WATER ADDITION AND FERMENTATION PERIOD EFFECTS ON THE PROXIMATE AND ANTI-NUTRITIONAL CONTENT OF CASSAVA PEEL FERMENTED WITH Aspergillus niger

Cassava peel is an agro-industrial residue with potential as a livestock feed ingredient, but its nutritional value and anti-nutritional constituents may be influenced by fermentation conditions. This study evaluated the effects of water-addition level and fermentation period on proximate composition and anti-nutritional factors of cassava peel fermented with Aspergillus niger. Water was added at substrate-to-water ratios of 1:0.5 and 1:1 (weight: volume) and samples were assessed after 48, 96, 144 and 192 h, with three replicates per treatment. Proximate components measured were crude protein (CP), ether extract (EE), crude fibre (CF), ash and nitrogen-free extract (NFE). Alkaloids, phytate, hydrogen cyanide (HCN), saponins and tannins were also determined. Water-addition level, fermentation period and their interaction significantly affected CP, EE, ash and NFE (p < 0.05). Fermentation period significantly affected CF (p < 0.001), while water-addition level and its interaction with time did not. Crude protein (CP) was highest at 1:1 water addition after 96 h (6.12%) and EE peaked under this treatment and period (12.10%). Nitrogen free extract (NFE) was highest at 1:0.5 after 192 h (67.53%). Fermentation period significantly affected all measured anti-nutritional factors. Alkaloids, phytate, HCN, saponins and tannins declined over time; the lowest recorded values occurred at 192 h for alkaloids, phytate, saponins and tannins, while HCN reached 0.68 mg/kg by 144 h and remained at that level at 192 h. Responses varied by component, indicating that fermentation conditions should be chosen according to the desired nutritional outcome.