Effects Of Pyrroloquinoline Quinine Disodium（PQQ.Na₂） On Performance And Lipid Mtabolism Of Laying Hens

This thsis was conducted to investigate the effect of dietary PQQ.Na2 on performance and lipid metabolism on normal hens and stressed hens induced by dexamethasone sodium phosphate. In addition, apoprotein metabolism was studied to provide possible mechanism to the effect of dexamethasone sodium phosphate on performance of laying hens. Experiment 1. Effect of dietary pyrroloquinoline quinone disodium on performance and lipid metabolism of laying hensThis experiment was conducted to evaluate the effect of dietary PQQ.Na2 on performance and lipid metabolism of laying hens. Two hundred and eighty-eight Jinghong hens of 23-week ages were randomly divided into 4 treatments with 6 replicates of 12 hens. The hens were fed for basal diets supplemented with 0(control group), 0.08, 0.8 and 1.6 mg/kg PQQ.Na2. The experiment lasted for 8 weeks. The result shows that 1) PQQ.Na2 increased laying rate(1.11%)(P<0.05) and Haugh unit(P>0.05), and had no significant effect on feed conversion ratio(P<0.05). 2) dietary PQQ.Na2 significantly decreased abdominal fat(P<0.05) but showed no effect on liver fat(P>0.05). 0.8 mg/kg PQQ.Na2 increased liver cholesterol and decreased cholesterol level in plasma and egg(11.27%)(P<0.05). PQQ.Na2 increased plasma high density lipoprotein cholesterol significantly(P<0.05) while had no significant effect on plasma low density lipoprotein cholesterol(P>0.05). 3) PQQ.Na2 decreased plasma MDA content(P<0.05) and increased liver T-SOD and T-AOC activity(P<0.05), but showed no effect on plasma T-SOD activity(P>0.05). 1.6 mg/kg PQQ.Na2 increased MDA content in liver significantly(P<0.05). The oxitest resulet showed that induction period in 0.8 mg/kg PQQ.Na2 group was delayed for 1 h 55 min than that in control group. This study indicates that appropriate level of dietary PQQ.Na2(0.8mg/kg) increases laying rate, enhances antioxidant capacity of laying hens and decreases egg cholesterol content. Experiment 2. Effect of dietary pyrroloquinoline quinone disodium on performance and lipid metabolism of stressed laying hens induced by dexamethasone sodium phosphateEffect of dietary pyrroloquinoline quinone disodium salt(PQQ.Na2) on laying performance impairment induced by dexamethasone sodium phosphate(Dex) and its possible mechanism were examined in its study. There hundred and thirty-three Roman hens were allocated into five group with 6 replicates of 12 hens. The control and Dex group were fed basal diet, the other three grou received basal diet with 0.08, 0.8 and 1.6 mg/kg PQQ.Na2. During 29~42 days, 1 mg/kg Dex was added to diet except control group. The result showed that 1) laying rate and feed conversion ratio were undermined by Dex(P<0.05) and inproved by PQQ.Na2 significantly(P<0.05). Egg quality was not influenced by Dex and PQQ.Na2(P>0.05). 2) Abdominal fat and liver weight were increased by Dex(P<0.05). PQQ.Na2 decreased abdominal fat and liver weight(P<0.05). Liver fat was not influenced by Dex and PQQ.Na2(P>0.05). 3) Dietary Dexsignificantly increased glutamic oxalacetic transaminase, glucose, total protein and albumen level in plasma compared to control group(P<0.05). Dietary PQQ.Na2 inhibited the increase of bilirubin oxalacetic transaminase and glucose(P<0.05). Dietary Dex and PQQ.Na2 did not influence plasma glutamic pyruvic transaminase and total bilirubin level(P<0.05). 4) Triglyeride, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol in plasma were increased by Dex(P<0.05). Dietary PQQ.Na2 inhibited the increase of plasma high density lipoprotein significantly(P<0.05). 5) Dex downregulated and upregulated apo B100 and apo A-Ⅰm RNA expression significantly, respectively(P<0.05). And PQQ.Na2 inhibited the effect of Dex on apo B100 and apo A-Ⅰm RNA expression(P<0.05). Apo VLDL- Ⅱ m RNA expression was not influenced by Dex and PQQ.Na2. 6) Dex increased plasma estradiol(P<0.05) and PQQ.Na2 suppressed the increase of estradiol significantly(P<0.05). PQQ.Na2 inhibited the increase of blood glucose by instimulated insulin secretion(P<0.05). In conclusion, laying performance of hens was impaired by Dex supplement, and PQQ.Na2 protenct hens from Dex via regulating lipoprotein metabolism.