Histopathology guide for freshwater fish

Abstract

Research on the health status of aquatic animals, wild or cultured can be done in several ways. Among them, histology is a tool that assists in the understanding and prevention of diseases, as well as increasing production yields and histological alterations can be used as possible indicators of environmental contamination. The technique basically consists in obtaining very thin slices of the organs of the animals so that, when stained, it is possible to visualize alterations in cellular and tissue levels. The degree of these alterations, usually found in the gills, liver, spleen, heart and intestine, may be directly related to the way these animals are kept in captivity or to the environment in which they are exposed. In order to protect and / or improve the health of these animals, the maintenance of water quality parameters within the appropriate range for the cultivated species, the care with feeding management, prophylactic actions regarding everyday utensils and the adoption of practices that minimize vector input must be maintained. In this way, the probability of finding healthy fish, with intact organs and their preserved functions, increases. Thus, the authors of this guide intend to assist researchers and fish farmers with the most used techniques for histological analysis, as well as to illustrate the main alterations associated with different organs of fish. The work is the result of scientific productions jointly developed by graduate students, professors and technicians of the Aquatic Organisms Health Laboratory (AQUOS) of the Aquaculture Department of the Federal University of Santa Catarina (UFSC), as part of the projects CNPq 446072/2014 -1 and 305869/2014-0. All animals procedures are performed by trained persons, with certificate of participation in the Ethics Committee on the Use of Animals (CEUA / UFSC) following the recommendations of well-being, anesthesia and euthanasia.