Introduction
Animals are associated with a diverse microbiome in their gut, which
affects the host’s health, immunity, and metabolites of the host
(Kinross et al., 2011). The composition of the gut microbiome may change
with host development, diets, and surrounding environments of the host
(Eckburg et al., 2005; Xu & Knight., 2015). Thus, gut microbiome may
provide an important insight into ecology of host animals and be related
to pathogen which can cause the zoonotic diseases (Andersen-Ranberg et
al., 2018). However, to date, the gut microbiome researches have been
primarily focused on human or captive animals, but gut microbiome and
its related functions of wild animals remain poorly understood (Davidson
et al., 2020).
In mammals, gut microbiome can be vertically transmitted since birth
though parental care during lactation phase by direct delivery of
maternal materials to offspring, so that it has a significant impact on
the gut microbiome formation in early growth stage of the offspring (Chu
et al., 2016; Wang et al., 2020). In a mouse model study, it has been
reported that most microbiota genera had been vertically transmitted
over generations (Moeller et al. 2018). In addition to the vertical
transmission, diet is also a major factor to facilitate the gut
microbiome formation. Microbiota can be also indirectly affected by diet
acquisitions of new-borns in different food conditions provided by
nursing mothers (Frese et al. 2015). Since the composition of a starter
diet can vary among families, host diet can shape microbial structure
and functions for digestion.
In this study, we investigated the feces of a wild herbivore from female
adults and calves in the high Arctic environments, collected during the
summer. The muskox (Ovibos moschatus ) is a large herbivore mammal
that inhabits in the Arctic environments (Salgado-Flores et al., 2016).
The dominant diets are willows (Salix spp.) in summer, graminoids
(Carex , Eriophorum ) in winter (Gustine et al., 2014; Thing
et al., 1987). Although the breeding season varies depending on the
annual temperature (Schmidt et al., 2020), calves are usually born in
April to May and start grazing from one week after birth, being closely
attached to their mothers. Calves completely wean after one year
(Adamczewski et al., 1994). By collecting fresh feces, the gut
microbiomes and diet compositions were compared between the female
adults and calves using bacterial 16S rRNA gene sequencing and stable
isotopes analysis. Here we questioned 1) if muskoxen have different gut
microbiomes with ages (female adults vs. calves) and 2) if the two age
groups have similar diets.