绵羊对不同蛋白水平日粮的消化与吸收

Digestion and Absorption of Diets with Different Protein Levels in Sheep

试验选用3只体重约35kg装有永久性瘤胃、十二指肠、回肠末端T型瘘管的健康成年雄性新疆美利奴绵羊,每期分别喂给蛋白水平为7.0%、10.0%、12.8%和15.5%的日粮,分别收集各个试验期每只羊的十二指肠、回肠食糜,以研究日粮蛋白水平对绵羊营养物质前胃消化和小肠吸收的影响。结果表明,日粮蛋白质水平影响到达小肠的粗蛋白、总氨基酸和微生物蛋白占采食粗蛋白的比率(Y=-8.43X+197.13,r2=0.7545,Y=-5.11X+129.85,r2=0.8039和Y=-8.2951X+157.62,r2=0.8473),还影响前胃纤维素、半纤维素的消化率以及前胃钙的表观吸收率,但对过瘤胃蛋白率和前胃有机物消失率无显著影响。到达小肠的氨基酸组分差异主要为最低蛋白水平日粮与其它三种日粮间在丙氨酸、精氨酸、天冬氨酸、胱氨酸和异亮氨酸上的差异。日粮蛋白水平影响小肠消化吸收的粗蛋白、氨基酸占采食粗蛋白的比例(Y=-8.96X+185.14,r2=0.7496和y=-4.6224x+112.42,r2=0.7537),但不影响小肠有机物的消化吸收率。本试验表明,在估算到达小肠的蛋白质率及氨基酸率、前胃微生物产率、到达小肠的氨基酸组分差异、及小肠消化吸收的粗蛋白、氨基酸占采食粗蛋白的比例时,应把日粮的蛋白质水平作为影响因素之一进行考虑。

Three 35Kg mature male Merino sheep, fitted with rumen cannula and T-type cannula at the proximal duodenum and terminal ileum, were fed diets with different protein levels (7.0%, 10.0%, 12.8% and 15.5%) respectively and the chyme of duodenum and ileum were collected to study the effect of protein levels of diets on forestomach digestion and absorption in small intestine. The results showed that the diet CP levels affected the rates of the CP , total amino acids, as well microbial protein arriving small intestine, against intaken CP (Y=-8.43X+197.13,r2=0.7545, Y=-5.11X+129.85, r2=0.8039 and Y=-8.30X+157.62,r2= 0.8473) respectively. The CP level of diets also affected the digestibility of cellulose and semicellulose and the apparent calcium absorption in fore stomach. However the CP level of diets did not significantly affect the by-pass protein and the disappearance of organic matter from forestomach. The composition difference of amino acids arriving small intestine was in Ala、Asp、Cys and Ile between 7% CP diet and other 3 diets. The CP level of diets affected the rates of the small intestine-absorbed CP and amino acids(Y=-8.96X+185.14,r^2=0.7496 and Y = -4.62X + 112.42,r^2 = 0.7537), but not organic matter, against intaken CP respectively. This study showed that the CP level of diet is an affecting factor when the rates of the protein, amino acids, microbial protein arriving small intestine and the proportion of small intestine absorbed protein and amino acids are estimated.