灌服黄芪多糖对奶牛生产性能及乳中风味物质的影响

Effects of astragalus polysaccharide on milk production and its flavor

本试验旨在研究黄芪多糖对奶牛瘤胃发酵、生产性能、乳品质及乳中风味物质的影响。选取体况良好,体重、产奶量、泌乳天数接近,胎次相同的中国荷斯坦奶牛44头,随机分为CK组、APS20组、APS55组、APS90组。所有试验牛均饲喂基础饲粮。试验组每日分别灌服20g、55g、90g的黄芪多糖溶液,进行为期70d(预饲期10d,正饲期60d)试验。结果表明:灌服黄芪多糖可显著提高瘤胃中乙酸浓度(P<0.05)、极显著提高丙酸和丁酸浓度(P<0.01)、显著提高NH3-N浓度(P<0.05)、显著提高MCP含量(P<0.05);灌服黄芪多糖可提高产奶量、乳中的乳脂率、乳蛋白率、乳糖率和非乳脂固体含量,但差异不显著;灌服黄芪多糖可极显著提高乳中风味物质醇类、酸类和烃类物质的含量;除APS55组总挥发性物质、酮类、醛类、酯类以及烃类物质的含量低于CK组,其余试验组均有所提高。综上所述,饲喂55g/d黄芪多糖可以改善瘤胃发酵模式,在一定程度上提高产奶量、乳脂率与乳蛋白率。

This experiment was to study the effects of astragalus polysaccharide on rumen fermentation,cow’ s milk production performance,milk quality and flavor. Forty-four Chinese Holstein dairy cows with good physical condition,similar on body weight,milk yield,lactation days and offspring numbers were randomly divided into CK group,APS20 group,APS55 group and APS90 group. All experimental cows were fed with a diet. The experimental groups were given 20g,55g and 90g APS liquid daily,respectively. The experiment lasted for 70 days(pre-feeding period was 10 days,normal feeding period was 60 days). The results showed that administration of APS significantly increased acetic acid concentration(P < 0.05),propionic acid and butyric acid concentrations(P < 0.01),NH3-N concentration(P < 0.05)and MCP content(P < 0.05)in rumen. Administration of APS increased milk production,milk fat content,milk protein content,lactose content and non-milk fat solid content,but the difference was not significant. The contents of flavoring substances such as alcohols,acids and hydrocarbons in milk were significantly increased by administration of APS. Except the contents of total volatile matter,ketones,aldehydes,esters and hydrocarbons substances in APS55 group were lower than those in CK group,other parameters of the experimental groups were all increased. In conclusion,55g/d APS feeding can improve rumen fermentation pattern and increase milk production,milk fat and protein percentage.