肉牛日粮精料进食水平对淀粉的瘤胃发酵和小肠表观消化率的影响

Effects of Dietary Concentrate Intake on Ruminal Fermentation and Intestinal Digestion of Starch in Steers

为了研究日粮精料进食水平对肉牛真胃食糜淀粉流量及其表观消化率的影响,试验选择体重650kg左右荷斯坦(Holstein)公牛3头,安装有瘤胃、真胃瘘管,按3×3拉丁方试验设计分别饲喂粗料进食量相同而精料进食量不同的3种日粮,以三氧化二铬(Cr2O3)作真胃食糜标记物,全收粪法收集粪样,测定真胃食糜和粪中的淀粉流量及在瘤胃内、真胃后段消化道(简称肠道)内的表观消化率。结果表明:日粮精料进食水平对瘤胃及全消化道的淀粉表观消化率没有显著影响(P>0.05),日粮精料水平明显影响到达真胃的淀粉量(P<0.05)。

The objective of this experiment was to examine the effects of increasing the amount of grain-based concentrate （4, 5, or 6 kg/d） on ruminal fermentation, passage of starch to the small intestine, and starch digestibility. For this purpose, three Holstein steers fistulated in the rumen and abomasum were used in a 3×3 Latin square design. Steers fed hay and concentrate were adapted to diets for 15 d followed by a 7-d collection period. Digestibilities in the rumen and total tract of starch were unaffected by increasing concentrate from 4 kg/d to 6 kg/d（P 〉 0.05）. They were 80.1% and 97.5%, respectively. Increasing concentrate increased the ruminal outflow of starch （P 〈 0.05）. Results of this study suggested that increasing the concentrate consumed by the steers increased the starch of apparently digested in the small intestine.