Effect of inorganic or organic selenium supplementation on productive performance, egg quality and some physiological traits of dual-purpose breeding hens

One hundred and twenty (100 female + 20 male) 30-weeks-old dual-purpose breeding hens of Gimmizah strain were housed in individual cages in a semi-open house. Birds were distributed randomly into five treatments of 20 female + 4 male. The 1(st) treatment was fed a control (unsupplemented) diet (17.5% CP and 11.4 MJ per kg diet) containing 0.10 mg Se/kg (low level). The 2(nd), 3(rd), 4(th) and 5(th) treatments were fed the control diet supplemented with 0.15 and 0.30 mg Se/kg from inorganic (sodium selenite) and organic (selenomethionine, as Se-yeast Selplex (R) Alltech, Nicholasville, USA) sources, respectively. The total concentration of Se in experimental diets was 0.25 (medium level) and 0.40 ppm (high level). Feed and water were provided ad libitum throughout the experimental period (30-50 weeks of age). Different Se levels of the organic and inorganic form and their interaction did not significantly (P > 0.05) affect egg production percentage, and most of egg quality traits. Egg weight and egg mass significantly (P < 0.002) increased and the feed conversion ratio (FCR) significantly (P < 0.04) improved due to Se supplementation compared with hens fed the control diet. Piped embryos and spleen percentage significantly (P < 0.05) decreased due to Se supplementation. In addition, the level of organic and inorganic Se and their interaction significantly (P < 0.0001) decreased the plasma cholesterol concentration. Tibia Ca and P percentages and yolk selenium concentration significantly (P < 0.03; P < 0.0001 and P < 0.0001, respectively) increased due to Se supplementation and the greatest increase was recorded by a group fed diet with the high level (0.40) of organic Se. The duodenal and intestinal mucosa of the ileum was negatively affected by the high level of inorganic Se while chickens fed the organic form showed less toxic effects in hepatic and splenic tissues than those receiving the inorganic form. In conclusion, the organic and inorganic Se supplementation at 0.15 and 0.30 mg/kg diet, which corresponded to a dietary level of 0.25 and 0.40 mg/kg diet, improved the productive and reproductive performance of Gimmizah breeding hens. A decrease in plasma total cholesterol and an improvement in the bone mineralization were observed. The level of 0.25 mg/kg diet of organic Se was adequate to enrich eggs, which may be recommended for practical application and which would improve the consumer health benefit.