Profile of Myxobolus infection in koi fish (Cyprinus carpio) gill tissue from Land Pond, Nglegok, Blitar Regency

Abstract

Koi (Cyprinus carpio) hatchery and aquaculture sector is highly beneficial as it is one of the Indonesian and international superior commodity. However, Koi are susceptible to pests and diseases. One of the diseases is Myxobolusis which is caused by the Myxobolus sp. parasite. The clinical symptom of Myxobolusis are lumps (boils) on the gills and cloudy reddish fluid secretion similar to pus. This research aims to determine the infection profile of Myxobolus through histology observation on gill tissue damage of koi cultivated in a ground pond. This research uses a descriptive method and a quantitative approach. This research observes the gill tissue damage of koi collected from the ground pond of Nglegok, Blitar Regency. The researcher observes the type of damage using a microscope with a magnification of 400x. This research uses a scoring method to assess the damage. Based on the result of histopathological observation, the infected fish exhibits oedema, haemorrhage, hyperplasia, lamellar fusion, and vacuolization. The percentage (%) of tissue damage in Myxobolus infected koi are 72%, 33%, 77%, 75% and 52% respectively. The average score shows moderate to severe damage levels. The observation result on water quality parameter (temperature, pH, DO, and CO2), as supporting parameter in water quality management, shows a tolerable condition and is not the primary cause of Myxobolus sp. infection. However, the transmission of infection may occur due to the presence of other organisms that act as Myxobolus sp. host.