Alternatives to antibiotics as growth promoters for broilers could reduce bacterial resistance to antibiotics, while at the same time maintaining growth and improving carcass composition. We investigated the benefits of adding the medicinal plants sumac and thyme at 1, 2 or 3% of the diet for male Ross broiler chicks, with four replicates of ten birds in each treatment group and a Control. Feed intake was reduced for chickens fed the sumac supplements, and, at the two higher doses, defeathered body weight was also reduced. Abdominal fat was reduced by 41% in chickens fed thyme and 62% in those fed sumac. This reflected reduced low density lipoproteins in their blood, and in higher dose thyme treatments and all sumac treatments, reduced high density lipoproteins in blood. Apart from this, there was little effect of the supplements on carcass composition. Blood glucose was reduced in the supplemented chickens. There was evidence of higher antibody titers to Newcastle disease and influenza in supplemented chickens. It is concluded that both thyme and sumac offer potential to reduce fat content and improve disease responsiveness in broiler production systems.
Keywords: feed additive; poultry nutrition; sumac; supplements; thyme; weight gain.