Effects Of Quercetin On Performance And Antioxidant Status In Laying Hens In Vivo And In Vitro

We studied the effect of quercetin on antioxidation in laying hens in vivo and in vitro. In vitro, the effect of quercetin on antioxidation was researched using three methods, including radical scavenging, protection of biological macromolecules and reducing power, and vitamin C was used as a positive control. To investigate the effect of quercetin on antioxidation, performance and the optimum dosage of quercetin for improving laying rate in vivo, 240 of 37-week-old healthy Hessian laying hens with the similar body weight and laying rate were randomly divided into 4 groups, 6 replicates each group, 10 hens each replicate. Control was fed basal diet, treatments were fed basal diet supplemented with 0.02%, 0.04% and 0.06% quercetin, respectively.1. The effect of quercetin on radical scavengingThe effect of quercetin on the superoxide anion, hydroxyl and 1,1-Diphenyl-2-picrylhydrazyl(DPPH) radicals scavenging were determined using pyrogallol autoxidation, salicylic acid and DPPH method, respectively. The results showed that superoxide anion scavenging capacity of quercetin was increased at first and then decreased with the increasing quercetin(P<0.01), 40 mg/L quercetin produced the highest scavenging capacity of superoxide anion(31.93%), and quercetin’s capacity of radical scavenging was greater than that of vitamin C. Hydroxyl radical scavenging capacity of quercetin increased at first and then decreased with the increasing quercetin(P<0.01), 300 mg/L quercetin produced the highest scavenging capacity of hydroxyl radical(61.79%), and IC50 was 218.4 mg/L. Quercetin’s capacity of hydroxyl radical scavenging was greater than that of vitamin C in the range of low concentration. Quercetin’s capacity of radical scavenging was lower than that of vitamin C with the increasing quercetin. Quercetin’s capacity of DPPH radical scavenging was increased with the increasing quercetin, and IC50 was 1.47 mg/L, quercetin’s capacity of DPPH radical scavenging was greater than that of vitamin C in the range of low concentration, activity of quercetin’s capacity of DPPH radical scavenging was lower than that of vitamin C with the increasing quercetin. In summary, the effects of quercetin for respective radicals scavenging were DPPH,·OH and O2-.2. Inhibition of quercetin on peroxidation of lipoprotein in yolkInhibition of quercetin on peroxidation of lipoprotein in yolk was studied using the peroxidation system of polyunsaturated fatty acid from yolk lipoprotein induced by ferrous iron. The results showed that inhibition of quercetin on peroxidation of lipoprotein from yolk was increased with the increasing quercetin(P<0.01), and IC50 was 11.89 mg/L, the inhibition of quercetin on lipid peroxidation was greater than that of vitamin C.3. Inhibition of quercetin on erythrocyte hemolysis and mitochondrial membrane swellingThe protective effects of quercetin on the red blood cells and mitochondria were researched using erythrocyte hemolysis induced by H2O2 and the mitochondria swelling induced by Vitamin C-Fe2+. The results showed that inhibition of 0.05-1.25 mg/L quercetin on erythrocyte hemolysis increased with the increasing quercetin(P<0.01), however, inhibition was decreased with the increasing quercetin at the dose of 31.25 mg/L, and IC50 was 0.16 mg/L. And the inhibition of quercetin was stronger than that of vitamin C. Inhibition of quercetin on mitochondrial membrane swelling was increased with the increasing quercetin, and it suggests that membrane integrity of mitochondrial in quercetin-treated groups was significantly higher than that in model group according to the swelling degree of mitochondria at 60 minutes(P<0.01).4.Total reducing power of quercetinThe total reducing power of quercetin was determined using Prussian blue spectrophotometry. The results showed that the total reducing power of quercetin was increased with the increasing quercetin(P<0.01), the total reducing power was correlated to the level of quercetin in a quadratic curve, its regression equation was y=-0.0001x2+0.0263x+0.0391, R2=0.9992. It suggests that the total reducing power of quercetin was less than that of vitamin C.5. Effect of quercetin on the antioxidant enzyme activities in laying hensThe results showed that total antioxidant capacity in serum were significantly increased by 0.02%, 0.04% and 0.06% quercetin(P<0.01), the content of serum malondialdehyde was significantly decreased by 0.04% quercetin(P<0.05), the activities of glutathione peroxidase and superoxide dismutase in serum were significantly increased by 0.04% quercetin(P<0.01), and the activities of serum superoxide dismutase were increased by 0.06% quercetin(P<0.05), compared with control. The activity of superoxide dismutase in liver was significantly increased by 0.02%, 0.04% and 0.06% quercetin(P<0.05, P<0.01, P<0.05).6. Effect of quercetin on performance in laying hensCompared with control, laying rate were significantly increased by 4.96%(P<0.01) and feed-egg ratio were significantly decreased by 6.55% at 0.02% quercetin(P<0.05). 0.04% quercetin significantly increased laying rate by 8.11% and significantly decreased feed-egg ratio by 11.72%(P<0.01).In conclusion, data from the experiment showed that quercetin increased antioxidation in a certain range of dosage, and improved antioxidant status and performance in laying hens at 37-45 weeks of age. The optimum supplementation of quercetin was 0.04% for increasing performance.