Bioprophylaxis of Saprolegniasis in Incubated Clarias gariepinus Eggs Using Pyocyanin Extracted from Pseudomonas aeruginosa
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Bioprophylaxis of Saprolegniasis in Incubated Clarias gariepinus Eggs Using Pyocyanin Extracted from Pseudomonas aeruginosa

Authors: G. A. Oladosu, P. O. Ogbodogbo, C. I. Makinde, M. O. Tijani, O. A. Adegboyega

Abstract:

Saprolegniasis is a major pathogenic infection that contributes significantly to poor hatching rates in incubated fish eggs in the African catfish hatchery in Nigeria. Malachite green, known to be very effective against this condition, has been banned because it is carcinogenic. There is therefore the need for other effective, yet safer method of controlling saprolegniasis in incubated fish eggs. A total of 50 ml crude, chloroform extract of pyocyanin from which solvent was removed to attain 30 ml, having a concentration of 12.16 ug/ml was produced from 700 ml broth culture of Pseudomonas aeruginosa isolated from a previous study. In vitro susceptibility of the fungus was investigated by exposing fungal infected eggs to two different time-concentration ratios of pyocyanin; 0.275 ug/ml and 2.75 ug/ml for 1 and 24 h, and 5 mg/L malachite green as positive control while normal saline was the control. Efficacy of pyocyanin was evaluated using the degree of mycelial growth inhibition in the different treatments. Fertilized Clarias gariepinus eggs (between 45 to 64 eggs) were then incubated in 20 ml of medium containing the similar concentrations of pyocyanin and malachite green, with freshwater as control for 24 hours. Hatching rates of the incubated eggs were observed. Three samples of un-hatched eggs were taken from each medium and observed for the presence of fungal pathogens using microscopy. Another batch of three samples of un-hatched eggs from each treatment was also inoculated on Sabourand dextrose agar (SDA) using Egg-Agar Transfer technique to observe for fungal growth. Mycelial growth was inhibited in fungal infected eggs treated with 2.75 ug/ml for 24 h and the 5 mg/L malachite green for both 1 h and 24 h. The mortality rate was 100% in fertilized C. gariepinus eggs exposed for 24 h to 0.275 and 2.75 ug/ml of pyocyanin. The mortality rate was least in the malachite green followed by the control treatment. Embryonic development was observed to be arrested in the eggs treated with the two pyocyanin concentrations as they maintain their color but showed no development beyond the gastrula stage, whereas viable eggs in the control and malachite green treatments developed fully into healthy hatchlings. Furthermore, microscopy of the un-hatched eggs revealed the presence of a protozoan ciliate; Colpidium sp. (Tetrahymenidae), as well as a pathogenic fungus; Saprolegnia sp. in the control, but not in the malachite green and pyocyanin treatments. Growth of Saprolegnia sp. was also observed in SDA culture of un-hatched eggs from the control, but not from pyocyanin and malachite green treated eggs. Pyocyanin treatment of incubated eggs of Clarias gariepinus effectively prevented fungal infection in the eggs, but also arrested the development of the embryo. Therefore, crude chloroform extract of pyocyanin from Pseudomonas aeruginosa cannot be used in the control of Saprolegniasis in incubated Clarias gariepinus eggs at the concentration and duration tested in this study.

Keywords: African catfish, bioprophylaxis, embryo, saprolegniasis.

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References:


[1] Anetekhai, M. A. (2013). Catfish aquaculture industry assessment in Nigeria. Inter-African Bureau for Animal Resources. African Union, pp. 96, 2013
[2] Potongkam K and Miller J. Manual on catfish hatchery and production; A guide for small and medium scale hatchery and farm producers in Nigeria. Aquaculture and Inland Fisheries Project. NSPFS/FAO. 30pp, 2006.
[3] Al-Shammari R. H., Al-Mukhtar, E. A. and Habib, K. A. Saprolegniasis on the eggs of the common carp (Cyprinus carpio L.) with the occurrence of micropredators at Al-Wahda fish hatchery, south of Baghdad. Iraqi J. Aquacul. Vol. (7) No. (1), pp. 65- 76, 2015.
[4] Fagbohun O. and Oladosu G.A. Detection of Saprolegnia species on incubated eggs of Clarias gariepinus (Burchell 1822) using morphological and molecular characterization. Journal of the Association of Nigerian Fisheries Scientists, Vol. 1, pp. 50-55, 2018.
[5] Srivastava S, Sinha R and Roy D. (2004). Toxicological effects of malachite green. Aquat Toxicol.66, pp. 319-329, 2004.
[6] Noga, E. J. Fish Disease: diagnosis and treatment (2nd ed.), Wiley-Blackwell. 519pp, 2010.
[7] Costa A.L. and Cusmano V. Anti-mycotic activity of pyocyanin in vitro and in vivo on a pathogenic strain of Candida albicans. Gen Bacteriol Virol Immunol 66, pp. 297-308, 1975.
[8] Kerr J.R., Taylor G.W, Rutman A., Hoiby N., Cole P.J. and Wilson R. Pseudomonas aeruoginosa pyocyanin and 1-hydroxyphenazine inhibit fungal growth. Journal of Clinical Pathology 52, pp. 385-387, 1999.
[9] Essar D.W., Eberly L., Hadero A. and Crawford I.P. Identification and characterization of genes for a second anthranilate synthase in Pseudomonas aeruginosa:interchangeability of the two anthranilate synthases and evolutionary implications. Journal of Bacteriology 172, pp. 884-900, 1990.
[10] Rehulka, J. Fungal Diseases In Diagnostics, prevention and therapy of fish diseases and intoxications: Manual for international training course on fresh-water fish diseases and intoxications: Diagnostics, Prophylaxis and Therapy (eds) Svobodova, Z and Vykusova, B. FAO. 270p, 1991.
[11] Jamu, D. M. and Ayinla, O. A. Potential for the development of aquaculture in Africa NAGA Vol.26 No 3, pp. 9-13, 2003.
[12] Anjaiah V., Koedam N., Nowak-Thompson B., Loper J. E., Höfte M., Tambong J. T. and Cornelis P. Involvement of phenazines and anthranilate in the antagonism of Pseudomonas aeruginosa PNA1 and Tn5-derivatives towards Fusarium sp. and Pythium sp. Molecular Plant- Microbe Interaction 11, pp. 847-854, 1998.
[13] Bano N. and Musarrat J. Characterization of a new Pseudomonas aeruginosa strain NJ-15 as a potential biocontrol agent. Current Microbiology 46, pp. 324-328, 2003.
[14] Muller M and Merrett N. D. Mechanism for glutathione-mediated protection against the Pseudomonas aeruginosa redox toxin, pyocyanin. Chemico-Biological Interacrtions Vol. 232, pp. 30-37, 2015.