The anti-nutritional values in raw, autoclaved, boiled, fermented, soaked and toasted castor oil seeds (Ricinus communis L.) collected from Ado-Ekiti metropolis, Nigeria were evaluated. The time allotted for each of the treatments include, 20, 30 and 40 min (CSCA20, CSCA30 and CSCA40) for autoclaving; 40, 50 and 60 min (CSCB40, CSCB50 and CSCB60) for boiling; 48, 72 and 96 h (CSCF48, CSCF72 and CSCF96) for fermenting; 48, 72 and 96 h (CSCS48, CSCS72 and CSCS96) for soaking and 20, 30 and 40 min (CSCT20, CSCT30 and CSCT40) for toasting. The raw sample which served as control was tagged CSCR00. The 15 processed and the raw samples were decorticated, after the wet samples (except toasted) had been sundried for four days, ground and then representative samples were taken to the laboratory for anti-nutrients determination according to AOAC (2006), Abeza et al., (1968), Reddy et al., (1982) and Wang et al., (1996) (tannin, oxalate, phytate and lectin respectively). 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 phytate, oxalate, tannin and lectin with increase in temperature of all the treatment methods adopted. Owing to the drastic reduction in virtually all the parameters examined, castor seed sample autoclaved for 30 min (CSCA30) was considered best level among others. It was therefore recommended for fish feed formulation.

Keywords: Castor oil seed, R. communis, phytate, oxalate,tannin and lectin.