Predictive Models Of Metabolizable Energy And Amino Acid Digestibility Of Wheat In Broilers

In this paper,there are three experiments conducted to analyze nutrient characteristics of wheat and its biological potency in broiler chickens,establish the optimal prediction model of nitrogen calibration apparent metabolic energy(AMEn),and standard ileal amino acid digestibility(SID).According to the relevant analysis of wheat resistance nutrient and caecum microorganism sequencing,An application program of enzyme preparation was proposed.Experiment 1 Analysis of the nutritional characteristics of wheatThe wheat cultivar from northwest agriculture and forestry university was selected,and the nutrient components of different components were determined by grinding powder.Six typical wheat diets were prepared according to certain proportion.The nutrient composition of wheat diets were analyzed from four aspects:conventional nutrients,pure nutrients,anti nutrients and physical properties.The results show that:1)There was a gradient in crude protein(CP),crude Ash,amino acids,pentosan and glucan of 6 kinds wheat diets;2)6 kinds of gradient of crude protein,crude fiber(CF)and crude Ash content covers the feed classification standard in our country from the secondary to first grade wheat variation within the scope of the maximum and minimum,wheat diets were representative;3)the variation coefficients of crude protein,acid washing fiber(ADF),total amino acid,pentosan and dextran were 11.78%,0.76,27.73%,10.28%and 21.74%respectively.Experiment 2 The biologic evaluation of wheat in different physiological stages of broilersThis trail was taken on 840 broilers aged 1 day,random been divided into seven processing,12 repeat and every repeat 10 chickens,feeding nitrogen free fodder and 6 kinds of wheat respectively test of fodder.Total feces collection method was taken to determine metabolic energy,marker in excreta method was taken to determine the amino acid digestibility.AMEn and SID was measured to do relevant analysis with wheat diets nutrient analysis indicators on the basis of experiment 1.Forecasting model was established through stepwise regression.The results show that:1)The age of 14,CP and Ash was the main effect factor of AMEn best prediction equation.The age of 28,bulk density is mainly effect factor.The best prediction equation:AMEn=6.423+0.427*CP-0.863*Ash(R~2=0.933,P=0.008);AMEn=5.376+0.01*bulk density(R~2=0.820,P=0.013.2)The age of 14,soluble pentosane and CF was the main effect factor of SID prediction equation.The age of 28,NDF,Cys,Arg and anti nutrients was the main effect factor.The prediction equation of the SID:The age of 14:Lys=1.099-0.276*soluble pentosane(R~2=0677,P=0.044);Thr=2.140-0.240*soluble pentosane-0.040*NSP(non-starch polysaccharide)-0.092*dextran(R~2=0.996,P=0.003);Leu=1.077-0.104*soluble pentosan-0.004*CF-0.190*NaCl(R~2=0.999,P=0.002);Val=1.098-0.219*soluble pentosane(R~2=0.772,P=0.021);Phe=1.137-0.139*soluble pentosane-0.009*CF(R~2=0.960,P=0.008);Gly=1.065-0.173*soluble pentosan-0.006*CF(R~2=0.987,P=0.001);Ser=1.053-0.135 soluble pentose-0.009*CF(R~2=0.953,P=0.001);Ala=1.070-0.198*soluble pentose-0.012*CF(R~2=0.985,P=0.020);Asp=1.070-0.213*soluble pentose-0.012*CF(R ~2=0.955,P=0.009),Gly=0.972-0.149*Ca(R~2=0.644,P=0.034);28 days old:Val=1.381+1.737*Cys-0.031*total anti-nutrient substance-0.148*Arg(R~2=0.999,P=0.001),Gly=0.853+0.01*NDF(R~2=703,P=0.037).3)Based on the data National feed grading standards(2004)and NRC(1994),the results show that the deviation of AMEn measured values and estimated calculating by the prediction model is under 1%,but with the standard authentication of The National feed grading standards(2004)and NRC(1994)standard authentication,deviation rate of AMEn were higher than 10%.Experiment 3 Correlation analysis of wheat anti-nutrients and cecum microorganismCecum chyme was collected for the analysis of 16 rDNA sequencing at 14 and 28 age.The relevant analysis of wheat resistance nutrient and caecum microorganism sequencing was conducted,the results showed that wheat pentosan and glucan had a significant positive correlation with intestinal pathogenic bacteria Clostridium and Salmonella(R>0,P<0.05).Lactobacillus has significant negative correlation(R<0,P<0.05).24 AA+broilers were choosed randomly assigned into six processing at 37 to 42 age,three kinds of wheat diets and three wheat mixed with xylanase and glucanase were fed,collected the cecum chyme to determinate absolute content of E.coli、Salmonella and Lactobacillus_salivarius.The results showed that wheat mixed with xylanase and glucanase can significantly increase the number of the cecum saliva lactobacillus(P<0.05),there was no effect on E.coli and Salmonella.Lactobacillus_salivarius is the beneficial bacteria in the intestinal,Lactobacillus_salivarius can degrade cellulose,and restrain harmful bacteria(Golden staphylococcus aureus,Escherichia coli,etc.)of breeding,increase the number of intestinal bacteria(bifidobacterium),improve the structure of intestinal flora.Above all,in this experiment,crude protein,coarse ash and bulk density are the main factors to establish the prediction model of wheat nitrogen.Crude fiber and soluble pentosan are the main main factors in the prediction model of wheat standard ileum amino acid digestibility.The addition of pentosan and dextran could significantly improve the number of Lactobacillus_salivarius in cecum.