ABSTRACT Kuruma shrimp ( Penaeus japonicus ) is an economically important shrimp perennially affected by diseases. In 2022, White Muscle Disease (WMD) was first characterised in this Penaeid species, caused by Photobacterium damselae subsp. damselae (Pdd). In this study, muscular and gut microbiome dynamics and their function in the disease progression are investigated by 16S rRNA metagenome sequencing using Illumina sequencing technologies. Alpha diversity indices showed that Pdd infection in the muscle, stomach, and intestine did not significantly change bacterial diversity between control and infected groups at all time points observed (Days 0, 1, 3, 5, 7 and 10). In the infected samples, the Shannon and Simpson indices increased starting Day 5 (D5), in congruence with the first observation of muscle whitening. Bacterial composition for the infected group at the genus level revealed that Photobacterium and Vibrio have increased their relative abundance in the muscle at Day 5 (D5) until Day 7 (D7), but declined at Day 10 (D10). As for stomach samples, Photobacterium declined in abundance and later increased significantly at Day 7 (D7). Photobacterium in the intestinal samples from the infected group increased at Day 5 (D5) but later decreased at Day 7 (D7). Meanwhile, linear discriminant analysis Effect Size (LEfSe) identified that most taxa belong to phylum Pseudomonadota, which can be potential markers for WMD. Moreover, the temporal dynamics of the amplicon sequencing variant ASV2, confirmed to be 100% homologous to the WMD‐P3 strain used in this study, were characterised. For all tissues, the logarithmic relative abundance is considered high and very apparent in infected samples collected at Day 7 (D7). Overall, our study provides an understanding of the muscle and gut microbial community, specifically at the genus level, distinguished between WMD‐infected and healthy Kuruma shrimps.
Alolod et al. (2026) studied this question.