Nutritive value and biochemical changes in broiler chickens fed detoxified castor kernel cake based diets
Castor bean (Ricinus communis Linn.) is an important oilseed rich in protein but rarely used as livestock feed due to antinutritional factors. Castor seed was detoxified using combined processing techniques of moist heating and fermentation (5 and 7- day) or lye treatment and fed to150 day-old Anak 2000 broiler chicks at varying levels (0, 10, 15 and 20%) in a 49-day experiment. There were 10 dietary treatments: a control diet, void of castor bean cake (CBC), 3 diets (at 10, 15 and 20%) each containing either heat cum lye treated CBC, heat cum 5-day fermentation or heat cum 7-day fermentation in a completely randomized design. The chemical constituent of detoxified castor kernel, performance, haematology and serum metabolites of the broilers served was evaluated. About 71% of haemaglutinin in the cake which constitutes the major impediment was removed via thermal cum lye treatment while thermal cum fermentation removed about 60%. Feed intake of lye treated CBC was not different (P>0.05) from control up to 20% inclusion although, the weight gained were not the same (P<0.05) with the bird on control. Both feed intake and weight gain in 5 and 7-day fermentation were similar (P>0.05) and significantly lower (P<0.05) than the control and lye treatment. Packed cell volume (PCV) value was highest in control and followed closely by lye treatment at 10% inclusion. A significant difference (P<0.05) was observed at 15% and 20% inclusion particularly on birds placed on fermented based diet. The white blood cell (WBC) increased significantly (P<0.05) with increased level of inclusion of CBC. There was downward trend in serum protein while an upward trend was observed for urea and creatinine with increasing levels of detoxified CBC. It was concluded that heat cum lye treatment can be used to detoxify CBC and such treated product maybe safely used at 15% inclusion rate.
Key words: Castor bean cake, detoxification, broilers, performance, blood component.