Lactiplantibacillus plantarum fermented broth improved survival of marble goby (Oxyeleotris marmoratus) after skin abrasion by regulating skin mucus microbiota

Skin abrasion makes fish more susceptible to pathogen infections, which may cause a substantial increase in fish mortality. Hence, a 22-day trial was carried out to investigate the effect of Lactiplantibacillus plantarum fermented broth on the survival and microbiome regulation of marble goby (Oxyeleotris marmoratus) after skin abrasion. 135 fish (initial average weight, 3.39 +/- 1.36 g) were divided into 9 tanks with triplicate treatment groups: control group (healthy fish), abraded group (skin abraded fish) and abraded & L. plantarum-treated group (skin abraded fish and 100 ppm L. plantarum fermented broth adding). The results showed that skin abrasion caused a 28.89% decrease in survival percentage of fish compared to the control group, whereas L. plantarum fermented broth significantly increased survival percentage by 44.45% when compared to the abraded group. Furthermore, skin abrasion reduced the diversity of bacterial and fungal communities in skin mucus and the abundance of Bacteroidetes phylum, Firmicutes phylum and Hydrogenophaga flava species, while increased the abundance of Aeromonas veronii and Cetobacterium somerae species. Nevertheless, L. plantarum treatment resulted in opposite results in fish, and it also increased the abundance of Lactobacillaceae family and potential bacterial and fungal probiotic species in gill and skin mucus. In conclusion, L. plantarum fermented broth may improve survival percentage of marble goby after abrasion by modulating the microbiota composition of fish skin mucus.