Acid detergent fiber (ADF) content was determined by following the same procedure for NDF except a different detergent solution was used i.e. acid detergent solution (20 g cetyl trimethylammonium bromide dissolved in 700 mL distilled water. 27.56 mL of 96.7% sulfuric acid was then added to the solution and the topped up to 1 L with distilled water). The ADF content was then calculated using the following equation: