用粪液法与尼龙袋法测定牧草有机物和蛋白质降解率的比较研究

Comparative study on nylon bag technique and feacal fluid method for determining organic matter and protein digestion

瘤胃尼龙袋法已广泛应用于测定饲料蛋白质和有机物的降解率,但用这种方法饲养瘘管动物费用较高。为寻求能在一般实验室条件下即可完成的体外评定饲料消化率的方法,国内外进行了大量的研究。为探索一种简单、实用、准确和低成本的体外测定牧草消化率的方法,分别用尼龙袋法和粪液法测定了黑龙江省主要栽培的29种牧草在瘤胃液中和粪液中培养48 h后有机物和蛋白质的降解率。实验统计分析了用粪液法与尼龙袋法测定牧草有机物和蛋白质降解率之间的相关关系。结果表明,两种消化实验方法对牧草有机物、粗蛋白降解率的测定结果呈极显著相关关系(P<0.01),粪液法测定值(X)对尼龙袋法测定值(Y)的回归方程分别为Y=0.97X+5.57,R2=0.82,RSD=4.46(有机物)和Y=0.90X+7.43,R2=0.94,RSD=2.18(蛋白质)。按降解率大小排序,两种方法对29种牧草排列的顺序也基本相同。粪液法测定的29种牧草样本有机物、粗蛋白降解率的平均值和尼龙袋法测定的平均值相比较分别低10.3%和4.84%,但差异不显著(P>0.05)。粪液法是在1963年Tilley和Terry提出的两步离体消化法的基础上发展起来的,和经典的尼龙袋法相比,该方法最大的优点是避免使用瘘管动物,可在一般实验室条件下操作完成。结果证明,粪液法具有准确、简单、实用和费用低等特点,是在养殖现场或放牧条件下批量测定干草或其他粗饲料体外消化率最有前途的方法。

It is well known tlaat dry matter digestibility is one of the most useful measures of the nutritional value of a feedstuff. Nylon bag digestion technique has been long used but met many limitations. A more serious practical disadvantage is the need for fitulated animals to provide the rumen fluid. Instead, a new procedure using fecal liquor as an inoculum was developed and proved successful with a range of feedstuffs. This method has a valuable feature, that is no need for fistulated ruminants and suitable for batch operation under normal commercial conditions. However, some questions remain as to potential use of faeces as an inoculum. The objective of the study was to search for a in vitro technique for determination of forage digestibility with precision, suitability and low-cost. The 29 varieties of legume and grass forage crop were planted in early May in 2003 at the experimental field of Heilongjiang Agriculture Academy under the same soil and environmental conditions. Relationship between nylon bag method and fecal liquor method for determination of DM or CP degradability of forages was investigated. The results indicated that there was a very significant correlation between estimates of fecal liquor method and values of nylon bag method（P 〈0.01 ）, estimates of fecal liquor method （X） and values of nylon bag method （Y） had following regression equation, namely, Y=0.97X＋5.57, R^2=0.82,RSD=4.46 （for organic matter）, Y=0.90X＋7.43, R^2=0.94, RSD=2.18（for protein）. There was a consistent ranking sequence in the two methods based on degradability. However, OM and CP degradability determined by using fecal fluid were 10.3% and 4.84% lower than values determined by using nylon bag technique, respectively （P 〉0.05）. On the basis of these results, it was concluded that the faeces liquor method would seem to have a distinct advantage in use. It is also suggested the method for determining OM and CP degradability using fecal liquor was appropriate for batch operation. However, more research with a wide range of feedstuff is required to confirm feasibility of the new method.