Current bacterial diseases of fresh water fishes

Abstract

From the beginning of fish cultivation, diseases have appeared as a serious problem in this branch of agriculture. In recent years, by the intensifying of production, fish diseases have become even more significant and complex field. Bacterial diseases are constant threat for fish farming, and because of rapid course and severity of clinical manifestations the represent significant part of fish pathology, and also have great economical importance. Harmful effects of bacterial diseases on fishes are: increased morbidity and mortality rate, decreased feed conversion efficiency, decreased growth rates, weakening of fishes, and reproduction problems. In order to examine epizootiological situation and occurrence of bacterial diseases among cultured fish in Serbia, three year research was carried out in 7 carp farms and 3 rainbow trout farms. Also, regular systematic examinations were conducted. Samples of internal organs, skin and gills were inoculated with streak-plate technique on standard and differential culture media plates. Inoculated plates were incubated for 24-48 hours at 20?C and 30?C. After incubation period, colonies were examined, and determination was done on the basis of following characteristics of colonies: form, color, mucosity granulation, roughness and hemolytic properties. Determination of bacterial isolates was done by using API 20E, API rapid. API Coryne systems, and by agglutination method with hyper immune aera. The most frequent diseases among the farmed carp and rainbow trout populations in the examined fish farms were: Bacterial gill disease, Columnaris disease. Yersiniosis Renibacteriosis, Erythrodermatitis. Motile Aeromonas and Pseudomonas infections. Based on the obtained results, modern diagnostic methods were implemented and proper prevention and successful therapy was taken.

Important bacterial diseases and their control in rainbow trout in Serbian aquaculture

“…Various environmental factors (high water temperature, low oxygen concentrations, sudden water pH changes, high levels of ammonia and nitrite, etc.) could predispose aquaculture fish to the disease (Jeremic et al, 2005). A. hydrophila is biochemically and serologically very heterogeneous (Đorđević et al, 2012), and this limits development of an effective commercial vaccine (Nayak 2020), even though a vaccine that could O n L i n e F i r s t offer protection to fishes in intensive aquaculture is urgently needed.…”

“…Various Pseudomonas are known fish pathogens, with P. fluorescens and P. putida causing severe losses in rainbow trout aquaculture (Oh et al, 2019). Pseudomonads are common disease agents in different aquatic animals, including rainbow trout in Serbia (Jeremic et al, 2005, Jeremic et al, 2011, Radosavljevic et al, 2013.…”

“…A. salmonicida subsp. salmonicida is often detected in rainbow trout farms in Serbia, and the outbreaks result in high mortalities of infected trout (Jeremic et al, 2005, Jeremic et al, 2011, Radosavljevic et al, 2013. However, the incidence of furunculosis has been reduced in food fish using vaccines (Braden et al, 2019).…”

“…It was detected in the USA in the 1950s, and it is now present in aquaculture all over the world (Plumb and Hanson, 2011). In Serbia, the disease was first diagnosed in 1987 (Ocvirk et al, 1987), but is now widespread and has become one of the most prevalent trout pathogens in Serbia (Jeremic et al, 2005;Radosavljevic et al, 2013). In the study by Jeremic et al, (2011), yersiniosis was present on the majority of examined trout farms in one-year-old rainbow trout.…”

Gut Peculiarities of Feed Deprived White Sturgeons (<i>Acipenser transmontanus</i>, Richardson 1836)

“…In parallel with intensifying production, fish diseases have in recent years acquired important practical and economic importance, and some of them may cause emaciation, among other signs, in cultured fish species [16]. Bacterial diseases, from both primary and secondary occurrences [17][18][19], do not spare sturgeon fish farms [20,21].…”