Effects Of 1,4-dihydropyridine On Fatty Liver Hemorrhagic Syndrome Of Laying Hens And Approach To The Mechanism

The experiment was conducted to investigate the effects of 1,4-dihydropyridine (DHP) on Fatty Liver hemorrhagic Syndrome of laying hens and approach to the mechanism.Six hundreds of Laying hens of 40 weeks of age were randomly allotted to three groups, each of which included four replicates of 50 hens. The groups were fed a basal corn-soybean diet, supplemented 0(control);150mg/kg, 300 mg/kg 1,4-dihydropyridine. Feed and water were provided ad. Zibitum and layers received 16h light/day. 12 layers from each group were picked out after 90 days of feeding to collected samples of liver, abdominal fat, ovary, oviduct and anterior pituitary. Serum bio-parameters, levels of hormone, liver fat percentage, abdominal fat percentage, hormone sensitive lipase(HSL) activities in abdominal fat, liver superoxide simutase (SOD) activities and apolipoproteinA I and apolipoproteinB concentrations, cAMP concentrations in liver and anterior pituitary, MDA concentrations and P, r, values of liver mitochondria were determined to study the mechanism of effects.The results indicated that DHP had significantly improved laying performance. Adding 150mg/kg, 300mg/kg DHP to the diet improved daily mean laying rate by 9.39%(P<0.01), and 12.97%(P<0.01), decreased feed/egg ratio by 9.54%(P<0.05) and 7.25%(P<0.05) respectively. However, there were no significantly difference between treatments in egg weight and daily feed intake.The determination of abdominal fat and liver samples showed that DHP had significant effect on percentage of abdominal fat and liver fat. Supplementation of 150 mg/kg, 300mg/kg DPH decreased percentage of abdominal fat by 35.4%(P<0.05) and 46.9%(p<0.05),and decreased liver fat by 32.4%(p<0.05) and 10.5%(p<0.05) respectively.Adding 150mg/kg, 300mg/kg DHP to the diet increased HSL activity of abdominal fat by 39.64%(p<0.05) and 48.48%(p<0.05). The dieting addition of 150mg/kg DHP increased liver SOD activity by 69.61%(p<0.05), and increased liver apoB concentration by 53.96%(p<0.05), but a similar significant effect on liver SOD activity and apoB concentration.The results from serum biochemical parameters analysis indicated that supplementing 150mg/kg , 300mg/kg DHP increased calcium concentration by 18.88% (p<0.01)and 22.64%(p<0.01), decreased LDH activities by 26.40%(p<0.05) and 54.76%(p<0.01) respectively. Adding 300mg/kg DHP to the diet decreased AST activity by 18.15%(p<0.05), but 150mg/kg DHP not.The investigation of levels of hormone in serum showed that adding 150mg/kg , 300mg/kg DHP to the diet increased T3 levels by 15.34% (p<0.05) and 11.88%(p<0.05); decreased insulin concentration by 40.44%(p<0.05) and 54.37%(p<0.05) respectively; but no significant effect occurred on T4 concentration.The present result indicated that supplemented 150mg/kg, 300mg/kg DHP increased the concentrations of cAMP in anterior pituitary by 14.67%(p<0.05) and 10.91%(p<0.05) respectively, but a similarity significant difference was not found.The results from liver mitochondria indicated that supplementation of 150mg/kg , 300mg/kg DHP decreased MDA concentration by 30.90%(p<0.01) and 10.39%(p<0.05), the liver mitochondria! membrane polarization fluorescence degree (P) lowered by 15.40%(P<0.01) and 7.56%(P<0.05), decreased the anisotropy( r) by 25.05%(P<0.01) and 13.10%(P<0.05), lowered the exiguity viscosities( n ) by 16.36%(P<0.01) and 8.07%(P<0.05) respectively. This result suggested DHP increase mitochondria membrane fluidity.The research on very low density lipoprotein receptor(VLDLR) indicated that adding DHP had the tendency for VLDLR activities of ovarian to be higher.