柠檬酸残渣饲喂肉仔鸡的试验

选取1500只1日龄AA肉仔鸡，随机分成5组，研究饲料中添加柠檬酸残渣对肉仔鸡生产性能的影响。结果表明：日粮柠檬酸残渣含量为8％和16％时，肉仔鸡的生产性能不受影响（P＞0．05），说明柠檬酸残渣可部分替代豆饼提供肉仔鸡氮源以用于生长；但当日粮柠檬酸残渣含量为24％和32％时，肉仔鸡生长性能有所降低，说明日粮柠檬酸残渣过高，可能会引起营养失衡，影响肉仔鸡生长。     

Pharmacokinetics and bioavailability of cefquinome in healthy piglets

A study on bioavailability and pharmacokinetics of cefquinome in piglets was conducted after intravenous (i.v.) and intramuscular (i.m.) administrations of 2.0 mg/kg of body weight, respectively. Plasma concentrations were measured by high‐performance liquid chromatography assay with UV detector at 268‐nm wavelength. Plasma concentration–time data after i.v. administration were best fit by a two‐compartment model. The pharmacokinetic values were distribution half‐life 0.27 ± 0.21 h, elimination half‐life 1.85 ± 1.11 h, total body clearance 0.26 ± 0.08 L/kg·h, area under curve 8.07 ± 1.91 μg·h/mL and volume of distribution at steady state 0.46 ± 0.10 L/kg. Plasma concentration–time data after i.m. administration were also best fit by a two‐compartment model. The pharmacokinetic parameters were distribution half‐life 0.88 ± 0.42 h, elimination half‐life 4.36 ± 2.35 h, peak concentration 4.01 ± 0.57 μg/mL and bioavailability 95.13 ± 9.93%.     

柠檬酸对肉仔鸡屠宰性能的影响

试验选择180只1日龄健康AA+肉仔鸡,按日粮中柠檬酸添加剂量的不同(0%、0.75%、1.5%)分为3个日粮处理组,每个处理组6个重复,每个重复10只鸡,进行为期42d的饲养试验,旨在研究日粮中添加不同梯度的柠檬酸对肉仔鸡屠宰性能的影响。试验结果表明:添加0.75%柠檬酸可显著提高21日龄肉仔鸡的屠宰率(P0.05),极显著提高腿肌率(P0.01),胸肌率和全净膛率却显著降低于对照组(P0.05);添加1.5%柠檬酸可使21日龄肉仔鸡的全净膛率显著降低(P0.05),对其他屠宰性能指标无显著影响。     

植酸酶和柠檬酸对肉鸡生产性能及钙、磷利用率的影响

试验以正常营养水平饲粮为对照 ,研究在低营养水平饲粮中添加植酸酶 (0、 30 0g/t)、柠檬酸 (0、 0 5% )对肉鸡生产性能和钙、磷利用率的影响。试验用 2 2 5羽 1日龄黄羽肉鸡随机分为 5个处理 ,每处理 3个重复 ,每重复 1 5只鸡进行 6周试验。结果饲粮营养水平降低 6 %可导致肉鸡日增重 (ADG)和饲料利用率下降 (P <0 0 5) ;在低营养水平日粮中 ,添加 30 0g/t植酸酶、 0 5 %柠檬酸 ,ADG和料肉比 (F/G)与正常营养水平饲粮组差异不显著 (P >0 0 5) ;各处理组的血清Ca、P、AKP活性及胫骨Ca、P差异不显著 (P >0 0 5) ;腿病发生率各处理组差异不显著 (P >0 0 5)。添加 30 0g/t植酸酶、 0 5 %柠檬酸的处理组P排泄量显著低于对照组 (P <0 0 5)。植酸酶与柠檬酸合用能进一步提高生产性能和钙、磷利用率 ,能达到正常营养水平饲粮的效果。植酸酶与柠檬酸合用存在协同效应     

Investigations on iron bioavailability of different sources and supply levels in piglets

Two experiments were conducted to investigate the iron bioavailability of different sources and supply levels in piglets. In experiment 1, the influence of feeding an iron deficient basal diet or the basal diet supplemented with 28 ppm Fe either in form of Fe-chelate, crystalline Fe-glycinate, or Fe-sulphate on apparent iron digestibility and on blood parameters was determined. In experiment 2, a dose-response approach was used to determine the effects of supplementing an iron-deficient basal diet with 30, 60, or 90 ppm of Fe either in form of crystalline Fe-glycinate or Fe-sulphate on digestibility of Fe, growth and blood parameters. In experiment 1, comparison of iron sources revealed a tendency (0.05 < p < 0.1) for a higher Fe digestibility from Fe-glycinate (40.9%) compared with Fe-chelate (30.8%) or Fe-sulphate (30.7%). Fe-balance was higher (p < 0.05) for Fe-glycinate compared with Fe-sulphate but iron balance was similar for iron sulphate and iron chelate. Those results, however, were not reflected in data of blood parameters. In experiment 2, iron digestibility, blood parameters and performance were significantly (p < 0.05) influenced by iron supply. Effects of iron source on digestibility of iron were lower than observed in the first experiment.     

Pharmacokinetics and renal clearance of oxytetracycline in piglets following intravenous and oral administration

Summary

The pharmacokinetics of oxytetracycline (OTC) in three weaned piglets was studied following three routes of administration: intravenously, orally as drench, both at a dose of 20 mg/kg, and orally as medicated (400 ppm OTC) pelleted feed administered during 3 consecutive days. Analysis of the intravenous data according to the three compartment pharmacokinetic model revealed that OTC was well distributed in the body (Vie 1.621/kg), had an overall body clearance of 0.25 litre/kg/h, and the elimination half‐lives were in the range between 11.6 and 17.2 hrs.

The mean OTC binding to plasma proteins was 75.5 ± 4%. Following the drench route of administration the maximum plasma OTC concentration was achieved between 1 and 5 h post application and ranged between 1.18 and 1.41 μg/ml. The mean maximum plasma OTC concentration during medicated feed administration was 0.20 ± 0.06 μg/ml, which was achieved approximately 30 hours after the onset of the administration. A steady state OTC plasma level (approximately 0.2 μg/ml) was maintained till the end of the trial. Within 48 hours after cessation of medicated feed administration the plasma OTC levels were beneath 0.06 μg/ml. The mean OTC bioavailabilities of the oral routes were low: after the drench route of administration 9.0 ± 0.67%, and after medicated pelleted feed administration 3.69 ± 0.8%.

The mean OTC renal clearances of each piglet ranged between 10.1 and 13.9 ml/min/kg (based on free OTC plasma fractions). The renal OTC clearance values were urine flow dependent in all piglets and significantly correlated with the renal creatinine clearance (P< 0.005), being 3–5 times higher than the latter. It is concluded that in piglets OTC is excreted mainly by glomerular filtration and partly by tubular secretion. The potential clinical efficacy of 400 ppm OTC as medicated feed with respect to treatment, e.g. atrophic rhinitis, is discussed.     

Pharmacokinetics and renal clearance of oxytetracycline in piglets following intravenous and oral administration

The pharmacokinetics of oxytetracycline (OTC) in three weaned piglets was studied following three routes of administration: intravenously, orally as drench, both at a dose of 20 mg/kg, and orally as medicated (400 ppm OTC) pelleted feed administered during 3 consecutive days. Analysis of the intravenous data according to the three compartment pharmacokinetic model revealed that OTC was well distributed in the body (Vf: 1.62 l/kg), had an overall body clearance of 0.25 litre/kg/h, and the elimination half-lives were in the range between 11.6 and 17.2 hrs. The mean OTC binding to plasma proteins was 75.5 +/- 4%. Following the drench route of administration the maximum plasma OTC concentration was achieved between 1 and 5 h post application and ranged between 1.18 and 1.41 micrograms/ml. The mean maximum plasma OTC concentration during medicated feed administration was 0.20 +/- 0.06 microgram/ml, which was achieved approximately 30 hours after the onset of the administration. A steady state OTC plasma level (approximately 0.2 microgram/ml) was maintained till the end of the trial. Within 48 hours after cessation of medicated feed administration the plasma OTC levels were beneath 0.06 microgram/ml. The mean OTC bioavailabilities of the oral routes were low: after the drench route of administration 9.0 +/- 0.67%, and after medicated pelleted feed administration 3.69 +/- 0.8%. The mean OTC renal clearances of each piglet ranged between 10.1 and 13.9 ml/min/kg (based on free OTC plasma fractions). The renal OTC clearance values were urine flow dependent in all piglets and significantly correlated with the renal creatinine clearance (P less than 0.005), being 3-5 times higher than the latter. It is concluded that in piglets OTC is excreted mainly by glomerular filtration and partly by tubular secretion. The potential clinical efficacy of 400 ppm OTC as medicated feed with respect to treatment, e.g. atrophic rhinitis, is discussed.     

柠檬酸对小鼠精子特性和睾丸组织形态结构的影响

60只雄性小鼠随机分为4组,每天分别腹腔注射0.2mL的0.9%生理盐水或7.5、15、30g/L CA,于14、21d测定曲细精管精子的生成及附睾内精子特性的相关数据。结果显示,随柠檬酸处理剂量的增加精子的生成数减少。14d时,对照组与15、30g/L CA组间、7.5、30g/L CA组间曲细精管内精子的生成差异显著（P〈0.05）;21d时,对照组与柠檬酸处理组间及7.5、15g/L CA与30g/L CA处理组间曲细精管内精子的生成有显著差异（P〈0.05）。柠檬酸对附睾精子品质的影响表现为：对照组与柠檬酸处理组间及柠檬酸处理组间精子密度和活动率差异均显著（P〈0.05）;对照组和15、30g/L CA处理组及15g/L CA与30g/L CA处理组间精子活力差异显著（P〈0.05）;精子的畸形率随柠檬酸浓度的增加而增加,15g/L CA处理组精子畸形率显著高于对照组（P〈0.05）,30g/LCA处理组显著高于对照组和7.5g/L CA（P〈0.05）处理组。组织形态学观察结果表明柠檬酸能破坏睾丸正常组织形态结构。柠檬酸高剂量组的生精小管内生精细胞排列疏松、紊乱,生精细胞间出现空隙;生精小管中的生精细胞脱落或退化,精原细胞、精母细胞和精子数量明显减少。研究表明,外源柠檬酸雄性小鼠具有显著的生殖遗传毒性。     

土霉素在斑节对虾体内药代动力学和生物利用度

在自然海水（盐度33）．水温为（28．0±1．0）℃养殖条件下,采用反相高效液相色谱法（RP—HPLC）,研究口灌（100mg／kg）和围心腔注射（20mg／kg）2种给药途径下,土霉素在斑节对虾（Penaeus7YlOylodoYl）体内的药代动力学和生物利用度。围心腔注射和口灌给药下,血药药时曲线均适合采用二室模型拟合。围心腔注射下血药达峰浓度（Cmax）、药时曲线下面积（AUC0-1）、消除半衰期（t,m）分别为（80．71±13．12）mg／L 378．25nag·h·L-1、17．398h;口灌给药下的相应值分别为（21．98±3．32）mg／I。324．52nag·h·L-1、23．372h,土霉素在斑节对虾体内的生物利用度（F）为17．16％。口灌土霉素后,肝胰腺Cmax为（138．655±21．375）μg／g,是血药的6．3倍、肌肉峰浓度的130．2倍,药物在肝胰腺中含量最高;然而。肌肉和肝胰腺中土霉素消除较快,消除半衰期（t1/2x）分别为28．18h和19．311 h。根据我国水产品中药物残留限量规定,水产品中土霉素的最高残留限量（NY5070—2002）为0．1mg／kg,结合本试验研究结果,斑节对虾使用土霉素后的休药期为5d,肌肉可食组织即符合无公害食品标准要求。     

Effect of dietary phytic acid on performance and nutrient uptake in the small intestine of piglets

An experiment was conducted with piglets to determine the effect of dietary phytic acid supplementation on performance, electrophysiological properties of jejunum mounted in Ussing chambers, sodium-dependent glucose transporter 1 (SGLT1) protein expression in jejunum, and plasma glucose and Na concentrations. Sixteen piglets with an average initial BW of 7.40 ± 0.36 kg were randomly assigned to 2 experimental diets with 8 piglets per diet. The diets were casein-cornstarch-based and were either unsupplemented or supplemented with 2% phytic acid (as Na phytate). The basal diet was formulated to meet the recommendation of NRC (1998) for energy, AA, minerals, and vitamins for piglets. The experiment lasted for 21 d, and at the end, BW gain and feed consumption were determined, and blood samples were collected for determination of plasma glucose and Na concentrations. The piglets were then euthanized to determine jejunal electrophysiological properties (transmural potential difference and short-circuit current) and SGLT1 protein expression. Phytic acid supplementation reduced ADG (P = 0.002), ADFI (P = 0.017), and G:F (P = 0.001) from 316.1 to 198.2 g, 437.4 to 360.3 g, and 0.721 to 0.539 g/g, respectively. Phytic acid supplementation also tended to reduce (P = 0.088) potential difference (-3.80 vs. -2.23 mV) and reduced (P = 0.023) short-circuit current from 8.07 to 0.1 μA/cm(2). However, phytic acid supplementation did not affect SGLT1 protein, and blood plasma glucose and Na concentrations. In conclusion, dietary phytic acid reduced growth performance and transmural short-circuit current in the jejunum of piglets. The reduced transmural short-circuit current in the jejunum by phytic acid implies reduced active Na transport in the jejunum by the phytic acid. Therefore, it seems that dietary phytic acid reduces growth performance of pigs partly through reduced capacity of the small intestine to absorb Na.     

The effect of citric acid on the availability of tetracyclines in calves

The effect of citric acid on the availability of tetracyclines was studied in calves. Citric acid did not significantly increase the serum levels of tetracyclines when calves were fed low doses (6-8 mg/kg) of oxytetracycline and chlortetracycline. When the dose of chlortetracycline was increased to 50 mg/kg, addition of citric acid caused higher serum levels the first two hours after feeding. The ratio citric acid: tetracyclines was 5:1 and 25:1. The palatability of the milk replacer was reduced when large amounts of citric acid was added.     

糖萜素在肉鸡日粮中替代土霉素钙的应用效果研究

试验旨在研究糖萜素替代传统抗生素——土霉素钙对肉鸡生长性能的影响。选用300只1日龄健康肉仔鸡,随机分3个处理组,每个处理组5个重复,每个重复20只鸡,分别饲喂3种日粮:对照组,基础日粮;土霉素钙组,基础日粮+50 mg/kg土霉素钙(有效成分计);糖萜素组,基础日粮+300 mg/kg糖萜素。试验期42 d。试验结果表明:肉鸡日粮中添加糖萜素和土霉素钙,21日龄体重和42日龄平均体重,糖萜素组显著高于对照组(P<0.05),较对照组分别提高了4.01%和3.72%;较土霉素钙组分别提高了1.64%和2.31%,但差异不显著(P>0.05)。土霉素钙组较对照组分别提高了2.33%和1.36%,但差异不显著(P>0.05)。就平均日增重而言,试验全期糖萜素组的平均日增重较对照组显著提高了3.81%(P<0.05),土霉素钙组的平均日增重较对照组提高了1.45%,但差异不显著(P>0.05)。就料重比而言,在0~3周,土霉素钙组和糖萜素组较对照组均有降低趋势(P>0.05),而在4~6周土霉素钙组和糖萜素组较对照组有升高趋势(P>0.05)。就平均日采食量而言,试验全期糖萜素组和土霉素钙组较对照组分别显著提高了4.54%和5.04%(P<0.05)。由此可见,日粮添加糖萜素可以显著提高肉鸡增重(P<0.05),改善肉鸡的生长性能,可以考虑作为传统抗生素——土霉素钙的替代品。     

柠檬酸对肉仔鸡肠道pH值及肠道微生物的影响

长期以来的大量研究证实,胃肠道微生物大多都是有益的并与动物存在着共生关系,这种共生关系表现在畜禽消化道为微生物提供适宜生长的环境,反过来微生物提供了动物所需要的某些营养物质。尽管对消化道微生物作用的认识还不全面,但已取得一些共识：消化道微生物参与机体物质代谢、营养转化和合成,影响营养物质的分解吸收（康白,１９８８）。同时饲料是影响消化道微生物区系建立的主要环境因素之一。本试验拟通过对肉仔鸡十二指肠、盲肠３种正常菌群的观察来研究柠檬酸对肠道正常微生物的影响。１材料与方法１．１试验设计和日粮试验采用…     

Irritation, bioavailability, and residue aspects of ten oxytetracycline formulations administered intramuscularly to pigs

After intramuscular administration to pigs (dosage 20-35 mg/kg) great differences were found among 10 injectable oxytetracycline (OTC) formulations with respect to irritation and persistence at the injection site and to the residue state of edible tissues. The OTC recovery percentages at the injection site 7-10 days after injection ranged from less than 0.001 to 0.15 per cent for three 10 per cent-formulations and from 0.12 to 20.5 per cent for seven 20 per cent-formulations. The OTC recovery percentage was obvious related to the extent of tissue irritation at the injection site, which was particularly evident for the 20 per cent-formulations. Serious doubt is expressed about advantages of so-called 'long-acting' formulations.     

Pharmacokinetics of chlortetracycline potentiation with citric acid in the chicken

Serum concentrations of chlortetracycline (CTC) in healthy chickens were determined for the 24-hour period after they were given CTC (with and without citric acid) as an oral (25 mg/kg) or IV (0.9 mg/kg) dose. The oral time-course drug data were fitted adequately by a 2-compartment pharmacokinetic model with absorption. The resulting absorption rate constant (Ka) for the birds orally given CTC with citric acid was nearly equal to that for the birds given CTC alone. Although the uptake of orally administered CTC was rapid, only a small fraction of the dose was absorbed. The administration of citric acid-CTC significantly increased the mean serum concentration of CTC and the fraction of the dose absorbed. The citric acid-CTC mixture also produced significantly higher elimination (Kel) and distribution (K12) rate constants for CTC.     

柠檬酸在水产动物营养中的应用

随着水产养殖业的发展,有机酸在渔业生产上的应用越来越广泛,其中柠檬酸是用得较为普遍的一种有机酸。柠檬酸具有无毒害、无残留等优点,对水产动物具有促进矿物质吸收、提高饲料利用率等作用,从而在水产动物营养中得到推广和应用。 1.柠檬酸的研究概况 柠檬酸是一种有机酸,又名枸橼酸,是一种状若沙糖的白色结晶体,呈柠檬型酸味,它以玉米为主要原料,经过发酵、提取、精制等一系列复杂化学工艺精制而成,所得产品主要为无水或一水柠檬酸。柠檬酸具有令人愉快的酸味,它入口爽快,无后酸味,安全无毒,是发酵法生产的最重     

壳聚糖对仔猪腹泻率的影响

本试验探讨不同的壳聚糖水平对仔猪腹泻率的影响,为壳聚糖在仔猪日粮中的科学应用提供理论依据。试验选用（60&#177;2）日龄雄性健康大白&#215;长白&#215;Ⅵ系杂种仔猪96头,分为4个处理,每个处理3个重复。4种日粮是在基础日粮中分别添加0、0．01％、0．05％和0．10％的壳聚糖配制而成。日粮壳聚糖对仔猪腹泻率的影响与添加剂量有关,添加0．01％和0．05％的壳聚糖对腹泻率的抑制作用效果较好。     

Effect of analgesics on the castration of male piglets

According to the current German animal welfare law, male piglets may be surgical castrated without anaesthesia up to four weeks of life. This surgical procedure is painful during and also after the operation, for newborn animals as well as for adults. This study was aimed to investigate the impact of preoperative application of analgesics (Meloxicam) on the postoperative castration - pain of four to six days old male piglets. In this investigation all animals were randomly distributed in three groups:the first one was only immobilized but had no surgery, the second one was castrated without analgesics, and the third group was castrated after application of Meloxicam. Blood samples were taken immediately before immobilization, castration or application of the analgesic as well as one, four and 28 hours afterwards to determine Cortisol-concentration in the blood serum and, via this stress-marker, to indirectly evaluate the postoperative und possible intraoperative castration-pain. As a result all piglets castrated without preoperative application of Meloxicam showed significantly increased Cortisol-concentration one and four hours after castration. In contrast, piglets castrated with analgesics resulted in no significant increase during the entire experiment.