1～3周龄雌性肉仔鸡精氨酸需要量

本试验旨在研究饲粮中精氨酸水平对l～3周龄雌性爱拔益加(AA)肉仔鸡的影响,并运用二次曲线模型进行需要量估计.试验选用540只1日龄雌性AA肉仔鸡,随机分成6组,每组5个重复,每个重复18只鸡.6个组饲粮精氨酸水平分别为1.000%、1.125%、1.250%、1.375%、1.500%和1.625%.结果表明:精氨酸...     

0～21和22～42日龄黄羽肉鸡可消化蛋氨酸需要量的研究

试验一和试验二分别选用1日龄和22日龄岭南黄鸡各2 000只和1 600只,按性别和体重分成10处理组(公、母鸡各5组),每组4重复栏,每栏50(试验一)和40只鸡(试验二)。2个试验均采用5(饲粮蛋氨酸水平)×2(性别)两因子试验设计,试验一和二分别设0.35%、0.40%、0.45%、0.50%和0.55%以及0.30%、0.35%、0.40%、0.45%和0.50%5个饲粮蛋氨酸水平。结果表明:随着饲粮蛋氨酸水平提高,0～21日龄和22～42日龄公、母鸡每日总蛋氨酸摄入量和真可消化蛋氨酸摄入量呈线性或二次曲线升高(P<0.05);0～21日龄公、母鸡的日增重呈二次曲线升高(P<0.05),0～21日龄和22～42日龄公、母鸡的饲料增重比呈二次曲线降低(P<0.05或0.1)。可见,在基础饲粮中添加适量蛋氨酸改善了黄羽肉鸡的生产性能。根据二次回归模型估测黄羽肉鸡获得最佳生产性能95%处的总蛋氨酸需要量和真可消化蛋氨酸需要量,0~21日龄母鸡为0.433%~0.435%和0.404%~0.406%,公鸡为0.445%~0.454%和0.416%~0.425%,22～42日龄母鸡为0.463%和0.437%,公鸡为0.375%和0.349%。     

肉鸡蛋氨酸铁生物利用率试验研究

选用1日龄狄高肉公雏252只,以研究蛋氨酸铁生物利用率,基础饲粮含铁138mg／kg,在此基础上,硫酸亚铁及蛋氨酸铁源的铁添加水平分别依次为200,400,600mg／kg,1-7日龄饲喂基础饲粮,8-21日龄饲喂试验饲粮,试验14天。研究结果表明,添加铁源及铁水平不影响肉鸡体重及饲料采食量(P>0.05),但极显著影响肝铁代谢(P<0.01),饲喂基础饲粮的肉鸡,导致血红蛋白显著下降(P<0.05),以对数转换后的肝铁含量为因变量,铁添加水平或日粮铁摄入为自变量建立多元线性回归模式,以硫酸亚铁为参比基础,采用斜率法综合求测肉鸡铁源生物利用率为:硫酸亚铁100％;蛋氨酸铁95％。该项研究表明,在实用饲粮条件下,测定肉鸡2周龄肝铁是铁源生物利用率评定的实用方法。     

Effects of Excess Methionine from Meeting Needs for Total Sulfur Amino Acids on Utilization of Diets Low in Crude Protein by Broiler Chicks

Failure to obtain optimum performance by broilers fed low CP diets supplemented with amino acids may be due to a number of factors, including potential toxic effects of amino acids in excess of requirements. The objective of the present study was to evaluate the effect of excess levels of Met on performance of broilers fed low CP diets. Corn and soybean meal of known composition were used to formulate diets with 22, 20, 18, and 16% CP with 100 and 110% of NRC recommendations. DL-Methionine was used to meet Met and TSAA requirements; the dietary levels of Met exceeded minimum needs. Within each CP level, 2 additional series were prepared. For one series, only the amount of DL-methionine needed to reach the Met requirement was added, leaving a calculated deficit of TSAA. For a second series, excess Met was replaced with sufficient Cys to meet Met and TSAA exactly. Each of the test diets and a 23% CP positive control were fed to 6 replicate pens of 5 male broiler chicks from 1 to 21 d of age. Performance of the birds fed 22% CP diets did not differ significantly from that of chicks fed the positive control. Chicks fed diets with less than 22% CP had significantly lower BW and increased FCR regardless of level of amino acid supplementation. There was no significant effect of Met status on performance, indicating that corn-soybean meal diets do not appear to be deficit in Cys and do not respond to levels of Met greater than minimum NRC recommendations for Met. Excess levels of Met in this study did not appear to contribute to the reduced performance at low CP levels.     

Effects of Intestinal Modification by Antibiotics and Antibacterials on Utilization of Methionine Sources by Broiler Chickens

A study was conducted to determine if the response to different sources of Met was influenced by the presence or absence of antibiotics and antibacterials that might alter intestinal microflora. A Met-deficient diet (0.33% by analysis), based on corn and soybean meal, was fed with or without a mixture providing 200 g/ton of bacitracin methylene disalicylate, 200 g/ton of chlortetracycline, 100 g/ton of penicillin, and 100 g/ton of sulfaquinoxaline. Diets were fortified with DL-Met or the liquid form of 2-hydroxy-4-methylbutanoic acid (HMB) to provide supplemental levels of Met ranging from 0.0 to 0.20% in increments of 0.04%, based on 99% activity for DLDL-Met and 88% activity for HMB. The experimental treatments consisted of a 2 × 2 × 6 factorial arrangement of treatments with 2 diet types (medicated and unmedicated), 2 Met sources (DL-Met and HMB) at 6 levels of supplementation for a total of 24 dietary treatments. Each of these was fed to 6 replicate pens of 5 male chicks from 0 to 21 d, stratified across tiers in the battery.Feeding the medicated diets resulted in a significant reduction in intestinal bacterial as measured by total aerobic plate count of ileal contents, with significant improvements in BW and feed conversion. However, there were no significant interactions between the medications and the response to the 2 sources of Met. There was no difference in BW or feed conversion related to the 2 different sources of Met when fed to provide equimolar amounts of Met activity. Chicks responded to increasing levels of Met, but there was no interaction between source and level of Met for BW or feed conversion. Peak response appeared to occur at approximately 0.08% supplemental (0.41% total) Met, somewhat below current NRC recommendations. It does not appear that a difference in antibiotic content of test diets is responsible for the discrepancy in reported responses to the 2 sources of Met.     

罗曼鸡可利用蛋氨酸维持需要的研究

试验选用30周龄罗曼公、母鸡72只,分为12个处理,每个处理6个重复,每个重复1只试鸡,单笼饲养,分别饲喂蛋氨酸水平为理想需要量的36%、50%、65%、75%、85%和100%的半纯合梯度日粮,建立蛋白质和蛋氨酸沉积量对蛋氨酸食入量间的回归方程,来确定30周龄罗曼公母鸡的可利用蛋氨酸维持需要量。结果表明:公鸡蛋白沉积量显著高于母鸡(P<0.05)。分别以蛋白质和蛋氨酸沉积量为因变量,所得公鸡可利用蛋氨酸维持需要分别为每天39.34mg/kgBW0.7(5或表示为266.81mg/kgBPM)和1.93mg/kgBW0.7(5或表示为13.11mg/kgBPM)。母鸡可利用蛋氨酸维持需要分别为每天52.32mg/kgBW0.7(5或表示为282.14mg/kgBPM)和7.76mg/kgBW0.7(5或表示为41.87mg/kgBPM);由蛋白质沉积量为因变量所得的回归方程外推零蛋白质沉积时的蛋氨酸维持需要量要显著高于以零蛋氨酸沉积所得的维持需要量(P>0.05),母鸡可利用蛋氨酸维持需要高于公鸡的测定结果。     

Effects of Betaine and Choline on Response to Methionine Supplementation to Broiler Diets Formulated to Industry Standards

A study was conducted to evaluate the Met-sparing effects of the methyl donors, choline (CHO) and betaine (BET). Male broilers of a commercial strain were fed corn-soybean meal-based diets formulated to meet nutritional levels typical of top broiler producers. Diets were fortified with a complete vitamin premix devoid of CHO. In test diets, Met levels were as formulated, or less 0.05, 0.10, 0.15, or 0.20% Met. Within each Met level, diets received no supplemental CHO or BET or 1,000 mg of CHO/kg, 1,000 mg of BET/kg, or a combination of 500 mg each of CHO and BET/kg. This resulted in a 4 × 5 factorial arrangement with each of the 20 treatments fed to 4 pens of 60 birds for a 56-d feeding trial. Samples of birds were processed at 42, 49, and 56 d to determine parts yield and dressing percentage. Intestinal segments were evaluated for tensile strength at these same ages.The dietary Met level had no significant impact on BW at 14 or 56 d of age, but at 35, 42, and 49 d reduction of the Met content resulted in loss of BW. Feed conversion was not affected by the Met level at 14 d but was significantly affected by reducing the Met level at all other ages. Breast meat yield was reduced in a linear manner by reductions in Met supplementation. The CHO or BET supplementation had no apparent sparing effect on Met needs but did improve feed conversion at 35 and 42 d. There was a positive effect of CHO and BET on breast yield that was independent of Met levels; CHO was as effective as BET for this purpose. No effect of CHO or BET on intestinal strength was observed in the present study.     

N-氨甲酰谷氨酸和精氨酸对京海黄鸡肉仔鸡生长性能和血液指标的影响

本试验旨在探讨N-氨甲酰谷氨酸(N-carbamylglutamate,NCG)和精氨酸(Arg)对京海黄鸡肉仔鸡生长性能、血清生化参数及游离氨基酸含量的影响。选用1日龄体重相近的京海黄鸡肉仔鸡600只,随机分为5组,每组6个重复,每个重复20只。对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ、Ⅳ组饲喂在基础日粮中分别添加0.05%、0.10%、0.15% NCG及0.10% Arg的试验日粮。试验期28 d。结果表明,与对照组相比,添加0.05%、0.10%、0.15% NCG及0.10% Arg组平均日增重(ADG)升高,添加0.10% NCG组料重比(F/G)显著降低(P<0.05);添加0.10% NCG组血清中血氨(AMM)、尿酸(UA)和低密度脂蛋白(LDL)含量相对于其他各组显著降低(P<0.05),添加0.15% NCG组血清中一氧化氮(NO)、一氧化氮合成酶(NOS)和碱性磷酸酶(ALP)含量显著高于对照组(P<0.05);与对照组相比,添加0.10%、0.15% NCG组和添加0.10% Arg组血清中Arg含量显著升高(P<0.05)。综上所述,日粮中添加NCG有助于提高京海黄鸡肉仔鸡血清中Arg和脯氨酸(Pro)的含量,改善血液指标,提高肉仔鸡的生长性能,其中NCG添加水平为0.10%时效果较好。     

Effects of Dietary N-Carbamylglutamate and Arginine on Growth Performance and Blood Parameters of Jinghai Yellow Broiler Chicks

This study was conducted to investigate the effects of N-carbamylglutamate (NCG) and arginine (Arg) on growth performance, serum biochemical indexes and serum free amino acid content of Jinghai Yellow broiler chicks.A total of 600 1-day-old chicks with similar weight were used and randomly assigned into 5 groups with 6 replicates per group and 20 chicks per replicate.The control group was fed with basal diet, groups Ⅰ to Ⅳ were fed with the basal diets supplemented with 0.05%, 0.10%, 0.15% NCG and 0.10% Arg, respectively.The trial lasted for 28 days.The results showed that compared with control group, the supplementation of 0.05%, 0.10%, 0.15% NCG and 0.10% Arg increased ADG, the supplementation of 0.10% NCG significantly decreased F/G (P<0.05).The supplementation of 0.10% NCG significantly decreased the contents of AMM, UA and LDL in serum compared with other groups (P<0.05), the supplementation of 0.15% NCG significantly increased the contents of NO, NOS and ALP in serum compared with control group (P<0.05).Compared with control group, the supplementation of 0.10%, 0.15% NCG and 0.10% Arg significantly increased the content of Arg in serum (P<0.05).These results indicated that supplementation with NCG could increase the contents of Arg and Pro in serum, improve blood parameters and growth performance of broiler chicks, and the appropriate supplemental level of NGG was 0.10%.     

胍基乙酸对肉鸡的适用阶段及饲粮蛋氨酸配套强化效果研究

本研究基于生长性能和肉品质,评价胍基乙酸(GAA)对肉鸡的适用阶段和饲粮蛋氨酸(Met)配套强化效果。选取1日龄雄性爱拔益加肉仔鸡1920只,随机分为16组,每组设6个重复,每个重复20只鸡。试验分前期(1~21日龄)和后期(22~42日龄)2个饲养阶段,1组为对照组,饲喂常规饲粮(Met水平前期为0.50%,后期为0.40%)。2~6组仅在前期设置Met或GAA处理,其中,2组只把饲粮Met的水平提高至0.65%;3~6组采用双因素完全随机设计,2个饲粮Met水平分别为0.50%和0.65%,2个GAA添加量分别为300和600 mg/kg。7~11组仅在后期设置Met或GAA处理,其中,7组只把饲粮Met水平提高至0.55%;8~11组采用双因素完全随机设计,2个饲粮Met水平分别为0.40%和0.55%,2个GAA添加量分别为400和800 mg/kg。12~16组在全期(1~42日龄)设置Met或GAA处理,前期和后期饲粮设置分别同2~6组和7~11组。试验期42 d。结果发现:1)与对照组相比,只在前期饲喂高剂量GAA并强化Met供应能够显著提高1~21日龄平均日增重和21日龄体重(P<0.05),显著降低1~21日龄料重比(P<0.05);仅在后期饲喂高剂量GAA能够显著提高22~42日龄平均日增重,显著降低22~42日龄料重比(P<0.05),同时强化Met供应还可显著提高1~42日龄平均日增重及42日龄体重、胸肌指数(P<0.05),显著降低22~42日龄和1~42日龄料重比及42日龄腹脂指数(P<0.05);全期饲喂高剂量GAA能够提高22~42日龄和1~42日龄平均日增重及42日龄体重和胸肌指数(P<0.05),显著降低22~42日龄和1~42日龄料重比及42日龄腹脂指数(P<0.05),同时强化Met供应还可显著提高1~21日龄平均日增重和21日龄体重(P<0.05),显著降低1~21日龄、22~42日龄和1~42日龄料重比(P<0.05)。2)与对照组相比,全期单独强化饲粮Met或联合添加低剂量GAA可以显著降低42日龄胸肌、腿肌亮度(L^∗)值和剪切力(P<0.05),提高红度(a^∗)值和24 h pH(pHu)(P<0.05);单独饲喂GAA对肉品质无显著影响(P>0.05)。由此可见,当全程饲喂高剂量GAA时,无需额外补充Met就可使肉鸡终末体重和胴体质量达到最佳;若要阶段性使用GAA,宜在后期高剂量添加且同时补充Met。     

饲粮精氨酸水平对黄羽肉种鸡产蛋高峰期繁殖性能的影响

本试验旨在研究不同饲粮精氨酸水平对黄羽肉种鸡繁殖性能的影响。试验选用780只36周龄的黄羽肉种鸡作为试验鸡,采用单因素随机分组试验设计分成5个组(饲粮精氨酸水平分别为0.65%、0.80%、0.95%、1.10%和1.25%),每组6个重复,每个重复26只鸡。试验预试验2周,饲喂精氨酸水平为0.65%的饲粮;正试期10周。结果表明:饲粮中添加不同水平精氨酸对试验全期种鸡产蛋率、平均蛋重和料蛋比均没有显著影响(P0.05)。1.10%精氨酸组的产蛋率最高,与0.65%和1.25%精氨酸组相比有提高的趋势(P0.10)。1.25%精氨酸组平均蛋重最低,与其他4组相比均有降低的趋势(P0.10)。饲粮中添加不同水平精氨酸对种蛋蛋壳强度、蛋壳厚度、蛋黄比例、蛋白质含量以及种鸡血浆中丙二醛含量和还原型谷胱甘肽/氧化型谷胱甘肽值均有显著影响(P0.05)。饲粮精氨酸水平对种蛋受精率、孵化率、健雏率和健雏平均出壳重均没有显著影响(P0.05)。由此可见,适度添加精氨酸一定程度上能提高黄羽肉种鸡产蛋率,增强种蛋蛋壳强度和种鸡抗氧化能力。综合分析本试验多项指标,推荐快大型黄羽肉种鸡产蛋高峰期饲粮中精氨酸水平为1.10%。     

临武鸭产蛋高峰期蛋氨酸需要量的研究

本试验旨在研究饲粮蛋氨酸水平对30~38周龄临武鸭生产性能、蛋品质和血清生化指标的影响,以确定临武鸭产蛋高峰期蛋氨酸的需要量。选取体重相近、健康状况良好的临武鸭200羽,随机分为5组,每组5个重复,每个重复8只鸭。饲粮蛋氨酸水平分别为0.27%、0.32%、0.37%、0.42%、0.47%,试验全期63 d。结果显示:1)饲粮蛋氨酸水平对产蛋率和合格蛋率无显著影响(P0.05)。0.37%、0.42%、0.47%组的平均日采食量和料蛋比均显著低于0.27%组(P0.05),而0.37%组的平均蛋重和日产蛋量显著高于0.27%组(P0.05)。0.37%组获得了除合格蛋率外最佳的产蛋性能。2)饲粮蛋氨酸水平对蛋鸭蛋形指数、蛋壳厚度、蛋黄色泽、蛋黄比例、蛋壳比例、蛋白比例的影响均不显著(P0.05),但0.42%组蛋白高度和哈氏单位最大且显著高于0.27%和0.32%组(P0.05)。3)饲粮蛋氨酸水平对蛋鸭血清中总蛋白、白蛋白、尿素氮、尿酸和丙二醛含量均无显著影响(P0.05)。与0.27%组相比,其他4组的血清超氧化物歧化酶活性显著提高(P0.05),0.37%、0.42%、0.47%组血清谷胱甘肽(GSH)含量和谷胱甘肽过氧化物酶(GSH-Px)活性均显著高于0.27%组(P0.05)。4)以作为评价蛋氨酸需要量敏感指标的料蛋比和血清中GSH含量为依据,通过回归分析估测得到产蛋高峰期临武鸭获得最小料蛋比和最大GSH含量所对应的饲粮中蛋氨酸需要量分别为0.41%和0.43%。综上所述,在本试验条件下,当蛋氨酸水平为0.41%~0.43%时,产蛋高峰期临武鸭可获得最佳产蛋性能、蛋品质和血清生化指标。因此30~38周龄临武鸭蛋氨酸推荐量为0.41%~0.43%。     

日粮中添加柠檬酸对肉鸡生产性能的影响

将36只21日龄的艾维茵仔鸡,随机分成6组(第一组为对照组),试验采用玉米-豆饼型基础日粮,各组日粮柠檬酸添加水平分别是0、0.15%、0.25%、0.5%、1%、2%,试验期5周,研究了日粮柠檬酸水平对肉仔鸡生产性能的影响.结果表明,日粮中添加0.25%的柠檬酸,鸡增重最快;添加2%柠檬酸,可显著降低肉鸡增重;添加0.15%、0.25%柠檬酸.鸡的饲料报酬最高.添加柠檬酸对日粮有机物质的消化率有显著影响,其中添加0.25%柠檬酸鸡的蛋白质消化率最高.因此认为,日粮添加0.25%柠檬酸为适宜添加量,添加2%柠檬酸为其最大耐受量.     

Hatchery Feeding of Starter Diets to Broiler Chicks

This study examined hatchery feeding of starter diets differing in amino acid density and moisture on live performance measurements up to 37 d and processing measurements at 38 d. Eggs from a Cobb × Cobb 500 slow-feathering cross broiler strain were set in a common incubator and hatched. Chicks were feather-sexed, placed in 36 chick trays (25 chicks of each sex), and weighed by tray. One of 4 dietary treatments was administered (454 g/tray) in crumble form: 1) no feed; 2) feed containing 1.24% digestible Lys, 0.84% digestible TSAA, 0.80% digestible Thr, 23.2% CP, and 3,080 kcal/kg of ME; 3) feed containing 1.45% digestible Lys, 0.94% digestible TSAA, 0.84% digestible Thr, 26.0% CP, and 3,080 kcal/kg of ME; and 4) treatment 3 plus 100 mL of potable water added to the crumbles 5 min before administration in the trays. Chicks received feed treatments in trays in the hatchery, during transportation to the research facility, and in the research facility until placement (5 h of total tray feeding). Body weight gain at d 7 was increased in birds fed the high density diet alone or in combination with water as compared with birds that were fasted. Subsequent live performance, processing, and small intestine weights, however, did not differ among treatments. Lack of 37-d improvements (average 4.6-lb birds) to early feed allocation may be a result of diet composition, duration of diet allocation, and the genetic strain of bird used, because much literature has pointed to the importance of posthatch nutrition of broilers.     

日粮蛋氨酸及赖氨酸水平对雌性肉仔鸡胴体组成的影响

本试验旨在探讨日粮蛋氨酸和赖氨酸水平对 3～ 6周龄艾维茵母鸡胴体组成及脂肪代谢的影响。试验采用 3× 5双因子试验设计 ,蛋氨酸设 3个水平 ( 0 32 % ,0 4 4% ,0 56 % ) ,赖氨酸设 5个水平( 0 7% ,0 85% ,1 0 % ,1 1 5% ,1 30 % ) ,一共形成 1 5个处理组。基础日粮由玉米、豆粕、花生粕、玉米蛋白粉等组成。含代谢能 1 2 73MJ/Kg ,粗蛋白 1 8 8% ,赖氨酸 0 7% ,蛋氨酸 0 32 %。试验末分别检测生产性能 ,屠宰性能及血液生化指标。结果表明 :日粮赖氨酸和蛋氨酸显著影响了肉仔鸡的胴体组成和脂肪代谢 (P <0 0 1 )。赖氨酸和蛋氨酸缺乏或过量 ,血浆尿酸、甘油三脂和极低密度脂蛋白浓度均呈上升趋势。日粮赖氨酸 ( 0 70 % )和蛋氨酸 ( 0 32 % )缺乏显著降低了肉仔鸡的体增重、胸肉率及全净膛率 (P<0 0 5) ,而腹脂沉积偏高。适度提高日粮赖氨酸和蛋氨酸水平可以提高全净膛率 ,胸肌率 ,降低腹脂沉积 ,从而改善胴体品质     

鲁禽3号麻鸡能量需要研究

为了研究鲁禽3号麻鸡的最佳能量需要,选用1日龄健康雏鸡1 080只,公母各1/2,随机分成9组,按不同营养水平饲喂,每组3个重复,每个重复公、母鸡各20只。试验分为一期(0~5周龄)、二期(6~10周龄)和三期(11~13周龄)3个试验期,利用SPSS软件对试验结果进行差异性分析。回归分析结果表明,在本研究条件下,鲁禽3号麻鸡能量需要量(MEI)可按下式估算:一期:MEI=(6 750.7 W0.75-69.2)△W 10.96 W0.75二期:MEI=(221.4-2 020.1 W0.75)△W 3.89 W0.75三期:MEI=(122.4-572.1 W0.75)△W 3.53 W0.75     

蛋氨酸螯合锌对环颈雉雏雉生长的影响

随机选取 7日龄健康环颈雉雏雉 72只 ,分成 3组 ,每组 2 4只。每组基础日粮相同 ,Ⅰ组为对照组 ,添加 0 0 4 %硫酸锌 ;Ⅱ、Ⅲ组为试验组 ,分别添加 0 0 4 %蛋氨酸螯合锌、0 0 2 %蛋氨酸螯合锌 +0 0 2 %硫酸锌。饲养试验结果表明 ,各试验组体长、翅长增长均显著大于对照组 (P <0 0 5 ) ,各试验组平均日增重均极显著高于对照组 (P >0 0 1) ,同时各试验组料重比均低于对照组 (P <0 0 5 ) ,各试验组尾长增长也大于对照组 (P <0 0 5 )。此外 ,各试验组成活率均高于对照组。综合比较 ,Ⅱ、Ⅲ组饲喂效果好且无显著差异 (P >0 0 5 )。     

Effects of Rice Bran Inclusion on Performance and Bone Mineralization in Broiler Chicks

Rice bran, a by-product of the rice industry, is available for animal feeds. However, it has not been a common part of poultry rations in Argentina. Hydrolytic and oxidative rancidity development, phytate content, enzyme inhibitor, and high fiber content are the most important antinutritive factors cited as limiting factors for its use. An experiment utilizing 1-d-old male broiler chicks was conducted to determine the responses of zootechnical and bone mineralization parameters to diets with different concentrations of rice bran. The feed conversion and tibia ash were more sensitive than weight gain to detect antinutritive factors in rice bran. High concentrations of rice bran (in excess of 20%) produced a significant reduction in body weight. Furthermore, feed conversion and bone mineralization variables were impaired by feeding 10% rice bran diets. The adverse effects of rice bran on weight gain, feed conversion, and mineralization in the current studies suggest that rice bran should be included in broiler diets at a level between 10 and 20% if strategies are not used to decrease the antinutritive activity.     

二次回归正交旋转组合设计优化1～21日龄肉仔鸡胆碱和蛋氨酸需要量

本试验以低胆碱、低蛋氨酸饲粮为基础饲粮,通过两因子二次回归正交旋转组合设计,旨在研究1～21日龄肉仔鸡胆碱和蛋氨酸的最佳需要量.试验选用1日龄爱拔益加(AA)肉仔鸡480只,随机分为12个组,其中1～8组为试验组,9～12组为中心组,每组4个重复,每个重复10只鸡,公母各占1/2.分别以胆碱和蛋氨酸为自变量,以反映肉仔鸡生长性能和屠宰性能的各项指标为因变量拟合回归方程,估计1～21日龄肉仔鸡胆碱和蛋氨酸需要量.试验期21d.结果表明:一定水平的胆碱和蛋氨酸可显著改善1～21日龄肉仔鸡的平均日增重、料重比、屠宰率和腹脂率.从响应面图可以看出,当蛋氨酸水平为0.50％～0.70％时,随着胆碱水平的降低,肉仔鸡平均日增重逐渐降低;当蛋氨酸水平为0.42％～0.50％,胆碱水平为1300～1738 mg/kg时,肉仔鸡的料重比达到最低;蛋氨酸水平为0.50％～0.70％时,屠宰率随着蛋氨酸水平的升高而下降,蛋氨酸为0.36％～0.50％时,随着胆碱水平的升高,屠宰率呈上升趋势;随着胆碱水平的升高,腹脂率逐渐降低,当胆碱水平为1300 ～1920 mg/kg时,腹脂率随蛋氨酸水平的降低而下降.在本试验条件下,当胆碱水平为1434～1631mg/kg,蛋氨酸水平为0.47％时,肉仔鸡可达到最佳生长性能;当胆碱水平为1984 mg/kg,蛋氨酸水平为0.49％时,肉仔鸡可达到最佳屠宰性能.