Effects of Cashew Nut Shell Extract on Ruminal Fermentation and Nutrient Digestibility under Continuous Culture

The overall objective of this study was to determine the dose response to four levels of cashew nut shell extract in a granulated form (CNSE, containing 59% anacardic acid and 18% cardol) on culture pH, rumen fermentation metabolites, and apparent nutrient digestibility in continuous culture fermenters. The study was conducted as a generalized randomized complete block design with four treatments and four replications per treatment. The four treatments were randomly assigned to eight fermenters for two incubation runs of 10 d. Treatments consisted of (1) Control (CO, no CNSE), (2) Control plus 100 ppm of CNSE, (3) Control plus 200 ppm of CNSE, and (4) Control plus 300 ppm of CNSE. Fermenters were fed 52 g/d (DM basis) of a total mixed ration (TMR; 17.0% crude protein (CP), 29.7% NDF, and 29.9% starch), divided between two feedings at 0800 and 2000 h. The apparent digestibility of dry matter (DM), organic matter (OM), and neutral detergent fiber (NDF) were not affected by CNSE supplementation. Similarly, CNSE had no effect on culture pH, total volatile fatty acids (VFA) or individual VFA molar proportions. These results suggest that at the dosages evaluated in this study, CNSE has no impact on the rumen fermentation profile and the apparent nutrient digestibility under continuous culture conditions.