| Two experiments was performed to invesgtied the tissue distribution, residue elimination and the metabolism, of phenethanolamine A in broiler chickens, aiming to provide scientific data for appropriate regulation of this illegal drug and to provide technical guidance to related risk assessment.Exp.l Study on the tissue distribution and residue elimination of phenethanolamine A in broiler chickensThis experiment was conducted to investigate the growth performance, tissue distribution and residue elimination of phenylethanolamine A in broiler chickens. A total of 400 21-day-old broiler chickens (AA) with similar initial body weight (0.812±0.006kg) were selected in this 35 days trial and randomly allotted into 4 treatments with 10 replications per treatment and 10 birds in each replication. During the first 21 days, the diets were included with 0,10,20 and 40 mg/kg of PEA to a corn-soybean meal basal diet.For the last 14 days, all the treatments diets were changed to basal diet.In compared with the control, the addition of 40mg/kg PEA significantly increased the mortality rate during 21-42 d (4% vs.20%) (p<0.01); and 40mg PEA per kg diet decreased body weight at 42 day by 4.86%, body weight gain during 21-42 d by 4.25%, and average daily feed intake by 5.33%(p<0.05). The feed efficiency was reduced by 10 and 40mg/kg PEA including groups by 14.36% and 25.64% compared with control diet, respectively.2) Supplementation of 20 mg/kg PEA increased the slaughter rate (by 1.21%, p<0.05); and decreased the half eviscerated rate (5.86%, p<0.05) as compared with the control.The breast meat yield in 40 mg/kg group was 7.36% and 9.53% lower than the control group and 10 mg/kg group respectively (p<0.05). The leg meat yield in 20 and 40 mg/kg group was significantly higher than the control group (11.79% and 7.35%, p<0.05).Chicks fed 20 mg/kg PEA reduced the thickness abdominal fat (17.14%, p<0.05).3) 40mg/kg PEA decreased the pH value of breast meat at 45min and 24h after slaughter(pH45min and pH24h), the variation of pH (△pH) and cooking loss (p<0.05); increased the red value of breast meat (a*) (p<0.05). There was pathologic change in kidney of broiler chickens repond to different levels dietary PEA supplementation.The kidney showed cellular swelling, cellular detachment and necrosis.At the same time, there was residual of PEA in blood and tissue of broiler chickens,such as liver,kidney, lung and pectoral major.The lung revealed the highest PEA retention followed by liver, kidney and blood.After the diet changed to basal diet,the residue of PEA in blood and tissues was eliminated slowly.The elimation of PEA in blood and tissues was conform to exponential regression model.The residual and elimination regulation was the same when suppilied different levels of PEA.Exp.2 Study on Metabolites and Metabolic Regularity of Phenylethanolamine A in broiler chickensThis experiment was aim to investigate the metabolic mechanism of PEA in broiler chickens by measurement its metabolic product in excreta after one-time oral diminsitration of PEA.Twenty birds were randomly distributed into 2 treatments for 3 days trail, with 10 replications per treatment and each bird as a replictate.these chickens were feed 0 or 67mg/kg PEA containing diet for one day,then changed to basal diet.At the time of 0.5,1,1.5,2,3,5,8,12,24 and 72 hours after feeding,6ml blood was collected from jugular vein each bird. Excreta was collected every 4h.PEA in blood and excreta was analyzed with HPLC-MS/MS.The metabolic product of PEA in excreta was determined using HPLC-Q-TOF.The result showed that there were four kinds of metabolic product of PEA in excreta of broiler chickens, such as tis methylation, demethylation, hydroxylation and ethanoyl.The concentration of PEA in blood and excreta presented a double peak phenomenon.The hightest levels of PEA in blood and excreta were IVmerged at 3h, 8h and 8h,16h post-administration respectively, and can be detected until 72h. |
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