Evaluation On Relative Bioavailability And Metabolism In Vivo And Requirement Of Choline In Broiler

In order to investigate the choline requirement of broiler, three trials were conducted, including theoptimal choline requirement level of of broiler; the bioavailability of choline in the feedstuffs; and thecholine chloride absorption and metabolism in broiler. It was expected to provide more detailedtheoretical basis for the practial production, as well as to offer a new methods and ideas for the researchof nutrient requirement from multiple perspectives.Exp.1Evaluate the Bioavailability of Choline in Various FeedstuffsThis Study was conducted to evaluate the relative biological value (RBV) of choline in corn, soybeanmeal, canola meal and distillers dried grains with soluble (DDGS). A total of132one-day-old broilerswere divided into22groups (6replicates per group and each replicate had1broiler). Groups S1-S6were standard curve group, Groups A1-A4were corn groups, Group B1-B4were soybean meal groups,Group C1-C4were canola meal groups, and Groups D1-D4were DDGS groups. The basic dietcontained the four feedstuffs above with lowered choline content through being extracted withmethanol/alcohol. All the test diets had the same composition as that of the basic diet except cholinecontent. A choline response curve was generated using crystalline choline chloride added to the basicdiet. The experiment diets were made from the basic diet in which the washed feedstuff was replacedwith the intact one with10%,20%,40%, and100%. In the slope ratio assays to determine cholineavailability, measured by average daily gain (ADG) and choline concentration in blood. The experimentlasted for21d. Using ADG as response criterion, the choline RBV of corn, soybean meal, canola meal,and DDGS were:63.95%,104.7%,37.98%, and72.09%; using choline concentration in blood asresponse criterion, the RBV of corn, soybean meal, and DDGS were:94.73%,184.11%, and canolameal,37.98%,134.23%.It is possible to evaluate the bioavailability of choline in feedstuffs using ADGand choline concentration in blood as criteria. But the values will be different in different criteria. Fromhigh to low, choline RBV of the four feedstuffs were soybean meal, DDGS, corn and canola meal,respectively.Exp.2Pharmacokinetic Study of Choline Chloride in Broiler by Oral AdministrationTo compare the pharmacokinetics of choline chloride in broiler after oral administration of differentdoses, a study was conducted.12male broilers received0,200,400mg/kg of choline (the form ofcholine chloride) by oral administration, respectively. Every treatment had4duplicates. Every duplicatehad1broiler. We took blood in different time according to the experimental design. The bloodconcentration of the choline was analyzed by ion chromatography. The pharmacokinetics parameterswere calculated by WinNonlin5.2using non-compartment model.The result showed that, endogenoussynthesis of choline was stable. The pharmacokinetics of choline chloride at the two doses was different,which was significant difference on Vz/F and CLz/F (P<0.01). It showed linear pharmacokinetics in broilers, when the dose was200to400mg/kg. The pharmaceutical parameters in broilers after singleadministration of the two doses of choline chloride orally were as follow.200mg: t_maxC_maxt1/2AUC_0-∞Vz/F and CLz/F were8.0h,399.88mg/kg,7.60h,5979.06mg/h/kg,876.99L/kg,83.27mg/h/kg;400mg: t_maxC_maxt1/2AUC_0-∞Vz/F and CLz/F were8.0h,445.88mg/kg,9.91h,10899.78mg/h/kg,318.43L/kg,21.22mg/h/kg. The dose of200mg had more possibility to enter to cell, inwhere the choline can be used to biosynthesize. We concluded that it was impossible that to enhancingthe bioavailability of choline only relying on increasing the dose of choline chloride.Exp.3Requirement of Choline and Methionine of Broiler Aged1to21Days by QuadraticOrthogonal Rotation Combination DesignA research on choline and methionine requirements for broilers aged1to21days were carried out. Atotal of480one-day old broilers were divided into12groups (4duplicates per group and each duplicatehad10broilers) in random. A diet with low level of choline and methionine was used as the basic diet inthis experiment, in which the contents of choline and methionine were680mg/kg and0.30%,respectively. To study the influence of different choline and methionine levels on growth performanceand slaughter performance, a two-factor combinational design of quadratic regression and orthogonalrotation was used. The results showed that a certain levels of choline and methionine could improveADG, F/G, dressing percentage and abdominal fat percentage of broiler aged1to21days. Whenmethionine levels were0.5⁰.7%, ADG of broilers was decreased with the reduction of choline levels.When the methionine levels were0.42⁰.5%, the choline levels were1300¹738mg/kg, F/G wasminimum. When methionine levels were0.5⁰.7%, the dressing percentage was decreased with theincreasing methionine levels; methionine were0.36⁰.5%, the dressing percentage was improved withthe addition of choline. Abdominal fat percentage was decreased with the rise of the choline levels;when choline levels were1300¹920mg/kg, abdominal fat percentage was decreased with thereducing methionine. It could be concluded that the requirements of choline and methionine for optimalgrowth performance were1434¹631mg/kg and0.47%. The requirements of choline and methioninefor optimal carcass performance were1984mg/kg and0.49%.Exp.4Requirement of Choline and Methionine of Broiler Aged21to42Days by QuadraticOrthogonal Rotation Combination DesignA research on choline and methionine requirements for broilers aged21to42days were carried out.A total of48021-day old broilers were divided into12groups (4duplicates per group and eachduplicate had10broilers) in random. A diet with low level of choline and methionine was used as thebasic diet in this experiment, in which the contents of choline and methionine were600mg/kg and0.30%respectively. To study the influence of different choline and methionine levels on growthperformance and slaughter performance, a two-factor combinational design of quadratic regression andorthogonal rotation to study the influence on production and slaughter performance in different choline and methionine was used. The results showed that choline and methionine have significant effects onADFI, F/G, abdominal fat and lowest liver fat of21to42days broilers. When choline levels were860¹120mg/kg, ADFI was enhanced with the rise of methionine, till the levels of methionine added at0.4%. When the methionine were0.35⁰.42%, choline were860¹120mg/kg, F/G was minimum.When methionine were0.3⁰.47%, abdominal fat percentage was decreased with the rise of the cholinelevels. When the levels of methionine were0.30⁰.40%,choline were1000¹400mg/kg, the liver fatof broilers was decreased with the rise of choline and the reducing methionine. In this experiment,choline and methionine requirements for best growth performance of broilers aged21to42days were990-1030mg/kg and0.40-0.43%, respectively. For best slaughter performance, choline and methioninerequirements were1780-1880mg/kg and0.37-0.38%, respectively.