酶制剂对仔猪早期断奶后腹泻的影响

选用４４头２８±２日龄断奶的仔猪分为对照组和试验组。对照组饲喂基础日粮,试验组饲喂基础日粮＋０．ｌ%酶制剂。结果表明,试验组与对照组相比,平均日增重提高了５．８８%,平均日采食量降低了４．８４%,料肉比降低了１０．３８%;试验组的腹泻发生率、腹泻频率和死亡率分别降低了４．５５%(Ｐ＞０．０５)、２８．０６%(Ｐ＜０．０５)和６６．６４%(Ｐ＞０．０５);干物质、粗蛋白和粗纤维的消化率分别提高了３．１４%、１６．７７%和４５．１４%。提示日粮中添加酶制剂可弥补仔猪早期断奶后内源酶的降低,提高饲料转化率,促进仔猪生长,降低仔猪腹泻发生率和死亡率。     

帕托珠利混悬液在仔猪体内的药代动力学及生物利用度研究

为研究帕托珠利混悬液在仔猪体内的药动学特征及生物利用度,采用平行实验设计方法,将16头 40 日龄健康仔猪随机分成两组,每组8头（公母各半）,分别进行单剂量静脉注射（6mg/kg bw）和单剂量口服给药（15mg/kg bw）,所有猪给药前禁食12h,给药2h后恢复正常饮食。给药后按预定的采血点采集血样,血浆中帕托珠利的含量采用经验证的 HPLC检测方法进行测定。实测血药浓度数据采用Graphad prism 8.0拟合药时曲线图,并用 Winnonlin5.2计算药动学参数。结果显示,单剂量静脉注射帕托珠利注射液后帕托珠利在仔猪体内主要药动学参数如下：平均消除半衰期（T1/2?）为136.98h,平均滞留时间（MRT）为165.92h,平均药时曲线下面积（AUC0-t）为1570.97 h?μg/mL,平均表观分布容积（Vz）为695.59 mL/kg,平均血浆清除率（CL）为3.77 mL/h?kg;单剂量口服帕托珠利混悬液后帕托珠利在仔猪体内主要药动学参数如下：平均消除半衰期（T1/2?）为134.05h,平均达峰时间（Tmax）为42.00h,平均峰浓度（Cmax）为14.03μg/mL,平均滞留时间（MRT）为173.19h,平均药时曲线下面积（AUC0-t）为2831.00 h?μg/mL,帕托珠利混悬液口服给药绝对生物利用度为72.08%。结果表明,帕托珠利在猪体内分布较差,消除缓慢;仔猪口服帕托珠利混悬液达峰时间较长,但吸收良好。     

Pharmacokinetics and bioavailability of a long-acting formulation of cephalexin after intramuscular administration to cats

The pharmacokinetic profile and bioavailability of a long-acting formulation of cephalexin after intramuscular administration to cats was investigated. Single intravenous (cephalexin lysine salt) and intramuscular (20% cephalexin monohydrate suspension) were administered to five cats at a dose rate of 10 mg/kg. Serum disposition curves were analyzed by noncompartmental approaches. After intravenous administration, volume of distribution (V_z), total body clearance (Cl_t), elimination constant (λ_z), elimination half-life (t_½λ) and mean residence time (MRT) were: 0.33 ± 0.03 L/kg; 0.14 ± 0.02 L/h kg, 0.42 ± 0.05 h⁻¹, 1.68 ± 0.20 h and 2.11 ± 0.25 h, respectively. Peak serum concentration (C_max), time to peak serum concentration (T_max) and bioavailability after intramuscular administration were 15.67 ± 1.95 μg/mL, 2.00 ± 0.61 h and 83.33 ± 8.74%, respectively.     

Species comparison of enantioselective oral bioavailability and pharmacokinetics of ketoprofen

As a part of ongoing research to further elucidate frequent and species-specific causes of differences in oral bioavailability, a 3 mg/kg dose of racemic ketoprofen, a high permeability/low solubility compound in the human biopharmaceutics classification system, was administered intravenously and orally to different species. Due to possible enantioselective disposition kinetics and inversion, enantiomers were quantitated separately using a stereospecific HPLC assay. The absolute bioavailability of R(−) and S(+) ketoprofen in chickens, turkeys, dogs and pigs was 31.5% and 52.6%, 42.6% and 32.5%, 33.6% and 89.1%, and 85.9% and 83.5% respectively. Incomplete bioavailability in poultry is probably due to incomplete absorption in addition to first-pass elimination. Low bioavailability of R(−) ketoprofen in dogs, strongly indicates first-pass metabolism. High bioavailability of S(+) ketoprofen in dogs and both enantiomers in pigs confirms that absorption of these substances is complete and controlled by gastric emptying rather than dissolution.     

Clindamycin bioavailability and pharmacokinetics following oral administration of clindamycin hydrochloride capsules in dogs

Oral bioavailability and pharmacokinetic behaviour of clindamycin in dogs was investigated following intravenous (IV) and oral (capsules) administration of clindamycin hydrochloride, at the dose of 11 mg/kg BW. The absorption after oral administration was fast, with a mean absorption time (MAT) of 0.87+/-0.40 h, and bioavailability was 72.55+/-9.86%. Total clearance (CL) of clindamycin was low, after both IV and oral administration (0.503+/-0.095 vs. 0.458+/-0.087 L/h/kg). Volume of distribution at steady-state (IV) was 2.48+/-0.48 L/kg, indicating a wide distribution of clindamycin in body fluids and tissues. Elimination half-lives were similar for both routes of administration (4.37+/-1.20 h for IV, vs. 4.37+/-0.73 h for oral). Serum clindamycin concentrations following administration of capsules remained above the MICs of very susceptible microorganisms (0.04-0.5 microg/mL) for 12 or 10 h, respectively. Time above the mean inhibitory concentration (MIC) is considered as the index predicting the efficacy of clindamycin (T(>MIC) must be at least 40-50% of the dosing interval), so a once-daily oral administration of 11 mg/kg BW of clindamycin can be considered therapeutically effective. For less susceptible bacteria (with MICs of 0.5-2 microg/mL) the same dose should be given but twice daily.     

Species comparison of oral bioavailability, first-pass metabolism and pharmacokinetics of acetaminophen

Species differences in oral bioavailability, first-pass metabolism and pharmacokinetics of biopharmaceutics classification system (BCS) class I compound acetaminophen were studied. The absolute bioavailability was 42.2%, 39.0%, 44.5%, 75.5% and 91.0% in chickens, turkeys, dogs, pigs and horses, respectively. After hydrolysis of metabolites by β-glucuronidase/sulfatase, apparent bioavailability increased significantly in all species (turkeys: 72.4%, dogs: 100.5%, pigs: 102.2%), except horses (91.6%). Mean metabolic ratios of [acetaminophen glucuronide]/[acetaminophen] between 0 and 1 h were significantly higher after oral dosing in turkeys, dogs and pigs, revealing the role of first-pass metabolism in incomplete bioavailability. Evidence of species differences in acetaminophen metabolism is provided by differences in plasma clearance, which was inversely proportional to bioavailability. In conclusion, differences in BA appeared to originate predominantly from differences in first-pass metabolism, demonstrating that the BCS high permeability classification of acetaminophen is consistent across the mammalian species studied. In turkeys, however, incomplete absorption additionally seemed to contribute to the low BA.     

Effects of low-protein diets supplemented with crystalline amino acids on performance and intestinal development in piglets over the first 2 weeks after weaning

This study was conducted to determine the effects of low-protein diets supplemented with crystalline amino acids (AA) on performance and intestinal development in barrows (n = 32) over 2 weeks after weaning at 18 ± 1 day. Four maize-soybean meal based diets providing 0.93 g standardized ileal digestible lysine/MJ ME were prepared. The treatments were a control diet containing 23.1% CP (crude protein) and three low-protein diets (21.2, 18.9, and 17.2% CP, respectively), which were supplemented with crystalline AA to achieve an ideal AA pattern. Piglets were raised individually and had free access to feed and water. Average daily gain (ADG) and average daily feed intake (ADFI) were measured weekly. Severity of diarrhea was monitored twice per day. Blood from all piglets was taken for determining serum urea nitrogen on d 0, 7, and 14 and serum free AA concentration on d 14. At the end of the experiment, all piglets were killed to measure morphology of the small intestine and disaccharidase activities. Reducing CP level did not affect ADFI (P > 0.10) but resulted in poorer (linear, P < 0.05; quadratic, P < 0.05) ADG and feed:gain ratio (F:G) over the 2-week study period. However, most of the effect of dietary CP was due to the significant deterioration of performance with the 17.2% CP diet. Faecal consistency was improved linearly (P < 0.01) with dietary CP decrease. Reducing dietary CP from 23.1 to 17.2% resulted in a linear (P < 0.001) and quadratic (P < 0.001) decrease in serum urea nitrogen levels on d 7 and 14. Serum arginine (P < 0.001), glutamine (P < 0.05), and proline (P < 0.05) concentrations were decreased in pigs fed the 17.2% CP diet compared with those fed the control diet on d 14. Villous height was decreased (P < 0.05) in the duodenum and jejunum by the reduction of dietary CP. As dietary CP declined, lactase and sucrase activities were reduced (P < 0.01) in the proximal jejunum. In conclusion, reducing CP concentration from 23.1 to 17.2% led to decreased growth performance associated with morphological changes of the gut and reduced disaccharidase activities in the small intestine. But reducing dietary CP from 23.1 to 18.9% did not affect intestinal morphology and disaccharidase activities.     

不同蛋白源对断奶前后仔猪消化道酶活的影响

早期断奶仔猪消化系统发育不成熟,消化酶系发育不健全,小肠粘膜抵抗能力弱,易被各种外源性蛋白抗原损伤（Dunsford等,1989;Li等1990,1991）。在实际生产中,3～5周龄断奶补饲,能保证足够的采食量,使仔猪适应日粮抗原。本试验研究了不同类型蛋白源对补饲期和断奶后仔猪消化道各种酶活的影响,为选择适合仔猪消化生理     

Changes in the fermentation end-product profile in the GIT of piglets during post-colostrum suckling period

Pre-weaning development of microbial activity has an effect on post-weaning establishment of the gastro-intestinal tract (GIT) microbiota. An in vivo study was conducted, to evaluate the effect of age on fermentation end-product profiles during the post-colostrum suckling period, as the variation in composition of mature milk is minimum. Sixteen piglets from two litters (eight per litter) were selected. During the study, piglets had free access to sow's milk, but no creep feed, nor antibiotic treatments. Two piglets from each litter were sacrificed on d 11, 18, 25 and 32 of age. The digesta samples were collected from the beginning and end of the small intestine, caecum and colon. Samples were analyzed for fermentation end-product concentrations. Combining the results from all the GIT sites, it was observed that, total VFA concentration increased with age of the piglets. There was a significant rise in acetic acid concentrations, with a significant decrease in lactic acid concentrations from d11 to d32, while the proportions of SCFA, (acetic acid  72%, propionic acid  15% and butyric acid  6% of total VFA) and ammonia concentrations remained unchanged. These results clearly suggest that, the microbial activity in terms of fermentation end-product profile skewed from lactic acid to acetic acid as a major product during the post-colostrum suckling period. This may be attributed to lower substrate availability due to increased number of microbes or increased diversity in the microbiota in time.     

Dietary selection for lysine by piglets at differing feeding regimen

The aim of the present study was to investigate preferences of piglets for diets varying in lysine (Lys) concentration and whether those preferences are influenced by changing position of diets on offer in feeders. For this purpose, a feeding trial was carried out over a period of 5 weeks. Piglets (equal proportions of barrows and gilts) with an initial BW of 7.4 ± 0.9 kg were randomly subdivided into four groups of 12 pigs each and were housed in single pens. Two reference groups were fed diets containing either 0.7% Lys (low-Lys group) or 1.0% Lys (high-Lys group). Two other groups had the choice from two diets containing 0.7 or 1.0% Lys offered simultaneously in identical feeders. For animals of one of these choice groups (Lys-choice 1 group) the position of diets in the feeders remained unchanged throughout the experimental period, but for animals of a second choice group (Lys-choice 2 group) position of the diets on offer in the feeders was changed two times a week.Average daily feed intake and daily gain were greatly (p < 0.05) decreased in animals of the low-Lys group compared to other treatments, and feed to gain ratio was increased. Performance of animals in Lys-choice 1 group was numerically decreased compared to animals of Lys-choice 2 group. Chosen diets of Lys-choice groups 1 and 2 contained on average 31 and 19% feed with 0.7% Lys, respectively. Resulting Lys contents of total diets were 0.94 and 0.98% for Lys-choice groups 1 and 2, respectively, as a mean of the experiment. In week 1 animals of both Lys-choice groups met approximately 50% of total feed intake by consumption of the 0.7% Lys diet. Animals of Lys-choice 1 group lowered this portion to 20% in the last experimental week and animals of Lys-choice group 2 to 11%. Preference for the 1.0% Lys diet was evident (p < 0.05) from week 3 to 5 in Lys-choice 1 group and from week 2 to 5 in Lys-choice 2 group.Piglets are able to distinguish between diets differing in Lys content and to prefer a better balanced diet over a Lys-deficient one. Changing the position of the diets on offer in the feeders two times a week does not impair the ability to select for a diet more adequate in Lys concentration, but led in contrary to a slightly higher preference for Lys.     

黄芪多糖在仔猪生产中的应用研究

黄芪多糖为中药黄芪主要的活性成分,具有广泛的生物学功能,在仔猪生产中可以用来增强免疫力、防治疾病和提高生产性能。本文就黄芪多糖的提取以及在仔猪生产中的应用作一综述。     

超早期断奶仔猪液态饲料的加工技术研究初报

液态饲料在超早期断奶仔猪生产中的应用优势非常明显,其加工技术及有关设备在我国仍属空白。试验选用玉米面粉、膨化全脂大豆、糖蜜、鱼粉、乳清粉、喷雾血浆蛋白粉、预混料、防腐剂等乳猪饲料原料,在实验室条件下制作应用于超早期断奶仔猪的液态饲料。摸索出液态饲料的部分加工技术要点;同时对液态饲料的理化性质和微生物学性质进行了研究。     

Performance and diarrhoea in piglets following weaning at seven weeks of age: Challenge with E. coli O 149 and effect of dietary factors

Four dietary factors (ad libitum versus feed restriction, control versus protein restriction at ad libitum feeding, control versus inclusion of lupin as a protein source at ad libitum feeding, and control versus extra vitamin E at ad libitum feeding) were tested in four separate experiments for the effect on diarrhoea. To introduce a diarrhoea-like condition, half of the piglets were challenged with an E. coli O 149 dose of 1 × 10⁸ colony forming units on days one and two after weaning (day of weaning = day zero). All piglets were susceptible since the dams were tested mono-zygotic susceptible to the attachment site of E. coli O 149 in the intestines. Each of the four experiments included 32 piglets from 4 sows. The design was a 2 × 2 factorial with dietary factor and E. coli O 149 challenge as the two factors, each at two levels. The piglets were housed individually during the experiment which lasted for 10 days from weaning at 7 weeks of age. The daily recordings included feed intake, weight and faecal score (from 1 = solid and cloddy to 6 = watery and yellow). Faeces from days 1 to 4 were tested for E. coli strains. In addition, blood was sampled and serum was analysed for antibodies to E. coli, IgG and IgM. Generally the E. coli challenge had no effect on growth and feed intake whereas faecal score and number of faecal haemolytic bacteria increased and faecal dry matter decreased. Feed restriction decreased the weight gain while faecal characteristics were unaffected. An analysis including all four experiments revealed that a feed intake of less than 200 g during the first day after weaning seems to be associated with a relatively high incidence of a post-weaning diarrhoea-like condition. Protein restriction decreased faecal score and increased faecal dry matter while weight gain tended to decrease. Inclusion of lupin affected neither weight gain nor faecal characteristics. Extra vitamin E did not affect weight gain while faecal dry matter decreased, and faecal score and number of faecal haemolytic bacteria increased. The dietary treatments had no effect on the measured immunoglobulins. In conclusion, the studied dietary factors could not alleviate a diarrhoea-like condition and at the same time maintain the growth rate. Furthermore, the results indicate that performance can be improved if piglets achieve a daily feed intake of at least 200 g during the first day after weaning.     

Pharmacokinetics of diclofenac and its interaction with enrofloxacin in sheep

The pharmacokinetics of diclofenac was investigated in sheep given diclofenac alone (1mgkg(-1), i.v. or i.m.) and in combination with enrofloxacin (5mgkg(-1), i.v.). The plasma concentration-time data following i.v. administration of diclofenac was best described by a two compartment open pharmacokinetic model. The elimination half-life (t(1/2beta)), area under concentration-time-curve (AUC), volume of distribution (Vd(area)), mean residence time (MRT) and total body clearance (Cl(B)) were 1.03+/-0.18h, 12.17+/-1.98microg h ml(-1), 0.14+/-0.02Lkg(-1), 1.36+/-0.16h and 0.10+/-0.02Lkg(-1)h(-1), respectively. Following i.m. administration of diclofenac alone and in conjunction with enrofloxacin, the plasma concentration-time data best fitted to a one compartment open model. The t(1/2beta), AUC, Vd(area), MRT and Cl(B) were 1.33+/-0.10h, 7.32+/-1.01microg h mL(-1), 0.13+/-0.01Lkg(-1) and 0.07+/-0.01Lkg(-1)h(-1), respectively. Co-administration of enrofloxacin did not affect Vd(area) and MRT but absorption rate constant (K(a)), beta, t1/2Ka, t1/2beta, AUC, AUMC, Cl(B) and bioavailability (F) were significantly increased. This may be due to direct inhibition of cytochrome P(450) isozymes by enrofloxacin. A dose of 1.4mgkg(-1) of diclofenac administered every 6h may be appropriate for use in sheep.     

女贞子多糖对仔猪抗氧化及MAPK通路的影响

为了研究女贞子多糖对人工感染大肠杆菌K88仔猪氧化应激的保护作用,将实验猪分为四组:对照组、模型组、女贞子多糖组和女贞子多糖饲喂后攻毒组。试验运用血清生化、ELISA和RT-PCR等技术,通过检测血清和肝肾组织的抗氧化酶和氧化产物,仔猪肝脏氧化应激相关基因转录水平和MAPK信号关键蛋白的转录,评价女贞子多糖的抗氧化机制。结果显示,女贞子多糖可以显著降低由大肠杆菌引起的仔猪血清MDA含量的升高,调节肝肾组织中MDA和SOD的水平;女贞子多糖可以提高仔猪肝脏中CAT和CuZnSOD的mRNA转录水平;正常情况下,女贞子多糖对仔猪肝脏TNF-α的mRNA转录表达无影响,但可以降低大肠杆菌攻毒后的转录水平;女贞子多糖抑制MAPK通路主要依靠调控ERK1起作用。结果表明,女贞子多糖可以通过调节肝脏抗氧化指标保护大肠杆菌引起的仔猪氧化应激反应,其作用分子机制可能与下调MAPK相关信号转录水平有关。     

在不同有效磷日粮中添加植酸酶对仔猪生产性能的影响

将体重相近的60头15kg左右的杜长大仔猪分为5个处理（对照组、AP降低0．1％、AP降低0．12％、AP降低0．1％＋酶、AP降低0．12％＋酶）,每个处理3个重复,每重复4头仔猪。研究结果表明：曰粮有效磷水平和植酸酶对仔猪生长、料重比都有显著的影响（P〈0．05）,与对照组相比,当日粮有效磷水平降低0．1％,仔猪体重、日增重会显著降低,而料重比显著上升;当有效磷降低0．1％添加植酸酶时,仔猪体重、日增重会显著增加,而料重比显著下降;当日粮有效磷降低0．12％时,不论加酶与否,其体重、日增重都会显著下降,而料重比会显著增加。     

The interaction between dietary crude protein and fermentable carbohydrate source on piglet post weaning performance, diet digestibility and selected faecal microbial populations and volatile fatty acid concentration

A 2 × 2 × 2 factorial arrangement was used to investigate a 21 day study on the interaction between dietary crude protein (CP) (160 versus 200 g/kg), lactose level (50 versus 230 g/kg), and inulin supplementation (0 versus 15 g/kg) on piglet performance, diet digestibility, faecal volatile fatty acid (VFAs) concentration and selected microbial populations post weaning. Two hundred and fifty six weaned piglets (24 days old, 7.4 kg live weight, S.D. = 1.5 kg) were blocked on the basis of live weight and were assigned to one of 8 dietary treatments (n = 8) for 21 days. There was an interaction between CP and lactose concentration on average daily gain (ADG) during the overall experimental period. Pigs offered high CP diets containing 230 g/kg lactose increased ADG compared to those pigs offered high CP diets containing 50 g/kg lactose. However, there was no effect of lactose concentration in the low CP diets. There was a significant interaction (P < 0.05) between lactose level and inulin supplementation on Lactobacilli spp., Enterobacteria spp. and branched chain VFAs. Pigs offered inulin supplemented 230 g/kg lactose diets increased Lactobacilli spp. (P < 0.05) and decreased Enterobacteria spp. (P < 0.05) and branched chain VFAs (P < 0.05) compared to those offered the inulin supplemented 50 g/kg lactose diets. However there was no effect of lactose concentration in the non inulin supplemented diets. In conclusion, high CP diets and high inclusion levels of lactose improved piglet performance post weaning. Inulin supplementation had an additional effect in the 230 g/kg lactose diets through increased Lactobacilli spp. and decreased Enterobacteria spp. and branched chain VFAs.     

Effects of magnesium on the performance of sows and their piglets

The objective of this study was to evaluate the effects of supplemental magnesium (Mg) on the performance of gilts and parity 3 sows and their piglets. Fifty-six gilts (Trial 1) and 56 sows (Trial 2) were assigned to one of 4 treatments according to their mating weight, respectively. The treatments comprised corn-soybean meal based gestation and lactation diets (0.21% magnesium) supplemented with 0, 0.015, 0.03, or 0.045% Mg from mating until weaning. The results showed that magnesium supplementation significantly (P < 0.05) reduced the weaning to estrus interval in both gilts and sows. There were significant effects (P < 0.05) of supplemental magnesium on the total number of piglets born, born alive and weaned in sows. In late gestation and lactation, the digestibility of crude fiber (quadratic effects, P < 0.05), and crude protein (P < 0.05), were significantly influenced by magnesium in gilts and sows, respectively. There were differences among the 4 groups in terms of the apparent digestibility of dry matter and crude fiber in sows (P < 0.05) during both early and late gestation. The apparent digestibility of gross energy was increased for sows in late gestation (P < 0.05), and lactation (quadratic effects, P < 0.05). At farrowing and weaning, serum prolactin levels and alkaline phosphate activities linearly increased in sows as the Mg supplementation increased (P < 0.05). Serum Mg of sows at farrowing and serum urea nitrogen of sows at weaning was significantly influenced by Mg supplementation (P < 0.05). The Mg concentration in sow colostrum and the serum of their piglets were increased by supplemental magnesium (P < 0.05). In addition, growth hormone levels were linearly elevated (P < 0.05) in the serum of piglets suckling sows. Our data demonstrated that supplemental magnesium has the potential to improve the reproduction performance of sows, and the suitable supplemental dose ranged from 0.015% to 0.03%.