影响内蒙古典型草原3种牧草饱和链烷回收率的因素研究

A study of fecal recovery of alkanes from sheep fed on three plant species in the Inner Mongolia steppe

2004年秋季在中国科学院内蒙古草原生态系统定位站,用不同放牧演替阶段的优势植物羊草、糙隐子草和冷蒿分别按30%、20%和50%的比例混合组成日粮,饲喂12只(39±2.1 kg)2岁羯羊(内蒙古细毛羊×蒙古羊)。试验分2个组,投喂胶囊组9只羊,每只羊投喂1粒QSM胶囊,对照组3只羊不投喂;试验期14 d内每天记录绵羊实际牧草采食量和排粪量,并收集牧草样品在45℃烘箱中烘干;粪便样品连续收集7 d,分别在45℃烘干和冷冻;利用气相色谱分析牧草和粪便样品中链烷含量,计算粪便中链烷的回收率。试验结果表明,牧草链烷含量存在物种间差异,绵羊粪便中链烷的回收率与链烷长度存在线性增加关系,烘干处理粪样的链烷回收率高于冷冻干燥处理的回收率,两者存在显著的正相关,且投喂QSM胶囊不会影响其他链烷的回收率。

An experiment to calculate the fecal recoveries of alkanes was carried out at the Inner Mongolia Grassland Ecosystem Research Station of the Chinese Academy of Sciences in autumn 2004. Twelve wethers （Inner Mongolia fine wool sheep × Inner Mongolia sheep） selected from a group of two year olds were fed fresh mixtures of Leymus chinensis （30%）, Cleistogenes squarrosa （20%） and Artemisia frigida （50%） in known proportions and amounts for 14 days. They were assigned to two groups in a randomized experimental design. Nine sheep were dosed with artificial QSM capsules （New Zealand Captec Company） and three sheep were not dosed. Samples of herbage and feces were collected daily for seven days and dried in oven at 45℃ before freeze drying for analysis of the alkane concentration by gas chromatography. The results showed that there was a different concentration of N-alkanes in the three forage species. Fecal recoveries of N-alkanes increased linearly with increasing carbon chain lengths, and were greater using oven drying than freeze drying. There was no significant effects of artificial QSM capsules on recoveries of alkanes from plant cuticular wax in sheep faeces.