Parasitic loads in the genetically improved (F7) Nile tilapia Oreochromis niloticus (L.) cultured in fish farms in Busia and Siaya Counties, Kenya: indicators of increased resistance and efficiencies of synergistic technologies adoptions

Abstract

In Kenya, breeding programmes whose source of genetic material is local water bodies are at inception with the National Aquaculture Research Center, Sagana being the Nile tilapia and African catfish breeding nucleus. Fish are susceptible to a variety of infections and diseases. These microorganisms are often present on the external surfaces and visceral organs of the fish. In order to minimize fish disease burdens a number of fish health management practices and biosecurity measures have been recommended. In this study, a combination of new genetically improved fish strains, liming, netting and biofloc technologies were used in selected fish farms in Busia and Siaya Counties for validation. A total of 113 Nile tilapia were collected (93 from Bukani Aquaparks and 20 from WOODM fish farm) using a seine net. The fish were killed by cervical dislocation. This was followed with measurements of the total lengths and weights. Standard examination procedures were used. A total of 6 different taxa of parasitic species were recovered during the study. These included: Protozoans such as Trichodina sp; Myxozoans such as Myxobolus sp.; Flatworms such as the monogenean Cichlidogyrus sp.; the Trematodes such as the digeneans Tylodelphys sp. and Euclinostomum sp. and the Acanthocephalans such as Acanthogyrus (Acanthosentis) tilapiae. Overall, the findings of this study showed that there were very few parasites infesting fish with also very low infection rates. This study concluded that with the improved fish strain, employment of adequate biosecurity measures, parasitic infestation levels can be significantly lowered to levels of little concern