过瘤胃脂肪对体外瘤胃发酵的影响

Effect of Rumen Protected Fat on Rumen Fermentation in Vitro

本试验采用3×4两因素设计,在饲粮中分别设置低、中、高三个蛋白质水平和0、3%、6%和9%的过瘤胃脂肪含量,共形成12组饲粮。蛋白质水平/过瘤胃脂肪分别为:低/0(1组)、低/3%(2组)、低/6%(3组)、低/9%(4组)、中/0(5组)、中/3%(6组)、中/6%(7组)、中/9%(8组)、高/0(9组)、高/3%(10组)、高/6%(11组)、高/9%(12组)。通过双外流连续培养系统,模拟人工瘤胃,对12组饲粮进行消化降解,测定过瘤胃脂肪对体外瘤胃发酵的影响。试验结果如下:不同蛋白质和过瘤胃脂肪水平对瘤胃pH无影响;第12组的瘤胃氨态氮浓度极显著高于1、2、3、4和9组(P<0.01),显著高于5、6、7和10组(P<0.05),8和11组显著高于1、2、3、4和9组(P<0.05);11组的乙酸浓度极显著高于1、6、7、8和9组(P<0.01),显著高于2和5组(P<0.05),3、4、10和12组显著高于1、6、7、8和9组(P<0.05);12组的丙酸浓度极显著高于6组(P<0.01),显著高于5和7组(P<0.05);2、3、10、11和12组总酸浓度极显著高于6和7组(P<0.01),显著高于5和9组(P<0.05),1、4、8组总酸浓度显著高于6和7组(P<0.05);11组乙酸/丙酸值极显著高于1、2、8和12组(P<0.01),显著高于4、6、7和9组(P<0.05),3、5和10组乙酸/丙酸值显著高于1、2、8和12组(P<0.05)。由上述结果得出,过瘤胃脂肪最佳添加量为中蛋白质水平下的6%。

This study was conducted to investigate the effect of rumen protected fat on rumen fermentation in vitro. Dual-flow continuous culture system was used at a completely randimized design employing in a 3×4 factorial arrangement of treatment. The experimental diet were formulated with 85%, 100%and 115% crude protein levels(abbreviated as L,M and H) and 0, 3%, 6%and 9% rumen protected fat level, respectively, therefor formed 12 diets in all. The results showed as follows:①The diet protein and rumen protected fat had no significant effect on rumen pH, however, diet protein levels had significant effect on concentration of ammoniacal nitrogen(P<0.05).②The diet protein levels had very significant effect on concentration of propionic acid(P<0.01)and significan effect on concentration of acetic, butyric acid and ratio of acetic/ propionic(P<0.05)respectively. These results indicated that the diet protein levels has significant effect on rumen fermentation, the optimum rumen protected fat supplemental levels under the standard protein condition was 6%.