Effects Of Dietary Pyrroloquinoline Quinone Supplementation On Performance And Anti-Oxidant Ability Of Laying Hens

This thesis was conducted to determine the effects of dietary pyrroloquinoline quinone (PQQ)supplementation on performance, egg quality, antioxidant capacity of laying hens. The effects of PQQon oxidative damage in the liver of laying hens fed an oxidized sunflower oil supplemented diet, and thepossible mechanism of PQQ performing its antioxidant function was discussed.Experiment1. Effects of dietary PQQ Supplementation on Laying Performance, Egg Qualityand Antioxidant Ability of Laying HensThe experiment was conducted to study the effects of dietary PQQ on performance, egg qualityand antioxidant function of laying hens. Three hundred and seventy-eight healthy Hyline Grey layinghens of50week-old were randomly divided into7dietary treatments with6replicates in each treatmentand9hens in each replicate. PQQ was dissolved in water, all the hens were fed basal dietssupplemented with0,0.005,0.010,0.020,0.040,0.080, and0.016mg/(d hen) PQQ, respectively. Theexperiment lasted for6weeks. The result showed that laying rate and egg quality of laying hens had atendency to increase in the PQQ supplemental groups, and dietary PQQ increased albumen height andHaugh unit, but there was no significant difference among the7groups; The activity of GSH-Px andT-SOD in serum and livers of laying hens were significantly increased (P<0.05); the ability of inhibitingsuperoxide anion and thehydroxyl radical were significantly increased (P<0.05); the content of MDA inserum and livers was significantly decreased compared with the control (P<0.05). This study indicatedthat the supplementation of PQQ in the diet has the trend to increase the laying rate and the egg qualityin laying hens, and it can enhance the antioxidant function. The optimal level is0.01mg/(d hen).Experiment2. Effects of PQQ on Laying Performance, Egg Quality, and AntioxidantCapacity in Laying Hens Fed an Oxidized Sunflower Oil Supplemented DietThis study was conducted to determine the effect of dietary supplementation of pyrroloquinolinequinone (PQQ) on laying performance, egg quality, plasma antioxidant index and levels of Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-superoxide dismutase (Mn-SOD), peroxisomeproliferator-activated receptor-γ coactivator-1(PGC-1) and nuclear factor E2-related factor2(Nrf2)mRNA in laying hens fed a diet including oxidized sunflower oil. HyLine Grey hens (n=360,53week-old; average egg production,82.02.0%) were allotted into one of the five dietary treatments,which were supplemented with2%fresh sunflower oil (fresh sunflower oil group, FO),2%thermallyoxidized sunflower oil (oxidized sunflower oil group, OO), or2%thermally oxidized sunflower oil inthe presence of100mg vitamin E/kg diet (vitamin E group, VE),0.08mg PQQ/kg diet (low PQQgroup, LP), or0.12mg PQQ/kg diet (high PQQ group, HP). Each treatment contained6replicates with12birds each. The feeding trial lasted for42d. Dietary PQQ had no significant effect on layingperformance and egg quality (P>0.05). The plasma glutathione content was higher in LP and HP groupsthan the other groups (P<0.05), as well as the plasma malondialdehyde content decreased significantly(P<0.05) in PQQ groups and VE group on d21and42. PQQ supplementation could decrease the detrimental effects of thermally oxidized oil by elevating the related antioxidant enzymes activities inplasma such as glutathione peroxidase (P<0.05) and total superoxide dismutase (P<0.05) and PGC-1(P<0.05) and Nrf2(P=0.07) mRNA expression in livers. The level of Cu/Zn-SOD mRNA increasedsignificantly in HP group (P<0.05)，while Mn-SOD increased in VE group (P<0.05) in livers. Thisstudy indicated that dietary PQQ addition could alleviate oxidative stress, enhance the antioxidantcapacity of laying hens, thus producing beneficial effects in laying hens.Experiment3. Effects of PQQ on Oxidative Damage in the Liver of Laying Hens Fed anOxidized Sunflower Oil Supplemented DietThis study was conducted to determine the effects of dietary pyrroloquinoline quinone (PQQ) onliver antioxidant capacity, oxidative damage, levels of extracellular signal-regulated kinase (ERK1/2),c-Jun amino-terminal kinase2(JNK2) and p38mitogen-activated protein kinase (p38MAPK) mRNA inlaying hens fed an oxidized sunflower oil diet. HyLine Grey hens (n=360,53weeks; average eggproduction,82.0±2.0%) were allotted into one of the five dietary treatments, which were supplementedwith2%fresh sunflower oil (fresh sunflower oil group, FO),2%thermally oxidized sunflower oil(oxidized sunflower oil group, OO), or2%thermally oxidized sunflower oil in the presence of100mgvitamin E/kg diet (vitamin E group, VE),0.08mg PQQ/kg diet (low PQQ group, LP),or0.12mgPQQ/kg diet (high PQQ group, HP). Each treatment contained6replicates with12birds each. Thefeeding trial lasted for42d. The liver glutathione (GSH) content in LP group was higher than the FO,OO and VE groups (P<0.05), as well as the liver malondialdehyde content decreased significantly(P<0.05) in PQQ groups and VE group. Dietary PQQ supplementation eliminated the detrimentaleffects of thermally oxidized oil by elevating the related antioxidant enzymes activities in liver such asglutathione peroxidase (P<0.05) and total superoxide dismutase (P<0.05) and ERK1/2(P<0.05) andp38MAPK (P=0.05) mRNA expression in liver. Oxidized sunflower oil increased the liver (reactiveoxygen species) ROS production to some extent (P=0.13). PQQ or vitamin E addition decreased theROS production and alleviated the oxidative damage in liver, such as carbonyl content (P<0.05), taillength (P<0.05) and tail moment (P<0.05). This study indicated that dietary PQQ could alleviateoxidized sunflower oil induced oxidative damage through activating MAPK signaling pathways(ERK1/2and p38MAPK), enhancement of GSH content and antioxidant enzymes activities.