Regular applications of poultry litter to a sandy arable soil: effects on nitrate leaching and nitrogen balance

Intensive poultry units often have insufficient land for spreading manure at agronomically and environmentally acceptable rates. This experiment measured the effects of annual applications, at several rates, on nitrate-N leaching and the soil–crop N balance on a sandy soil. Poultry litter from a broiler unit was applied each autumn 1992–1995. Total loadings on the main experiment area (instrumented with ceramic and Teflon water samplers at 1·0 and 1·5 m, and monolith lysimeters, 1·5 m deep) were 0, 60 and 150 t ha⁻¹. Additional plots (not instrumented) received 30, 90 or 120 t ha⁻¹. There was good agreement in the nitrate-N concentrations measured by the Teflon and ceramic water samplers and the lysimeters; all three methods gave acceptable measurements of nitrate leaching on structureless sandy soils. Autumn applications of poultry manure should be avoided: leaching was much greater than when delayed into December. At rates of broiler litter which supplied more N than the crop required (generally above 10 t ha⁻¹ each year), nitrate-N leaching losses were large; at the largest application rate (akin to a disposal, rather than a planned fertiliser strategy), concentrations peaked at c 500 mg litre⁻¹ N. Despite the movement of dissolved organic carbon to 1 m depth, the N concentration profiles measured by the water samplers did not provide clear evidence of subsoil denitrification. A nitrogen balance sheet, based on available N applied (as either fertiliser or manure) with some adjustment for mineralisation of the manure's organic fraction (10% annually) and for volatilisation (15%) was strongly correlated with soil mineral N each spring. © 1998 Society of Chemical Industry.     

三种氟喹诺酮类药物在鸡体内的组织残留

建立了鸡组织中环丙沙星、诺氟沙星、恩诺沙星的高效液相色谱(HPLC)测定方法,并测定了鸡单次内服(10mg/kg·d)单种药物和混合药物后组织中的药物残留特征。组织样品用磷酸盐缓冲液提取,用100mgC18固相萃取柱净化,收集洗脱液作HPLC检测。色谱柱为HypersilBDS-C18柱;荧光检测器,激发波长278nm,发射波长445nm;流动相为磷酸/三乙胺(pH2.5)-乙腈(86:14)溶液,pH值为2.5。环丙沙星、诺氟沙星、恩诺沙星三种药物标准溶液的最低检测限分别为20、25和25ng/ml(g);血浆样品回收率大于82%,组织样品回收率大于72%。     

益生素对肉鸡免疫器官指数及血液生化指标的影响

探讨发霉日粮添加益生素对内鸡免疫器官指数及血液生化指标的影响.结果表明:在7～21日龄时,益生素组肉鸡血液中谷丙转氨酶活性、谷草转氨酶活性和料重比与发霉组相比,降低显著(P<0.05);与对照组相比,肉鸡血液中性粒细胞数降低显著(P<0.05),浆细胞数提高显著(P<0.05).在22～42日龄时,益生素组肉鸡血液中淋巴细胞数显著高于对照组及发霉组(P<0.05);法氏囊指数与发霉组相比提高显著(P<0.05).     

肉鸡中金刚烷胺残留测定及其残留代谢规律研究

目的 建立液相色谱-串联质谱测定肉鸡中金刚烷胺残留量的分析方法, 探究鸡肉和鸡肝中的残留代谢规律。方法 样品用乙腈-乙酸-1%三氯乙酸(70:2:30, V:V:V)溶液提取, 固相萃取小柱净化后, 用液相色谱-串联质谱仪进行测定, 利用金刚烷胺-D6为内标定量。结果 金刚烷胺在0~10 μg/kg范围内线性良好, 相关系数(r2)为0.9995, 方法检测限为1 μg/kg。在添加质量浓度1~10 μg/kg范围内回收率为90.1%~95.7%, 相对标准偏差为1.17%~1.62%(n=6)。药物饲喂实验结果表明, 金刚烷胺在肉鸡中吸收快、分布广, 鸡肉中的残留明显高于鸡肝中残留含量, 鸡肉更容易产生药物蓄积。在停药13 d后, 鸡肉中金刚烷胺仍有药物蓄积, 而鸡肝中的金刚烷胺残留量为未检出。结论 该方法操作简单、灵敏度高、稳定性好, 适用于肉鸡中金刚烷胺残留的测定, 揭示金刚烷胺在肉鸡中残留代谢规律。     

Estimating kinetic parameters in TGA using B-spline smoothing and the Friedman method

The pyrolysis of biomass occurs via several parallel/serial decomposition reactions. The kinetic parameters, namely the activation energy (E) and the pre-exponential factor (k_o), do not remain constant during the pyrolysis process. A modified empirical method is introduced for calculating the activation energy (E) and the pre-exponential factor (k₀) based on the Friedman analysis [Friedman HL. Kinetics of thermal degradation of char-forming plastics from thermogravimetry – application to a phenolic plastic. J Polym Sci C 1963;6: 183–95]. The kinetic parameters are expressed as a function of the conversion (x) during the biomass pyrolysis process. The reactions are assumed to be of first order. At least three data sets obtained at different dynamic heating rates are required. From the Friedman analysis, the conversion (x) related functions E = E(x) and k_o = k_o(x) can be obtained by a B-spline regression method. The pyrolysis can hence be described as: x/t=k(1−x)=k_o(x)·exp(−E(x)/RT)(1−x).In this paper, the adapted method is applied to pyrolysis of cellulose and two biomass fuels (meat & bone meal, chicken litter). Experiments were carried out at 2, 10 and 50 K min⁻¹ by thermogravimetric analysis. A good fit of the calculated conversion with experimental data was found.     

沸石、凹凸棒石黏土对肉鸡生产性能、免疫指标和肠道形态的影响

360羽1d龄AA肉鸡随机分成3组,即饲喂基础日粮的对照组及在基础日粮中分别添加5%沸石和5%凹凸棒石黏土（凹土）的试验组。结果表明：与对照组相比,沸石组肉鸡前期生产性能显著降低,后期和全期的生产性能无显著影响;凹土组全期的生产性能无显著影响;但均能降低单位增重成本。沸石组肉鸡后期脾脏指数提高16.8%、胸腺指数显著提高;凹土组后期胸腺指数提高26.3%。并且沸石和凹土对肉鸡后期免疫功能和空肠形态具有改善作用。     

竹叶提取物对肉鸡早期血液生化和机体抗氧化功能的影响

本研究旨在探讨日粮中添加竹叶提取物(Bamboo leaf extract,BLE)对肉鸡早期血液生化和机体抗氧化功能的影响,以期改善肉鸡健康,为人类提供安全放心肉产品。选用1日龄爱拔益佳(Arbor Acres,AA)雄性肉鸡256只随机分成4组,每组8个重复,每个重复8只鸡。对照组饲喂基础日粮,样品组分别在基础日粮中添加0.10%、0.20%和0.40% 竹叶提取物,试验周期21 d。结果表明:与对照组相比,日粮添加竹叶提取物可降低血清中总胆固醇含量,其中0.20% 竹叶提取物组降低效果显著(P<0.05),并且可显著降低血清中尿素氮含量(P<0.05);日粮添加竹叶提取物对肉鸡胸肌抗氧化酶活无显著影响,但可促进胸肌谷胱甘肽的生成。竹叶提取物可促进肝脏谷胱甘肽合成,其中0.20%和0.40%组肝脏谷胱甘肽含量显著高于对照组(P<0.05);此外,与对照组相比,日粮添加竹叶提取物对肝脏超氧化物歧化酶、谷胱甘肽过氧化物酶的活性具有一定的提高作用;与对照组相比,0.10%和0.20%组肉鸡血清中谷胱甘肽过氧化物酶活性分别提高5.82%和4.90%,其中0.10% 竹叶提取物组显著高于对照组(P<0.05)。此外,与对照组相比,0.10%、0.20% 和0.40% 竹叶提取物组血清丙二醛含量分别降低了11.18%、14.59%和4.05%。综上,肉鸡早期日粮中添加一定剂量竹叶提取物未对肉鸡代谢造成影响,可提高机体抗氧化能力,从一定程度上达到改善肉鸡健康作用,可作为食品抗氧化剂使用。     

不同品位及改性沸石对肉鸡生产性能及养分消化率的影响

将504羽1日龄AA肉鸡随机分为四个处理,每个处理6个重复,分别饲喂空白对照日粮、空白对照日粮添加5%普通沸石、高品位沸石和高品位改性沸石的试验日粮,研究不同品位沸石对肉鸡生产性能、饲料养分及氨基酸消化率的影响。结果表明:添加沸石后肉鸡后期的增重分别比对照组提高了2.05%、7.62%和4.73%,饲料转化率改善了0.98%、5.39%和3.43%;高品位和改性高品位沸石使肉鸡全期的增重提高了4.10%和2.41%,饲料转化率改善1.56%;但添加沸石后前期的增重和饲料转化率均有所下降。与对照组相比,三种沸石使饲料干物质的消化率分别提高了4.05%、5.86%及3.03%,粗蛋白消化率分别提高了2.25%、6.16%和11.41%,能量消化率分别提高了3.59%、7.60%和7.16%;但未能提高钙的消化率,高品位和改性高品位沸石提高了磷的消化率;除蛋氨酸外,添加沸石均提高了所有氨基酸的消化率,分别使总必需氨基酸表观消化率分别提高了2.69%、4.79%和4.53%,总非必需氨基酸表观消化率分别提高了2.77%、7.56%和6.08%,总氨基酸表观消化率分别提高了2.74%、6.11%和5.26%;改性高品位沸石降低了肉鸡粪便中的水分含量。饲料中添加沸石可提高肉鸡的生产性能,改善对饲料养分的利用率,高品位沸石的效果优于普通沸石。     

大蒜素对AA肉仔鸡生长性能的影响

选择健康1日龄AA肉仔鸡1 080羽随机分成6个组,在各组基础日粮中分别添加0、100、200、300、400和500 mg/kg的大蒜素,饲喂7周。结果表明,日粮中添加大蒜素对不同生长阶段肉仔鸡的存活率、平均日增重及料肉比均有不同程度的改善作用,其中300 mg/kg的大蒜素对肉仔鸡生长性能的影响达到了显著(P<0.05)或极显著(P<0.01)水平。故本试验得出日粮中添加300 mg/kg的大蒜素是改善肉仔鸡生长性能的最适添加量。     

沸石、凹凸棒石黏土对肉鸡抗氧化性能和组织胆固醇的影响

选用1日龄AA肉鸡240羽,随机分成4组。第1组为对照组,第2、3、4组分别在基础日粮中添加5%沸石、5%凹凸棒石黏土、5%改性凹凸棒石黏土,研究沸石、凹凸棒石黏土和改性凹凸棒石黏土对肉鸡抗氧化性能和组织胆固醇含量的影响。结果表明:日粮中分别添加5%的沸石、5%凹凸棒石黏土和5%改性凹凸棒石黏土均能显著提高血浆中SOD酶活性和降低血浆中MDA含量(P<0.05),不同程度的提高血浆中GSH-Px酶、肝脏中SOD酶活性和降低肝脏中MDA和胆固醇含量。