日粮中添加恩拉霉素对仔猪生产性能和肠道菌群的影响

试验研究日粮中添加恩拉霉素及停用后对断奶仔猪生长性能和肠道菌群结构的影响。采用单因素试验设计,将20头仔猪分为4个处理,每个处理5个重复;分别在基础饲粮中添加0、5、20 mg/kg和80 mg/kg恩拉霉素。试验分为3个阶段,加药期28 d,饲喂试验日粮;停药期7 d和LPS诱导应激期3 d,均饲喂基础日粮。结果表明:加药期与对照组相比,5、20mg/kg添加组平均日增重增加(P>0.05),80mg/kg添加组却显著降低(P<0.05),3个添加组直肠总菌数显著下降(P<0.05)。停药期,5、20 mg/kg添加组平均日增重与对照组相比有下降的趋势(P>0.05),20、80mg/kg添加组直肠总菌数和乳酸杆菌/大肠杆菌显著下降(P<0.05)。应激后,盲肠乙酸和丁酸含量显著下降(P<0.05)。     

铁和维生素A及其互作效应对产蛋鸡体内糖脂代谢的影响

为明确铁与维生素A对蛋鸡体内糖脂代谢的影响,选用26周龄商品代海兰褐育成母鸡432只,随机分成6组,每组6个重复,采用3×2(Fe×维生素A)完全随机试验设计,日粮铁的添加量为0,30,60 mg/kg,维生素A的添加量为4 000,8 000 IU/kg。结果表明:高铁(60 mg/kg)组可显著增高蛋鸡血清胰岛素浓度(P0.05);高维生素A(8 000 IU/kg)组可显著降低蛋鸡后期血清总胆固醇浓度(P0.05);高铁(60 mg/kg)与高维生素A(8 000 IU/kg)互作组可显著增高蛋鸡前期血清胰岛素、三酰甘油浓度(P0.05);0,30 mg/kg铁和高维生素A(8000 IU/kg)组互作时蛋鸡血清总胆固醇浓度偏低,但差异不显著(P0.05)。结果提示,在蛋鸡日粮中添加铁(0～30 mg/kg)和维生素A(8 000 IU/kg)不会影响蛋鸡体内糖脂代谢,同时还可以显著降低血清总胆固醇浓度(P0.05)。     

日粮中添加恩拉霉素和脂多糖攻毒对断奶仔猪生产性能和血清生化指标的影响

本试验旨在研究在正常与免疫应激条件下添加恩拉霉素对仔猪的作用效果及安全性。将36头21日龄断奶、健康、DLY阉公仔猪随机分为3个处理,每个处理12个重复;分别饲喂基础日粮及在基础日粮中添加5、80 mg/kg恩拉霉素日粮(加药期),21 d后,各组均饲喂基础日粮(停药期),7 d后,每处理随机取出6头仔猪腹腔注射LPS 200μg/kg体重(应激期),剩余6头仔猪腹腔注射等量生理盐水。分别于应激前和应激后2.5 h、3 d采血。结果表明:日粮添加5 mg/kg和80 mg/kg恩拉霉素不同程度提高0～7、8～14、15～21 d和0～21 d仔猪的日增重和采食量,而对饲料增重比无影响;前期添加恩拉霉素组仔猪的生产性能在停药期仍略优于对照组;LPS应激导致仔猪平均日增重和平均日采食量显著下降(P<0.05);加药期添加恩拉霉素可显著提高应激期仔猪平均日采食量(P<0.05)。注射LPS前,各组血清理化指标没有显著差异(P>0.05);注射LPS 2.5 h后,血清丙二醛、皮质醇和IGF-1的含量显著提高(P<0.05);注射LPS3 d后,血清IGF-1浓度显著提高(P<0.01),NO浓度显著降低(P<0.01),皮质醇浓度有提高的趋势(P<0.1);日粮添加恩拉霉素显著降低了血清中IGF-1的浓度(P<0.01),与LPS具有显著互作效应(P<0.05)。     

3种兽药及其主要代谢产物在猪粪中的排泄规律

以磺胺二甲嘧啶、金霉素和泰乐菌素为研究对象,探讨在饲粮中添加兽药后,猪粪中3种兽药原形及其主要代谢产物的排泄规律。试验选取60头33kg左右的长大二元杂交母猪,在饲粮中加入200mg/kg的磺胺二甲嘧啶、75mg/kg的金霉素和100mg/kg的泰乐菌素,分用药期和休药期收集猪粪检测其中的兽药原形及其代谢产物残留。结果表明,7d用药期内猪粪中磺胺二甲嘧啶及其主要代谢产物对位氨基乙酰化磺胺二甲嘧啶的平均残留分别为59.50,15.98μg/g;金霉素及其代谢产物4位差向异构金霉素平均残留分别为239.92,217.79μg/g;泰乐菌素A及其代谢产物泰乐菌素D的平均残留分别为10.50,65.99μg/g。进入休药期后,猪粪中兽药原型及其代谢产物残留下降很快,到休药期结束时,相应试验组的猪粪中已检测不出金霉素及其代谢产物残留,但仍可检出磺胺二甲嘧啶及其代谢产物和泰乐菌素A及其代谢产物。由此可知,兽药的体内代谢产物在兽药的排泄中占重要比例,提示除兽药原形外还应重视其代谢产物进入环境后的生态毒理学效应。     

硒酵母对西门塔尔牛瘤胃发酵及尿嘌呤衍生物的影响

本试验旨在研究硒酵母对瘤胃发酵及尿嘌呤衍生物浓度的影响。选用8头体重(430±20)kg,年龄2.5岁,装有永久性瘤胃瘘管的中国西门塔尔牛阉牛,采用4×4重复拉丁方设计,以硒酵母为硒源,分别在日粮中添加硒0、0.3、0.6和0.9 mg/kg。结果表明:试验各组瘤胃pH、乙酸、丁酸和总挥发性脂肪酸差异不显著(P>0.05);处理组较对照组丙酸显著提高,而乙酸/丙酸比例和NH3-N浓度显著降低(P<0.05),0.6 mg/kg组NH3-N浓度显著低于0.3和0.9 mg/kg组;0.6 mg/kg组豆粕干物质、粗蛋白质有效降解率显著高于对照及其他处理组(P<0.05);0.6 mg/kg组玉米秸秆干物质、中性洗涤纤维有效降解率显著高于对照组和0.9 mg/kg组(P<0.05)。处理组尿嘌呤衍生物和微生物氮显著增加(P<0.05),0.6 mg/kg组显著高于0.3和0.9 mg/kg组(P<0.05)。硒酵母显著促进瘤胃代谢和提高尿嘌呤衍生物浓度,适宜添加水平为0.6 mg/kg。     

鸡蛋中磺胺嘧啶、磺胺氯哒嗪、磺胺间甲氧嘧啶残留消除规律研究

本研究旨在分析磺胺嘧啶、磺胺氯哒嗪、磺胺间甲氧嘧啶在鸡蛋中残留消除规律,为蛋鸡在开产前合理用药制定休药期提供依据,并建立一种检测3种磺胺类药物在鸡蛋中残留的超高效液相色谱法。将60只试验鸡随机分为4组(试验组I、试验组II、试验组III、空白组),各药物按照说明书剂量拌料给药,空白组饲喂不含任何抗生素的空白料,连续给药5 d。收集的鸡蛋样品经乙酸乙酯超声提取,正己烷除酯,复溶液复溶,高效液相色谱C18柱分离后用紫外检测器检测(该方法的检测限为0.01 mg/kg)。结果显示,停药后12 d,磺胺嘧啶检出浓度低于0.01 mg/kg;停药后9 d,磺胺氯哒嗪检出浓度低于0.01 mg/kg;停药后12 d,磺胺间甲氧嘧啶检出浓度低于0.01 mg/kg;该结果提示磺胺嘧啶、磺胺氯哒嗪、磺胺间甲氧嘧啶分别在产蛋前12 d、9 d、12 d停用。     

小檗碱对肉兔消化代谢的影响

本试验旨在研究小檗碱对肉兔消化代谢的影响。采用单因子随机区组试验设计,选择128只50日龄、体重相近的健康新西兰兔,随机分为4组,1个对照组和3个试验组,每组32个重复,每个重复1只。对照组饲喂基础饲粮,3个试验组分别饲喂在基础饲粮中添加10、20及30mg/kg盐酸小檗碱的试验饲粮。预试期为7d,正试期为27d。正试期第10～15天收集试验兔排出的全部粪便和尿液。结果表明:对照组试验兔干物质表观消化率显著或极显著低于其余3组(P<0.05或P<0.01),有机物和粗纤维表观消化率均显著或极显著低于10mg/kg组和20mg/kg组(P<0.05或P<0.01),粗脂肪表观消化率显著或极显著低于20 mg/kg组和30mg/kg组(P<0.05或P<0.01)。对照组试验兔总能表观消化率显著或极显著低于其余3组(P<0.05或P<0.01);20mg/kg组试验兔消化能利用率显著高于对照组和30mg/kg组(P<0.05),而总能利用率极显著高于其余3组(P<0.01);10mg/kg组和20mg/kg组试验兔氮表观消化率均显著或极显著高于对照组和30mg/kg组(P<0.05或P<0.01);对照组试验兔氮利用率和消化氮利用率显著或极显著低于其余3组(P<0.05或P<0.01)。对照组和30mg/kg组试验兔盲肠内容物微生物总脱氢酶活性均极显著低于10mg/kg组和20mg/kg组(P<0.01),而氨氮浓度则均极显著高于10mg/kg组和20mg/kg组(P<0.01);对照组试验兔盲肠内容物微生物蛋白质浓度显著或极显著低于其余3组(P<0.05或P<0.01)。结果提示:饲粮中添加小檗碱可改善肉兔干物质、有机物、粗纤维、粗脂肪、总能和氮的利用效率,提高盲肠内容物微生物总脱氢酶活性和微生物蛋白质浓度,降低氨氮浓度。综合而言,肉兔饲粮中添加20mg/kg盐酸小檗碱较为适宜。     

3种兽药及其主要代谢产物在猪粪中的排泄规律

以磺胺二甲嘧啶、金霉素和泰乐菌素为研究对象,探讨在饲粮中添加兽药后,猪粪中3种兽药原形及其主要代谢产物的排泄规律。试验选取60头33k左右的长大二元杂交母猪,在饲粮中加入200mg／kg的磺胺二甲嘧啶、75mg／kg的金霉素和100mg／kg的泰乐菌素,分用药期和休药期收集猪粪检测其中的兽药原形及其代谢产物残留。结果表明,7d用药期内猪粪中磺胺二甲嘧啶及其主要代谢产物对位氨基乙酰化磺胺二甲嘧啶的平均残留分别为59．50,15．98μg／g;金霉素及其代谢产物4位差向异构金霉素平均残留分别为239．92,217．79μg／g;泰乐菌素A及其代谢产物泰乐菌素D的平均残留分别为10．50,65．99／μg／g。进入休药期后,猪粪中兽药原型及其代谢产物残留下降很快,到休药期结束时,相应试验组的猪粪中已检测不出金霉素及其代谢产物残留,但仍可检出磺胺二甲嘧啶及其代谢产物和泰乐菌素A及其代谢产物。由此可知,兽药的体内代谢产物在兽药的排泄中占重要比例,提示除兽药原形外还应重视其代谢产物进入环境后的生态毒理学效应。     

地克珠利对肉鸡生长、屠宰性能、免疫机能及血清生化指标的影响

选用288只1日龄AA肉鸡,随机分为4组,每组6个重复,每重复12只鸡.对照组饲喂基础日粮,试验组分别于基础日粮中添加1、2、4 mg/kg地克珠利,试验期49 d.结果表明,基础日粮中添加1～4 mg/kg地克珠利对肉鸡生长性能和屠宰性能均无显著影响(P＞0.05);1 mg/kg地克珠利组肉鸡免疫器官指数、新城疫抗体效价和外周血T淋巴细胞转化率与对照组均无显著差异(P＞0.05),2、4 mg/kg组外周血T淋巴细胞转化率显著低于对照组(P＜0.05或P＜0.01),4mg/kg组肉鸡于28日龄免疫器官指数显著高于对照组(P＜0.05),血清新城疫抗体效价显著低于对照组(P＜0.05);肉鸡血清淀粉酶活性,2、4 mg/kg组于28、35(停药0d)、42日龄(停药7d)显著低于对照组和1 mg/kg组(P＜0.05或P＜0.01);3个试验组血清总蛋白含量于28、35(停药0d)、42日龄(停药7d)均显著或极显著(P＜0.05或P＜0.01)高于对照组;血清总超氧化物歧化酶活性,2、4 mg/kg组于28日龄显著或极显著(P＜0.05或P＜0.01)高于对照组和1 mg/kg组;4 mg/kg组于35日龄(停药0d)和42日龄(停药7d)显著低于对照组和其他2个试验组(P＜0.05或P＜0.01);血清葡萄糖含量各组间均差异不显著(P＞0.05).49日龄(停药14 d)各组间上述血清生化指标差异均不显著(P＞0.05).相关分析表明,血清总蛋白含量和葡萄糖含量与平均日增重间存在着极显著的正相关关系(P＜0.01),总超氧化物歧化酶活性与平均日增重间存在着极显著的负相关关系(P＜0.01).     

不同剂量氟苯尼考对猪血液生化指标及猪瘟抗体的影响

40头70日龄健康猪随机分为高、中、低剂量组和对照组,每组10头,各试验组注射猪瘟弱毒疫苗(2头份/猪),同时高、中、低剂量组分别按每千克体质量于饲料中加入120、60、30 mg氟苯尼考,连续给药7 d,停药后1、8、15、22、29 d,对相关的血液生化指标以及猪瘟抗体水平进行检测分析.结果表明,停药后1、8 d,所有氟苯尼考添加组的猪瘟抗体滴度下降,仅120 mg/kg组差异显著(P<0.05),停药15 d后抗体水平恢复至正常水平;60和120mg/kg给药组TP含量在停药后1、8 d均显著下降(P<0.05);所有给药组的ALT活性在所有检测时间内均显著上升(P<0.05或P<0.01);所有给药组的γGT活性在停药后1 d均显著上升(P<0.05),而60和120 mg/kg组γGT在第8天仍显著上升(P<0.05);所有给药组的BUN含量在停药后1 d均显著升高(P<0.05或P<0.01);AST、LDH、CHE活性和ALB、CRE含量与对照组相比无显著差异(P>0.05);表明每千克体质量60 mg以上氟苯尼考在饲料中饲喂7 d后,对部分生化指标有一定的影响,应引起重视.     

五种抗菌药物从猪、鸡饲料至有机肥中的药物残留迁移规律研究

为研究抗菌药物从饲料向畜禽粪肥转移的残留迁移规律,将40头猪和200羽鸡分为饲喂组和空白对照组进行饲喂对照实验和粪便堆肥发酵实验,其中空白对照组使用普通全价饲料,饲喂组在饲料中加入盐酸金霉素50 mg/kg、磷酸泰乐菌素50 mg/kg、磺胺对甲氧嘧啶各50 mg/kg、恩诺沙星150 mg/kg、二甲氧苄啶10 mg/kg,每日及时对各组实验动物粪便进行采集,样品经提取和净化后使用液相色谱-串联质谱进行分析定量。所得结果表明,猪、鸡饲喂含多种抗生素饲料后粪便中可以检出抗菌药物原型,其可能进入有机肥料发酵制作的环节。参照猪、鸡粪便中排出抗菌药物含量峰值建立模型对发酵期间粪肥中抗菌药物含量进行采样测定,结果显示,恩诺沙星、泰乐菌素和二甲氧苄啶在堆肥过程中会由于温度升高和氧化作用发生降解,其半衰期在5周左右,到10周后其含量低于检测限;但金霉素和磺胺对甲氧嘧啶被少量降解,残留迁移风险较高。     

The survival of multidrug‐resistant bacteria in thermophilic and mesophilic anaerobic co‐digestion of dairy manure and waste milk

Anaerobic digestion is considered as a promising method to manage animal waste with antibiotic‐resistant bacteria. Current research was conducted to investigate the survival of multidrug‐resistant bacteria (MDRB) resistant to three groups of antibiotics: (i) cefazolin, neomycin, vancomycin, kanamycin (group 1); (ii) penicillin, oxytetracycline, ampicillin, streptomycin (group 2); and (iii) cefazolin, neomycin, vancomycin, kanamycin, penicillin, oxytetracycline, ampicillin, streptomycin (group 3), in anaerobic digestion of dairy manure and co‐digestion of dairy manure and waste milk at 37°C and 55°C for 22 days, respectively. The population densities of three groups of MDRB on peptone, tryptone, yeast and glucose agar plates incubated at 30°C for 7 days before and after digestion showed 100% destruction in both digestates at thermophilic temperature. Overall reduction of more than 90% of three groups of MDRB was observed in mesophilic digestion with no significant differences (P > 0.05) between manure and milk mixture. Co‐digestion of dairy manure and waste milk always produced significantly (P < 0.05) higher total gas and methane gas than digestion of manure alone at both temperatures. Gas production in each case was significantly (P < 0.05) higher in thermophilic digestion than in mesophilic digestion. The results demonstrate that thermophilic co‐digestion of dairy manure and waste milk offers more benefits in terms of the environment and economy.     

Concentrations of trimethoprim and sulfamethoxazole in cerebrospinal fluid and serum in mares with and without a dimethyl sulfoxide pretreatment.

Each of seven mares was given an intravenous (IV) injection of 40% dimethyl sulfoxide (DMSO) at a dosage of 1 g/kg, over 35 min, immediately followed by a single IV injection of a trimethoprim (TMP) and sulfamethoxazole (SMZ) combination (SMZ 83%, TMP 17%) at a combined dosage of 44 mg/kg (7.48 mg/kg TMP; 36.52 mg/kg SMZ). Each horse served as its own control and was alternately treated with an identical dose of TMP-SMZ treatment alone at least seven days following or preceding the DMSO and TMP-SMZ treatment. Serum and cerebrospinal fluid (CSF) concentrations of TMP and SMZ were measured over a six hour period. Dimethyl sulfoxide treatment caused no significant difference in the mean serum concentration of SMZ or in the mean CSF concentrations of TMP or SMZ. The mean serum concentration of TMP was significantly (p less than 0.05) increased at the two, four and six hour sampling time in the mares receiving pretreatment with DMSO. The clearance of TMP was also significantly (p less than 0.05) decreased from 675 mL/h/kg to 327 mL/h/kg by DMSO administration. Concentrations of TMP and SMZ in the CSF in both treatment groups exceeded the minimum inhibitory concentrations for many common bacterial pathogens of equine origin. In addition, CSF concentration of TMP exceeded the serum concentrations required for 50% inhibition of dihydrofolate reductases of protozoan origin. Serum TMP and SMZ concentration were similar to those reported to be effective against Toxoplasma gondii in in vitro studies on the killing or inhibition of the organism.     

Swine manure composition affects the biochemical origins,composition, and accumulation of odorous compounds

Odors from swine production facilities are associated with the storage and decomposition of manure. Diet is linked to manure composition and will likely affect odor, but the microbial mechanisms responsible for manure decomposition and odor production are poorly understood. To identify the sources of odor during manure fermentation, substrates (starch, casein, and cellulose) were added to slurries of fresh swine manure, and the anaerobic accumulation of fermentation products and the consumption of substrates were measured relative to no addition of substrates. Volatile fatty acids and alcohols were the dominant fermentation products in all treatments. The total VFA concentration from starch treatment was greater (P < 0.001) than for all other treatments. Branched-chain VFA and aromatic compounds accumulated in all treatments, but accumulation in the casein treatments was greater (P < 0.001) than in all other treatments. Thus, addition of carbohydrate to swine manure slurries did not circumvent protein fermentation, as was previously observed in cattle manure slurries. Based on substrate loss, starch and protein fermentation were equivalent in all treatments, with losses of each exceeding 4% of the DM. Substrate additions had a limited effect on the overall accumulation of odor compounds in manure and on odor compound composition. Compared with the results of the earlier fermentation study of fresh cattle manure, swine manure fermentation produced less lactate and more products of protein fermentation (branched-chain VFA and aromatic ring compounds). We hypothesize that differences in manure organic matter composition between cattle and swine, a result of diet and digestion, select for bacterial communities that are adapted to the available substrate composition.     

Pharmacokinetics of trimethoprim-sulphamethoxazole in two-day-old foals after a single intravenous injection

Six healthy two-day-old foals (3 pony foals and 3 horse foals) were given a single intravenous (iv) injection of trimethoprim (TMP)--sulphamethoxazole (SMZ) at a dosage of 2.5 mg of TMP/kg bodyweight (bwt) and 12.5 mg of SMZ/kg bwt. Serum TMP and SMZ concentrations were measured serially during a 24 hour period. The overall elimination rate constant (K) for TMP in the pony and horse foals was 0.45/h, whereas the K values for SMZ for the pony and horse foals were 0.12/h and 0.07/h, respectively (no significant difference; P greater than 0.05). Based on published minimum inhibitory concentration values for equine pathogens (Adamson et al 1985), the primary indication for the use of TMP/SMZ in foals may be in the treatment of infections caused by gram-positive bacteria. A dosage of 2.5 mg of TMP/kg bwt and 12.5 mg of SMZ/kg bwt, given iv at 12 h intervals would be appropriate.     

Effect of aluminum chloride and dietary phytase on relative ammonia losses from swine manure

Ammonia (NH3) losses from swine manure contribute to odor problems, decrease animal productivity, and increase the risk of acid rain deposition. This study was conducted to determine whether aluminum chloride (AlCl3) or dietary manipulation with phytase could decrease relative NH3 losses from swine manure. Twenty-four pens of nursery pigs were used in two trials, and the pigs were fed normal or phytase-supplemented (500 IU/kg) diets. Aluminum chloride was added to manure pits (1.9 x 1.2 x 0.5 m) under each pen at 0, 0.25, 0.50, or 0.75% (vol:vol) of final manure volume. Manure pH and NH3 losses (measured by relative NH3 flux) were determined twice weekly. The addition of AlCl3 at 0.75% decreased (P < 0.05) manure pH from 7.48 to 6.69. Phytase decreased (P < 0.05) manure pH to 7.07 compared with 7.12 in the normal diet manure. Aluminum chloride administered at 0.75% without phytase reduced (P < 0.05) relative NH3 losses 52% for the entire 6-wk period. Relative NH3 losses were decreased (P < 0.05) from 109 mg of NH3/(m2 x h) in pens containing pigs fed the normal diet without AlCl3 to 81 mg of NH3/(m2 x h) in pens housing pigs administered the phytase diet, a 26% reduction. When the phytase diet and 0.75% AlCl3 additions were used in combination, relative NH3 losses were reduced (P < 0.05) by 60% compared with pens of pigs fed the control diet without AlCl3. Decreases in manure pH were likely responsible for the observed reduction in NH3 losses. Multiple regression was performed with relative rates of NH3 losses as the dependent variable and rate of AlCl3 addition, diet, and manure pH as independent variables. The model was tested using a stepwise regression (P < 0.001), and results indicated that the most important factors determining NH3 losses were manure pH and diet. However, the contribution of AlCl3 cannot be discounted. When manure pH was regressed against AlCl3 and dietary phytase, AlCl3 levels accounted for 64% of the variation in manure pH (P < 0.001). Dietary manipulation with phytase and application of AlCl3 to manure are promising management practices for the reduction of NH3 from swine facilities.     

3-Acetyl-4'-isovaleryl tylosin for prevention of swine dysentery

The 21 field isolates of Treponema hyodysenteriae which were tested were sensitive to 3-acetyl-4'-isovaleryl tylosin (AIV); the minimal inhibitory concentration was 0.25 to 16 micrograms/ml. 3-Acetyl-4'-isovaleryl tylosin administered prophylactically to pigs at concentrations of 5 to 100 mg/kg of feed and tylosin at 110 mg/kg of feed for 28 or 31 days prevented swine dysentery induced by tylosin-sensitive T hyodysenteriae strain SQ2; 15 nonmedicated, inoculated control pigs had bloody diarrhea, and 9 pigs died. In 2 additional trials, AIV administered prophylactically for 28 days at 55 or 110 mg/kg of feed prevented swine dysentery induced by tylosin-insensitive T hyodysenteriae strain B204. All of the inoculated principal pigs medicated with AIV at 55 or 110 mg/kg of feed or carbadox at 55 mg/kg of feed and the noninoculated sentinel pigs for each group had solid feces throughout the 56-day trial. In the nonmedicated, inoculated control groups, bloody diarrhea began at 4 to 5 days after inoculation was done, and 9 of 10 principal pigs and 6 of 9 sentinel pigs had dysentery; 2 pigs died. In the groups medicated with AIV at 27.5 or 5.5 mg/kg of feed, all 5 principal pigs and 3 or 4 sentinel pigs in each group had dysentery; 3 or 4 pigs in each group died. In the group medicated with tylosin at 110 mg/kg of feed, 7 of 10 principal pigs and all 9 sentinel pigs had dysentery; 1 pig died.(ABSTRACT TRUNCATED AT 250 WORDS)     

三七总皂苷亚慢性毒性试验研究

[目的]评价三七总皂苷(PNS)用药安全性,为临床用药提供参考依据。[方法]将40只昆明系小白鼠随机分为4组,每组10只,3个药物处理组小鼠通过腹腔注射的方式分别给予11.34、56.70、113.40mg/(kg·BW)的PNS,每天1次,连续给药14d;空白对照组小鼠腹腔注射生理盐水0.3mL/只,连续注射14d。测定并比较各组小鼠在试验期间的体重、脏器指数(肝脏、脾脏、肾脏指数)以及血液生化指标;取各组小鼠肝脏、脾脏、肾脏组织,制备病理组织切片,利用显微镜观察上述组织是否出现病理变化。[结果]3个PNS给药组小鼠在试验期间的体重与空白对照组小鼠相比,均无显著性差异(P>0.05);11.34mg/(kg·BW)PNS组小鼠的脾脏指数显著低于空白对照组(P<0.05);113.40mg/(kg·BW)PNS组小鼠的谷草转氨酶活力和肌酐含量显著低于空白对照组(P<0.05),而尿素氮含量显著升高(P<0.05);病理组织学观察结果表明,PNS对肝脏、脾脏、肾脏组织无明显损伤。[结论]PNS实际无毒,长期用药会产生肾毒性,提示用药不宜过量。     

Pharmacokinetics and body fluid and endometrial concentrations of trimethoprim-sulfamethoxazole in mares

Six healthy adult mares were each given a single IV injection of trimethoprim (TMP)-sulfamethoxazole (SMZ) at a dosage of 2.5 mg of TMP/kg of body weight and 12.5 mg of SMZ/kg. Serum concentrations of each drug were measured serially over a 24-hour period. For TMP, the mean overall elimination rate constant (K) was 0.43/hr and the elimination half-life (t1/2) was 1.9 hours. The apparent volume of distribution (at steady state) was 1.62 L/kg and TMP clearance was 886 ml/hr/kg. For SMZ, K was 0.22/hr and t1/2 was 3.53 hours. The apparent volume of distribution at steady state was 0.33 L/kg and SMZ clearance was 78.2 ml/hr/kg. Each mare was then given 5 consecutive oral doses of TMP-SMZ at a rate of 2.5 mg of TMP/kg and 12.5 mg of SMZ/kg at 12-hour intervals. Trimethoprim and SMZ concentrations were measured in serum, synovial fluid, peritoneal fluid, CSF, urine, and endometrium. Although both mean TMP and SMZ serum concentrations were higher after the 5th dose than after the 1st dose, only the mean TMP concentration was significantly (P less than 0.05) different. After the 5th oral dose, concentrations of TMP and SMZ attained in body fluids (except CSF) and endometrial tissue were equal to or exceeded reported minimum inhibitory concentrations for Corynebacterium pseudotuberculosis, Staphylococcus sp, Streptococcus zooepidemicus, and several obligate anaerobes. Absorption of both drugs was variable after oral administration.     

Prevention of swine dysentery with a combination of lincomycin and spectinomycin and resistance of swine dysentery to tylosin and sodium arsanilate.

The addition of a combination of lincomycin and spectinomycin to feed at the total concentrations of 44 and 77 mg/kg, beginning at the time of exposure and continuing for 8 weeks, prevented experimentally induced swine dysentery in swine. The disease did not develop after the medication was withdrawn. In contrast, swine dysentery, similar to that seen in the nonmedicated swine, did develop in simultaneously exposed swine treated with feed containing either 44 mg of tylosin or 99 mg sodium arsanilate/kg. The swine fed sodium arsanilate and which developed hemorrhagic diarrhea had a more severe form of this type of diarrhea than did the nonmedicated swine. After reexposure to inefective inoculum of swine dysentery 86 days after initial exposure, all remaining swine previously medicated with either tylosin or sodium arsanilate and all nonmedicated swine were immune; whereas 17 of the 24 swine fed the combination of lincomycin and spectinomycin were susceptible to swine dysentery and developed diarrhea.