Study On Dietary Methionine Requirement Of Jing Brown Layers From Hatch To The Age Of17Week

The modulation of dietary methionine(Met) levels on China’s new cultivation of JingBrown Layers from hatch to the age of17week was studied. The test divided into three stages,each stage of random points five dietary treatments, and each treatment consisted of5replicates. Combined with the average daily gain, feed/gain, community evenness and othereconomic indicators, immune index, digestive system, index of blood, the stduy achieves theoptimal methionine requirement of Jing Brown Layers in each stage, and summarizes theregularity of growth model fitting and the laws of the organ development of Jinghong laying.The experiments in each stage are as follows:1Studies on dietary methionine requirement of Jing Brown Layers from hatch tothe age of4weekThree hundred1-day-old Jing Brown Layers were randomly alloted to1of the5dietarytreatments, and each treatment consisted of5replicates with5pens per replicate and12birdsper pen. The methionine levels are0.2%,0.3%,0.4%,0.5%and0.6%. The corn-soybean dietswere prepared according to NRC(1994) and chicken rearing standards(NY/T33-2004).Thestudy uses conventional breeding management.The results are as follows:1) No significantdifferences were found on average daily feed intake (P>0.05),but the average daily gain wassignificantly different (P<0.05), and the0.4%Met group showed the maximum value with8.31g/d, a quadratic curve of rising trend; Besides, feed/gain ratios were also significantaffected (P<0.05), in which, the0.5%Met group was the best (2.13:1); Community evennessalso showed the tendency of a quadratic curve of rising, the0.5%Met group (85.19%) wassignificantly higher than the other groups (P<0.05).2) By the2th week,no-significantinfluence on the relative weights of the thymus and bursa of fabricius (P>0.05) by differentdietary methionine levels; Significant impact on the relative weights of the spleen (P<0.05),the0.4%Met group has reaches the maximum. The4th week, The relative weights of thethymus, spleen and bursa of fabricius as dietary Met levels was significantly positivecorrelation (P<0.05) and had all shown the rise-fall tendency. The relative weights of thespleen and bursa of fabricius which0.4%Met group were the largest, the thymus index which 0.5%Met group was the largest.3) Methionine levels significantly affected the relativeweights of the duodenum, jejunum and ileumor or the relative lengths of the jejunum andileum (P<0.05). With the increasing of methionine, except the relative weights of pancreaswhich showed the rise-fall tendency, all the indexes had shown the fall-rise tendency.4)There were significant difference among groups in the level of serum urea nitrogen, uric acidand alkaline phosphatase (P<0.05). The0.5%Met group was the minimum of serum ureanitrogen, while alkaline phosphatase was significantly higher than other groups (P<0.05).0.6%Met group of uric acid was significantly higher than the other groups (P<0.05). To sumup, the optimum Met requirement for Jing Brown Layers of0to4weeks is0.49%.2Studies on dietary methionine requirement of Jing Brown Layers from5to8weekThree hundred29-day-old Jing Brown Layers were randomly alloted to1of the5dietarytreatments, and each treatment consisted of5replicates with5pens per replicate and12birdsper pen. The methionine levels are0.30%,0.37%,0.44%,0.51%and0.58%. Thecorn-soybean diets were prepared according to NRC(1994) and chicken rearingstandards(NY/T33-2004). The study uses conventional breeding management. The results areas follows:1) No significant differences were found on average daily gain and average dailyfeed intake (P>0.05); Besides, feed/gain ratios and weight were also significant affected(P<0.05), in which, the0.44%Met group was the best (3.13:1and608.67g); Communityevenness also showed the tendency of a quadratic curve of rising, in which, the0.37%Metgroup was the best; the pectorales index, leg muscles index,chest width and shinbone lengthwere significantly different (P<0.05), it showed the tendency of a quadratic curve of rising, inwhich, the0.44%Met group of pectorales index and shinbone length were the best.2) The6th week, significant influences of Met were found on the relative weights of the spleen, thethymus and bursa of fabricius (P<0.05); The8th week, no significant differences were foundon the relative weights of the thymus and bursa of fabricius (P>0.05)but the relative weightsof the spleen was significantly different (P<0.05), and the0.44%Met group of the relativeweights of the thymus showed the maximum value with0.26%,the0.37%Met group of therelative weights of bursa of fabricius showed the maximum value.3) Methionine levelssignificantly affected the pancreas, duodenum index, jejunum index and jejunum length(P<0.05). With the increasing of methionine, all the indexes showed the fall-rise tendency.4)There were significant difference on uric acid and alkaline phosphatase (P<0.05). The uricacid and alkaline phosphatase in the0.44%Met group was significantly higher than othergroups (P<0.05). To sum up, the optimum Met requirement for Jing Brown Layers of5to8weeks is0.42%. 3Studies on dietary methionine requirement of Jing Brown Layers from9to17weekThree hundred and seventy-five57-day-old Jing Brown Layers were randomly alloted to1of the5dietary treatments, and each treatment consisted of5replicates with5pens perreplicate and15birds per pen. The methionine levels are0.23%,0.27%,0.31%,0.35%and0.39%. The corn-soybean diets were prepared according to NRC(1994) and chicken rearingstandards(NY/T33-2004).The study uses conventional breeding management.The results areas follows:1) No significant differences were found on the average daily feed intake,feed/gain, average daily gain and body weight (P>0.05), but community evenness weresignificantly different (P<0.05), and the0.31%Met group of community evenness showed themaximum value with97.14%.2) Methionine levels significantly affected the relative weightsof the jejunum (P<0.05). With the increasing of methionine, the small intestine developmentshowed the tendency of a quadratic curve of rising.3) Methionine levels significantly affectedreproductive system development (P>0.05),0.27%～0.31%Met level were the best, therelatively high of reproductive hormone was0.27%Met group. To sum up, the optimum Metrequirement for Jing Brown Layers of9to17weeks is0.29%.4Studies on growth model fitting and the laws of the organ development of JingBrown LayersEvery week, the study measures its economic growth traits and organ developmentindicators and the birds are the two groups with the range of the optimum Met requirement forJing Brown Layers. The dynamic radar chart of the growth rate of organ differentiation anddevelopment was drawn by Excel2003. Data was analyzed by the subroutine nonlinearregression model of SPSS17.0software. To establish and evaluate the growth models, theestimated optimization values (A, B and K) of the internal organs weight data in the differentweeks were calculated according to the fitting degree (R2) and the sum of squared residuals(E).The inflection age, inflection point of body quality and the biggest weekly incrementswere calculated. The value and estimated values were measured according to the chi-square.The results are as follows:1) According differentiation growth rate and Radar map, the firstdevelopment was the small intestine and the latest development was ovary.2) The best modelof spleen, bursa of fabricius and lung were Gompertz model, and the best model of weight,thymus, liver, pancreas, intestine, heart and kidney were Bertalanffy model. The internalorgans development order was small intestine, thymus and bursa of fabricius, heart, kidney,pancreas, liver, spleen and lungs.To sum up, the internal organs development order of JingBrown Layers was the digestive system--the immune system--the circulatory system--theurinary system--the respiratory system--reproductive system.