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151.
152.
《The Journal of Applied Poultry Research》2014,23(3):456-469
Crude protein in corn and soybean meal have been documented to vary, and such inherent variability can result in under- or over-feeding of CP when feeds are formulated, leading to reduced bird growth, added input costs, and increased environmental pollution. The purpose of this study was to compare 2 grain-handling techniques and 2 feed formulation methods (linear vs. stochastic programming) to reduce CP variability in finished feeds and determine resulting costs or savings. The 2 grain-handling techniques were placing all the random batches of each delivered ingredient in to (1) a single bin (1-bin method) or (2) segregating above- and below-average samples into 2 bins (2-bin method). A fast way of estimating the composition of the ingredients is now available (near-infrared reflectance spectroscopy). Microsoft Excel workbooks were constructed to solve broiler starter feed formulation problems. Formulating feeds by linear and stochastic models based on the 2-bin method reduced CP variability by at least 50% compared with the 1-bin method. Formula cost was reduced by ˜20 cents per ton (averages of August 2012 United States ingredient prices) when the 2-bin method was used with the linear model. Formulating feed with a margin of safety increased formula cost by $3.40 per ton. Stochastic feed formulation increased formula cost to meet the specified CP level in feed at any probability of success, and formula cost was reduced substantially with the 2-bin method (up to $6.47 per ton). The magnitude of savings and reduced feed variability suggested that, regardless of the costs associated with building extra bins, the 2-bin method can be economically efficient in the long run. Therefore, it could be possible to split the batches of feed ingredients at a feed mill into above- or below-average bins before feed formulation to reduce CP variability and to maximize savings. 相似文献
153.
ABSTRACT1. The objective of this study was to investigate the effect of supplementing broiler diets with xylanase or xylo- oligosaccharide (XOS) on growth performance, the concentration of non-starch polysaccharide (NSP) hydrolysis products in the ileum and concentration of short chain fatty acids (SCFA) in the caeca of broiler chickens.2. In total, 500 male Ross 308 broilers were used in this 29-day (d) study. The treatments were organised into a 2 × 2 plus 1 factorial arrangement consisting of two additives (xylanase or XOS) at two levels (low or high) plus a control treatment with no additives. This gave five treatments with 100 birds in each treatment group. The diets were slightly deficient in protein by 20 g/kg and energy by 1 MJ/kg.3. On d 14 and 28, two birds per pen were euthanised, the caeca content collected and analysed for short chain fatty acid (SCFA) concentration. On d 29, six birds per pen were euthanised and ileal digesta were collected and analysed for the concentration of NSP fractions.4. On d 14, caecal acetic acid, iso-butyric acid, iso-valeric acid, n-valeric acid and total SCFA concentrations were significantly greater (P ≤ 0.05) when diets were supplemented with XOS compared with xylanase.5. Ileal concentration of arabinose, galactose and glucuronic acid (GlucA2) were significantly greater (P ≤ 0.05) in the insoluble NSP fraction when diets were supplemented with a high level of xylanase, compared with the control treatment. Ileal concentration of fructose was significantly greater (P ≤ 0.05) in the water soluble NSP when a high level of xylanase or low level of XOS were included in the diet compared with the control.6. It was concluded that xylanase and XOS had similar effects on NSP concentration and SCFA in the caeca, although there was little effect on performance. This observation demonstrated further benefits of xylanase supplementation in wheat-based broiler diets beyond digesta viscosity reduction and the release of extra nutrients. 相似文献
154.
Soil physical changes and maize growth in a structurally fragile tropical soil due to mulching and duration between irrigation intervals
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E. G. Moura V. R. A. Macedo V. G. L. Sena L. S. Campos A. C. F. Aguiar 《Soil Use and Management》2017,33(4):631-638
Under tropical meteorological conditions, the volume of soil explored by plant roots is crucial for crop growth as it allows increased water and nutrient use efficiency. We hypothesized that, under different irrigation intervals, leguminous mulch can extend the duration between irrigation events but maintain crop performance, because decreased evaporative fluxes also reduce constraints to root exploration imposed by mechanical stress. We evaluated the combined effects of leguminous mulch and irrigation intervals on soil physical properties to determine whether the growth and productivity of maize were modified in a structurally fragile tropical soil. The experiment involved the following treatments: 4‐day irrigation intervals with soil mulched (4C) or bare (4S), 6‐day irrigation intervals with soil mulched (6C) or bare (6S), 8‐day irrigation intervals with soil mulched (8C) or bare (8S) and 10‐day irrigation intervals with soil mulched (10C) or bare (10S). Mulch decreased soil penetration resistance and increased to 4 days the favourable time for root development in drying soil. Relative to bare soil, mulch with a 6‐day irrigation interval almost doubled nitrogen uptake post‐tasselling, which decreased nitrogen remobilization and increased the crop growth rate during this stage. These conditions had a positive effect on the transpiration rate and stomatal conductance as well as on the growth and yield of maize. A 6‐day irrigation interval with mulch compared to 4 days with bare soil resulted in similar conditions for root development, but greater uptake of nitrogen (102.73–78.70 kg/ha) and better yield (6.2–5.3 t/ha), which means greater efficiency in nitrogen and water use. 相似文献
155.
Maize harvest index and water use efficiency can be improved by inhibition of gibberellin biosynthesis
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Possibilities to improve maize harvest index and nutrient utilization efficiency by application of plant growth regulators were investigated. In container experiments, the effects of different growth regulators on the development of the maize (Zea mays L.) cultivars Pioneer 3906 and Fabregas were tested. Paclobutrazol (PAC) and chlorocholine chloride (CCC), two inhibitors of gibberellin biosynthesis, as well as gibberellic acid (GA3) were applied at growth stage V5. Three weeks after application of PAC, shoot growth of both maize cultivars was strongly affected with a significant decrease in plant height in the PAC treatment by 44% and 36% for Pioneer 3906 and Fabregas, respectively. The growth‐retarded plants had higher leaf areas and reduced transpiration rates. The higher shoot growth after GA3 application was accompanied by a reduction in leaf area and an increase in transpiration rate during 1 week before anthesis. CCC treatment showed no significant effects on plant height, leaf area and transpiration rate. The PAC‐treated cultivar Pioneer 3906 produced several cobs per plant, which were mainly barren at maturity. However, PAC application to Fabregas resulted in just one cob per plant with good kernel development and a grain yield, which was not significantly reduced in comparison with the control. With this similar grain yield in combination with a straw yield decrease of 32%, the harvest index was significantly improved by 12%. In addition, with PAC‐treated Fabregas plants, a 19% increased water use efficiency of the grain (WUEgrain) during the critical period of kernel setting was achieved. In this maize cultivar, CCC application also improved harvest index by 5%, but no effect on WUEgrain occurred. GA3 treatment decreased harvest index of both maize cultivars, and it either reduced WUEgrain (Pioneer 3906) or showed no effect (Fabregas). Utilization efficiencies of N, P and K were not increased with growth regulator application, even in the PAC‐treated Fabregas plants with a significantly improved allocation of assimilates to the grain, mirrored by the higher harvest index. The results indicate that fertilizer applications must be adjusted to the reduced demand of growth‐retarded plants, most likely leading to higher nutrient utilization efficiencies. 相似文献
156.
《Soil Use and Management》2018,34(1):9-17
Reuse of phosphorus (P) from waste streams used for bioenergy conversion is desirable to reduce dependence on nonrenewable P resources. Two different ash materials from low‐temperature biomass gasification of wheat straw and sewage sludge, respectively, were investigated with regard to their P bioavailability. A set of pot experiments with spring barley was carried out to compare the ash P fertiliser value with mineral P fertiliser and the sewage sludge feedstock. An indirect radioactive labelling approach with 33P was used to determine the amount of P taken up from the fertiliser materials. Depending on the application rate, straw gasification ash produced a fertiliser response comparable to mineral P. However, P uptake from the ash was generally less than uptake from equivalent amounts of mineral P, and the calculated relative effectiveness was 44% after 6 weeks of plant growth. In contrast, the P fertiliser value of Fe‐rich sewage sludge after low‐temperature gasification was practically zero. These results suggest that ash from low‐temperature gasification could be developed into alternative P fertilisers; however, as the P bioavailability depends greatly on the feedstock used, a greater emphasis on feedstock composition is required. 相似文献
157.
不同施肥措施对灰枣园土壤速效养分含量的影响 总被引:2,自引:0,他引:2
为了探讨灰枣生长期内不同施肥处理措施对枣园土壤速效养分含量的影响情况,于2014年3月采用不施肥、常规施肥和施用不同种类生物肥共3大类9种处理进行田间试验,并于同年7~10月在灰枣不同生长期测定了各处理区域土壤中的碱解氮、速效磷、速效钾、有机质这4种养分的含量,研究了不同施肥处理下灰枣不同成熟期土壤各养分的动态变化情况。结果表明,不同处理、不同成熟期土壤各养分含量间均有差异,施用生物肥可以显著提高土壤中各养分的含量。 相似文献
158.
本试验旨在研究固态发酵醋糟饲料(SFVD)对育肥猪生长性能、养分表观消化率、血清指标及粪便中挥发性脂肪酸(VFA)含量的影响。选择体况相近[(59.04±0.33)kg]的健康“杜×长×大”三元杂交生长育肥猪60头,随机分为2个组,每组3个重复,每个重复10头猪。对照组饲喂基础饲粮+150 mg/kg土霉素钙,试验组饲喂基础饲粮+5%的SFVD。预试期6 d,正试期35 d。结果表明:与对照组相比,基础饲粮中添加5%的SFVD对育肥猪平均日采食量(ADFI)具有一定的促进趋势(P=0.056);显著降低了育肥猪饲粮中干物质(DM)、粗蛋白质(CP)、有机物(OM)和总能(GE)的表观消化率(P<0.05),对粗脂肪(EE)表观消化率有一定的促进趋势(P=0.052);显著提高了育肥猪血清谷草转氨酶(AST)和谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05),血清高密度脂蛋白(HDL)和免疫球蛋白A(IgA)含量也呈现出一定的升高趋势(P=0.055和P=0.077);显著提高了育肥猪粪便中丙酸含量(P<0.05),粪便中甲酸和总挥发性脂肪酸(TVFA)含量也呈现出一定的升高趋势(P=0.071和P=0.054)。由此可见,基础饲粮中添加5%的SFVD对育肥猪生长性能、肠道健康及免疫性能的提高具有潜在的促进作用。 相似文献
159.
通过对海南省文昌市南阳镇、琼海市大路镇、乐东县黄流镇3个地区‘马来西亚1号’菠萝蜜叶片氮、磷、钾3种营养元素的周年变化规律跟踪调查分析,结果表明:3个地区菠萝蜜叶片营养元素变化规律相似。元素年平均含量表现为氮>钾>磷。根据实际生产中的生育期调研分析,将菠萝蜜的生长周期大致划分为2个批次3个时期:第一批次养树期(11—12月)、花芽分化期(1—2月)、结果期(3—4月);第二批次养树期(5—6月)、花芽分化期(7—8月)、结果期(9—10月)。生长周期内,氮元素含量年变化呈现“N”字型变化趋势;磷含量在1—4月呈先上升后下降的趋势,随后呈缓慢上升趋势;钾含量变化趋势与氮含量变化相似,但钾元素含量变化没有氮元素变化明显。菠萝蜜叶片中大量元素含量的适宜范围为:全氮21.03~22.15 g/kg,全磷2.86~3.40 g/kg,全钾13.49~14.47 g/kg。在生长发育过程中,菠萝蜜需氮、钾元素较多,特别是在花芽分化期和结果期,应注意增施氮肥与钾肥,磷肥应于养树期施足。 相似文献
160.
本试验旨在探讨单宁酸对生长猪胃、小肠仿生消化中消化酶活性及玉米-豆粕型饲粮干物质和粗蛋白消化率的影响,为评价单宁酸的生物学效应提供参考。试验一采用单因素完全随机设计,考察在无饲粮下2种单宁酸对猪模拟胃液、模拟小肠液消化酶活性的影响。设5个处理,单宁酸添加量分别为0 mg (胃液体积为20 mL,小肠液体积为22 mL);单宁酸1,10 mg;单宁酸1,20 mg;单宁酸2,10 mg;单宁酸2,20 mg。测定各处理的胃蛋白酶、淀粉酶、胰蛋白酶和糜蛋白酶的活性。试验二考察玉米-豆粕型饲粮添加单宁酸对猪仿生消化中胃、小肠阶段消化酶活性及养分消化率的影响。采用单因素完全随机设计,设5个处理,单宁酸在饲粮中的含量分别为0 mg·(2 g)-1;单宁酸1,10 mg·(2 g)-1;单宁酸1,20 mg·(2 g)-1;单宁酸2,10 mg·(2 g)-1;单宁酸2,20 mg·(2 g)-1。测定仿生消化中胃阶段0.5和4 h时胃蛋白酶活性,小肠阶段0.5、4和8 h时淀粉酶、胰蛋白酶和糜蛋白酶活性及生长猪胃-小肠仿生消化测定饲粮的干物质和粗蛋白消化率。结果表明:1)无饲粮的情况下,和空白对照组相比,2种单宁酸对模拟胃液中胃蛋白酶活性无显著影响(P>0.05),单宁酸1比单宁酸2更高地降低了模拟小肠液中淀粉酶、胰蛋白酶和糜蛋白酶的活性(P<0.05)。2)在饲粮进行仿生消化的胃消化0.5~4 h内,除4 h时10 mg·(2 g)-1添加量外,添加单宁酸1时胃蛋白酶的活性均显著高于添加单宁酸2时的相应值(P<0.05),除单宁酸2在消化0.5 h外,2种单宁酸在添加10 mg·(2 g)-1时胃蛋白酶活性均显著高于20 mg·(2 g)-1添加量的相应值(P<0.05)。在小肠仿生消化0.5 h时,饲粮中添加单宁酸1、2的2个水平对消化液中淀粉酶活性无显著影响(P>0.05),但均显著降低了糜蛋白酶的活性(P<0.05);单宁酸1的消化液中胰蛋白酶活性高于单宁酸2的相应值(P<0.05)。在小肠仿生消化4 h时,除添加水平为20 mg·(2 g)-1时的糜蛋白酶活性外,饲粮中添加单宁酸1消化液中淀粉酶、糜蛋白酶活性高于添加单宁酸2的相应值,而胰蛋白酶活性低于添加单宁酸2的相应值(P<0.05)。单宁酸1、2的两个添加量均降低了胰蛋白酶和糜蛋白酶的活性(P<0.05)。在小肠仿生消化8 h时,饲粮中单宁酸的添加量影响了淀粉酶的活性,但单宁酸1和单宁酸2各两个添加量在淀粉酶的平均活性上无显著差异(P>0.05)。单宁酸1、2的两个添加量均降低了胰蛋白酶、糜蛋白酶的活性(P<0.05)。3)与对照组相比,两种单宁酸在两种添加水平下均显著降低了饲料粗蛋白消化率(P<0.05),且单宁酸2比单宁酸1更多地降低了饲粮粗蛋白的消化率(P<0.05)。综上所述,在有、无饲粮条件下,单宁酸对消化酶活性呈现不一致影响。单宁酸影响饲粮粗蛋白的消化率可能主要与消化液中糜蛋白酶活性降低以及单宁酸与饲粮中的化学成分形成螯合物降低了小肠消化酶的水解效率有关。 相似文献