Context Methane (CH4) accounts for loss of dietary gross energy in ruminants and is a potent greenhouse gas. Feedstuffs that could alter ruminal fermentation by decreasing methane production without reducing total volatile fatty acid (VFA) concentration are desirable. Aims Tropical fruit peels, which can be simply collected and exploited, were compared with lucerne (Medicago sativa) in order to assess their potential to modify in vitro and in situ rumen fermentation and CH4 production of goats. Methods For the in vitro study, buffered rumen fluid (30 mL from each of four rumen-fistulated goats fed concentrate and lucerne hay) was mixed with 250 mg dry matter (DM) of each peel sample (dokong, mangosteen, papaya, pineapple, rambutan) and incubated for 48 h. A total of 250 mg DM of lucerne was mixed with rumen fluid as control. For the in situ study, dried samples (lucerne, and peel of dokong, mangosteen, papaya, pineapple, rambutan) were passed through a 2-mm sieve, weighed (5 g) into nylon bags, and individually placed in the rumen of four fistulated goats for 48 h. Key results In the in vitro study, tropical fruit peels lowered (P < 0.05) the production of CH4 compared with lucerne. Tropical fruit peels did not cause inhibition of total VFA (e.g. acetic, butyric and propionic acids) or decrease the concentration of ammonia-N compared with lucerne. In the in situ study, effective DM degradability of papaya (62.99%) and pineapple (54.45%) peels were higher than of lucerne (51.04%). Potential DM degradability of pineapple (75.07%), dokong (72.62%), papaya (66.88%) and rambutan (59.15%) were also higher than of lucerne (57.55%). Conclusions Tropical fruit peels had no negative effect on ruminal fermentation and reduced CH4 production in vitro. However, in vivo studies should confirm these effects. Implications Tropical fruit peels may be suitable as a feedstuff for goats and could be an effective way to reduce methane gas emissions; however, more research under in vivo conditions is needed to elucidate the mechanisms by which tropical fruit peels mitigate of methane production in ruminants.

中文翻译：

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热带果皮作为山羊瘤胃发酵特性的潜在调节剂：体外和原位评估

背景 甲烷 (CH4) 是反刍动物日粮总能量损失的原因，是一种强效温室气体。可以通过降低甲烷产量而不降低总挥发性脂肪酸 (VFA) 浓度来改变瘤胃发酵的饲料是可取的。目的 将可以简单收集和利用的热带果皮与苜蓿（Medicago sativa）进行比较，以评估它们在体外和原位瘤胃发酵和山羊 CH4 生产方面的潜力。方法 在体外研究中，缓冲的瘤胃液（四只瘤胃瘘，每只饲喂浓缩物和苜蓿干草的山羊各 30 毫升）与 250 毫克干物质 (DM) 的每个果皮样品（多空、山竹、木瓜、菠萝、红毛丹）并孵育 48 小时。总共 250 mg DM 的苜蓿与作为对照的瘤胃液混合。对于原位研究，将干燥的样品（苜蓿、多空果皮、山竹果、木瓜、菠萝、红毛丹）过 2 毫米筛，称重（5 克）装入尼龙袋中，分别放入四只有瘘管的山羊的瘤胃中 48 小时。主要结果 在体外研究中，与苜蓿相比，热带水果皮降低了（P < 0.05）CH4 的产生。与苜蓿相比，热带果皮不会抑制总 VFA（例如乙酸、丁酸和丙酸）或降低氨氮浓度。在原位研究中，木瓜 (62.99%) 和菠萝 (54.45%) 果皮的有效 DM 降解率高于苜蓿 (51.04%)。菠萝（75.07%）、多空（72.62%）、木瓜（66.88%）和红毛丹（59.15%）的潜在DM降解率也高于苜蓿（57.55%）。结论 热带水果皮对瘤胃发酵没有负面影响，并降低了体外 CH4 产量。然而，体内研究应证实这些影响。影响 热带果皮可能适合作为山羊的饲料，并且可能是减少甲烷气体排放的有效方法；然而，需要在体内条件下进行更多研究，以阐明热带水果皮减轻反刍动物甲烷产生的机制。