Abstract This experiment aimed to establish the fatty acid profiles of oils from selected insect species and to evaluate their effects on in vitro rumen fermentation and methanogenesis. Insect samples, namely maggots, krotos, superworms, mealworms and crickets, were subjected to oil extraction using hexane in a Soxhlet apparatus. The fatty acid composition of the oils was subsequently determined. The insect oils were added at 5% dry matter to two kinds of diets, high forage (70% forage + 30% concentrate) and high concentrate (30% forage + 70% concentrate), which represented the diets of dairy cows and beef cattle, respectively. These diets, together with a control for each (without any addition of insect oil), were incubated in an in vitro rumen fermentation system, performed for three runs, with each run represented by two incubation units. Therefore, in total 2 × 6 treatments were incubated: the two types of diet (high forage and high concentrate) and the addition (or not) of insect oils (no addition, maggot, kroto, superworm, mealworm and cricket). The data were analysed by using two-way analysis of variance (ANOVA), followed by Tukey’s test. The results revealed that maggot oil was dominated by C12:0 (43.1% from total fatty acids), whereas the main fatty acids present in kroto oil were C18:1n-9 (38.8%) and C16:0 (20.8%). Superworm oil, mealworm oil and cricket oil were rich in C16:0 (19.5–31.2%), C18:1n-9 (25.8–44.6%) and C18:2n-6 (24.0–27.9%). In no case was the interaction between substrate and the addition of insect oil significant for any of the parameters. The addition of insect oil reduced the methane emission of the incubated substrates (p < .05) without altering total volatile fatty acid concentration, with mealworm oil resulting in the lowest level of methane among the insect oils. The oils had no significant effect on ruminal ammonia concentration. Generally, the addition of insect oil reduced the dry and organic matter digestibility of the substrates (p < .05). In conclusion, insect oils are rich in medium-chain and monounsaturated fatty acids (MUFA), and have the ability to mitigate enteric methane emission. Highlights Oils from various insects, namely maggots, krotos, superworms, mealworms and crickets, were extracted, characterised for their fatty acid profiles, and evaluated for their effects on in vitro rumen fermentation and methanogenesis. Maggot oil was dominated by C12:0, whereas the main fatty acids present in kroto oil were C18:1n-9 and C16:0. Superworm, mealworm and cricket oils were rich in C16:0, C18:1n-9 and C18:2n-6. The addition of all the insect oils reduced methane emissions in the high forage and high concentrate substrates, without altering total volatile fatty acid concentration.

中文翻译：

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一些昆虫油的脂肪酸分布及其对体外牛瘤胃发酵和产甲烷的影响

摘要 本实验旨在建立来自选定昆虫物种的油的脂肪酸谱，并评估它们对体外瘤胃发酵和产甲烷的影响。昆虫样品，即蛆、克罗托斯、超级蠕虫、粉虫和蟋蟀，在索氏装置中使用己烷进行油提取。随后确定油的脂肪酸组成。将昆虫油以5%干物质添加到高草料（70%草料+30%精料）和高精料（30%草料+70%精料）两种日粮中，分别代表奶牛和肉牛的日粮， 分别。这些饮食连同每种饮食的对照（不添加任何昆虫油）在体外瘤胃发酵系统中孵育，进行三轮，每轮由两个孵化单位代表。因此，总共培养了 2 × 6 个处理：两种类型的饮食（高草料和高浓缩物）和添加（或不添加）昆虫油（不添加、蛆、kroto、超级蠕虫、粉虫和蟋蟀）。通过使用双向方差分析 (ANOVA) 和 Tukey 检验分析数据。结果表明，蛆油以C12:0（占总脂肪酸的43.1%）为主，而克罗托油中的主要脂肪酸为C18:1n-9（38.8%）和C16:0（20.8%）。超级蠕虫油、黄粉虫油和蟋蟀油富含 C16:0 (19.5–31.2%)、C18:1n-9 (25.8–44.6%) 和 C18:2n-6 (24.0–27.9%)。在任何情况下，底物和添加昆虫油之间的相互作用对于任何参数都不重要。添加昆虫油减少了培养底物的甲烷排放（p < . 05) 在不改变总挥发性脂肪酸浓度的情况下，粉虫油导致昆虫油中甲烷含量最低。这些油对瘤胃氨浓度没有显着影响。通常，添加昆虫油会降低底物的干物质和有机物质消化率 (p < .05)。总之，昆虫油富含中链和单不饱和脂肪酸 (MUFA)，并具有减少肠道甲烷排放的能力。摘要 提取了来自各种昆虫的油，即蛆、克罗托斯、超级蠕虫、粉虫和蟋蟀，并对其脂肪酸谱进行表征，并评估它们对体外瘤胃发酵和产甲烷的影响。蛆油以 C12:0 为主，而克罗托油中存在的主要脂肪酸是 C18:1n-9 和 C16:0。超级蠕虫，粉虫和蟋蟀油富含 C16:0、C18:1n-9 和 C18:2n-6。所有昆虫油的添加减少了高草料和高浓缩基质中的甲烷排放，而不会改变总挥发性脂肪酸浓度。