凋萎和不同添加剂对紫花苜蓿青贮品质的影响

Effects of wilting and additives on fermentation quality of alfalfa(Medicago sativa)silage

以孕蕾后期至初花期紫花苜蓿为材料,在实验室条件下研究了两种凋萎程度(晾晒3h和晾晒12h),对应含水率分别为72.6%和61.8%的苜蓿草分别添加乳酸菌接种剂(LAB)、甜菜粕(SB)、乳酸菌+甜菜粕(LAB+SB)、甲酸钠(SF)、甲酸钠+甜菜粕(SF+SB)五组不同添加剂处理及对照组(CK)对苜蓿青贮发酵品质和主要营养成分含量的影响。青贮65d开封,对青贮进行了感官评定和实验室评定。结果表明,1)添加剂对苜蓿青贮发酵品质有极显著的影响(P<0.01),各种添加剂均不同程度地提高了苜蓿青贮饲料的发酵品质,显著降低了青贮饲料的pH和氨态氮含量;2)两种凋萎程度下苜蓿青贮的NDF、ADF和干物质回收率均与对照组差异不显著,LAB+SB和SF处理显著提高了青贮饲料WSC的含量(P<0.05),添加SB显著降低了青贮饲料的CP值(P<0.05);3)提高原料的凋萎程度能够改善苜蓿青贮饲料的发酵品质,显著提高青贮饲料的CP和WSC含量(P<0.05)。总体来说,不同添加剂的青贮效果不同,添加LAB+SB的青贮品质最佳。

The effect of wilting and different additives on alfalfa silage fermentation and nutritive value were studied under laboratory conditions. Alfalfa （at the early bloom stage of maturity）, wilting 3 and 12 h respec- tively, was ensiled at 72. 6% and 61.8% moisture content either untreated （CK） or treated with inoculant （LAB）, sugar beet pulp （SB）, inoculant and sugar beet pulp （LAB＋SB）, sodium formate （SF） and the com- bination of sodium formate and sugar beet pulp （SFq-SB）. Silo was opened and analysed after 65 d of ensiling. The results showed that additives addition generally had an significantly effect on alfalfa silage characteristics in terms of lower pH and ammonia-N concentration （P〈0.01）. Treated silage had a similar concentration of neu- tral detergent fiber （NDF）, acid detergent fiber （ADF） and dry matter recovery compared with untreated si- lage. The addition of sugar beet pulp （SB） greatly reduced crude protein concentrations （P〈0.05）. Water-sol-uble carbohydrate concentrations were found increased in silage from alfalfa herbage treated with inoculant and sugar beet pulp combined and sodium formate prior to ensiling （P〈0.05）. As silage wilting enhanced, silage quality was improved. In general, different additives had different effect on ensiling. Inoculant and sugar beet pulp combined （LABq-SB） was found to be the most effective additive.