Aflatoxin B1 (AFB1) is a potent hepatotoxic and carcinogenic agent. Curcumin possesses potential anti-inflammatory, anti-oxidative and hepatoprotective effects. However, the role of LncRNAs in the protective mechanisms of curcumin against AFB1-induced liver damage is still elusive. Experimental broilers were randomly divided into 1) control group, 2) AFB1 group (1 mg/kg feed), 3) cur + AFB1 group (1 mg/kg AFB1 plus 300 mg/kg curcumin diet) and 4) curcumin group (300 mg/kg curcumin diet). Liver transcriptome analyses and qPCR were performed to identify shifts in genes expression. In addition, histopathological assessment and oxidant status were determined. Dietary AFB1 caused hepatic morphological injury, significantly increased the production of ROS, decreased liver antioxidant enzymes activities and induced inflammation and apoptosis. However, dietary curcumin partially attenuated the abnormal morphological changes, oxidative stress, and apoptosis in liver tissues. Transcriptional profiling results showed that 34 LncRNAs and 717 mRNAs were differentially expressed with AFB1 and curcumin co-treatment in livers of broilers. Analysis of the LncRNA-mRNA network, GO and KEGG enrichment data suggested that oxidative stress, inflammation and apoptosis pathway were crucial in curcumin's alleviating AFB1-induced liver damage. In conclusion, curcumin prevented AFB1-induced oxidative stress, inflammation and apoptosis through LncRNAs. These results provide new insights for unveiling the protective mechanisms of curcumin against AFB1-induced liver damage.

建立了德拉昔布咀嚼片溶出度测定的高效液相色谱法,并对德拉昔布咀嚼片和Deramaxx咀嚼片的溶出度进行比较.方法为浆法,转速为50 r/min,0.8％十二烷基硫酸钠为溶出介质,于5、10、15、20、30、40、50 min分别采样;采用Waters XSelect H88 C18(4.6 mm×250 mm,5μm)色谱柱,磷酸盐缓冲液(pH4.5)-乙腈(52:48,V/V)为流动相,检测波长252 nm;柱温30℃;外标法定量.结果表明,德拉昔布在5～25μg/mL浓度范围内线性良好(r2=0.9992),检测限与定量限分别为0.81μg/mL、2.57μg/mL;平均回收率为101.8％ ±0.91％;德拉昔布咀嚼片与Deramaxx溶出度在30 min内分别为87.78％ ±1.91％和88.76％ ±2.05％,符合规定.试验所建立的方法简便、准确、专属性强,可用于德拉昔布咀嚼片的溶出度测定.

为建立检测德拉昔布咀嚼片含量的方法,本试验采用高效液相色谱法对德拉昔布咀嚼片和Deramaxx咀嚼片进行含量测定.样品经粉碎与甲醇溶解,超声处理20 min,0.22 μm滤膜滤过后进样测定.色谱条件:色谱柱Wasters C18(4.6 mm×250 mm,5 μm);流动相为磷酸盐缓冲液(pH =4.5)∶乙腈(52∶48,v/v);检测波长252 nm;流速1 mL/min;柱温30℃.结果显示,德拉昔布标准品以甲醇为溶剂,进样浓度在0.5～8 μg/mL,建立标准曲线,样品浓度与峰面积的线性关系良好(r2 =0.999 2).仪器精密度为0.56％,日内差异为0.94％,日间差异为1.85％,溶液稳定性为0.57％,平均加样回收率为(99.68±0.53)％.表明所建立的高效液相色谱含量检测方法简便、准确、专属性强,可用于德拉昔布咀嚼片含量的测定.

Improper use of antibiotics results in poor treatment and severe bacterial resistance. In this study, ultrafiltration probes were successfully placed in the ileum of piglets with the aid of anesthetic. After the fluoroquinolone antimicrobial drug danofloxacin (DAN) was intramuscularly administered, blood and ileum ultrafiltrate were collected at different time points and then determined by High Performance Liquid Chromatography (HPLC). Pharmacokinetics (PK) parameters for plasma and ileum ultrafiltrate were calculated by WinNonlin software. The DAN concentration in ileum ultrafiltrate was much higher than that in plasma during the period 1.2–48 h. The DAN concentration in plasma reached its maximum at 1.10 ± 0.03 h, but reached at 6.00 ± 0.00 h in the ileum ultrafiltrate. The mean C max of the ileum is 13.59 times that of plasma. The elimination half-life (T 1/2β ) in the ileum ultrafiltrate (6.84 ± 1.49 h) was shorter than those in plasma (7.58 ± 3.20 h). The MIC, MBC and MPC of DAN in MH broth against Escherichia coli (O 158 ) were 0.5 µg/mL, 0.5 µg/mL and 4 µg/mL, respectively. Both in vitro and ex vivo kill curves indicated that the killing mechanism of DAN against E. coli is concentration-dependent. The AUC/MPC ratio is 21.33 ± 2.14. Mean PK/PD index (AUC 24h /MIC) for ileum ultrafiltrate that achieved bacteriostatic, bactericidal, and eradication were 99.85, 155.57, and 218.02 h, respectively. Three different dosages (1.49 mg/kg, 2.42 mg/kg, and 3.24 mg/kg) were calculated respectively based on AUC 24h /MIC ratio above, which might provide a novel approach to the rational design of dosage schedules.

It has been reported that oral intake of aflatoxin B1 (AFB1)-contaminated feed could cause acute, sub-chronic, or chronic toxicity in livestock and poultry. However, the harmful effect of AFB1 on the small intestine is still controversial. Therefore, blocking the entry of AFB1 into the body through the digestive tract is one of the important methods to prevent its toxicity. In the present study, 1-day-old Arbor Acres broilers were randomly divided into 6 groups including control group, curcumin control group (450 mg curcumin/kg feed), curcumin low-, medium-, and high-dose group (150, 300, and 450 mg curcumin/kg feed + 5 mg AFB1/kg feed), and AFB1 group (5 mg AFB1/kg feed). After 28 d, the samples of chickens' duodenums were collected for further analyses. AFB1 caused abnormal functional and morphological changes in the duodenum, including histological lesions, increased the length of the duodenum and depth of crypt, decreased the unit weight of the duodenum, height of villus, and the value of villus height/crypt depth. Meanwhile, AFB1 administration enhanced malonaldehyde activity, 8-HOdG level, and the mRNA expression of cytochrome P450 (CYP450) enzymes, and reduced superoxide dismutase, catalase, adenosine triphosphatase (ATPase) activity and the mRNA expression of Abcb1. Importantly, curcumin supplementation partially ameliorated AFB1-induced abnormal functional and morphological signs of the duodenum, alleviated AFB1-induced oxidative stress, and decreased the mRNA expression of CYP450 enzymes. Furthermore, curcumin ameliorated AFB1-induced decrease in the Abcb1 mRNA expression, P-glycoprotein (P-gp) level, and ATPase activities. It has been suggested from these results that curcumin supplementation in the feed could ameliorate AFB1-induced duodenal toxicity and damage through downregulating CYP450 enzymes, promoting ATPase activities, and inducing P-gp in chickens.

Background： Apramycin is used exclusively for the treatment of Escherichia coli ( E.coli ) infections in swine around the world since the early 1980s. Recently, many research papers have demonstrated that apramycin has significant in vitro activity against multidrug-resistant E.coli isolated in hospitals. Therefore, ensuring the proper use of apramycin in veterinary clinics is of great significance of public health. The objectives of this study were to develop a wild-type cutoff for apramycin against E.coli using a statistical method recommended by Clinical and Laboratory Standards Institute (CLSI) and to investigate the prevalence of resistance genes that confer resistance to apramycin in E. coli . Results: Apramycin susceptibility testing of 1230 E.coli clinical isolates from swine were determinded by broth microdilution testing according to the CLSI document M07-A9. A total number of 310 E.coli strains from different minimum inhibitory concentration (MIC) subsets (0.5-256 µg/mL) were selected for the detection of resistance genes ( aac(3)-IV ; npmA ; apmA ) in E. coli by PCR. The percentage of E. coli isolates at each MIC (0.5, 1, 2, 4, 8, 16, 32, 64, 128, and 256 µg/mL) was 0.08%, 0.08%, 0.16%, 2.93%, 31.14%, 38.86%, 12.85%, 2.03%, 1.46%, and 10.41%. The MIC 50 and MIC 90 were 16 and 64 µg/mL. All the 310 E.coli isolates were negative for npmA and apmA gene, and only the aac(3)-IV gene was detected in this study. Conclusions: The wild-type cutoff for apramycin against E.coli was defined as 32 µg/mL. The prevelance of aac(3)-IV gene mainly concentrated in these MIC subsets ‘MIC ≥ 64 µg⁄ mL’, which indicates that the wild-type cutoff established in our study is reliable. The wild-type cutoff offers interpretion criteria of apramycin susceptibility testing of E.coli .

以前期获得的25株猪源耐药大肠杆菌为试验菌株,采用药敏纸片法测定以上分离菌株对氟苯尼考、多西环素、庆大霉素等11种药物的敏感性,并分析其多重耐药表型;采用PCR方法和实时荧光定量PCR方法分别检测25株猪源大肠杆菌中AcrAB-TolC主动外排基因的携带率以及不同耐药数量的多重耐药菌株的外排泵基因arA和acrB的表达量,同时分析其主动外排调控基因marA、soxS、robA和acrR相对表达量的差异,从mRNA水平上探讨外排泵基因表达量和调控因子与大肠杆菌多重耐药性的相关性.结果 显示,25株耐药大肠杆菌中acrA、acrB和tolC等3种主动外排基因的携带率分别为68.00％、72.00％和76.00％;acrA、acrB这2种主动外排基因以及调控基因marA和soxS的相对表达量和多重耐药的耐药谱数呈正相关,调控基因acrR的相对表达量和多重耐药的耐药谱数呈负相关;robA调控基因的表达量均低于标准菌株,且与耐药谱数无明显相关性.结果 表明,猪源耐药大肠杆菌携带acrA、acrB、tolC等3种基因主动外排基因的携带率较高,且与多重耐药菌株的耐药谱具有相关性;调控因子的表达量亦与多重耐药的耐药谱具有相关性.

In this study, we identified AFB1 adducts as potential markers and investigated the role of curcumin in alleviating AFB1-induced liver damage by suppressing the production of AFB1 adducts and oxidative stress in AA broilers liver. A total of 64 one-day-old Arbor Acres (AA) broilers were randomly divided into four groups, including control group, AFB1 group (5 mg/kg AFB1), cur + AFB1 group (300 mg/kg curcumin + 5 mg/kg AFB1) and curcumin group (300 mg/kg). Serum biochemical parameters, liver antioxidant abilities, AFB1 adducts and oxidative stress mechanism were studied in broilers. AFB1 administration accompany with signs of liver injury, including hepatic histological lesions, increased serum enzymes activities, decreased liver antioxidant enzymes activities and the suppression of ROS and 8-OHdG. Meanwhile, Nrf2/HO-1 pathway was depressed by AFB1 treatment. Immunohistochemistry and ELISA showed that AFB1 significantly increased AFB1-DNA adduct in liver (p < 0.05) and AFB1-lysine adduct in serum (p < 0.05). Importantly, supplementation of curcumin can ameliorate these alterations. Intriguingly, curcumin alleviated AFB1-induced toxicity and oxidative stress by inhibiting the generation of ROS, 8-OHdG and AFB1 adducts, and activated Nrf2 signaling pathway in broilers. Conclusively, our experiments suggest that curcumin could be considered as a potential agent for prevention of AFB1-induced toxicity and oxidative stress, and AFB1 adducts could be suitable therapeutic targets.

The aim of this study is to evaluate the safety and efficacy of gamithromycin (GAM) for the treatment of naturally occurring bacterial swine respiratory disease (SRD) administered IM. A total of 240 pigs (nine-weeks old) were selected from two sites in Heilongjiang Province of China. The pigs showed severe signs of respiratory disease. Among them, 120 pigs were randomly divided into 4 groups of low dose (3 mg/kg), middle dose (6 mg/kg), high dose (12 mg/kg) GAM IM injection and 2.5 mg/kg tulathromycin (TUL) IM injection (positive control group) for phase II clinical trial to screen effective therapeutic dose. The other 120 pigs were randomly divided into 2 groups of 6 mg/kg GAM IM injection and 2.5 mg/kg TUL IM injection (positive control group) for phase III clinical trial to further confirm the efficacy. Animals were clinically observed daily for 14 days after treatment initiation. The predominant pathogens present in pretreatment respiratory tract samples were Streptococcus suis (S. suis) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae). Haemophilus parasuis (H. parasuis) and Pasteurella multocida (P. multocida) were also found in the respiratory tract. All isolates were subjected to in vitro sensitivity testing and the measured minimal inhibitory concentrations (MIC) of GAM were from 0.0625 μg/mL to 8 μg/mL. In all treatment groups, rectal temperature dropped and clinical index (mental status and respiratory symptom) significantly improved after treatment (P ≤ .05). As a result, 82.76% animals treated with the 6 mg/kg GAM injection were cured. This was significantly higher than that of 3 mg/kg GAM injection (P ≤ .05) and similar to that of 12 mg/kg GAM injection and 2.5 mg/kg TUL injection (P > .05) in phase II clinical trial. In phase III clinical trial, 80.70% of animals treated with the 6 mg/kg GAM injection were cured and the cure rate was similar to that of 2.5 mg/kg TUL injection (P > .05). In conclusion, we recommended a single dose (6 mg/kg) of GAM IM injection for the treatment of bacterial SRD.

Improper use of antimicrobials results in poor treatment and severe bacterial resistance. Breakpoints are routinely used in the clinical laboratory setting to guide clinical decision making. Therefore, the objective of this study was to establish antimicrobial susceptibility breakpoints for danofloxacin against Escherichia coli (E.coli), which is an important pathogen of digestive tract infections.

为评价加米霉素注射液对靶动物猪的安全性,将24头70日龄大长二元杂交猪随机分为4组,每组6头,分别为空白对照组(生理盐水)、1倍推荐剂量组(6 mg/kg·bw)、3倍推荐剂量组(18 mg/kg·bw)、5倍推荐剂量组(30 mg/kg·bw),分别于试验第0天、5天、10天各肌肉注射给药一次.通过观察猪的临床表现、增重情况,测定其血液常规指标、血液生化指标,观察组织病理变化等评价加米霉素注射液的安全性.试验结果显示,加米霉素注射液1倍、3倍、5倍推荐剂量组的各项指标与空白对照组相比无显著性差异(P＞0.05).试验结果表明,加米霉素注射液以5倍推荐剂量给药对靶动物猪安全.