青贮时间对再生稻头季全株青贮品质和体外瘤胃发酵特性的影响

Effects of Silage Time on Quality and in Vitro Rumen Fermentation Characteristics of First Season Ratoon Rice Whole Silage

本试验旨在探究青贮时间对再生稻头季全株青贮品质和体外瘤胃发酵特性的影响。以再生稻头季全株为青贮原料,对不同青贮时间(45、53和60 d,分别记为S45组、S53组和S60组)开包取样,分析其青贮品质和体外瘤胃发酵特性。结果表明:1)青贮结束后,S53组的干物质含量显著高于S60组(P<0.05),S53组和S60组的粗蛋白质含量显著高于S45组(P<0.05),S53组和S60组的中性洗涤纤维和酸性洗涤纤维含量显著低于S45组P<0.05),S53组和S60组的相对饲用价值显著高于S45组(P<0.05),S45组的丙酸含量显著高于S53组和S60组(P<0.05)。各组之间pH、氨态氮/总氮及乙酸、丁酸、异戊酸、正戊酸含量无显著差异(P>0.05)。2)体外发酵24 h后,S60组的24 h累积产气量和慢速降解部分的产气速率显著高于S45组和S53组(P<0.05),S60组的pH显著低于S45组和S53组(P<0.05),S60组的乙酸、丙酸、丁酸、异戊酸、总挥发性脂肪酸和氨态氮含量显著高于S45组和S53组(P<0.05),S60组的干物质、有机物和粗蛋白质降解率显著高于S45组和S53组(P<0.05)。由此可见,延长青贮时间可以改善再生稻头季全株青贮的品质以及体外瘤胃发酵特性,在生产实际中,建议青贮时间延长至60 d以上再饲用,营养价值更佳。

This experiment was conducted to investigate effects of silage time on quality and in vitro rumen fermentation characteristics of first season ratoon rice whole silage.First season whole ratoon rice as silage raw materials,which were sampled at different silage time(45,53 and 60 days,which were recorded as S45,S53 and S60 groups),and analyzed the silage quality and in vitro rumen fermentation characteristics.The results showed as follows:1)after silage,the dry matter content of S53 group was significantly higher than that of S60 group(P<0.05),the crude protein content of S53 and S60 groups was significantly higher than that of S45 group(P<0.05),the contents of neutral detergent fiber and acid detergent fiber of S53 and S60 groups were significantly lower than those of S45 group(P<0.05),the relative feed value of S53 and S60 groups was significantly higher than that of S45 group(P<0.05),and the propionate content of S45 group was significantly higher than that of S53 and S60 groups(P<0.05).There were no significant differences in pH,ammonia nitrogen/total nitrogen and contents of acetate,butyrate,isovalerate and valerate among all groups(P>0.05).2)After 24 h in vitro fermentation,the 24 h cumulative gas production and gas production rate of slow degradation component of S60 group were significantly higher than those of S45 and S53 groups(P<0.05),the pH of S60 group was significantly lower than that of S45 and S53 groups(P<0.05),the contents of acetate,propionate,butyrate,isovalerate,total volatile fatty acid and ammonia nitrogen of S60 group were significantly higher than those of S45 and S53 groups(P<0.05),and the degradation rates of dry matter,organic matter and crude protein of S60 group were significantly higher than those of S45 and S53 groups(P<0.05).It is concluded that prolonging silage time can improve the quality and in vitro rumen fermentation characteristics of first season ratoon rice whole silage,and it suggests that prolonging silage time to more than 60 days which has better nutrition value in actual production.