Cultural and nutritional studies of zoopathogenic fungi associated with livestock feeds in Nigeria

Abstract

Mycelial growth and nutritional physiology of zoopathogenic Aspergillus fumigatus FRES., Thermoascus aurantiacus MIEHE, and Thermomyces lanuginosus TSIK., obtained from livestock feeds and poultry droppings in Nigeria were studied. An optimal pH-temperature range of 5.5-6.5 and 37 degrees - 45 degrees C was recorded for the growth of these fungi. Various sources of carbon supplied in the growth medium, except sorbose and rhamnose, were utilized for growth. Only Aspergillus fumigatus caused considerable weight losses of the filter papers supplied and hydrolyzed the carboxy-methyl cellulose (CMC) in the medium. The culture filtrates of this fungus contained CM-cellulases which also hydrolyzed CMC to reducing sugar at 45 degrees C. D-glucose and L-asparagine concentrations in the range of 15-20 g/liter and 2.5-5 g/liter, respectively, were best for growth of the test fungi. Various forms of organic and inorganic nitrogen provided were also utilized. The inorganic sources of nitrogen could readily substitute the organic forms at the optimal growth conditions.