Ampapon Thiwakorn, Wanapat Metha
Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
Asian-Australas J Anim Sci. 2020 May;33(5):763-769. doi: 10.5713/ajas.19.0342. Epub 2019 Aug 3.
The experiment was conducted to study the effect of rambutan (Nephelium lappaceum) fruit peel powder (RP) on feed consumption, digestibility of nutrients, ruminal fermentation dynamics and microbial population in Thai breed cattle.
Four, 2-year old (250±15 kg) beef bull crossbreds (75% Brahman×25% local breed) were allotted to experimental treatments using a 4×4 Latin square design. Four dietary supplementation treatments were imposed; non-supplementation (control, T1); supplementation of RP fed at 2% of dry matter intake (DMI) (low, T2); supplementation of RP fed at 4% of DMI (medium, T3) and supplementation of RP fed at 6% of DMI (high, T4). All cattle were given a concentrate supplement at 1% of body weight while Napier grass was provided as a free choice.
The findings revealed that RP supplementation did not negatively affect (p>0.05) DMI of Napier grass, while RP intake and total DMI were the greatest in the RP supplementation at 4% and 6% DMI. Nevertheless, the nutrients (dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber) digestibilities were not changed in the RP supplementation groups. Rumen fermentation parameters especially those of total volatile fatty acids, acetate and butyrate were not significantly changed. However, the propionate concentration was remarkably increased (p<0.05) in the RP supplementation. Notably, the ratio of acetate to propionate, the number of protozoa, as well as the methane estimation were significantly reduced in the RP supplemented groups (4% and 6% of DMI), while the counts of bacteria was not altered.
Supplementation of RP (4% of DMI) improved rumen propionate production, reduced protozoal population and methane estimation (p<0.05) without a negative effect on feed consumption and nutrients total tract digestibilities in beef cattle. Using dietary rambutan fruit peel powder has potential promise as a rumen regulator.
本试验旨在研究红毛丹果皮粉（RP）对泰国品种肉牛采食量、养分消化率、瘤胃发酵动态及微生物种群的影响。
选用4头2岁（250±15 kg）的肉用公牛杂交种（75%婆罗门牛×25%本地品种），采用4×4拉丁方设计分配到各试验处理组。设置4种日粮添加处理；不添加（对照组，T1）；按干物质摄入量（DMI）的2%添加RP（低剂量，T2）；按DMI的4%添加RP（中剂量，T3）；按DMI的6%添加RP（高剂量，T4）。所有牛均按体重的1%给予精料补充料，同时提供象草供其自由采食。
研究结果表明，添加RP对象草的干物质采食量没有负面影响（p>0.05），而在按DMI的4%和6%添加RP时，RP摄入量和总干物质采食量最大。然而，添加RP组的养分（干物质、有机物、粗蛋白、中性洗涤纤维和酸性洗涤纤维）消化率没有变化。瘤胃发酵参数，特别是总挥发性脂肪酸、乙酸和丁酸的参数没有显著变化。然而，添加RP后丙酸浓度显著升高（p<0.05）。值得注意的是，在添加RP组（DMI的4%和6%）中，乙酸与丙酸的比例、原虫数量以及甲烷排放量均显著降低，而细菌数量没有改变。
添加RP（DMI的4%）可提高瘤胃丙酸产量，减少原虫数量和甲烷排放量（p<0.05），且对肉牛的采食量和养分全肠道消化率没有负面影响。日粮中使用红毛丹果皮粉作为瘤胃调节剂具有潜在的应用前景。
