Host phylogeny and life history stage shape the gut microbiome in dwarf (Kogia sima) and pygmy (Kogia breviceps) sperm whales

Abstract

Gut microbiomes perform crucial roles in host health and development, but few studies have explored cetacean microbiomes especially deep divers. We characterized the gut microbiomes of stranded dwarf (Kogia sima) and pygmy (K. breviceps) sperm whales to examine the effects of phylogeny and life stage on microbiome composition and diversity. 16S rRNA gene sequence analysis revealed diverse gut communities (averaging 674 OTUs) dominated by a few symbiont taxa (25 OTUs accounted for 64% of total relative abundance). Both phylogeny and life stage shaped community composition and diversity, with species-specific microbiome differences present early in life. Further analysis showed evidence of microbiome convergence with host maturity, albeit through different processes: symbiont ‘accumulation’ in K. sima and ‘winnowing’ in K. breviceps, indicating different methods of community assembly during host development. Furthermore, culture-based analyses yielded 116 pure cultures matching 25 OTUs, including one isolate positive for chitin utilization. Our findings indicate that kogiid gut microbiomes are highly diverse and species-specific, undergo significant shifts with host development, and can be cultivated on specialized media under anaerobic conditions. These results enhance our understanding of the kogiid gut microbiome and may provide useful information for symbiont assessment in host health.

Turning the tide on sex and the microbiota in aquatic animals

“…Among marine mammals, which differ in their gut microbiota compared to terrestrial relatives (Nelson et al, 2013a ), the majority of studies indicate that the microbiota is not strongly influenced by host sex. Studies in leopard seals ( Hydrurga leptonyx (Blainville, 1820)) (Nelson et al, 2013b ), dugongs ( Dugong dugon (Müller, 1776)) (Eigeland, 2012 ), manatees ( Trichechus manatus Linnaeus, 1758) (Merson et al, 2014 ), bottle nose dolphins ( Tursiops truncatus (Montagu, 1821)) (Bik et al, 2016 ), and kogiid whales ( Kogia sima (Owen 1866) & Kogia breviceps (de Blainville, 1838)) (Erwin et al, 2017 ; Denison et al, 2020 ) have all not found a significant association between host sex and gut microbiota. By contrast, elephant seals ( Mirounga leonina (Linnaeus, 1758)) do exhibit pronounced differences in the microbial communities of males and females.…”

Elasmobranchs Exhibit Species-Specific Epidermal Microbiomes Guided by Denticle Topography

“…The coupling of the eukaryotic host and its respective microbial communities ("microbiome") has been reclassified as a meta-organism, representing the mutualistic dependence between a multicellular organism and its respective microbial communities 1 . Factors such as host age 2 , life history 3 , diet 4,5 , environment 6,7 , and body site 8 contribute to the composition of microbial communities to varying extents, both internally (e.g., oral, gut, reproductive tracts, etc.) and externally (integumentary system, i.e.…”

Gut bacterial communities in Atlantic bottlenose dolphins (Tursiops truncatus) throughout a disease-driven (Morbillivirus) unusual mortality event

“…Recent investigations have focused on characterizing the microbiomes of marine mammals to gain new insights into their roles in host biology , ecology , and evolution (e.g. Apprill et al 2014, Nelson et al 2015, Erwin et al 2017, Godoy-Vitorino et al 2017, Nishida and Ochman 2018, Suzuki et al 2019, Apprill et al 2020, Centelleghe et al 2020, Denison et al 2020, Robles-Mala gamba et al 2020. Micr obiome c har acterization has also been identified as an important tool for monitoring the health of marine mammals in a r a pidl y c hanging ocean envir onment (r eview ed b y Nelson et al 2015, Apprill 2017.…”