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吴世春 《国外畜牧学(猪与禽)》1999,(3):14-17
豆粕是全世界家禽日粮中最重要的蛋白质源。显然,尽可能获取最佳质量的豆粕是极为重要的。尿素酶指数法和氢氧化钾蛋白质溶解度法已被广泛地用作测定豆粕加热不足或加热过度的方法。蛋白质水溶解度指数(水中的溶解度,PDI)也许是鉴别最佳质量豆粕的灵敏得多和好得多... 相似文献
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国标GB10380 -89中除规定豆粕的感观性状、水分、夹杂物标准外 ,还规定了豆粕质量指标和分级标准 ,主要依据粗蛋白、粗纤维、粗灰分来分等级 ,用脲酶活性(≤0.4)检测豆粕品质。应用脲酶活性检测加热适度的豆粕是可靠的 ,但对于评价加热过度则无作用 ,因为在豆粕加热过度以前 ,脲酶活性已为零。Dale等(1987)创立了蛋白质溶解度法(PS) ,可以用它来评价过度加热的豆粕 ,认为PS值为75 %~85 %之间为加热适宜。目前 ,人们已采用多种方法检测豆粕质量 ,如有效赖氨酸、氮的水溶解度、蛋白质水溶解度等 ,但均未被… 相似文献
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豆粕作为目前最好的植物蛋白饲料,在饲料生产中应用最为广泛。但生豆粕中含有抗胰蛋白酶、抗维生素因子、尿酶、植酸等有害的物质,会影响氨基酸利用率和代谢能值,进而影响畜禽生产性能,降低饲料的转化效率。需要适当加热将其破坏。判断豆粕品质多采用尿素酶活性这一化学指标。Balloun、Abrahan等指出尿素酶活性只能作为加热至适合程度的评价指标,而对受热过度的豆粕却没有任何意义。而Rinehart提出的采用0.2%KOH溶液测定蛋白质溶解度的方法,克服了测定尿素酶活性的不足,可以真实反映出豆粕的品质。本试验旨在通过对0.75mm… 相似文献
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评价豆粕品质方法的比较 总被引:10,自引:0,他引:10
大豆中存在多种抗营养因子,对动物健康和生产性能都会产生不利影响。适当加热能使胰蛋白酶抑制因子(TI)等抗营养因子活性丧失;加热不足对胰蛋白酶抑制因子等抗营养因子破坏不够充分;加热过度又会破坏热敏氨基酸,特别是会使赖氨酸、精氨酸变性,从而降低大豆蛋白质品质。由于大豆中脲酶的含量与胰蛋白酶抑制因子的多少成正相关,因此以大豆饼粕中的脲酶活性(UA)评价大豆饼粕加热后质量的方法已被广泛采用。Ealloun等指出,脲酶活性只能作为加热至适合程度的评价指标,对判断是否加热过度无意义,因为脲酶活性为零时并不能表明是否加热过度。本试验对蛋白质溶解度法、脲酶活性pH增值法、脲酶活性及酚红法测定豆粕生熟度的效果进行了比较。 相似文献
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本研究采用Sibbald(1976)真代谢能(TME)法测定了八种不同来源的豆饼与豆粕的氨基酸表现和真利用率,同时测定了其蛋白溶解度(PS),并选择四种PS值梯度不同的豆饼、粕作为唯一的蛋白质来源配制无鱼粉日粮供作试验日粮。结果表明:两种生豆饼除组氨酸外,其它16种氨基酸表现和真利用率均低于正常豆饼、粕,两种过热豆饼赖和精氨酸利用率分别比正常豆粕低7%和5%。正常豆粕配制的三个不同蛋白或赖氨酸水平 相似文献
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大豆制品中氨基酸的生物利用率完整蛋白质中的氨基酸首先必须被消化 ,然后才能被猪利用。猪对大豆蛋白质中的氨基酸有较高的消化率。表 1显示了在小肠末端 (即回肠末端 )测得的常规豆粕、去皮豆粕、加热大豆和二种大豆制品中蛋白质表观消化率系数和真消化率系数。真消化率系数已就内源氨基酸排泄量 (脱落的肠细胞、肠道中的酶以及其它非日粮来源的氨基酸 )作了校正 ,真消化率系数略高于表观消化率系数。 表 1 猪对豆粕中氨基酸的消化率氨基酸豆粕去皮豆粕加热大豆浓缩大豆蛋白离析大豆蛋白回肠表观消化率系数 (% )精氨酸 9190 8997 91组氨… 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献