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《饲料研究》2016,(7)
试验旨在探讨松萝酸粗提物对小鼠急性毒性的影响。试验选用100只健康的体质量为(19.67±1.38)g昆明小鼠,按Bliss法进行预试验和正式试验,分别找出各样品LD_(100)值(绝对致死量)、LD_0值(最大耐受剂量)、r值、LD_(50)(半数致死量)及LD_(50)的95%可信限。松萝酸对小鼠的急性毒性试验结果表明:小鼠LD_0和LD_(100)结果分别为50和150 mg/kg,LD_(50)结果为79.32 mg/kg,LD_(50)的95%可信限为72.78~86.46 mg/kg。解剖观察结果为高剂量的松萝酸可使雌雄小鼠心脏表面出现白点、肝发黄和肾发青,且所有上述脏器出现肿大,甚至出现小面积水泡。精神状态表现为低剂量松萝酸组小鼠精神明朗、被毛光滑、呼吸平缓、活泼及食欲正常;高剂量精神极度萎靡、耸毛、呼吸急促、卷缩不动和基本上不吃不喝,临死前出现全身抽搐,四肢呈游泳状,而后死亡。从临床试验得知,剂量为50.00 mg/kg时,在试验期内小鼠无死亡现象,1 h后未死亡小鼠症状逐渐减轻,而后基本恢复正常,开始正常进食和饮水。以上试验结果说明,松萝酸为低毒化合物,高剂量的松萝酸对小鼠肝、心脏、肾和肺有一定的损伤,但持续影响较小。 相似文献
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《中国兽医杂志》2016,(11)
为了研究藏橐吾地上部分水提液对小鼠的急性毒性作用,将100只体质量30±2 g昆明系小鼠随机分成10组(灌胃6组,腹腔注射4组),每组10只,雌雄各半。灌胃给药剂量为53.00~135.00 g/kg(以生药量计),灌胃量为1 mL/30 g,分3次灌胃,每次间隔4 h;腹腔注射剂量为8.88~21.90 g/kg(以生药量计),注射量为0.8 mL/30 g,1次腹腔注射。给药后,每天观察小鼠的临床表现和死亡情况,连续观察14 d,记录小鼠出现的毒性反应及病理剖检变化,统计死亡数,用改良寇氏法计算LD50。结果表明,小鼠灌胃和腹腔注射的LD50分别为91.69 g/kg和15.75 g/kg,95%可信限分别为83.10~101.16 g/kg和14.01~17.72 g/kg;两种染毒方式的中毒症状相似,均出现精神沉郁、运动迟缓、食欲及饮水废绝、呼吸频率降低;病理剖检可见胃肠道臌气,肝脏、脾脏坏死。结合中毒小鼠的临床症状和病理剖检变化,综合分析后认为藏橐吾有毒性,主要损伤器官为胃肠道、肝脏和脾脏。 相似文献
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《中国兽医杂志》2018,(11)
为了比较三氮脒及含苯磺酰胺结构单元的新型三氮脒衍生物在不同给药方式下对小鼠的毒性,以评估两种药物的安全性,根据改良寇氏法测定三氮脒及三氮脒衍生物在不同给药方式下对小鼠的半数致死量(LD_(50))及95%的可信限,给药方式分为腹腔注射和皮下注射两种。试验结果显示,腹腔注射时三氮脒和新型衍生物的LD_(50)分别为235.0 mg/kg、251.8 mg/kg,95%可信限为157.0～351.7 mg/kg、168.6～376.0 mg/kg;皮下注射时三氮脒的LD_(50)为257.6 mg/kg,95%可信限为171.2～387.8 mg/kg,新型衍生物的LD_(50)500.0 mg/kg。以上试验结果表明,新合成的衍生物其毒性和三氮脒相比,仅皮下注射时LD_(50)显著降低。对含苯磺酰胺结构单元的新型三氮脒衍生物的研发将具有重要的意义。 相似文献
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硫酸卡那霉素和氟苯尼考联合用药的急性毒效应评价 《畜牧与饲料科学》2016,37(3):7-7
通过对小鼠进行硫酸卡那霉素和氟苯尼考联合应用的急性毒效应评价,初步探讨这2种抗菌药联合应用的合理性,以期为进一步评价其安全指标提供可靠依据。经查证,硫酸卡那霉素对小鼠腹腔注射的LD_（50）为1 973.95 mg/kg,其95%可信限为1 969.22~1 978.71 mg/kg;氟苯尼考对小鼠腹腔注射的LD_（50）为636.68 mg/kg,其95%可信限为538.5~735.1 mg/kg,该试验利用等效应线图法求出硫酸卡那霉素和氟苯尼考联合用药时的LD_（50）。试验表明,硫酸卡那霉素和氟苯尼考联合用药中,硫酸卡那霉素对小鼠腹腔注射的LD_（50）为510.51mg/kg,其95%可信限为437.52~595.66 mg/kg;氟苯尼考对小鼠腹腔注射的LD_（50）为765.60 mg/kg,其95%可信限为656.15~893.31 mg/kg。结果显示,硫酸卡那霉素和氟苯尼考联合应用后的LD_（50）剂量直线交点落在95%可信限上限之外,即这2种抗菌药的联合用药产生毒效应颉颃,初步认为联合使用具有一定的合理性与可靠性。 相似文献
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为初步评价普拉沙星的安全性，进行了小鼠急性毒性试验。采用递加法进行预试验，测得最小致死剂量(LD100)和最大耐受剂量(LD0),确定正式试验给药剂量范围、组数和组间剂量比。正式试验采用寇氏法，观察小鼠口服普拉沙星后的体征变化，记录死亡时间和每组死亡率，对死亡小鼠进行剖检和组织病理学观察，确定普拉沙星对主要脏器的毒性作用。结果显示，小鼠口服普拉沙星的半数致死剂量(LD50)为1 606.9 mg/kg, 95%可信限为1 342.8～1 923.1 mg/kg。在给药剂量大于1 562 mg/kg时，普拉沙星对小鼠的肺脏、肝脏、脾脏和肾脏均可造成明显损伤。根据化学物质的急性毒性剂量分级，可将普拉沙星判定为低毒化学物。 相似文献
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为评价抗鸡球虫病药物常山口服液的安全性,本试验采用改良寇氏法和剂量递增法对小鼠进行急性毒性试验研究,并通过病理组织学观察来明确常山口服液毒性损伤的主要靶器官。取60只昆明系小鼠,雌雄各半,随机分为6组,1个对照组和5个给药组,给药组分别按1.00、1.40、1.96、2.74和3.84 g/kg体重的剂量灌胃给药,连续观察7 d,记录小鼠急性毒性反应过程,并运用改良寇氏法公式计算半数致死量（LD50）及LD50的95%可信限。结果显示,小鼠经口灌胃LD50为2.0961 g/kg体重,LD50的95%可信限为1.7414~2.5429 g/kg体重;剖检可见1.96、2.74和3.84 g/kg体重剂量组部分小鼠的肝脏、肾脏出现较严重的水肿、充血和明显的白色坏死灶;病理组织学检查显示小鼠出现急性肝脏损伤,表现为肝细胞退行性改变,病变主要是小叶周边变性、坏死及崩解,而肾脏损伤表现为肾淤血、间质水肿、肾曲小管上皮浊肿和广泛变性,各主要脏器以肝脏损害较为严重,可确定常山口服液损伤的靶器官主要为肝脏。结果表明,常山口服液按常规剂量使用是安全的,临床用于抗球虫病安全性较高,但大剂量、长疗程的用药会出现毒性反应,由于急性毒性试验观察时间较短,故还应结合长期毒性试验的毒性表现及多种检查结果综合分析评价其毒性。 相似文献
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《中国饲料》2020,(17)
为评价新制剂环丙-林可霉素长效注射液的安全性,本研究采用急性毒性试验、溶血性试验、局部刺激性试验和亚慢性毒性试验对兽药新制剂环丙-林可霉素长效注射液安全性进行评价。结果表明:环丙-林可霉素长效注射液小鼠肌肉注射LD_(50)为4.81 mg/kg,LD_(50)的95%可信限为4.50～5.53 mg/kg;该注射液在4 h内不产生溶血现象;肌肉注射部位及周围组织均未见充血、水肿、出血和坏死;肌肉注射部位充血范围0.5 cm×1 cm;以相当于临床用量2倍的剂量涂抹皮肤,停药后1、24、48、72 h观察均未见明显异常变化;对肝脏和肾脏组织学观察表明,治疗剂量和中剂量组肝脏和肾脏组织结构清晰,而高剂量组肾小球内有大量出血,肾间质出现坏死,肝细胞排列紊乱,肝细胞肿胀融合,肝血窦间有大量出血。综上,环丙-林可霉素长效注射液按照治疗剂量在本试验条件下是安全的。 相似文献
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《中国畜牧兽医》2019,(12)
本研究旨在评估氟苯尼考预混剂对Wistar大鼠的口服急性毒性,使用OECD修订的改良上下法(UDP)测定半数致死量(LD_(50)),通过体重、脏器系数、血液学、临床化学检查及组织病理学检查确定在急性暴露下氟苯尼考预混剂对Wistar大鼠的生物系统和主要器官的不良影响。根据氟苯尼考的LD_(50)5 000 mg/kg,选择上下法的限度试验,使用固定数量(5只)的动物,给药剂量为2 000 mg/kg,连续观察14 d,记录毒性反应及死亡情况,并由AOT425StatPgm程序计算得到LD_(50),另外用3只大鼠给予相同剂量的生理盐水作为对照。试验结果显示,5只大鼠均未死亡,LD_(50)2 000 mg/kg;试验期间,给药组未表现出可见的毒性反应迹象;与对照组相比,给药组的血液学参数无显著性变化;在临床化学检查中,给药组的谷丙转氨酶(ALT)水平变化显著高于对照组(P0.05),提示药物制剂对肝脏存在毒性损伤;剖检观察中无明显的眼观变化,组织病理学检查结果显示,给药组对主要器官心脏、肝脏、脾脏、肺脏、肾脏及十二指肠均无毒性损伤作用,暂无法确定其毒性靶器官。结果表明,氟苯尼考预混剂在安全剂量范围内使用是安全可靠的,更多的毒性信息仍需进行长期毒性试验来确定。 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
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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献