Influences of the diurnal cycle on gut microbiota in the Chinese swamp shrimp (Neocaridina denticulata)

ABSTRACT

The circadian rhythm is an essential environmental factor affecting several physiological activities in organisms, including crustaceans. However, daily variations in the gut bacterial community composition of crustaceans remain poorly understood. This study aimed to elucidate variations in the gut bacterial community composition of the Chinese swamp shrimp Neocaridina denticulata with the diurnal cycle. The gut samples of 600 shrimps were collected at four time points (6:00, 12:00, 18:00, and 24:00) within a 24 h period and 16S rRNA high-throughput gene sequencing was applied. The alpha-diversity and richness of the gut bacterial community were highest in the 24:00 group. Food digestion- and absorption-related pathways were highly enriched, indicating that metabolic process pathways are influenced by the daily cycle. Opportunistic pathogenic bacteria, including Flavobacterium, Acinetobacter, and Pseudomonas, were well-represented in the 18:00 and 24:00 groups, suggesting that the daily cycle shapes pathogenic bacterial community composition in the shrimp intestine. Our findings provide new insights into the role of diurnal cycles on gut bacteria in crustaceans and may aid in improving N. denticulata aquaculture.

KEYWORDS:

• Daily cycle
• Chinese swamp shrimp
• Neocaridina denticulata
• gut microbiome
• crustacean

Acknowledgments

We thank Bio JuXing Aquatic Organism Co. Ltd for providing the shrimps.

Author contributions

He Zhang, Yingdong Li, and Qing Liu conceived and designed the study. He Zhang and Yingdong Li collected the specimens and performed the experiments. Yingdong Li and Qing Liu analyzed the data. He Zhang and Yingdong Li drafted the manuscript. All authors read and approved the final version of the manuscript.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/09291016.2022.2106711

Additional information

Funding

This work was supported by the Scientific Research Project of the Liaoning Provincial Education Department (No. LSNQN202006), the Liaoning Provincial Natural Science Foundation of China (No. 2019MS274), and the earmarked fund for Modern Agro-Industry Technology Research System (Grant No. CARS-48)