Effects Of Selenium Source On The Performance, Egg Quality And Blood Biochemical Parameters Of Laying Hens

The purpose of the present paper was to compare the effect of organic selenium and inorganicselenium on the performance, egg quality, egg cholesterol and lecithin content, egg seleniumconcentrations, antioxidative function and plasma lipid content of hens to provide experimentalevidence for the further development of selenium products.Six hundred and thirty131-day old Hyline Brown hens were randomly allocated into seven groupswith6replicates of15hens in each. The basal diet was as control (1group) and3000mg/kg sodiumselenite,15000mg/kg selenium-enriched yeast,5000mg/kg,15000mg/kg,25000mg/kg and35000mg/kg selenomethionine were added into basal diet. The experiment lasted for120days. During theexperiment, laying rate, egg weight, daily feed intake and feed/egg ratio were recorded. All the eggswere collected on days30,60,90and120for eggshell strength, shell thickness, albumen height, eggyolk color, haugh unit, egg cholesterol and lecithin content, and counted the soft shelled or cracked eggsrate, and blood was sampled from two hens in each replicate for the T-AOC, the content of MDA, totalcholesterol (TC), total triglycerides (TG), high density lipoprotein cholesterol (HDL-C) and low densitylipoprotein cholesterol (LDL-C) in plasma. On day120for the activities of GSH-Px and SOD inplasma.Two eggs per replicate from each group were randomly collected on days5,10,15,20,30and60for the egg selenium concentrations. The results were as follows:1. The effect of selenium source on the performance of hensThe laying rate and daily feed intake trended to increase by the supplementation of selenium andthe feed/egg ratio did not affected significantly (P>0.05). Supplementation of3000mg/kg sodiumselenite was better than15000mg/kg selenium-enriched yeast and selenomethionine, and there was nosignificant difference between the selenium-enriched yeast and selenomethionine. The laying ratetrended to reduce and the daily feed intake significantly increased (P<0.05) by supplementation of35000mg/kg selenomethionine. As the dietary selenomethionine level increasing, the egg weighttrended to increase, but it was not affected significantly (P>0.05).2. The effect of selenium source on the egg quality, cholesterol content, lecithin content and seleniumconcentrations in eggsEggshell strength, shell thickness, albumen height, haugh unit, cholesterol and lecithin content ineggs were not affected significantly (P>0.05) by supplementation of selenium (P>0.05).Supplementation of15000mg/kg selenium-enriched yeast and15000mg/kg selenomethioninesignificantly increased the egg yolk color during days60-90(P<0.01). Supplementation of15000mg/kg selenium-enriched yeast significantly decreased the soft shelled or cracked eggs rate (P<0.05).However, the soft shelled rate or cracked eggs rate was significantly increased by supplementation of35000mg/kg selenomethionine (P<0.05). Supplementation of selenium significantly increased the eggselenium concentrations (P<0.01), the effect of organic selenium was better than sodium selenite, andselenomethionine group was better than selenium-enriched yeast group (P<0.01). As the dietaryselenomethionine level increasing, the egg selenium concentrations increased significantly (P<0.01). 3. The effect of selenium source on the antioxidative function and lipid content in plasma of hensSupplementation of selenium significantly increased the plasma GSH-Px activity (P<0.01), anddecreased the plasma MDA content (P<0.01), the effect organic selenium was better than sodiumselenite, and selenomethionine group was better than selenium-enriched yeast group (P<0.01). Theplasma T-SOD activity (P<0.05) and T-AOC (P<0.01) also significantly increased by thesupplementation of selenium, and trended to decrease the plasma TG, the effect of organic selenium wasbetter than sodium selenite, but there was no significant difference between the organic selenium(P>0.05) and the content of TC, HDL-C and LDL-C were not affected significantly. As the dietaryselenomethionine level increasing, the plasma GSH-Px activity increased, but there was nothing to dowith the T-SOC activity.It was concluded that the addition of selenium to the diet trended to increase the laying rate, dailyfeed intake and significantly increased egg selenium concentrations, plasma GSH-Px activity, plasmaT-SOD activity and T-AOC, significantly decreased the plasma MDA content and trended to decreasethe plasma TG content, the effect of organic selenium was better than sodium selenite. On the aspects ofincreasing egg selenium concentrations, plasma GSH-Px activity and decreasing plasma MDA content,the effect of selenomethionine was better than selenium-enriched yeast.