Effects of essential oils of Cashew and Castor on intake, digestibility, ruminal fermentation and purine derivatives in beef cattle fed high grain diets

Abstract

The objective of this study was to determine the effects of essential oils of Anacardium occidentale (Cashew) and Ricinus communis (Castor) on intake, digestibility, ruminal fermentation and excretion of purine derivatives in beef cattle fed high grain diets. Five Nellore steers fitted with ruminal cannula were used in a 5x5 Latin square design (21 days period). The treatments were control MON (0.2 g monensin animal day-1¬) and 1, 2, 4 and 8 g EO animal day-1 (Essential oils - Oligobasics®). All the animals had a basal diet, corn silage-based total mixed ration (TMR) of 80:20 concentrate:forage ratio. Intake, digestibility, ruminal fermentation and excretion of purine derivatives were determined over five consecutive days in each period. Intake and digestibility of dry matter (DM), neutral detergent fibre (NDF) and crude protein (CP) were not influenced by treatments (P > 0.05). However, increasing levels of EO showed a quadratic effect (P < 0.014) above 2 g animal day-1 on the ruminal pH. The excretion of allantoin and uric acid were not influenced by the treatments (P > 0.05), but levels above 2 g day decreased the synthesis of microbial proteins (P < 0.05). It is concluded that the EO of A. occidentale and R. comunnis effectively controlled ruminal fermentation as well as sodium monensin at the studied levels. EOs have the potential to be used in place of monensin in the studied levels.