Effects Of Dihydropridine On Growth Performance And Residue And Clearance In Duck

Two experiments were carried out in this study to investigate the patterns of Dihydropridine residue and withdraw in plasma, tissues, excrements and the effects of Dihydropridine on growth performance of duck.Exp.l Effects of Dihydropridine on the growth performance and residue and clearance in duck.This study was conducted to evaluate the effects of DHP on growth performance, health, tissue residue and clearance of DHP in duck. A total of 480 Cherry Valley male ducks were randomly allocated into 3 groups with 10 replicates per group and 16 birds per replicate in a single factorial experiment design. The experiment lasted for 49 days, and 3 dietary treatments included basal containing 0,150 and 300mg/kg DHP for the starter(1～14d) and grower (15～35d) period respectively,36～49d was withdraw period. On the 35th day, one bird per replicate was killed and the serum, plasma, excrements, tissues (include liver and pectoral muscle) were collected for determination of DHP residual levels. And the growth performance, carcass quality, organ index and serum biochemical parameters of duck were measured. From 36d, the DHP diet was removed, all ducks gave basal diet, at Id,2d,4d,7d and 14d sampling plasma, excrements and tissues as 35d to test the clearance of DHP. The results showed that:1) The DHP had no significant effect on the growth performance of ducks (P> 0.05); There were no significant effect on the activity of GOT and GPT, levels of TP, UN and CRE in serum (P>0.05); Also DHP had no effect on the carcass quality, organ index of ducks (P>0.05);2) Compared with the controll group, there were not detected the residue of DHP in plasma, liver and pectoral muscle, but only detected DHP in excrement. The residue in excrement was significantly increased with the levels of DHP in diet (P<0.05). After 1 d with the DHP diet changed to the basal diet, the DHP residue of excrements in two groups were decreased by 97.18% and 97.38%, respectively.It was concluded that addition of 150 or 300mg/kg DHP in duck’s diet had no significant effect on the growth performance, organ index and health of duck, And there were not detected DHP residue in plasma, liver and pectoral muscle, but the DHP in excrement was cleared quickly after the DHP diet changed to the basal diet.Exp.2 Metabolism of dihydropridine after force-fed in duckIn order to study the metabolism of DHP after force-fed in duck,2442-day-old male Cherry Valley ducks were randomly divided into 2 groups:basal diet group and basal diet with addition of 1500mg/kg DHP group. The control group had 6 birds, and DHP group had 18 birds, each bird was in single cage as a replicate. All the ducks were force-fed the basal diet or DHP diet by 60g. Then at beginning and 0.5,1,2,3,5,8,12, 24,36 and 48h after force-fed, the plasma of 6 birds from each group were sampled to measure the residue of DHP. At 4,8,12,16,24,30,36 and 48h, the excrements were collected to measure the DHP and its metabolites. The results showed that:1) There was not detected the DHP in plasma, but two kinds of metabolites, the 2,6-dimethyl-3,5-diethoxycarbonylpyridine and monoethyl eater of 2,6-dimethylpyridine-3,5-dicarboxylic acid were found. The hightest level of monoethyl eater of 2,6-dimethylpyridine-3,5-dicarboxylic acid was at 3h and 8h respectively, and not detected at 24h.2) There were detected the DHP and three possible metabolites in excrements. The highest DHP in excrements was found at 8h, while at 48h, there was a few DHP could be found in the excrements. But only total 1.13%～2.38% DHP was excreted from excrements in 48h. The highest concentration of monoethyl eater of 2,6-dimethylpyridine-3,5-dicarboxylic acid in excrements was found at 4-8h.It was concluded that the dihydropyridine was metabolized quickly in duck and generated two kinds of metabolites in plasma; And excreted as dihydropridine and three metabolites in excrements.