Protective Effect of Pseudomonas Fluorescens as a Probiotic in Controlling Fish Pathogens

Abstract

Abstract:The use of Pseudomonas fluorscens isolates as biological control agents against two fish pathogens;Pseudomonas angulliseptica and Streptococcus faecium in Nile tilapia were investigated in vivo and vitro. Pseudomonas fluorscens biovars I, II & III were tested in vitro using the agar diffusion method and showed effectiveness in inhibiting growth of P. angulliseptica and Strep. faecium. Pseudomonas fluorscens biovar II was the most effective with largest inhibition zones against both pathogens. For oral administration, P. fluorscens biovars were incorporated into the mixed feed diet. A significant reduction in mortality rate and a significant increase in hematological parameters, total protein, and globulin in fish groups fed Pseudomonas fluorscens incorporated diet following challenge by P. angulliseptica and Strep. faecium. It could be concluded that P. fluorescens has a protective effect against different Nile Tilapia pathogens and could be used as a probiotic bacteria and an eco-friendly alternative measure to chemical antimicrobials and further research studies to clarify its protective mechanisms on cellular and molecular levels.

Possible Mechanisms of Action of Two Pseudomonas fluorescens Isolates as Probiotics on Saprolegniosis Control in Rainbow Trout (Oncorhynchus mykiss Walbaum)

“…Our results differ from the findings of Eissa et al [27] who supplemented the diet with Pseudomonas fluorescens in Nile tilapia (Oreochromis niloticus) and observed a significant reduction in the mortality rate and an increase in hematological parameters, total protein, and globulin after challenge with Pseudomonas anguilliseptica and Streptococcus faecium. However, our results do coincide with the findings by Korkea-aho et al [28] who saw no rise in blood cell counts, phagocytic activity or serum and intestinal mucus lysozyme activity in rainbow trout after administration of Pseudomonas sp.…”

Expression of Hsp70, Igf1, and Three Oxidative Stress Biomarkers in Response to Handling and Salt Treatment at Different Water Temperatures in Yellow Perch, Perca flavescens

“…Thereby, maintaining water and ionic homeostasis is of vital importance, as changes in water temperature or salinity impose problems of metabolism alteration, severe ion depletion, alongside alteration of water entry and hemostasis. Furthermore, probiotics show a promise in improving the aquatic animal health and increasing the stress tolerance (Eissa et al, 2010 , 2014 ; Eissa and AbouElgheit, 2011 ; Mohapatra et al, 2013 ; Eissa and Abou-ElGheit, 2014 ). Therefore, future studies are required to investigate this aspect.…”

Mixed Bacillus Species Enhance the Innate Immune Response and Stress Tolerance in Yellow Perch Subjected to Hypoxia and Air-Exposure Stress

“…Therefore, our study show that mixed bacillus species can increase early innate immunity and compensate the mucus removal. Several reports also linked the beneficial effects of probiotics with the upregulation of immune related genes, which refer to appropriate functions of the innate immune response 8 , 9 , 21 , 22 . However, an aberrant immune activation results in detrimental effects that impact overall health 11 , 23 – 26 supporting the potential immunomodulatory of mixed bacillus species by accelerating the recovery from the acute phase innate immune response in this study.…”

“…Probiotics can enhance the stress tolerance, immune responses and pathogen antagonism 6 – 9 . Stress is a contributing factor in the high mortality and diseases in aquaculture and fisheries stock enhancement 10 .…”