Time and Dose Dependent Effect of Pseudomonas aeruginosa Infection on the Scales of Channa punctata (Bloch) Through Light and Electron Microscopy

摘要

Channa punctata (freshwater murrel) is an economically important fish species in Asian countries, including India. The present investigation demonstrates the pathogenic effects of Pseudomonas aeruginosa DJ1990 on the scales of fresh water C. punctata through optical and scanning electron microscopy. In order to determine the adverse effects of P. aeruginosa DJ1990, fish were exposed to different doses of bacterial load and sacrificed at 12 h interval up to 72 h of post-infection period. The light microscopic and electron microscopic examination of C. punctata scale clearly disclosed the bacterial invasion and concomitant destruction of the scale structure such as uprooted damaged lepidonts and dispersal of chromatophores. In the present study, it was observed that the advent of anomaly in scale structure (chromatophore dispersion, circuli damage, circuli disorganization, lepidontal breakage, lepidontal uprooting, lepidontal sockets exposing, lepidont displacement and scale loosing) was dependent on the pathogen loads and time of expose. Till date, several studies have been conducted in the field of fish pathology; however, scales are given less priority in comparison to hematopoietic organs. To the author’s best knowledge, it is the first report describing the effect of bacterial pathogen on the scale of a fish species, C. punctata.