Environmental Sources of Bacteria Differentially Influence Host-Associated Microbial Dynamics

Area of Science:

• Microbiology
• Animal Ecology
• Aquatic Mammal Health

Background:

• Host-associated microbial communities are influenced by diet and immunity.
• The impact of exogenous microbial exposure on host-microbe dynamics is not well understood.
• Aquarium environments present unique challenges for maintaining microbial balance in resident animals.

Purpose of the Study:

• To investigate how exogenous microbial exposure influences the microbiota of aquarium-housed dolphins.
• To characterize the skin, rectal, and respiratory tract-associated microbiota over time.
• To assess the impact of a probiotic intervention and environmental microbial sources on dolphin microbiota.

Main Methods:

• Daily characterization of dolphin skin, rectal, and respiratory tract microbiota over six weeks.
• Analysis of environmental bacterial sources: handlers, air, water, and food.
• Administration of a probiotic supplement during weeks 4-6.
• Correlation analysis between water physicochemistry and microbial diversity.

Main Results:

• Each body site maintained a distinct microbiota despite continuous exposure.
• Water physicochemistry weakly correlated with bacterial richness but not diversity.
• Food and air microbiota influenced other microbiota, especially during probiotic administration.
• Probiotic intervention stabilized the dolphin microbiota, with food being a key factor.

Conclusions:

• Respiratory and gastrointestinal tract interactions with air and food microbes significantly influence host-microbe dynamics.
• Skin transmission plays a minor role in dolphin microbial dynamics.
• Direct oral administration of exogenous microbes can profoundly impact microbial stability.
• Aquarium water disinfection procedures may influence dolphin microbial dynamics.