日粮能氮比对塔里木马鹿瘤胃体外发酵的影响

Effects of Feed Energy to Nitrogen Ratio on Rumen Fermentation in vitro of Tarim Red Deer

为了解塔里木马鹿对低质粗饲料的适应机理,试验探讨了RDN/DOM对其瘤胃发酵指标的影响,旨在科学有效地利用粗饲料,提高塔里木马鹿养殖经济效益。试验根据以瘤胃尼龙袋法对饲料原料降解特性(有机物和粗蛋白质的有效降解率)研究的结果,在相同营养水平下,设计了8个等距离能氮释放梯度不同(RDN/DOM为15~29)的试验日粮作为发酵底物,利用体外消化试验,检测各组发酵液pH、氨态氮(NH3-N)浓度、总挥发性脂肪酸(TVFA)含量和微生物蛋白质(MCP)含量。结果表明,以RDN/DOM=19的配合饲料作为培养底物进行体外产气试验时,12 h时,MCP含量显著高于其他时间点(P<0.05),因此最终培养时间确定为12 h;RDN/DOM=23时,体外培养液NH3-N浓度最低(8.34 mg/dL),MCP合成量(11.76 mg/dL)、TVFA含量(71.24 mmol/dL)和乙酸/丙酸(2.79)均最高。综上,在本试验条件下,塔里木马鹿最适宜RDN/DOM为23,这对后续研究塔里木马鹿日粮能氮释放同步性指数(SI)提供了重要依据,为进一步研究塔里木马鹿氮代谢规律提供了数据支撑。

In order to understand the adaptation mechanism of Tarim Red deer to low quality roughage and promote more scientific and effective utilization of roughage to improve the economic benefit of Tarim Red deer breeding,the effect of feed energy to nitrogen ratio on rumen fermentation was studied.Based on the experimental results of the degradation characteristics of feed raw materials(effective degradation rate of organic matter and crude protein)by rumen nylon bag method,eight experimental diets with different gradients of energy nitrogen release(RDN/DOM=15 to RDN/DOM=29)at the same nutritional level were designed as fermentation substrates.The pH and ammonia nitrogen(NH3-N)of fermentation products and total volatile fatty acid(TVFA)content and microbial protein(MCP)content were measured and compared by in vitro digestion test.The results showed that when RDN/DOM=19 compound feed was used as culture substrate to produce gas in vitro,the MCP production at 12 h was significant higher than that at other time points(P<0.05).Therefore,the culture time was determined as 12 h.When RDN/DOM was 23,the concentration of NH3-N in culture medium was the lowest(8.34 mg/dL),the MCP production(11.76 mg/dL),TVFA content(71.24 mmol/dL)and acetic acid/propionic acid(2.79)were highest.Therefore,the optimum RDN/DOM of Tarim Red deer was 23 under the experiment condition,which provided an important basis for the follow-up study of synchronization index(SI)of energy and nitrogen release in the diet of Tarim Red deer.It also provided data supporting for further study of nitrogen metabolism of Tarim Red deer.