凋萎和添加剂对稻草裹包青贮发酵品质和营养价值的影响

本试验旨在研究凋萎和添加剂对稻草裹包青贮发酵品质和营养价值的影响。将10月底收割的鲜稻草和凋萎24 h稻草(干鲜比分别为36.5%、42.3%)均设4个组,即对照组、糖蜜组(单独添加糖蜜)、青贮宝组(单独添加青贮宝)和糖蜜+青贮宝组(糖蜜和青贮宝联合添加),每组制作3包。常温裹包青贮50 d后,开包采样进行感官品质、发酵参数和营养价值评定。结果显示:无论鲜稻草是否凋萎,稻草单独青贮难以成功,添加剂糖蜜、青贮宝的添加有利于稻草的裹包青贮;单独添加青贮宝显著降低凋萎稻草青贮的氨态氮(NH_3-N)含量(P0.05);单独添加糖蜜显著提高凋萎稻草青贮的乙酸含量(P0.05),显著降低凋萎稻草青贮的中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量(P0.05);联合添加糖蜜和青贮宝可显著提高鲜稻草或凋萎稻草青贮的粗蛋白质(CP)和钙(Ca)含量(P0.05),显著降低鲜贮稻草青贮的NDF含量(P0.05),显著降低凋萎稻草青贮的NH_3-N含量(P0.05),显著增加凋萎稻草青贮的乙酸、丙酸和丁酸含量(P0.05)。凋萎显著降低稻草青贮的干物质回收率和丙酸含量(P0.05),提高稻草青贮的CP和NH_3-N含量(P0.05)。综上,稻草单独青贮难以成功,添加糖蜜和青贮宝有利于提高稻草青贮的发酵品质,稻草青贮前凋萎要适度。

Effects of Wilting and Addtives on Fermentation Quality and Nutritional Value of Round-Baled Rice Straw Silages

The aim of this study was to determine the effects of wilting and additives on fermentation quality and nutritional value of round-baled rice straw silages. Four groups were allocated both on fresh and wilting 24 h rice straw [ the dry matter ( DM) to fresh matter ( FM) ratio was 36.5% and 42.3%, respectively] har-vested on the end of October. The four groups were control group, molasses group ( only adding molasses) , Qingzhubao group ( only adding Qingzhubao ) and molasses+Qingzhubao group ( both adding molasses and Qingzhubao) , and each group made 3 round bales. After rice straw round baled and ensiled for 50 days on open cement floor, each silage round bale was opened to evaluate sensory quality, fermentation parameters and nutritional value. The results showed that whatever fresh or wilting, rice straw alone was hard to achieve good silage. Adding additives such as molasses and Qingzhubao were helpful to round baled rice straw ensiling. Only adding Qingzhubao could significantly decrease the ammoniacal nitrogen ( NH3-N) content in wilting rice straw silage ( P<0.05) . Only adding molasses could significantly increase acetic acid contents ( P<0.05) and signifi-cantly decrease neutral detergent fiber ( NDF) and acid detergent fiber ( ADF) contents in wilting rice straw si-lage ( P<0.05) . Both adding molasses and Qingzhubao could significantly increase the crude protein ( CP) and calcium (Ca) contents (P<0.05) in fresh or wilting rice straw silage (P<0.05), significantly decrease the NDF content in fresh rice straw silage and NH3-N content in wilting rice straw silage ( P<0.05) , and signifi-cantly increase the acetic acid, propionic acid and butyric acid contents in wilting rice staw silage ( P<0.05) . Wilting significantly decreased the DM recovery rate and propionic acid content of rice straw silages ( P<0.05), but significantly increased the CP and NH3-N contents of rice straw silages (P<0.05). In all, rice straw alone is hard to achieve good silage. Adding Qingzhubao or/and molasses are helpful to improve the fer-mentation quality of rice straw silages, and rice straw need optimal wilting before ensiling.