Nutritive values in raw, autoclaved, boiled, fermented, soaked and toasted castor oil seeds (Ricinus communis L.), Zibo Castor No. 3 variety, collected from Ado-Ekiti metropolis, Nigeria were evaluated. The treatments consisted of six processing methods and three levels. Samples exhibited significant difference (p˂0.05) compared to the control sample and among one another in terms of all the parameters examined. There was reduction in crude protein (CP), moisture, lipids and ash contents with increase in all the treatment methods adopted. However, moisture and ash increased irregularly along the periods of autoclave treatment. There was increase in Crude fiber (CF) and nitrogen free extract (NFE) with increase in autoclaving, boiling, fermenting, soaking and toasting. Cases of irregular decrease and increase of values were however observed along the trend of periods of each treatment. Owing to its quality of parameters examined, particularly protein, CF, ash and NFE, castor seed sample boiled for 40 minutes (BCSC40)) was considered best level among others. It was therefore recommended for fish feed formulation.

Keywords: Castor oil seed, R. communis, autoclaving, boiling, fermenting, soaking and toasting.