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101.
本试验旨在研究低磷饲粮中超量添加植酸酶对肉鸡生长性能、屠宰性能、消化器官指数、养分表观利用率及胫骨指标的影响。选取1日龄罗斯308商品肉仔鸡公雏2 160只,随机分为5组,每组12个重复,每个重复36只。正对照组(PC组)饲喂基础饲粮,负对照组(NC组)饲喂低磷饲粮(钙和有效磷水平均比PC组降低0.15%),试验组在低磷饲粮的基础上分别添加500(NC500)、1 500(NC1500)和4 500 FTU/kg(NC4500)的植酸酶。试验期39 d。结果表明:1)NC和NC500组14、25和38日龄体重以及1~14日龄、15~25日龄和1~38日龄平均日增重(ADG)、平均日采食量(ADFI)、育肥指数显著低于PC组(P<0.05)。除NC4500组1~38日龄ADFI显著高于PC组(P<0.05)外,NC1500和NC4500组38日龄体重以及1~38日龄ADG、ADFI、育肥指数与PC组差异不显著(P>0.05)。2) NC组钙表观利用率显著低于PC组(P<0.05),NC500、NC1500和NC4500组日均排钙量显著低于PC组(P<0.05)。NC500、NC1500和NC4500组磷表观利用率显著高于NC和PC组(P<0.05),日均排磷量显著低于NC和PC组(P<0.05)。3)NC组胫骨强度显著低于其他各组(P<0.05),NC4500组胫骨强度显著高于其他各组(P<0.05)。4) NC组26、39日龄肝脏指数显著高于PC组(P<0.05),NC1500和NC4500组26日龄空肠、回肠指数显著低于PC和NC组(P<0.05),NC1500和NC4500组39日龄肝脏、胰腺、十二指肠、空肠指数显著低于NC组(P<0.05)。5) NC组全净膛率、腿率均显著低于PC组(P<0.05),NC1500和NC4500组全净膛率显著高于NC组(P <0.05),NC500、NC1500和NC4500组腿率显著高于NC组(P<0.05)。6)与PC组相比,NC1500、NC4500组每只鸡收益分别增加了0.61、0.49元。由此可见,本试验条件下,低磷饲粮中超量添加植酸酶能改善肉鸡生长性能、屠宰性能,提高钙、磷利用率及胫骨强度,提高经济效益,其中植酸酶适宜添加量为4 500 FTU/kg。 相似文献
102.
103.
The relationship between the moisture content (MC) of wood blocks and the feeding activities of two Japanese subterranean termites, Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe), was investigated with two choice tests. When three wood blocks with low MC (6%–12%), middle MC (79%–103%), and high MC (140%–182%) were exposed to workers of C. formosanus and R. speratus in a choice test, the feeding preferences were found in the middle MC blocks for C. formosanus, and the middle and high MC blocks for R. speratus, although wood blocks of low MC were also attacked. In a second choice test, wood blocks consisting of five pieces with water-impregnated (MC: 133%–191%) top, middle, or bottom piece were exposed to workers of both species. Higher consumptions were generally obtained in water-impregnated wood pieces and bottom pieces. 相似文献
104.
本文采用数量化分析方法 ,对呼伦贝尔草原黄羊春季采食生境选择进行了研究。研究发现 ,影响呼伦贝尔草原黄羊春季采食生境选择的主要因子是放牧家畜干扰、水源、人为干扰 ,其次是坡度、坡位、坡向、植被类型、食物丰盛度 ,风向也有一定影响。其采食生境选择的倾向性依次为 :放牧家畜干扰距离 >2 0 0 0m ,水源距离≤ 10 0 0m ,坡度 5~ 2 5° ,人为干扰距离 >10 0 0m ,坡位在中坡 ,植被类型是针茅或针茅 羊草群落 ,食物丰盛度中等以上 ,阳坡或半阴半阳坡 相似文献
105.
DemofsellecraneisthesmalleStoneofallcrans,ithasgreatdistributioninChinaandhasvarioushabitatThebredngareaismoStiylocatedineastInnerMongchaAUtonomousedOn,HeilowiirePrednceandWesternhlinPrOvince.ItwigratshereinthendddleofMarh,laysopboearyMaytothendddleofJune,andbonstondgratetothesouthinthelateoctobe.TherearelotsofreportSaboutecolOgicalndesOfbooiselecranes,butfewreportSabootthedeveoPInenofneshiop.TherehasbeenafewstUdiesaboutedngofdemoisel1ecranesinsomezoosinChina.msresearchmaterialisfrOm… 相似文献
106.
松针粉饲用价值及市场展望 总被引:2,自引:0,他引:2
松什粉是一种高效绿色饲料添加剂。松针资源在全国各地十分丰富,但这种资源没有得到合理有效地利用。从松针粉的饲用价值、生产工艺、市场前景以及研究应用现状说明松针资源和松针产品应该引起社会足够的关注。 相似文献
107.
Jennifer D. Knoepp Barbara C. Reynolds D.A. Crossley Wayne T. Swank 《Forest Ecology and Management》2005,220(1-3):300-312
Soil nutrient concentrations decreased in an aggrading southern Appalachian forest over a 20-year period. Construction of nutrient budgets showed significant nutrient sequestration aboveground including increased forest floor mass. We hypothesized that the changes in forest floor mass resulted from decreased litter decomposition rates because of decreased litter quality. In 1992 and 1993, we repeated a litter decomposition experiment conducted in 1969 and 1970 to test this hypothesis. In addition, we examined microarthropod populations and functional groups as litter decomposed. For four of the five species tested, first-year decomposition rates were about the same in both experiments. Initial litter nutrient concentrations of P were lower in all tree species in the most recent sampling. N, Ca, and Mg concentrations also declined in some species. These declines often resulted in decreased nutrient release rates during decomposition. Microarthropod populations differed significantly among litter species, as well as between years (probably resulting from differences in growing-season rainfall). For some litter species we found significant relationships between microarthropod populations and nutrient concentration (primarily C and N); however, most r2-values were low. Data suggest that changes in forest floor mass probably resulted from decreased litter quality and that those changes may have an effect on microarthropod populations. 相似文献
108.
The influence of variable photoperiods on the feeding activity and fecundity of Galendromus occidentalis (Nesbitt) was studied on a diet of Tetranychus urticae Koch eggs. Starved G. occidentalis females were fed T. urticae eggs under ten 24-h light:dark regimes. Half of the tests started during photophase and the other half during scotophase. T. urticae eggs that were consumed and G. occidentalis eggs that were laid were counted at the end of each photophase and scotophase in a 24 h period. In general, G. occidentalis consumed more T. urticae eggs per h in the first phase of the experiment than in the second, regardless of whether the lights were on or off. In contrast to egg consumption, there were no statistical differences in the mean daily fecundity at the end of the 24-h periods. However, when the experiment was started during photophase, higher fecundity/h was encountered during scotophase than during the photophase. As a result, egg consumption rates were affected by photoperiods in both phases of the experiments. Logistic regression analysis revealed that variable photoperiods and egg consumption did not influence the fecundity of G. occidentalis. 相似文献
109.
Tobias Rütting 《Soil biology & biochemistry》2007,39(9):2351-2361
15N tracing studies in combination with analyses via process-based models are the current “state-of-the-art” technique to quantify gross nitrogen (N) transformation rates in soils. A crucial component of this technique is the optimization algorithm which primarily decides how many model parameters can simultaneously be estimated. Recently, we published a Markov chain Monte Carlo (MCMC) method which has the potential to simultaneously estimate large number of parameters in 15N tracing models [Müller et al., 2007. Estimation of parameters in complex 15N tracing models by Monte Carlo sampling. Soil Biology & Biochemistry 39, 715-726].Here, we present the results of a reanalysis of datasets by Kirkham and Bartholomew [1954. Equations for following nutrient transformations in soil, utilizing tracer data. Soil Science Society of America Proceedings 18, 33-34], Myrold and Tiedje [1986. Simultaneous estimation of several nitrogen cycle rates using 15N: theory and application. Soil Biology & Biochemistry 18, 559-568] and Watson et al. [2000. Overestimation of gross N transformation rates in grassland soils due to non-uniform exploitation of applied and native pools. Soil Biology & Biochemistry 32, 2019-2030] using the MCMC technique. Analytical solutions such as the ones derived by Kirkham and Bartholomew [1954. Equations for following nutrient transformations in soil, utilizing tracer data. Soil Science Society of America Proceedings 18, 33-34] result in gross rates without uncertainties. We show that the analysis of the same data sets with the MCMC method provides standard deviations for gross N transformations. The standard deviations are further reduced if realistic data uncertainties are considered. Reanalyzing data by Myrold and Tiedje [1986. Simultaneous estimation of several nitrogen cycle rates using 15N: theory and application. Soil Biology & Biochemistry 18, 559-568] (Capac soil) resulted in a model fit similar to the one of the original analysis but with more precise estimates of gross N transformations. In addition, our analysis showed that small N transformations such as heterotrophic nitrification, which was neglected in the original analysis, could be quantified for this soil. Watson et al. [2000. Overestimation of gross N transformation rates in grassland soils due to non-uniform exploitation of applied and native pools. Soil Biology & Biochemistry 32, 2019-2030] provided evidence of a non-uniform exploitation of applied and native N that led to an overestimation of gross N transformations. Reanalyzing the data (CENIT soil, low N application) with the Müller et al. [2007. Estimation of parameters in complex 15N tracing models by Monte Carlo sampling. Soil Biology & Biochemistry 39, 715-726] model where oxidation was set to Michaelis-Menten kinetics resulted in a satisfactory fit between modeled and observed data, indicating that the observed artifact by Watson et al. [2000. Overestimation of gross N transformation rates in grassland soils due to non-uniform exploitation of applied and native pools. Soil Biology & Biochemistry 32, 2019-2030] was mainly due to inappropriate kinetic settings. Our study shows that the combination of a MCMC method with 15N tracing models is able to consider more complex and possibly more realistic models and kinetic settings to estimate gross N transformation rates and thus overcomes restriction of previous 15N tracing techniques. 相似文献
110.