (4) the ruminal digestibility of nostructural nonstarch polysaccharides was less than that of starch, but varied with by-products. 3.In the experiment 3, when high by-product diets with different proportions of heated-rice bran and beet pulp were fed ; (1) a high proportion of the rice bran in the diet resulted in an increase of the ruminal propionate concentration and decreased ruminal fiber digestibility, the microbial synthesis and DE intake, (2) the rice bran content did not affect the digestibilities of fat and nonstructural catbohydrate. 4.Through the three experiments, in situ DM degradability had significant linear relationships with the ruminal digestibility and the microbial synthesis, and this indicates that in situ degradability is an useful variable as a new evaluation method of feed.