Mohammad Mohammadi - Department of Animal Science, Higher Education Complex of Saravan. P.O. Box: ۹۹۵۱۶-۳۴۱۴۵, Saravan, Sistan and Baluchestan, Iran
Mohammad Taher Mirakzehi - Department of Animal Science, Higher Education Complex of Saravan. P.O. Box: ۹۹۵۱۶-۳۴۱۴۵, Saravan, Sistan and Baluchestan, Iran
Hassan Saleh - Department of Animal Science, Higher Education Complex of Saravan. P.O. Box: ۹۹۵۱۶-۳۴۱۴۵, Saravan, Sistan and Baluchestan, Iran
Tayebeh Baranzehi - Department of Biology, University of Sistan and Baluchestan, P.O. Box: +۹۸۱۵۵-۹۸۷, Zahedan, Iran

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 ۲۸K (CALB۱) gene expression in broiler chickens. Treatments were arranged in a CRD with a ۲ × ۳ × ۲ factorial arrangement consisted of two dietary Ca levels (low: ۳۰% less than normal Ca level, and adequate: normal Ca level), three concentrations of WS (۰, ۱۰۰ and ۲۰۰ mg/kg diet) and two concentrations of fish oil (۰ and ۲ %). A total of ۶۰۰ one-day-old Ross ۳۰۸ male broilers were divided into ۱۲ treatments with ۵ replicates and ۱۰ chickens in each. At ۲۴ 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 < ۰.۰۵). Birds fed diets supplemented with WS had significantly higher Ca content in the tibia (P < ۰.۰۵). Dietary inclusion of fish oil significantly increased the width of the bone proliferative zone (P < ۰.۰۵). In biomechanical properties, dietary supplementation of WS and fish oil significantly increased the shear force (P < ۰.۰۵). Synergistic effects of WS and fish oil showed that the addition of WS at ۲۰۰ mg/kg in birds fed diets containing fish oil led to a significant increase in tibial stiffness (P < ۰.۰۵). Low-Ca diet up-regulated duodenal CALB۱ mRNA expression (P < ۰.۰۵). Supplementation of WS also resulted in a significant up-regulation in the gene expression of CALB۱in both duodenum and jejunum (P < ۰.۰۰۱). In conclusion, dietary supplementation of WS may have beneficial effects on bone calcification and strength by increasing the CALB۱ gene expression and Ca retention. Also, synergistic effects of WS and fish oil may improve the mechanical properties of the tibia.

Bone, Fish Oil, Broiler chicken, Withania somnifera, CALB۱ gene expression