柠条叶提取物对苜蓿青贮品质及抗氧化活性的影响

Effects of leaf extracts of caragana on silage quality and antioxidant activity of alfalfa

为了研究柠条叶提取物(LEC)对苜蓿(Medicago sativa)青贮品质及抗氧化活性的影响,在新鲜苜蓿中添加1%(LEC_(1))、2%(LEC_(2))和3%(LEC_(3))的柠条叶提取物,以不添加LEC为对照组(CON)。青贮60 d后测定苜蓿青贮营养品质、发酵品质和抗氧化活性指标。结果表明:1)LEC_(2)组和LEC_(3)组的干物质(DM)含量和乳酸(LA)含量显著高于CON组(P<0.05),LEC_(2)组和LEC_(3)组的DM损失显著低于CON组(P<0.05)。LEC_(3)组的可溶性碳水化合物(WSC)含量显著高于其他组(P<0.05)。添加LEC显著降低苜蓿青贮pH、丙酸含量和酵母菌数量(P<0.05),显著增加乳酸菌数量(P<0.05),其中LEC_(2)组和LEC_(3)组的乳酸含量显著高于CON组(P<0.05)。2)添加LEC显著增加苜蓿青贮类黄酮含量、总抗氧化能力(T-AOC)、谷胱甘肽过氧化物(GSH-Px)活性和超氧化物歧化酶(SOD)活性(P<0.05),LEC_(3)组的总酚含量和总多糖含量均显著高于CON组(P<0.05)。此外,LEC_(2)和LEC_(3)组的1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率显著高于CON组(P<0.05),其中LEC添加组的DPPH自由基清除率均在90%以上。3)主成分分析和综合得分排名为LEC_(3)>LEC_(2)>LEC_(1)>CON。综上,添加LEC可改善苜蓿青贮营养品质和发酵品质,且提高苜蓿青贮的抗氧化活性,其中添加3%LEC对苜蓿青贮品质和抗氧化活性改善效果最好。

The aim of this study was to investigate the effects of caragana leaf extract(LEC)on silage quality and the antioxidant activity of alfalfa(Medicago sativa).The supplemental LEC levels were 0(control group,CON),1%(LEC_(1)),2%(LEC_(2)),and 3%(LEC_(3))in fresh alfalfa.After 60 days,the nutritional quality,fermentation quality,and antioxidant activity indices of the alfalfa silage were determined.The results showed that:1)the dry matter(DM)and lactic acid(LA)contents of the LEC_(2)and LEC_(3)groups were significantly higher than those of the CON group(P<0.05),and the DM loss of the LEC_(2)and LEC_(3)groups was significantly lower than that of the CON group(P<0.05).The water-soluble carbohydrate content of the LEC_(3)group was significantly higher than that of the other groups(P<0.05).LEC significantly decreased the pH value,propionic acid content,and yeast population of alfalfa silage(P<0.05),and significantly increased the lactic acid bacteria population(P<0.05).The LA contents of the LEC_(2)and LEC_(3)groups were significantly higher than those of the CON group(P<0.05).2)LEC significantly increased the flavonoid content,total antioxidant capacity,glutathione peroxidation activity,and superoxide dismutase activity of alfalfa silage(P<0.05),and the total phenol and total polysaccharide contents of the LEC_(3)group were significantly higher than those of the CON group(P<0.05).The scavenging rates of 1,1-diphenyl-2-doctoral programs in public health(DPPH)free radicals in the LEC_(2)and LEC_(3)groups were significantly higher than those in the CON group(P<0.05),and the DPPH radical scavenging rate was>90%in all LEC addition groups.3)The rankings of the principal component analysis and comprehensive score were LEC_(3)>LEC_(2)>LEC_(1)>CON.In conclusion,the addition of LEC improved the nutritional and fermentation quality of alfalfa silage and enhanced the antioxidant activity of alfalfa silage.The 3%LEC treatment performed better than the other treatments.