Optimization of Solid-State Fermentation of Sorghum bicolor Using Aspergillus niger and Its Impact on Nutritional Composition

Abstract

The production of poultry contributes significantly to global food security by offering a reasonably priced source of protein. However, a major obstacle is the high cost of feed components, especially maize. Because of its high fiber content and anti-nutritional elements like tannins and phytates, sorghum stalk, an abundant agricultural residue, presents a possible substitute but is still neglected. This study aimed to optimize the solid-state fermentation of sorghum stalk using aspergillus niger to enhance its nutritional composition for inclusion in broiler feed formulation as maize replacement. The fermentation process was optimized by varying pH, ranging from pH levels of 5 to 8 and temperature of 200C to 350C together with fermentation duration to maximize enzymatic activity and microbial biomass growth in six days. From the results pH6 and temperature 350C has the highest biomass growth. The proximate composition at pH6 were; moisture (45.63% to 37.37%), crude fat (2.41% to 1.24%), crude fibre (4.41% to 2.91%), Crude protein (2.47% to 2.01%), Ash (5.56% to 3.60%) and Carbohydrate (39.83%). The proximate result at temperature 350C were; moisture (38.83%), crude fat (2.87%), crude fibre (4.27%), Crude protein (2.80%), Ash (5.27%), and Carbohydrate (45.95%). The results obtained highlighted the potential of solid-state fermentation as an effective method for improving the nutritional quality of sorghum stalk enhancing its value as animal feed.