Wanapat M, Cherdthong A, Pakdee P, Wanapat S
Tropical Feed Resources Research and Development Center (TROFREC), Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand.
J Anim Sci. 2008 Dec;86(12):3497-503. doi: 10.2527/jas.2008-0885. Epub 2008 Aug 15.
This experiment was conducted to investigate the effect of lemongrass [Cymbopogon citratus (DC.) Stapf.] powder (LGP) on rumen ecology, rumen microorganisms, and digestibility of nutrients. Four ruminally fistulated crossbred (Brahman native) beef cattle were randomly assigned according to a 4 x 4 Latin square design. The dietary treatments were LGP supplementation at 0, 100, 200, and 300 g/d with urea-treated rice straw (5%) fed to allow ad libitum intake. Digestibilities of DM, ether extract, and NDF were significantly different among treatments and were greatest at 100 g/d of supplementation. However, digestibility of CP was decreased with LGP supplementation (P < 0.05), whereas ruminal NH(3)-N and plasma urea N were decreased with incremental additions of LGP (P < 0.05). Ruminal VFA concentrations were similar among supplementation concentrations (P > 0.05). Total viable bacteria, amylolytic bacteria, and cellulolytic bacteria were significantly different among treatments and were greatest at 100 g/d of supplementation (4.7 x 10(9), 1.7 x 10(7), and 2.0 x 10(9) cfu/mL, respectively). Protozoal populations were significantly decreased by LGP supplementation. In addition, efficiency of rumen microbial N synthesis based on OM truly digested in the rumen was enriched by LGP supplementation, especially at 100 g/d (34.2 g of N/kg of OM truly digested in the rumen). Based on this study, it could be concluded that supplementation of LGP at 100 g/d improved digestibilities of nutrients, rumen microbial population, and microbial protein synthesis efficiency, thus improving rumen ecology in beef cattle.
本试验旨在研究柠檬草[香茅（DC.）Stapf.]粉（LGP）对瘤胃生态、瘤胃微生物以及养分消化率的影响。四头装有瘤胃瘘管的杂交（婆罗门本地）肉牛按照4×4拉丁方设计随机分组。日粮处理为分别添加0、100、200和300 g/d的LGP，并饲喂尿素处理稻草（5%），自由采食。干物质、乙醚提取物和中性洗涤纤维的消化率在各处理间差异显著，且在添加量为100 g/d时最高。然而，随着LGP添加量增加，粗蛋白消化率降低（P<0.05），而瘤胃氨氮和血浆尿素氮随着LGP添加量的增加而降低（P<0.05）。不同添加浓度下瘤胃挥发性脂肪酸浓度相似（P>0.05）。总活菌数、淀粉分解菌和纤维素分解菌在各处理间差异显著，且在添加量为100 g/d时最高（分别为4.7×10⁹、1.7×10⁷和2.0×10⁹ cfu/mL）。LGP添加显著降低了原生动物数量。此外，基于瘤胃中真正消化的有机物质，LGP添加提高了瘤胃微生物氮合成效率，尤其是在添加量为100 g/d时（瘤胃中每千克真正消化的有机物质可合成34.2 g氮）。基于本研究，可以得出结论，每天添加100 g LGP可提高养分消化率、瘤胃微生物数量和微生物蛋白合成效率，从而改善肉牛瘤胃生态。
