Sixty brown trout and 60 rainbow trout (mean length 5.5 ± 0.5 cm, mean weight 2.3 ± 0.5 g) were placed in flow-through aquaria. Prior to infection, the water supply to each aquarium was stopped and the volume reduced to 4 l. Free Tetracapsuloides bryosalmonae spores in suspension, released from 12 mature sacs, were added to all aquaria, which were then maintained with vigorous aeration for 24 h at 16.5 ± 1°C. Flow-through water was then restarted, and fish were maintained at 16.5 ± 1°C. Additionally, 30 brown trout and 30 rainbow trout were held as non-infected controls for comparison of behavior, clinical signs, and qRT-PCR and immunohistochemistry analyses.
Ten fish from each exposure group and 5 control fish from each group were sampled at 6, 8, 10, 12, 14, and 17 wpe. Fish were euthanized with an overdose of MS-222 anesthetic, and fish lengths and weights were measured. Kidney, spleen, and liver were sampled from all fish. Tissues were divided into 2 portions, 1 fixed in 10% neutral buffered formalin for histology, and 1 in RNAlater (Qiagen) for molecular work.
Ten fish from each exposure group and 5 control fish from each group were sampled at 6, 8, 10, 12, 14, and 17 wpe. Fish were euthanized with an overdose of MS-222 anesthetic, and fish lengths and weights were measured. Kidney, spleen, and liver were sampled from all fish. Tissues were divided into 2 portions, 1 fixed in 10% neutral buffered formalin for histology, and 1 in RNAlater (Qiagen) for molecular work.
