The effects of Hydroalcoholic Extract of Withania Somnifera Leaf and Fish Oil on Growth Performance, Bone Calcification, Morphological and Mechanical Characteristics and Gene Expression in Broiler Chickens

This experiment was conducted to study the effects of hydroalcoholic extract from Withania somnifera (WS) leaf and fish oil on performance, mineral retention, bone morphological and mechanical characteristics, and Calbindin-D 28K (CALB1) gene expression in broiler chickens. Treatments were arranged in a CRD with a 2 × 3 × 2 factorial arrangement consisted of two dietary Ca levels (low: 30% less than normal Ca level, and adequate: normal Ca level), three concentrations of WS (0, 100 and 200 mg/kg diet) and two concentrations of fish oil (0 and 2 %). A total of 600 one-day-old Ross 308 male broilers were divided into 12 treatments with 5 replicates and 10 chickens in each. At 24 d of age, one bird per replicate was randomly killed, and tibiae were removed. Results showed that dietary supplementation of WS significantly improved feed conversion ratio (FCR) (P < 0.05). Birds fed diets supplemented with WS had significantly higher Ca content in the tibia (P < 0.05). Dietary inclusion of fish oil significantly increased the width of the bone proliferative zone (P < 0.05). In biomechanical properties, dietary supplementation of WS and fish oil significantly increased the shear force (P < 0.05). Synergistic effects of WS and fish oil showed that the addition of WS at 200 mg/kg in birds fed diets containing fish oil led to a significant increase in tibial stiffness (P < 0.05). Low-Ca diet up-regulated duodenal CALB1 mRNA expression (P < 0.05). Supplementation of WS also resulted in a significant up-regulation in the gene expression of CALB1in both duodenum and jejunum (P < 0.001). In conclusion, dietary supplementation of WS may have beneficial effects on bone calcification and strength by increasing the CALB1 gene expression and Ca retention. Also, synergistic effects of WS and fish oil may improve the mechanical properties of the tibia.