Bacterial Microbiome Composition and Functional Potentials Across Digestive Regions of Wild New Zealand Abalone (Haliotis iris)

Abstract

Abalone are valuable commercial marine gastropods, supporting both aquaculture and fishery markets. An important ecological aspect of their survival and physiological performance in a given habitat is a complex and balanced symbiotic relationship with microbes in their digestive system. 16S rRNA Illumina MiSeq sequencing was used to investigate the microbial composition of New Zealand abalone (Haliotis iris) digestive regions (buccal cavity, foregut, and hindgut), seaweed, and sediment samples from the Cook Strait, New Zealand. The findings revealed an overlap in the microbial communities in the foregut and hindgut samples which differed from buccal cavity samples. The foregut and hindgut were dominated by Fusobacteria, Firmicutes, and Proteobacteria. Proteobacteria were abundant in the buccal cavity, seaweed, and sediment samples. Despite distinct overall microbial compositions in the abalone digestive tract and environmental samples (seaweed and sediment), observed overlaps in bacterial richness and diversity suggest that surrounding habitats may serve as significant reservoirs for the abalone gut microbiome, reflecting potential microbial exchange and microbial functional adaptions. Establishing this microbial baseline for wild H. iris provides a reference for detecting microbiome shifts associated with environmental stress, dietary changes, and supports the development of microbiome‐targeted feeds that can be used to enhance abalone growth in an aquaculture setting.