ABSTRACT This in vitro study aimed to evaluate the effects of Yucca schidigera powder (YSP) and inulin (IN) on protein fermentation metabolites (short-chain fatty acids [SCFA] and branched-chain fatty acids, phenolic and indolic compounds, biogenic amines, ammonia and pH) by using faecal inocula from dogs fed either a low (L) or a high (H) protein diet (crude protein 201 or 377 g/kg as fed). Four treatments for each diet were evaluated in an in vitro batch culture system over 24 h: (1) control with no addition of substrates; (2) 4 g YSP/l; (3) 5 g IN/l; (4) 4 g YSP/l in combination with 5 g IN/l of faecal culture of dogs fed Diet L or H. Several changes in fermentation metabolites were analysed. Samples incubated with the faecal inocula of dogs fed Diet L produced higher concentrations of total SCFA, propionate (p = 0.001), acetate (p ≤ 0.001), d-lactate (p = 0.041) and indole (p = 0.003), whereas pH (p = 0.004) was decreased. Supplementation of IN increased the content of putrescine, d- and l-lactate, total SCFA, acetate, propionate, n-butyrate (p ≤ 0.001) and n-valerate (p = 0.003), while i-valerate, indole and pH (p ≤ 0.001) were reduced. Ammonia was lower (p = 0.013) in samples with faecal inocula from dogs fed Diet H and further reduced by the addition of IN (p ≤ 0.001). Samples with faecal inocula from dogs fed Diet L had a fewer quotient of ammonia and total SCFA (p = 0.040). Supplementation of YSP (p = 0.021), IN (p ≤ 0.001) and YSP in combination with IN (p = 0.047) led to a higher reduction of the quotient of ammonia and total SCFA. In conclusion, dietary protein concentration and the supplementation of IN resulted in a stimulation of fermentation while YSP appeared to have only minor effects.

中文翻译：

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丝兰和菊粉对饲喂低或高蛋白质浓度饮食的狗粪便微生物群发酵潜力的影响的体外评估

摘要 这项体外研究旨在评估丝兰粉 (YSP) 和菊粉 (IN) 对蛋白质发酵代谢物（短链脂肪酸 [SCFA] 和支链脂肪酸、酚类和吲哚类化合物、生物胺、氨和 pH 值）通过使用来自饲喂低 (L) 或高 (H) 蛋白质饮食（粗​​蛋白质 201 或 377 g/kg 饲喂的狗）的粪便接种物。在 24 小时内在体外分批培养系统中对每种饮食的四种处理进行评估：（1）不添加底物的对照；(2) 4 克 YSP/l；(3) 5 克 IN/l；(4) 4 g YSP/l 与 5 g IN/l 饲喂饮食 L 或 H 的狗的粪便培养物相结合。分析了发酵代谢物的几种变化。与饲喂饮食 L 的狗的粪便接种物一起孵育的样品产生更高浓度的总 SCFA、丙酸盐 (p = 0.001)、乙酸盐 (p ≤ 0.001)、d-乳酸 (p = 0.041) 和吲哚 (p = 0.003)，而 pH (p = 0.004) 降低。补充 IN 增加了腐胺、d-和 l-乳酸、总 SCFA、乙酸、丙酸、正丁酸 (p ≤ 0.001) 和正戊酸 (p = 0.003) 的含量，而 i-戊酸、吲哚和 pH ( p ≤ 0.001) 减少。在饲喂饮食 H 的狗的粪便接种样本中氨含量较低（p = 0.013），并且通过添加 IN 进一步降低（p ≤ 0.001）。来自喂食饮食 L 的狗的粪便接种物样本中氨和总 SCFA 的商数较低 (p = 0.040)。补充 YSP (p = 0.021)、IN (p ≤ 0.001) 和 YSP 与 IN (p = 0.047) 导致氨和总 SCFA 的商降低更多。综上所述，