体外产气法评价反刍动物饲料营养价值的研究

试验旨在通过体外产气法评定反刍动物常用饲料原料的营养价值。饲料原料包括3种能量饲料(玉米、玉米皮、麸皮)和3种粗饲料(苜蓿草粉、苜蓿干草、玉米秸秆),通过体外发酵试验,测定各种饲料原料2、6、12、24h累积产气量、体外发酵参数及营养物质降解率,并分析不同类型饲料发酵动力学参数及发酵动力学与营养成分之间的相关关系。结果表明,能量饲料中,玉米体外发酵24h的产气量(GP₂₄)、理论最大产气量(A)最高,产气曲线的平滑度(B)与其他能量饲料相比没有显著差异(P>0.05);玉米的干物质降解率(DMD)最高,玉米皮的中性洗涤纤维降解率(NDFD)最高,麸皮的粗蛋白质降解率(CPD)最高;粗饲料间GP₂₄差异不显著(P>0.05),苜蓿草粉的GP₂₄、A、DMD、CPD均最高,而粗饲料间B部分差异不显著(P>0.05);GP₂₄和A与粗蛋白质(CP)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、灰分(Ash)均呈极显著负相关关系(P<0.01)。综上所述,不同类型饲料间产气量及动力学参数存在显著差异,能够为奶牛日粮配制提供参考。

Nutrient Value Evaluation of Different Type Feeds by in vitro Gas Production Method

The experiment was conducted to evaluate nutrient value of ruminant feeds by in vitro gas production method.The volume of gas production(GP) at 2, 6, 12 and 24 h, in vitro fermentation parameters and nutrient degradation rate of three energy feeds(corn, corn bran and wheat bran) and three roughages(alfalfa meal, alfalfa hay and corn silage) were measured, and gas production kinetic parameters among different feeds and the relationship between fermentation kinetics and nutritent composition were analyzed.The results showed that the GP₂₄, theoretical gas production(A) and B of corn was the highest among energy feeds, but there was no significant differences of B among different energy feeds(P>0.05).The DMD of corn, the NDFD of corn bran and the CPD of wheat bran were the highest;There were no significant differences in GP₂₄ among roughages.The GP₂₄, A, DMD, CPD of alfalfa meal were the highest, while there was no significant differences of B among roughages(P>0.05).Correlation analyses indicated that the theoretical maximum gas production and the accumulative gas production were extremely significant negatively related to CP, NDF, ADF and Ash(P<0.01).Therefore, the experiment revealed that significant differences were observed in in vitro gas producetion kinetic parameters among different feeds, which could supply scientific basis for diet formulation in dairy practice.