添加剂对多花黑麦草青贮发酵品质、α-生育酚和β-胡萝卜素含量的影响

Effects of additives on the fermentation quality andα-tocopherol and β-carotene contents in Italian ryegrass silage

为提高多花黑麦草青贮发酵品质,减少α-生育酚、β-胡萝卜素含量损失,以无添加为对照,研究了添加剂:0.4%丙酸(PA)、植物乳杆菌(LP)、环状芽孢杆菌(BC)、植物乳杆菌和环状芽孢杆菌菌株混合添加(LP+BC)对青贮发酵品质、α-生育酚和β-胡萝卜素的影响,在青贮3、7、35和70 d后开窖取样,检测发酵品质、营养成分、α-生育酚和β-胡萝卜素含量。结果表明:添加剂对多花黑麦草发酵品质有显著影响(P<0.05),LP+BC组提高青贮发酵品质的效果最好,其次为LP组。青贮70 d后,与对照组相比,添加剂组均降低了饲料的pH,且pH都在4.0以下。LP、BC和LP+BC组提高了乳酸含量和乳酸乙酸比(P<0.05);PA组在青贮初期抑制了乳酸发酵,后期提高了青贮发酵品质,但提高效果不如其余3种添加剂。在各个青贮时期,PA组的α-生育酚含量均显著高于其余4组(P<0.05);在青贮35和70 d时,除PA组外,LP组α-生育酚含量最高(P<0.05)。青贮7 d后,各添加剂组β-胡萝卜素含量均显著高于对照组(P<0.05),LP组在青贮7和35 d时β-胡萝卜素含量最高(P<0.05)。综上所述,LP组处理下多花黑麦草青贮发酵品质良好且减少了α-生育酚含量损失,增加了β-胡萝卜素含量。

The objective of this study was to improve the fermentation quality of Italian ryegrass silage and inhibit the loss ofα-tocopherol andβ-carotene during ensilage.Italian ryegrass was ensiled without additives(CK),or with 0.4%propionic acid(PA),Lactobacillus plantarum B11(LP),Bacillus circulans 12(BC),or the combination of LP and BC(LP+BC).At days 3,7,35,and 70 after ensiling,the Italian ryegrass silage fermentation quality,nutritional quality,α-tocopherol content,andβ-carotene content were evaluated.It was found that additives significantly affected the silage fermentation quality(P<0.05).The silage fermentation quality was the highest in the LP+BC treatment,followed by the LP treatment.In the later period of ensilage,compared with CK,all treatment groups showed lower pH values,all of which were below 4.0.Compared with CK,silages fermented with LP,BC,and LP+BC showed significantly increased lactic acid content and lactic acid/acetic acid ratio(P<0.05).The addition of PA inhibited lactic acid fermentation in the early stage of ensilage and improved the fermentation quality in the later stage,but the effect of PA was weaker than those of the other three additives.During ensiling,theα-tocopherol content was significantly higher in silages fermented with PA than in those fermented with other additives or in CK(P<0.05).After ensiling for 35 and 70 days,except for silages fermented with PA,those fermented with LP had the highestα-tocopherol contents(P<0.05).After ensiling for 7 days,theβ-carotene contents were higher in all the treatment groups than in CK(P<0.05),and silage fermented with LP had the highestβ-carotene content at days 7 and 35 after ensiling(P<0.05).In conclusion,the addition of LP to Italian ryegrass silage resulted in good fermentation quality,reducedα-tocopherol losses,and increased theβ-carotene content.