含无患子皂甙的精料对后备牛生产性能和瘤胃发酵的影响

Effects of Sapindoside-containing concentrate on productive performance and rumen fermentation in heifers

为探讨无患子皂甙对25-28月龄中国荷斯坦后备奶牛生产性能、营养物质消化率、瘤胃发酵和血液生化指标的影响,试验选用16头平均月龄为（25.75±0.94）、产前为（144.94±22.98）d的健康中国荷斯坦后备奶牛,采用配对设计分为2组,每组8头。对照组和试验组分别饲喂质量分数为0和0.15%无患子皂甙的精料。试验期95d,其中预饲期7d,正式期88d,试验末期采集粪样、血样和瘤胃液样品。结果表明：与对照组相比,试验组后备牛的体高、体斜长、胸围和估测体质量有一定提高（P〉0.05）,平均日增质量提高了31%（P=0.05）,饲料质量比显著下降（P〈0.05）;干物质（P〈0.01）、有机物（P〈0.01）、粗蛋白（P〈0.01）、中性洗涤纤维（P〈0.05）、酸性洗涤纤维（P〈0.01）和粗灰分（P〈0.01）消化率均升高;原虫密度、氨态氮质量浓度、总挥发性脂肪酸及乙酸和丙酸都没有发生显著变化（P〉0.05）,乙酸丙酸浓度之比和估测甲烷产量降低（P〈0.05）;各个血液生化指标也没有显著变化。表明饲喂含无患子皂甙的精料对25-28月龄后备牛生产性能有提高的趋势,并在一定程度上改善了瘤胃发酵模式。

Summary Sapindoside is a type of triterpenoid saponins and is extracted from Sapindus mukorossi pericarp by anhydrous ethanol.Previous studies reported that Sapindoside can regulate rumen fermentation in vitro,but whether it is effective in vivo is still unknown.Thus,the objective of the study is to investigate the effects of Sapindoside-containing concentrate on productive performance,nutrient digestion,rumen fermentation and plasma biochemical indexes in 25-28month-old heifers.Sixteen Chinese Holstein heifers,144 days left to give birth,were used in a 95dtrial（7dfor adaptation）.The animals were assigned to two treatments：basal diet with or without 0.15% Sapindoside（powder of 80%triterpenoid saponins）in concentrate.The adding level was based on our previous experiment in vitro.At the last week of the trial,a total of 12 heifers,six from each treatment,were randomly selected,and subjected to a digestion trial by index method with acid insoluble ash as index.The samples of blood and rumen fluids were collected on the day before the last day of the trial.Body size indexes were measured every month and body masswas calculated by formula.Results showed that body height,body length,heart girth and estimated body mass had an increase trend（P0.05）in Sapindoside-containing group,and the estimated average daily gain of the whole period was increased by31% compared with the control（P=0.05）.Apparent total tract digestibility of dry matter（DM,P0.01）,organic matter（OM,P0.01）,crude protein（CP,P0.01）,ether extract（EE,P0.05）,neutral detergent fiber（NDF,P 0.05）,acid detergent fiber（ADF,P 0.01）and crude ash（P 0.01）were greater in Sapindoside-containing group compared with the control.Protozoa counts,concentration of ammonia-nitrogen,total volatile fatty acids as well as acetate and propionate were not affected by Sapindoside-containing concentrate（P0.05）.However,butyrate concentration,acetate to propionate ratio and estimated methane production decreased in Sapindoside-containing group（P 0.05）. Moreover,no difference was found in blood biochemical indexes,including total protein,albumin,globulin,urea nitrogen,glucose,total cholesterol,triglyceride,non-esterified fatty acid,β-hydroxybutyrate,total bilirubin,creatinine,glutamic-pyruvic transaminase,glutamic-oxalacetic transaminase,alkaline phosphatase and superoxide dismutase between two groups（P0.05）.In summary,feeding Sapindoside-containing concentrate presents a trend to improve the productive performance of 25-28month-old heifers.Meanwhile,further studies are required to explore the Sapindoside’s adding level and the long-term effects of Sapindoside on heifers.