【作者】 韩立英；

【导师】 周禾；

【作者基本信息】 中国农业大学 ， 草业科学， 2014， 博士

【摘要】 以全株高油玉米为试验材料,探讨其青贮中脂肪酸变化过程,以期找出提高青贮饲料中脂肪酸含量尤其是不饱和脂肪酸含量的有效措施。共设计6组试验,得出如下试验结果：高油玉米不同生长时期脂肪酸含量及组成研究结果表明,全株高油玉米授粉后干物质积累量主要由果穗干物质积累迅速增加所致；而且全株高油玉米中脂肪酸主要来自果穗中脂肪酸的积累,其变化趋势与果穗中脂肪酸变化趋势一致,均在授粉后42d出现最高值；脂肪酸组成方面以亚油酸为主,占总脂肪酸的一半以上,同样在授粉后42d亚油酸含量最高。全株高油玉米青贮过程中脂肪酸变化规律研究结果表明,随着青贮时间的延长,全株高油玉米青贮饲料中总脂肪酸含量呈下降趋势,其中饱和脂肪酸所占比例呈增加趋势,不饱和脂肪酸所占比例呈下降趋势,差异显著时期均出现在青贮的前2-3d。植物酶和微生物对全株高油玉米青贮饲料中脂肪酸影响的试验结果表明,当植物酶受到完全抑制的情况下,青贮饲料中总脂肪酸含量显著高于对照,饱和脂肪酸所占比例显著低于对照,而不饱和脂肪酸所占比例显著高于对照,说明植物酶对青贮过程中脂肪酸的含量和组成有显著影响。乙酰辅酶A羧化酶对全株高油玉米青贮饲料中脂肪酸影响的试验结果表明,在完全抑制乙酰辅酶A羧化酶的情况下,处理组与对照组在脂肪酸总量和组成方面均无显著差异,说明青贮过程中未发生脂肪酸的从头合成过程,饱和脂肪酸所占比例的提高是由于不饱和脂肪酸减少所致。脂肪酶和脂氧合酶对全株高油玉米青贮饲料中脂肪酸的影响研究结果表明,在两种酶单独受到抑制和同时受到抑制的情况下,其脂肪酸总量和不饱和脂肪酸所占比例均显著高于对照组,且脂氧合酶完全抑制处理与两种酶同时完全抑制处理间无显著差异,说明脂氧合酶的存在导致了青贮饲料中脂肪酸总量和不饱和脂肪酸含量的下降。抗氧化剂提高全株高油玉米青贮饲料中脂肪酸含量的研究结果表明,所选择的抗氧化剂均能显著提高青贮饲料中脂肪酸的总量和不饱和脂肪酸的含量,各抗氧化剂间比较,以茶多酚和叔丁基对苯二酚两种抗氧化剂效果更好。通过研究得出如下结论,全株高油玉米青贮过程中脂肪酸含量的降低主要是由于不饱和脂肪酸被脂氧合酶氧化造成的,生产实践中可通过选择适宜的抗氧化剂,提高青贮饲料脂肪酸,尤其是不饱和脂肪酸的含量,为家畜提供更加健康营养的饲料。更多还原

【Abstract】 High oil corn was chosen as materials, studying the changing process of fatty acid in its silages, and explored effective measures to improve the fatty acid concentration, especially the unsaturated fatty acid in silages. Six experiments were designed in this text, and the results were as follows:The concentrations and compositions of fatty acid in high oil corn at different growth periods were detected, and the results showed that, the dry matter accumulation of high oil corn after pollination continuously increased, the total fatty acid concentration and the percentage of linoleic acid in total fatty acid in whole plant corn were mainly from ear, and the maximal value both appeared in the42d after pollination.The dynamic changes of fatty acid during whole plant high oil corn ensiling was detected, and the results showed that, the total fatty acid concentration and the percentage of linoleic acid in total fatty acid decreased, whereas the percentage of saturated fatty acid increased, and all the significant difference appeared in the2-3d after ensiling.The effect of plant enzyme and microbes on fatty acid of whole plant high oil corn silages were detected, the results showed that, only when the plant enzyme was limited, higher concentration of total fatty acid and percentage of unsaturated fatty acid obtained, whereas the limitation of microbes had no difference compared with control.The effect of acetyl-CoA carboxylase on fatty acid of whole plant high oil corn silages were detected, the results showed that, when the acetyl-CoA carboxylase was limited totally, its total fatty acid concentration and composition were not different from control.The effect of lipase and LOX on fatty acid of whole plant high oil corn silages were detected, the results showed that, higher concentration of total fatty acid and percentage of unsaturated fatty acid obtained either these two enzyme limited alone or together, and the effect of LOX was higher.The effect of antioxidants on fatty acid of whole plant high oil corn silages were detected, the results showed that, adding antioxidants during ensiling could increase the fatty acid concentration and the percentage of unsaturated fatty acid, and the effect of TPP and TBHQ were better than other antioxidants in present study.Through the research, some conclusions could obtain, the losses of fatty acid during ensiling mainly due to the oxidative of unsaturated fatty acid by LOX, and the application of antioxidants could reduce this losses.更多还原