Dietary Influence of Charcoal Supplementation on Theobromine Remediation in Cocoa Bean Shell Fed to Broiler Chickens

Abstract

Cocoa bean shell (CBS) is one of the by-products generated by cocoa producing and processing countries that have potential as livestock feed resource. However, its use has been limited largely due to theobromine toxicity. In this study, a feeding trial was conducted to determine whether the adsorbing capacity of charcoal would suppress theobromine toxicity and support growth performance, carcass characteristics and haematology of broiler chickens fed CBS based diets. Five diets were formulated with a standard diet 1 (as control). Diets 2 and 3 contained 5% and 10% CBS respectively, while diets 4 and 5 contained 5% and 10% CBC with 25gkg-1 charcoal supplementation arranged in 2x2 factorial lay-out plus the control.  Growth performance was examined at the starter (2-4 weeks), finisher (5-8 weeks) and combined starter/finisher phases (2-8weeks). Overall performance showed that broilers on control had a higher (P <0.05) weight gain and better feed conversion ratio than the other diets. At 10% inclusion level of CBS, a significant (P<0.05) reduction in weight gain was observed, which did not improve with supplemental charcoal. Broilers fed CBS diets consumed more (P<0.05) feed than the birds fed control diet. Carcass yield was significantly lower (P<0.05) in broilers fed CBS with supplemental charcoal, while haematological parameters exhibited no significant (P>0.05) variations across treatments. It could be concluded that growth performance was consistently low at 10% level of CBS compared to 5% CBS and 0% CBC (control diet). Moreover, supplemental charcoal at 25g/kg^-1d in this study could not suppress the negative impact of theobromine contained in either 5 or 10% CBC. Caution should also be exercised in the use of charcoal as feed supplement because of their adsorbing property capable of compromising micronutrients availability in vivo.