Mulberry (Morus alba) leaves are rich in proteins, vitamins and trace elements, which serve as ingredients of feed. However, the application of mulberry leaves is limited by the anti-nutritional factors present in them. In this study, we fermented the mulberry leaves using complex microorganisms containing lactic acid bacteria and yeast and investigated the effects of feed containing 0%, 5%, 10%, 15% and 20% FMLs on growth performance, serum antioxidant capacity, digestive capacity and intestinal microbiota composition in crucian (Carassius carassius). The intestinal microbiota composition was investigated using high-throughput sequencing of 16S rRNA gene. Our results showed that adding 5% FMLs to feed promoted growth performance, serum antioxidant capacity and intestinal digestive enzyme activities of crucian. There was no significant difference between the gut microbiota composition of crucian fed 5% FMLs and the blank control. When added FMLs exceeded 10%, the growth performance, serum antioxidant capacity and intestinal digestive enzyme activities decreased, and the homeostasis of gut microbiota was destroyed. These findings indicated that addition of 5% FMLs not only significantly promoted the growth of crucian, but also improved the antioxidant capacity and digestive capacity.

中文翻译：

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发酵桑叶对鲫鱼(Carassius carassius)生长、血清抗氧化能力、消化酶活性和肠道微生物组成的影响

桑（桑树）叶含有丰富的蛋白质，维生素和微量元素，它用作饲料原料。然而，桑叶的应用受到其中存在的抗营养因子的限制。在这项研究中，我们使用含有乳酸菌和酵母的复合微生物发酵桑叶，并研究了含有 0%、5%、10%、15% 和 20% FML 的饲料对生长性能、血清抗氧化能力、消化能力的影响鲫鱼肠道菌群组成及肠道菌群组成）。使用 16S rRNA 基因的高通量测序研究肠道微生物群组成。我们的结果表明，在饲料中添加 5% FML 可促进鲫鱼的生长性能、血清抗氧化能力和肠道消化酶活性。饲喂 5% FML 的鲫鱼的肠道微生物群组成与空白对照之间没有显着差异。FMLs添加量超过10%时，生长性能、血清抗氧化能力和肠道消化酶活性下降，肠道菌群稳态被破坏。这些研究结果表明，添加5% FMLs不仅显着促进了鲫鱼的生长，而且提高了抗氧化能力和消化能力。