体外法评价张杂谷秸秆、全株青贮张杂谷和燕麦草的营养价值

Nutritional value evaluation of millet straw, whole silage Zhangzagu and oat grass in vitro

试验旨在通过体外产气法评价张杂谷秸秆、全株青贮张杂谷和燕麦草的营养价值。采用单因素试验设计,将1 g张杂谷秸秆、全株青贮张杂谷和燕麦草分别进行体外发酵,每组设4个重复,测定和分析三种粗饲料对体外产气量、挥发性脂肪酸、营养物质降解率、pH值、微生物蛋白、氨态氮的影响。结果表明,张杂谷秸秆、全株青贮张杂谷4、8、16、24、36、48、72 h的产气量及理论最大产气量(B)均极显著小于燕麦草的(P<0.01),全株青贮张杂谷8、16、24、36、72 h的产气量极显著大于张杂谷秸秆(P<0.01);产气速率(c)和延搁时间(Lag)张杂谷秸秆和燕麦草的差异均不显著(P>0.05),极显著低于全株青贮张杂谷(P<0.01)。体外发酵72 h后,乙酸、丁酸、总挥发性脂肪酸浓度均是张杂谷秸秆产生的极显著低于全株青贮张杂谷、燕麦草的(P<0.01);丙酸、乙酸/丙酸浓度张杂谷秸秆极显著低于全株青贮张杂谷(P<0.01),全株青贮张杂谷极显著低于燕麦草(P<0.01)。干物质、粗蛋白质、中性洗涤纤维和酸性洗涤纤维降解率均表现出张杂谷秸秆极显著低于全株青贮张杂谷(P<0.01),全株青贮张杂谷极显著低于燕麦草(P<0.01);pH值变化为张杂谷秸秆、全株青贮张杂谷极显著高于燕麦草(P<0.01);微生物蛋白质产量三者差异均不显著(P>0.05),NH3-N浓度为张杂谷秸秆显著低于全株青贮张杂谷(P<0.05),两者与燕麦草差异不显著(P>0.05)。因此,该试验条件下,张杂谷秸秆、全株青贮张杂谷体外发酵在产气量、营养物质降解率方面相对次于燕麦草,全株青贮张杂谷相对优于张杂谷秸秆,具体原因及实际饲喂应用效果有待研究。

We investigated the nutritional value of millet straw(MS), whole silage Zhangzagu(WSZ) and oat grass(OG) using an in vitro rumen fermentation system. A single factor experiment was designed with MS, WSZ and OG were tested by 1 g with four replicats. Gas production(GP), volatile fatty acids(VFA), rate of nutrition degradation, pH, microbial crude protein(MCP) and ammonia nitrogen(NH3-N)were measured. The results showed that, compared with OG, GP of 4, 8, 16, 24, 36, 48, 72 h and B of MS and WSZ were extremely significantly lower(P<0.01). But GP of 8, 16, 24, 36, 72 h of WSZ was extremely significantly higher than MS(P<0.01). However, c and Lag did not different among MS and OG,but were extremely significantly lower than WSZ(P<0.01). Acetic acid, butyric acid, total volatile fatty acids of MS were extremely significantly lower than MS and WSZ(P<0.01). Both propionic acid and acetic acid/propionic acid of MS were extremely significantly lower than WSZ(P<0.01)then WSZ were extremely significantly lower than OG of 72 h were measured. All degradations of dry matter, crude protein, neutral detergent fiber and acid detergent fiber of MS were extremely significantly lower than WSZ, and WSZ were extremely significantly lower than OG(P<0.01). pH of MS and WS were extremely significantly improved than OG(P<0.01). MCP had no difference(P>0.05). But NH3-N of MS was significantly lower than WSZ(P<0.05), but these two had no difference with OG(P>0.05). Conclusion: Compared with OG, the characteristics of MS and WSZ in vitro fermentation was lower on gas production and rate of nutrition degradation within the condition of this experiment, but WSZ relatively better than MS. The specific reason and actual application effect remains to be studied.