evaluation effect of antibiotic alternatives on egg yolk lipids, blood metabolites and egg quality traits in laying hens

this experiment was conducted to investigate the effect of antibiotic, organic acid, probiotic and prebiotic on quality traits of eggs, egg yolk lipids and blood metabolites of laying hens strain hy-line (w-36). the experiment was carried out as a completely randomized design from 32 to 42 weeks of age with 5 treatments, 4 replicates and 8 hens in each replicate. the experimental treatments consisted: 1- control, 2- basal diet + 150 g/ton antibiotic (oxy tetracycline), 3- basal diet + 3 kg/ton of organic acid supplementation (orgacid), 4- basal diet + 50 g/ton probiotic (protexin) and 5- basal diet + 2 kg/ton prebiotic (mannan oligosaccharide). the results showedthat among the traits of eggs, egg weight significantly increased by treatments receiving organic acid and prebiotic (p<0.05). egg yolk cholesterol significantly decreased by diet containing probiotic (p<0.05). blood glucose concentration wassignificantly increased by dietary organic acid (p<0.05). alk enzyme activity in blood serum by use of probiotic significantly increased compared to treatment containing antibiotic (p<0.05). the results of this experiment showed that the use of dietary supplements, have beneficial effects on egg characteristics and blood metabolites of laying hens