ISSN: 2639-216X
Authors: Coban N, Sahin T*, Yilmaz S and Ergun S
Fish are considerably susceptible to fluctuating environmental conditions thus, sudden changes in the parameters such as oxygen, pH, and especially the temperature of water cause stress in fish. In this circumstance, stress causes deterioration of the immune system, weakening of the defense mechanism against pathogens, and stimulation of secondary infections in fish. To cope with such issues, the use of drugs in aquaculture is gradually increasing. However, as the use of drugs makes the pathogens more resistant to antibiotics, the efficiency of the treatments decreases over time. In recent applications, the aim is not only to cure the disease but also to take preventive measures against the disease. Therefore, the search for alternative methods to reduce stress, enhance immunity, and prevent pathogen formation is important and up to date. Humic substances whose effects are investigated by scientific studies are formed as a result of the decomposition of plants and they are naturally found in the environments where organic substances are present. Since humic substances are part of the natural environment where fish live, the defense mechanism of the fish does not perceive this foreign matter as a threat. Humic acids, which generally have positive results in living organisms, may result in positive changes on some vital parameters of fish such as increased growth rate, healing of lesions, prevention of pathogen entry into the body, reduced pathogen load, and enhanced immune system when used as a feed additive. Besides, it has been supported by studies that the humic acid may help reduce negative physiological and histopathological results caused by stress, reduce toxic effects of heavy metal and organic pollutants and repair the damage caused by the disease more quickly. In this review, the latest knowledge on the effects of humic acid substances on two of the greatest problems of aquaculture systems which are fish diseases and relevant pathogens is discussed.
Keywords: Humic Acid; Fish Health; Fish Parasites; Amyloodinium; Aquaculture
