Nutritional value of rice husks as an animal feed / Norasmah Misban

Methods for improving the feeding value of crop residues including rice husks by physical, chemical and biological treatment were reviewed. The objectives of this research were to detemiine the chemical composition and digestibility of rice husks and to identify a method of upgrading its nutritional value. Rice husks were treated with 4% urea or 4% sodium hydroxide solution or fermented by the white-rot fungus, Pleurotus sajor -cajn for 0, 10 and 25 days. Three nitrogenous supplements, PKC rice bran, and urea were compared as supplements to the rice-husk substrate. Untreated and chemically treated rice husks as well as the spent waste after fermentation were analysed for total ash, neutral detergent fibre, ash insoluble in neutral detergent solution, in vitro digestibility and cellulase degradability. Data were statistically analysed on a SAS (Statistical Analysis System) package. NaOH-treated husks were significantly lower in NDF and significantly higher in IVD compared to the control. Fermentation by Pleurotus increased in vitro digestibility, the highest value obtained with the rice bran supplement after 25 days. Rice husks may have potential as an animal feedstuff but only after chemical or biological pre-treatment.