TOXIGENIC MOLDS ON FISH FEEDS-I: IMPACT OF CLIMATIC FACTORS

Abstract

The present communication is a survey report carried out to assess the
incidence of toxic mycoflora on seven types of agriculture products/byproducts
incorporated during fish culture as supplementary dietary items. Samples
were obtained from various sources at Darbhanga, Madhubani and
Samashtipur districts during summer, winter and monsoon months. Out of
the total 177 4 samples, only 894 appeared to be fresh visually reflecting
average incidence of contamination around 46.6%. However, the apparently
fresh samples, when subjected to culture, 26.9% of them were found to be
contaminated. Thus, degree of fungal spoilage in feed ingredients in parts of
north Bihar appears to be significantly high (73.5%). The present study
illustrates the facts with special reference to Aspergillus flavus, A parasiticus
(elaborating aflatoxins) A. ochraceous, Penicilium viradicatum (elaborating
ochratoxins) andAversicolor (elaborating sterigmatocystin). The other strains
already known for their toxigenic potentials that appeared on the present
substrates included A. niger, A. fumigatus, A. candidus, P. islandicum,
Rhizopus spp. and Mucur spp. Studies indicate that the prevelent climatic
factors like temperature and relative humidity facilitate a congenial condition
almost all through the year and in particular during summer and monsoon
months. But water content of the substrates is a vital factor that further
accelerates the pace of mycobial spoilage. A thorough sun-drying of the
agricultural commodities before prolonged storage to bring water content
below the ''low risk limit" may significantly reduce the incidence of molds.
Keywords : Toxigenic molds, fish feeds, fungal spoilage