A Promising New Chemotherapeutant for Use in Treatment of Fusarium solani Infections in Penaeid Shrimp

Abstract

A commercially available microbicide, composed of 5‐Chloro‐2‐methyl‐4‐isothiPzolin‐3‐one and 2‐methyl‐4‐isothiazolin‐3‐one, was tested for its in vivo effectiveness in controlling pathogenicity and mortalities in the marine shrimp Penaeus stylirostris, caused by the fungus Fusurium solani. Sub‐adult shrimp (100% with Fusurium lesions) were treated with the microbicide at levels of 5.0 and 7.5 ppm (Trial 1) and with 1.0, 2.5 and 5.0 ppm (Trial 2), and each compared to a non‐treated control. In Trial 1, treatments were administered during the first 9 days of the 22 day experiment, approximately every other day as 8 h static baths. The mean levels of Fusarium lesions on Day 22 for the 0, 5.0 and 7.5 ppm treatments were 87%, 25% and 13%, respectively. Statistically both levels of treatment (5.0 and 7.5 ppm) had significantly lower levels of Fusurium lesions when compared to the controls. In Trial 2, treatments of the microbicide were administered (8 h static bath) every seventh day over the course of the 64 day experiment. The Day 64 mean Fusarium lesion levels for the 0, 1.0, 2.5 and 5.0 ppm treatments were 54%, 59%, 10% and 7%, respectively. Treatment with 2.5 and 5.0 ppm reduced the prevalence of Fusarium lesions to statistically lower levels when compared to the 0 and 1.0 ppm treatments. The microbicide had earlier been reported to be highly toxic to fish. The use of activated charcoal filters on the microbicide‐treated effluent appeared to remove any residual compound from the water. The data in the present study indicate a possible inverse relationship between the level of “BG 101” and growth rate. The data from both trials suggest that periodic treatment over a longer test period could limit or eliminate Fusurium lesions, which are known to be the potential cause of substantial mortalities, particularly in captive broodstock populations.

Characterization and PCR Detection Of Binary, Pir-Like Toxins from Vibrio parahaemolyticus Isolates that Cause Acute Hepatopancreatic Necrosis Disease (AHPND) in Shrimp

“…Cumulative mortality (dead and moribund shrimp) was recorded until 48 hours after injection. Moribund shrimp were fixed with Davidson's fixative [ 10 ] and processed for histological confirmation of AHPND pathology. The experiments were repeated twice with two different lots of shrimp and different AS preparations.…”

“…Slides of shrimp cephalothorax tissue sections fixed and processed for histological examination [ 10 ] were viewed using the light microscope for the presence of massive sloughing of HP tubule epithelial cells in the absence of bacteria to confirm AHPND histopathology [ 1 ].…”

Outbreaks of Edwardsiella ictaluri Infection in Ayu Plecoglossus altivelis in Japanese Rivers

“…Heart, liver, spleen, kidney, muscle and digestive tract were dissected from three moribund ayu sampled in Yamaguchi Prefecture, and fixed in Davidson's solution (Bell and Lightner, 1988). Each sample was embedded in paraffin.…”

Mass Mortality of Cultured Kuruma Prawn Penaeus japonicus Caused by Vibrio nigripulchritudo

“…Six moribund prawns were sampled and fixed in Davidson's solution (Bell and Lightner, 1988). Each sample was embedded in paraffin.…”