CAN DIETARY DRIED OREGANO IMPROVE THE DIGESTIBLE NUTRIENT INTAKE OF GROWING GOATS?

Abstract

The aim of this study was to evaluate the effect of dietary dried oregano on the intake of dry matter and digestible nutrients in growing goats. Fifteen 7-month old male goats were fed on diets with 0, 10 and 50 g kg-1 of dried oregano based on dry matter (DM). A completely randomized design was used, and each animal was assigned to one pen and treatment (3 treatments x 5 replicates) for 45 days. Voluntary intake of DM and nutrient digestibility were measured using acid insoluble ash as an indigestible marker. Daily weight gains were 146, 126 and 122 g d-1 per treatment (P = 0.08). A positive effect on digestible nutrient intake was obtained with both oregano concentrations. Linear and quadratic effects were obtained in the digestible neutral detergent fibre (NDF) and the other nutrient intakes, respectively. No effect was observed in DM or digestible acid detergent fibre (ADF) intakes. Therefore, there was a positive effect on the coefficient of DM in both treatments and NDF digestibility in the treatment with the highest concentration of dietary dried oregano. The positive effect of dried oregano on the goats’ diet in terms of digestible nutrient intake suggests that oregano essential oil (EO) modifies the ruminal microflora by improving digestibility, rather than having an effect on the feeding behavior of the animal due to the flavour of the diet. The treatment containing 10 g kg-1 of dietary dried oregano promoted voluntary DM consumption and increased the intake of digestible nutrients, while that containing 50 g kg-1 of dried oregano only promoted the intake of digestible NDF.