A. awamori is in fact in widespread use in the food industry in eastern countries such as Japan, known as koji. The strains tend to have been 'in captivity' in human hands for thousands of years (e.g. Tea fermentation) and are thought to be quite harmless to humans.
The experimenters found that the use of Aspergillus increased the amount of meat produced when the amount of food uptake by the chickens actually fell. This surprising result suggests that the fungus may help the chickens digest their food, but it is also suggested that chicken muscle tissue growth is also encouraged.