Fungal screening
A microbiological analytical procedure of Kaufman et al. (1968)
with some modifications was used in this study and carried out
under aseptic condition. Accordingly, 1 g of ground sample was
weighed into a sterile test tube, suspended in 9 ml of sterile Ringer's
solution and vortexed. The suspension (1 ml) was serially diluted in
9 ml of the Ringers' solution further to 10À6. One ml from each
dilution was cultured on Ohio Agricultural Station agar (OAESA)
and potato dextrose agar (PDA) and incubated for 5e7 days at 30 C.
After incubation, fungal colonies were counted macroscopically
using a colony counter. Colony forming units per gram (CFU/g) of
sample was calculated. Isolates of A. flavus and A. parasiticus were
further sub-cultured on PDA, Czapek yeast agar (CYA) and malt
extract agar (MEA) under aseptic conditions and incubated at 30 C
for 7 days. Pure colonies were harvested and stained with lacto
phenol in cotton blue and viewed microscopically. The macro- and
microscopic identifications of the species (Fig. 1) isolated from the
compound feed study samples were done following the identifi-
cation keys of Klich and Pitt (1988) and Klich