聚乙二醇对柠条体外发酵特性及干物质降解率的影响

EFFECT OF POLYETHYLENE GLYCOL ON FERMENTATION AND DRY MATTER DEGRADATION OF CARAGANA IN VITRO

选择3只体况良好安装有永久性瘤胃瘘管的蒙古羊羯羊作为瘤胃液供体,通过体外批次培养技术研究了不同剂量的聚乙二醇(PEG)对柠条体外发酵参数及干物质(DM)降解率的影响。根据PEG添加剂量试验分4个组,分别为对照组(不添加PEG),处理1组(PEG添加量∶单宁含量=1∶1),处理2组(PEG添加量∶单宁含量=2∶1)和处理3组(PEG添加量∶单宁含量=4∶1)。在3h、6h、9h、12h和24h 5个培养时间点测定培养液p H值、NH3-N浓度、菌体蛋白浓度、产气量和柠条的DM降解率,并应用多项指标综合指数(MFAEI)对体外发酵参数进行综合评定。试验结果表明:各培养时间点添加PEG组的产气量均高于对照组,在培养的12 h 2∶1组和4∶1组的产气量显著高于对照组和1∶1组(P<0.05);添加PEG对培养液p H值没有显著影响;添加PEG降低了培养液NH3-N浓度,增加了微生物蛋白的合成量。DM体外降解率在培养的24h,4∶1组和2∶1组高于对照组,但统计分析差异不显著。运用多项组合效应指数对体外发酵参数进行综合评定,发现4∶1组,体外发酵效果最佳。

The aim of this study was to investigate the effects of polyethylene glycol （PEG）on in vitro rumen fermentation and dry mat- ter degradation of Caragana. Three healthy Mongolia castrated sheep, with permanent rumen cannula, were used to provide rumen flu- id for in vitro incubation. According to PEG dosage, four experimental groups were designed. Caragana as a substrate was added without （control） or with 3 different dose of PEG （PEG ： tannin = 1：1, PEG ： tannin =2：1 and PEG ： tannin =4：1）. At 3h, 6h, 9h, 12h and 24h of incubation, gas production, pH value, concentration of ammonia and microbial protein as well as DM degradation were determined. Multiple factors associative effects index （MFAEI） was applied to evaluate in vitro fermentation parameters. The results showed that gas production was higher in PEG supplement groups than in control group, and at 12h of incubation gas produc- tion in groups of 2 ： 1 and 4 ： 1 were significantly higher than that of control and 1 ： 1 group （ P 〈 0.05 ）. pH value was not affected by PEG supplement. Ammonia concentration was tended to decrease with increasing of PEG dosage, and reverse tendency was observed for concentration of microbial protein. DM degradation was higher for 4 ： 1 and 2 ： 1 groups than for control group. Fermentation effect was best for 4 ： 1 group when MFAEI was applied to evaluate fermentation parameters in vitro.