The acquisition and maturation of the gastrointestinal microbiome is a crucial aspect of mammalian development, particularly for specialist herbivores such as the koala (Phascolarctos cinereus). Joey koalas are thought to be inoculated with microorganisms by feeding on specialized maternal faeces (pap). We found that compared to faeces, pap has higher microbial density, higher microbial evenness and a higher proportion of rare taxa, which may facilitate the establishment of those taxa in joey koalas. We show that the microbiomes of captive joey koalas were on average more similar to those of their mothers than to other koalas, indicating strong maternal inheritance of the faecal microbiome, which can lead to intergenerational gut dysbiosis when the mother is ill. Directly after pap feeding, the joey koalas' microbiomes were enriched for milk-associated bacteria including Bacteroides fragilis, suggesting a conserved role for this species across mammalian taxa. The joeys' microbiomes then changed slowly over 5 months to resemble those of adults by 1 year of age. The relative abundance of fibrolytic bacteria and genes involved in the degradation of plant cell walls also increased in the infants over this time, likely in response to an increased proportion of Eucalyptus leaves in their diets.

中文翻译：

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考拉肠道微生物组的母系遗传及其在幼年发育过程中的组成和功能成熟

胃肠道微生物组的获得和成熟是哺乳动物发育的一个重要方面，特别是对于专业的食草动物，如考拉 ( Phascolarctos cinereus)）。乔伊考拉被认为是通过以专门的母体粪便（pap）为食来接种微生物的。我们发现，与粪便相比，pap 具有更高的微生物密度、更高的微生物均匀度和更高的稀有类群比例，这可能有助于这些类群在乔伊考拉中的建立。我们表明，圈养的乔伊考拉的微生物组平均与它们母亲的微生物组比其他考拉更相似，这表明粪便微生物组具有很强的母系遗传性，当母亲生病时，这可能导致代际肠道菌群失调。喂奶后，乔伊考拉的微生物组中富含与牛奶相关的细菌，包括脆弱拟杆菌，表明该物种在哺乳动物分类群中的保守作用。然后，乔伊的微生物组在 5 个月内缓慢变化，与 1 岁时的成年人相似。在此期间，婴儿中参与植物细胞壁降解的纤维溶解细菌和基因的相对丰度也在增加，这可能是由于他们饮食中桉树叶比例的增加。