IN OVO SELENIUM (SE) INJECTION OF INCUBATING CHICKEN EGGS: EFFECTS ON EMBRYO VIABILITY, TISSUE SE CONCENTRATION, LIPID PEROXIDATION, IMMUNE RESPONSE AND POST HATCH DEVELOPMENT
Studies were conducted to investigate the effects of in ovo injection of selenium (Se) either as seleno-methionine (Se-Met) or sodium selenite (Na2SeO3) into the yolk of incubating eggs on tissue Se concentration, embryo livability, lipid peroxidation, immune response and growth performance. When white-shelled eggs were injected with 0.1ml of solutions providing 0, 2.5, 5, 10 or 20 μg Se/egg, no detrimental effects on embryo viability at 20 days of incubation were noted. The effects on tissue Se concentrations suggested that Se-Met and Na2SeO3 were metabolized differently by the chick embryo. In a subsequent study using injection doses up to 60 μg/egg, a greater linear response in tissue Se was obtained with Se-Met, compared with Na2SeO3 (P \u3c 0.01). Minimal changes in heart and breast muscle Se concentrations were noted above the 40 μg dose when Na2SeO3 was used (P \u3e 0.05). In a study with broiler eggs, injection doses of 0, 2.5, 5, 10, 20 and 40 μg Se/egg were used. Se-Met or Na2SeO3 at doses up to 40 μg Se/egg had little effect on embryo viability. Injecting Se-Met resulted in greater tissue Se accumulation than Na2SeO3 at 20 days of incubation. In another study with broiler eggs using injection doses up to 40 μg Se/egg, Se-Met injection resulted in higher hatchability, reduced lipid peroxidation in the lung and heart muscle of the embryos after 20 days incubation and higher Se concentrations in heart and breast muscle of hatched chicks through 7 days and in lung through 21 days of growth. In a feeding trial with broiler breeder hens, adding 0.3 mg/kg of Se as Se yeast or Na2SeO3 to the diet improved tissue Se status at hatching of progeny chicks. Taken together, these results indicate that injection of Se into the yolk of incubating eggs may be useful for enhancing Se status during embryonic and early post-hatch development. Therefore, the improvement in Se status using this method in conjunction with dietary Se supplementation of breeder hens would be much greater than with only using dietary supplementation
