Circadian dynamics of the teleost skin immune-microbiome interface

Circadian rhythms of host immune activity and their microbiomes are likely pivotal to health and disease resistance. The integration of chronotherapeutic approaches to disease mitigation in managed animals, however, is yet to be realised. In aquaculture, light manipulation is commonly used to enhance growth and control reproduction but may have unknown negative consequences for animal health. Infectious diseases are a major barrier to sustainable aquaculture and understanding the circadian dynamics of fish immunity and crosstalk with the microbiome is urgently needed. We demonstrate daily rhythms in fish skin immune expression and microbiomes, that are modulated by photoperiod and parasitic infection. We identify putative associations of host clock and immune gene profiles with microbial composition. Our results suggest circadian perturbation that shifts the magnitude and timing of immune and microbiota activity, is detrimental to fish health. This study represents a valuable foundation for investigating the utility of chronotherapies in aquaculture, and more broadly contributes to our understanding of circadian health in vertebrates.