This investigation explored the impact of dietary frankincense resin oil (FO) on growth performance parameters, intestinal histomorphology, fatty acid composition of the breast muscle, and the immune status of broilers. We allotted 400, three-day-old, male chicks (Ross 308 broiler) into four treatment groups (ten replicates/group; ten chicks/replicate). They were fed a basal diet with different concentrations of FO (0, 200, 400, and 600 mg kg-1). FO supplementation increased the overall body weight (BW) and body weight gain (BWG) by different amounts, linearly improving the feed conversion ratio with the in-supplementation level. Total feed intake (TFI) was not affected. Growth hormones and total serum protein levels also linearly increased with the FO level, while albumin was elevated in the FO600 group. Moreover, total globulins increased linearly in FO400 and FO600 treatment groups. Thyroxin hormone (T3 and T4) levels increased in all FO treatment groups without affecting glucose and leptin serum values. Different concentrations of FO supplementation in the diet increased the activities of Complement 3, lysozyme, and interleukin 10 levels in the serum. Dietary FO in broilers increased the total percentage of n-3 and n-6 fatty acids. It also increased the ratio of n-3 to n-6 linearly and quadratically. Additionally, FO supplementation led to the upregulation of immune clusters of differentiation 3 and 20 (CD3 and CD20) in the spleen, along with improving most of the morphometric measures of the small intestine. In conclusion, FO up to 600 mg kg-1 as a feed additive in broiler chicken production is valuable for promoting their growth, intestinal histomorphology, and immune status along with enriching breast muscle with polyunsaturated fatty acids (PUFA).
Keywords: biochemical indices; broiler chickens; fatty acid profile; frankincense oil; growth; histomorphology; immune.