富含十八碳不饱和脂肪酸的植物油对体外瘤胃发酵和甲烷生成的影响

选取3种典型的植物油:菜籽油、豆油和亚麻油,利用体外培养系统进行体外发酵,研究植物油的类型和添加水平对瘤胃体外发酵和甲烷生成的影响。3种植物油分别添加底物干物质的3%、5%和7%,未添加植物油组为对照,共10个处理,每个处理设3个重复。结果表明,菜籽油对甲烷产量无显著影响(P>0.05),豆油7%添加水平显著抑制了甲烷生成,而亚麻油所有添加水平均显著降低了甲烷生成量(P<0.05)。在豆油和亚麻油处理组中,随着添加水平的提高,甲烷产量线性下降(P<0.01)。3种植物油均显著改变了瘤胃发酵模式,随着植物油中所含不饱和脂肪酸不饱和度的增加,乙酸和丁酸的摩尔比例显著降低,丙酸摩尔比例显著升高(P<0.05);植物油添加水平的提高显著降低了乙酸和丁酸摩尔比例,显著升高了丙酸摩尔比例(P<0.05),乙酸丙酸比例显著降低。本试验结果表明植物油降低甲烷的效果跟其来源和添加水平有关;随着植物油添加水平的提高和所含不饱和脂肪酸不饱和度的增加,甲烷生成量显著降低。

Effects of vegetable oils rich in unsaturated octadeca fatty acids on in vitro rumen fermentation and methane emission

Three types of vegetable oils rich in different content of unsaturated octadeca carbon fatty acids were investigated on in vitro fermentation and methanogenesis at different inclusion levels. Rapeseed, soybean and linseed oil were added to basal subatrate at levels of 0, 3, 5 and 7 % of substrate DM, respectively. Rapeseed oil had minor effect on methane emission, soybean oil at 7 % inclusion level and linseed oil at all levels decreased methane emission significantly (P<0. 05); Methane formation was decreased linearly by increasing level of oils. Three types of oils changed fermentation pattern significantly, molar proportign of acetate and butyrate decreased and propionate proportion increased significantly with increasing unsaturation of fatty acids in vegetable oils; Elevating vegetable oil level significantly decreased molar proportion of acetate and butyrate and increased propionate proportion. From the present study, it is postulated that the effect of vegetable oils on methane emission is concerned with the type and inclusion levels. Methane formation was decreased significantly with increasing levels and unsaturation of fatty acids in vegetable oils.