. Fungal culturing of test ingredient
Freshly harvested cassava root tubers (TMS 30572) were washed, chipped, dried (100–122 g/kg DM) and ground (2.5 mm
sieve) to form unpeeled cassava root meal (UCRM). Pure laboratory strain of A. niger (Chinese International Centre for Type
Culture Collection; CICC, No. 41126) was used for inoculation. Briefly, 200 g UCRM was weighed each into ten (10) conical
flasks (n = 10), moistened (250 g/kg MC) with nutrient solution (containing analytical grade of 80 g urea, 7 g MgSO4·2H2O, 13 g
KH2PO4 and 20 g citric acid) and inoculated with 2 × 107 fungal spore per gram of UCRM. Each conical flask was air-sealed
and the substrate incubated (30 ◦C) for 6 days in a bed-packed incubator. At the end of incubation period, fermented UCRM
was sterilized (120 ◦C for 20 min) and used for chemical analysis. All laboratory protocol was done at the Key Laboratory of
Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan,
China.