Evaluation de la qualité mycologique de l’eau d’élevage et de l’aliment destiné à la nourriture du Tilapia du Nil « Oreochromis niloticus » (Linnaeus, 1758)

Abstract

The present work focuses mainly on the presence of fungi in fish farm water and in feed for Nile Tilapia "Oreochromis niloticus". Analysis of the results of fungal contaminant monitoring carried out by several researchers across several countries in the world [East Africa (Kenya, Tanzania, Uganda, Rwanda); Nigeria and Brazil] shows that all water and feed samples analysed were contaminated with various fungal genera with the presence and levels of contamination varying from one region to another, except for one category of imported commercial feeds collected in East Africa which were free of any contamination. The study of macroscopic, microscopic and molecular aspects of strains isolated from food showed the presence of 29 fungal species which are : Aspergillus flavus, A. tamarii, A. niger A. oryzae, A. sp., A. versicolor, A. fumigatus, A. candidus, Penicillium citrinum, P. glabrum, P. minioluteum, P. corylophilum , P. citreonigrum , P. italicum , P. variabile, P. notatum, P. chrysogenum, P. sp..., Cladosporium sp, C. herbarum, Fusarium (hyalophragmial), Mucor sp, Wallemia sp, Eurotium sp, E. rubrum, Aureobasidium sp, Nigrospora sp, Phoma sp, Hyphopichia burtonii, in addition to unidentified yeasts and endophytic fungi. Concerning farmed water, and according to the results of the literature, 14 species of fungi were revealed and are as follows: Aspergillus niger, Aspergillus sp., A. flavus, A.penicilloides, A.terreus, Penicillium notatum, Penicillium sp., Mucor sp., Saccharomyces cerevisiae, Zygosaccharomyces bailii, Rhizopus stolonifer, Scopulariopsis brevicaulis, Alternaria alternata, Trichophyton sp and unidentified yeasts. The quality of fish reared in aquaculture is related to the quality of the water used for rearing and the quality of the feed used for their food. However, the contamination of the latter by toxinogenic fungi leads to a real problem in aquaculture and is particularly dangerous for the health of humans and consumer animals.