Prevalence of endoparasites and histopathological evaluation of intestine in Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) from aquaculture pond in Janti, Polanharjo District, Klaten Regency

Abstract
Parasitic disease in aquaculture brings a great challenge to fish production. Appropriate control measure and treatment can be carried out if farmers are equipped with sufficient information on the existence of infection and its consequences on fish health. This study aimed to examine the prevalence of endoparasites in the intestine of Nile tilapia (Oreochrois niloticus) and any histological changes associated with the infection. Forty fishes were collected using purposive sampling technique at two location of aquaculture ponds in Janti village from September to December 2019. Each sampling size consisted of 10% of the total fish population in the pond. Identification of parasites was performed based on their morphology according to the standard method. Three genera of nematodes were found from fishes cultured at aquaculture ponds from local farmers, but not from that of PBIAT (Hatchery and Freshwater Fish Aquaculture). The endoparasites were identified as Cichlidogyrus sp., Acanthocephalus sp., and Ceratomyxa sp. with prevalence of 25% and intensity of 1.2%. Histological sections of the intestine of fish infected with these parasites showed alteration in the mucosa layers, such as edema and extension of the mucosa. Information on the presence of endoparasites and its effect on nile tilapia culture is important for fish farmers because it can be used as reference to control fish parasites effectively.