Fig 1

(A) Experimental setup for UV irradiation of rotifers, including (1) a UV-C LED mounted in a cap of a round bottom flask and (2) rotifers in a 4 ppt NaCl solution. (B) Bacterial concentration in the rotifer suspension as a function of the number of UV exposure cycles, each 30 minutes on/30 minutes off. (C) Fraction of motile rotifers as a function of the number of UV exposure cycles. In panels B and C, open symbols represent different replicates, and solid symbols and error bars indicate the mean and SD. (D) Bacterial concentration in the rotifer suspension before and after incubation with antibiotics for 3.5 hours. (E) Schematic diagram of the protocol for assessing bacterial load in initially germ-free zebrafish subject to different feeding methods. (F) Bacterial abundance per larval zebrafish after 1, 2, and 3 days of feeding with rotifers under different treatments, or unfed at the same days. Each symbol indicates a measurement from an individual fish; boxes indicate the median (line within the box), first and third quartiles (top and bottom of the box), and 95% confidence intervals (bars). The dashed line indicates the approximate limit of detection, 10 bacteria per fish.