N -ethyl- N -nitrosourea induces retinal photoreceptor damage in adult rats

Seven-week-old male Lewis rats received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (100, 200, 400 or 600 mg/kg), and retinal damage was evaluated 7 days after the treatment. Sequential morphological features of the retina and retinal DNA damage, as determined by a TUNEL assay and phospho-histone H2A.X (γ-H2AX), were analyzed 3, 6, 12, 24 and 72 hr, 7 days, and/or 30 days after 400 mg/kg ENU treatment. Activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP) was analyzed immunohistochemically by poly (ADP-ribose) (PAR) expression in response to DNA damage of the retina. All rats that received ≥ 400 mg/kg of ENU developed retinal degeneration characterized by the loss of photoreceptor cells in both the central and peripheral retina within 7 days. In the 400 mg/kg ENU-treated rats, TUNEL-positive signals were only located in the photoreceptor cells and peaked 24 hr after ENU treatment. The γ-H2AX signals in inner retinal cells appeared at 24 hr and peaked at 72 hr after ENU treatment, and the PAR signals selectively located in the photoreceptor cell nuclei appeared at 12 hr and peaked at 24 hr after ENU treatment. However, degeneration was restricted to photoreceptor cells, and no degenerative changes in inner retinal cells were seen at any time points. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after ENU treatment. In conclusion, ENU induced retinal degeneration in adult rats that was characterized by photoreceptor cell apoptosis through PARP activity.     

Two-week Toxicity of Multi-walled Carbon Nanotubes by Whole-body Inhalation Exposure in Rats

To evaluate pulmonary toxicity of multi-walled carbon nanotubes (MWCNTs), F344 rats of both sexes were exposed by inhalation to 0.2, 1 or 5 mg/m³ MWCNT aerosol for 6 h/day, 5 days/week for 2 weeks using a whole-body exposure system. At the end of the 2-week exposure period, one-half of the rats were necropsied, and at the end of an additional 4-week postexposure period, the remaining rats were necropsied. MWCNTs were deposited in the lungs of all MWCNT-exposed groups and mostly remained in the lungs throughout the 4-week postexposure period. Granulomatous changes in the lung were found in the rats exposed to 5 mg/m³ MWCNTs, and these changes were slightly aggravated at the end of the 4-week postexposure period. In the bronchoalveolar lavage fluid (BALF), the numbers of neutrophils, percentages of bi- and multinucleated alveolar macrophages, levels of ALP activity and concentrations of total protein and albumin were elevated in the rats exposed to 1 and 5 mg/m³ MWCNTs. At the end of the 4-week postexposure period, the values of the BALF parameters tended to remain elevated. In addition, goblet cell hyperplasias in the nasal cavity and nasopharynx were observed in the rats exposed to 1 and 5 mg/m³ MWCNTs, but these lesions had largely regressed by the end of the postexposure period. Based on the histopathological and inflammatory changes, the no-observed-adverse-effect level (NOAEL) for inhalation of MWCNTs for 2 weeks was 0.2 mg/m³.     

Concordance between Results of Medium-term Liver Carcinogenesis Bioassays and Long-term Findings for Carcinogenic 2-Nitropropane and Non-carcinogenic1-Nitropropane in F344 Rats

This study was conducted to determine the concordance of results for a pair of structural isomers, 2-nitropropane (2-NP) and 1-nitropropane (1-NP), using the rat medium-term liver carcinogenesis bioassay (Ito test) and previously published long-term carcinogenicity tests. Male F344 rats were given a single intraperitoneal injection of DEN (200 mg/kg b.w.) to initiate hepatocarcinogenesis. After 2 weeks, they received per os 0, 0.8, 4 or 20 mg/kg/day of 2-NP or 1-NP six times a week and were subjected to two-thirds partial hepatectomy at week 3. Non-initiated groups receiving 0 or 20 mg/kg/day were also included. The animals were sacrificed for quantitative analysis of GST-P-positive foci at week 8. With the highest dose of 2-NP, significantly increased numbers and areas of GST-P-positive foci were demonstrated as compared with the respective control but were not noted with 1-NP. In the non-DEN-initiated groups, many small GST-P-positive foci of less than 0.2 mm in diameter were also induced in the rats treated with 2-NP at 20 mg/kg/day but were lacking with 1-NP. These results strongly support that 2-NP is a complete hepatocarcinogen with a potent initiation activity, whereas 1-NP is not.     

蒙古族传统奶酪中8种脂溶性维生素和β-胡萝卜素高效液相色谱检测方法的建立

[目的] 建立同时测定蒙古族传统奶酪中VA、VD₂、VD₃、α-生育酚、β-生育酚、γ-生育酚、δ-生育酚、VK₁共8种脂溶性维生素及天然色素β-胡萝卜素含量的高效液相色谱方法（high performance liquid chromatography,HPLC）。[方法] 选取蒙古族传统奶酪为试样,经无水乙醇提取,酶解后用正己烷萃取,旋蒸浓缩,复溶过滤膜。经Agilent poroshell 120 EC-C18（150 mm×4.6 mm,4 μm）色谱柱分离,以甲醇和水（体积比为95∶5）为流动相,采用FLD和VWD检测器检测,外标法定量。[结果] VA、α-生育酚、β-生育酚、γ-生育酚、δ-生育酚、VK₁、β-胡萝卜素在0.1~1.0 μg/mL浓度范围内线性关系良好,VD₂、VD₃在0.05~1.00 μg/mL浓度范围内线性关系良好,相关系数R²均大于0.998。[结论] 建立的HPLC方法具有简便、快捷、灵敏度高、回收率高、分析时间短等优点,可为蒙古族传统乳制品中多种脂溶性维生素及天然色素的快速检测提供技术支撑。     

Plasma Peak and Trough Gentamicin Concentrations in Hospitalized Horses Receiving Intravenously Administered Gentamicin

Background

Gentamicin is an aminoglycoside antimicrobial commonly used in horses at 6.6 mg/kg IV once daily. Therapeutic drug monitoring (TDM) can confirm desired peak concentration is reached for common bacterial isolates, and detect toxicosis associated with high trough values.

Objectives

Determine the relationship between gentamicin dose and plasma concentration in hospitalized horses, and identify a starting dose range to achieve peaks > 32 μg/mL.

Animals

Sixty‐five horses (2002–2010) receiving once‐daily gentamicin with TDM performed (N = 99 sets).

Methods

Retrospective study. Data from hospitalized horses including weight, dose, plasma peak, and trough gentamicin concentration, creatinine concentrations and presence of focal or systemic disease were collected from medical records. Peak concentrations measured 25–35 minutes after administration were included (N = 77). Data were divided into low (<7.7 mg/kg), medium (7.7–9.7 mg/kg) and high (>9.7 mg/kg) dose groups, and were grouped by the horse having focal or systemic disease.

Results

Peak concentrations resulting from doses ≥7.7 mg/kg were 5.74 μg/mL (SE 2.1 μg/mL) greater than peaks from doses <7.7 mg/kg (P = .007). Peak concentrations was 3.6 times more likely to be >32 μg/mL if dose was ≥7.7 mg/kg (P = .04). There were no significant effects of dose on trough or creatinine concentration. At a given dose, horses with focal disease had higher peaks than those with systemic disease (P = .039).

Conclusions and Clinical Importance

These data suggest gentamicin dosage should be individually determined in horses using TDM, but support an initial once‐daily dose of 7.7–9.7 mg/kg IV to achieve peaks >32 μg/mL and trough concentrations <2 μg/mL. Further studies evaluating the safety of doses >6.6 mg/kg are required.     

Cytokine response in Balb/c mice infected with Francisella tularensis LVS and the Pohang isolate

We investigated the immune response induced by the Francisella (F.) tularensis live vaccine strain (LVS) and the Pohang isolate. After the Balb/c mice were infected intradermally (i.d) with 2 × 10⁴ cfu of F. tularensis LVS and Pohang, respectively, their blood and organs were collected at different times; 0, 3, 6, 24, 72, 96, 120 and 168 h after infection. Using these samples, RT-PCR and ELISA analysis were carried out for the comparative study of the cytokines, including TNF-α, INF-γ, IL-2, IL-4, IL-10 and IL-12. In the Pohang-infected mice at 120 h, the liver showed a 53 times higher level of TNF-α and a 42 times higher level of IFN-γ than the respective levels at the early time points after infection. The levels of TNF-α and IFN-γ induced by LVS were 5 times lower than those induced by the Pohang isolate. Also, the organs from the Pohang-infected mice showed higher levels of TNF-α, IFN-γ, IL-10 and IL-12 than the levels in the LVS-infected mice. The blood from the Pohang-infected mice at 120 h revealed about a 40 times increased level of IFN-γ, and IL-10 was also increased by 4 times at 96 h compared to an early infection time point, while IL-4 was not induced during the whole infection period. These results suggest that F. tularensis may induce a Th1-mediated immune response to in vivo infection and the Pohang isolate has a higher capacity than the LVS to induce an acute immune response in Blab/c mice.     

Dietary inclusion of multispecies probiotics to reduce the severity of post-weaning diarrhea caused by Escherichia coli F18+ in pigs

This study was aimed to determine the efficacy of multispecies probiotics in reducing the severity of post-weaning diarrhea caused by enterotoxigenic Escherichia coli (ETEC) F18⁺ on newly weaned pigs. Thirty-two pigs (16 barrows and 16 gilts, BW = 6.99 ± 0.33 kg) at 21 d of age were individually allotted in a randomized complete block design with 2 × 2 factorial arrangement of treatments. Pigs were selected from sows not infected previously and not vaccinated against ETEC. Pigs were fed experimental diets for 25 d based on 10 d phase 1 and 15 d phase 2. The factors were ETEC challenge (oral inoculation of saline solution or E. coli F18⁺ at 2 × 10⁹ CFU) and probiotics (none or multispecies probiotics 0.15% and 0.10% for phase 1 and 2, respectively). Body weight and feed intake were measured on d 5, 9, 13, 19, and 25. Fecal scores were measured daily. Blood samples were taken on d 19 and 24. On d 25, all pigs were euthanized to obtain samples of digesta, intestinal tissues, and spleen. The tumor necrosis factor alpha (TNFα), malondialdehyde (MDA), peptide YY (PYY), and neuropeptide Y (NPY) were measured in serum and intestinal tissue. Data were analyzed using the MIXED procedure of SAS. The fecal score of pigs was increased (P < 0.05) by ETEC challenge at the post–challenge period. The ETEC challenge decreased (P < 0.05) jejunal villus height and crypt depth, tended to increase (P = 0.056) jejunal TNFα, increased (P < 0.05) ileal crypt depth, and decreased (P < 0.05) serum NPY. The probiotics decreased (P < 0.05) serum TNFα, tended to reduce (P = 0.064) jejunal MDA, tended to increase (P = 0.092) serum PYY, and increased (P < 0.05) jejunal villus height, and especially villus height-to-crypt depth ratio in challenged pigs. Growth performance of pigs were not affected by ETEC challenge, whereas the probiotics increased (P < 0.05) ADG and ADFI and tended to increase (P = 0.069) G:F ratio. In conclusion, ETEC F18⁺ challenge caused diarrhea, intestinal inflammation and morphological damages without affecting the growth performance. The multispecies probiotics enhanced growth performance by reducing intestinal inflammation, oxidative stress, morphological damages.     

An Open‐label Phase 1 Dose‐escalation Clinical Trial of a Single Intravenous Administration of Gemcitabine in Dogs with Advanced Solid Tumors

Background

A broad range of gemcitabine dosages have been used in dogs.

Hypothesis/Objectives

To determine maximally tolerated dose (MTD), dose‐limiting toxicity (DLT), and preliminary antitumor activity of intravenous administration of gemcitabine in dogs with advanced solid tumors.

Animals

Twenty‐two client‐owned dogs.

Methods

Dogs with advanced cancer were prospectively enrolled in an open‐label Phase 1 study of gemcitabine. Gemcitabine was administered as a 30‐minute intravenous bolus starting at 800 mg/m², using escalation of 50 mg/m² increments with 3 dogs per dose level. MTD was established based on the number of dogs experiencing DLT assessed after 1 cycle. Treatment continued until disease progression or unacceptable toxicosis. Additional dogs were enrolled at MTD to better characterize tolerability, and to assess the extent and duration of gemcitabine excretion.

Results

Twenty‐two dogs were treated at 4 dose levels, ranging from 800 to 950 mg/m². Neutropenia was identified as DLT. MTD was 900 mg/m². DLT consisting of grade 4 febrile neutropenia was observed at 950 mg/m² in 2 dogs. There were no nonhematologic DLTs. Twenty dogs received multiple doses, and none had evidence of severe toxicosis from any of their subsequent treatments. At 900 mg/m², 2 complete and 5 partial responses were observed in dogs with measurable tumors. The amount of gemcitabine excreted in urine decreased over time, and was undetectable after the first 24 hours.

Conclusions and Clinical Importance

The recommended dose of gemcitabine for future Phase 2 studies is weekly 900 mg/m². In chemotherapy‐naïve dogs with advanced solid tumor this dose level merits further evaluation.     

Effects of increased ambient temperature and supplemental altrenogest before pregnancy establishment in gilts

Heat stress (HS) mitigation strategies are critically needed to combat the substantial economic effects on animal agriculture. The manifestations of seasonal infertility include delayed puberty onset, reduced conception rates, decreased litter size, and increased wean to estrus interval. To assess the effects of HS during early gestation and evaluate the benefit of supplemental altrenogest (ALT) as a mitigation strategy, 30 crossbred postpubertal gilts (157 ± 11 kg body weight) were subjected to estrous synchronization via 14 d oral administration of ALT. Artificial insemination during estrus was performed, and gilts were then placed into one of four treatment groups: HS (35 ± 1 °C for 12 h/31.60 ± 1 °C for 12 h) with (HSALT, n = 7) or without (HSCON, n = 7) 15 mg/d ALT supplementation or thermal neutral (TN; 20 ± 1 °C) conditions with (TNALT, n = 8) or without (TNCON, n = 8) 15 mg/d ALT supplementation until 12 d post-estrus (dpe). Administrating ALT occurred at 0600 hours from 3 to 12 dpe, and rectal temperatures (T_R) and respiration rates (RR) were recorded. Blood was collected via jugular venipuncture on 0, 4, 8, and 12 dpe. Gilts were euthanized humanely at 12 dpe followed by the collection of ovarian tissue, and uterine flushing for conceptus collection. In HS compared with TN gilts, RR and T_R were increased (P < 0.01) but unaffected by ALT supplementation. Feed intake was reduced (P < 0.01) by HS but unaltered by the ALT treatment. Corpora lutea (CL) weight was reduced (P < 0.01) in HSCON gilts when compared with TNCON and HSALT gilts despite progesterone concentrations in serum and luteal tissue not being affected by treatment (P ≥ 0.10). CL diameter was reduced (P ≤ 0.05) in HSALT gilts compared with other treatments. Interleukin-1β (IL1B) uterine flush concentration was not affected (P > 0.20) by environment or ALT supplementation, although moderate (P = 0.06) interaction between environment and ALT existed, as IL1B concentration in TNALT was increased (P = 0.03) compared with TNCON gilts. While environment did not affect conceptus development (P = 0.90), ALT supplementation advanced conceptus elongation (P < 0.01). Collectively, these data demonstrate that HS may affect luteal development before pregnancy establishment, and ALT increases conceptus elongation by 12 dpe.     

Experimental infection with Mycobacterium avium, serotype 2, in pigs. 1. Intravenous inoculations

A porcine strain of Mycobacterium avium, Serotype 2, was used for intravenous inoculation of pigs in doses 5, 1, 10⁻¹, 10⁻² and 10⁻³ mg (1 mg = 78 × 10⁶ viable units), 2 pigs per dose.Dose 5 mg proved fatal for both of the inoculated pigs, which were killed in extremis 64 and 69 days, respectively, after inoculation. Dose 1 mg caused clinical disease in 1 of 2 pigs, but was not lethal. Post mortem, the clinically affected pigs showed a generalized granulomatous tuberculosis. The other pig given 1 mg and the pigs given smaller doses, showed no clinical signs, and lesions and presence of acid-fasts were mostly limited to the lymph nodes of the lung, liver and digestive tract.All the pigs showed delayed hypersensitivity to avian PPD tuberculin (1000 t.u.) and some of them cross-reacted with human PPD tuberculin (1000 t.u.). The clinically affected pigs gave a very weak response to tuberculin, the others a strong response.The smallest dose capable of establishing an infection and producing tuberculous lesions was not determined, but seems to be less than 10⁻³ mg (78000 viable organisms).     

Effects of filtration,vacuum cleaning and washing in pighouses on aerosol levels and pig performance

Three techniques to reduce the exposure of humans and pigs to aerosols in pig houses have been investigated; filtration and recirculation of air in weaner rooms (FR), weekly vacuum cleaning in a finishing house (VC) and weekly washing with water of weaned piglets (WA). All experiments have been carried out in rooms for 70 (FR), 96 (VC) or 72 (WA) animals. For FR seven replications, for VC two replications and for WA six replications have been carried out.Average reduction in gravimetrical dried aerosol concentrations was 40% (1.58 vs. 2.65 mg/m³) for FR (P<0.0001), but did not result in significant changes in daily feed intake nor daily gain of piglets during the weaning stage. Incidence of respiratory health disorders was very low in both groups.Average reduction in aerosol concentrations was 6% (2.34 vs. 2.50 mg/m³) for VC (P>0.05). Reductions improved from −2% on the day following vacuum cleaning to over 10% from 4 days after vacuum cleaning onwards. No significant differences in feed intake or daily gain of pigs were observed. Pigs in rooms without vacuum cleaning received more veterinary treatments for respiratory health disorders, resulting in less pigs with lung lesions.Average reduction in aerosol concentrations was 10% (4.17 vs. 4.66 mg/m³) for WA (P<0.05) compared to the reference level. For weekly washing of piglets the reduction in aerosol concentration was highest (25%) on the day of washing. No significant improvements in production of pigs have been found.Costs of reducing aerosol concentrations in pighouses are not compensated by improved production of pigs.     

Hypercoagulability in Dogs with Blastomycosis

Background

Blastomycosis is a potentially fatal fungal disease that most commonly affects humans and dogs. The organism causes systemic inflammation and has a predilection for the lungs. The inflammation might lead to a hypercoagulable state with microemboli in the pulmonary circulation which could contribute to inadequate oxygen exchange in infected dogs.

Hypothesis/Objectives

Dogs with blastomycosis will be hypercoagulable compared with healthy case‐matched controls.

Animals

Client‐owned dogs with a diagnosis of blastomycosis (n = 23) and healthy case‐matched controls (n = 23).

Methods

Prospective case‐controlled study of client‐owned dogs presented to a veterinary teaching hospital with clinical signs compatible with blastomycosis. Complete blood counts, fibrinogen, PT, aPTT, thromboelastometry (TE), thrombin antithrombin complexes (TAT), and thrombin generation were evaluated.

Results

Cases had a leukocytosis compared with controls [mean (SD) 16.6 (7.6) × 10³/μL versus 8.2 (1.8) × 10³/μL, P < .001], hyperfibrinogenemia [median 784 mg/dL, range 329–1,443 versus median 178 mg/dL, range 82–257, P < .001], and increased TAT concentrations [mean (SD) 9.0 (5.7) μg/L versus 2.0 (2.8) μg/L, P < .001]. As compared to controls, cases were also hypercoagulable as evaluated by thromboelastometry and had increased in vitro thrombin generation on calibrated automated thrombography.

Conclusions and Clinical Importance

Hypercoagulability occurs in dogs with systemic blastomycosis. Additional studies are needed to explore a possible contribution of thrombogenicity to the clinical manifestations of systemic blastomycosis.     

Behavioral response and cost comparison of manual versus pharmacologic restraint protocols in healthy dogs

Although sedatives are routinely administered to dogs for diagnostic and minimally invasive procedures, manual restraint is often used. The study compared intra-procedural behavioral response, scored on a 100-point, visual analog scale, and cost of restraint in healthy dogs given 1 of 5 treatments: manual restraint, dexmedetomidine at 125 μg/m² (Dex 125) or 375 μg/m² (Dex 375), Dex 125 plus butorphanol at 0.4 mg/kg (Dex 125 + Bu), or Dex 375 plus butorphanol at 0.4 mg/kg (Dex 375 + Bu). Mean behavioral response scores in dogs declined from baseline in the manual restraint group and improved in a linear fashion in the group order Dex 125, Dex 375, Dex 125 + Bu, and Dex 375 + Bu. Dexmedetomidine at 375 μg/m² or at 125 μg/m² or at 375 μg/m² in combination with butorphanol produced the best intra-procedural behavioral response. The cost of sedative drugs was offset by the opportunity cost of diverting personnel from revenue-generating activity to manual restraint.     

Disposition kinetics and urinary excretion of ciprofloxacin in goats following single intravenous administration

We evaluated the pharmacokinetics of ciprofloxacin in serum (n = 6) and urine (n = 4) in goats following a single intravenous administration of 4 mg/kg body weight. The serum concentration-time curves of ciprofloxacin were best fitted by a two-compartment open model. The drug was detected in goat serum up to 12 h. The elimination rate constant (β) and elimination half-life (t_1/2β) were 0.446 ± 0.04 h^-1 and 1.630 ± 0.17 h, respectively. The apparent volume of distribution at steady state (Vd_ss) was 2.012 ± 0.37 l/kg and the total body clearance (Cl_B) was 16.27 ± 1.87 ml/min/kg. Urinary recovery of ciprofloxacin was 29.70% ± 10.34% of the administered dose within 36 h post administration. In vitro serum protein binding was 41% ± 13.10%. Thus, a single daily intravenous dose of 4 mg/kg is sufficient to maintain effective levels in serum and for 36 h in urine, allowing treatment of systemic, Gram-negative bacterial infections and urinary tract infections by most pathogens.     

Effects of dietary sodium butyrate on growth,digestive enzymes,body composition and nutrient retention-related gene expression of juvenile yellow catfish (Pelteobagrus fulvidraco)

An 8-week feeding trial was conducted to evaluate the effects of sodium butyrate (SB) on growth, digestive enzymes, body composition and nutrient retention-related gene expression of juvenile yellow catfish (Pelteobagrus fulvidraco). Five isonitrogenous and isolipidic diets (420 g/kg protein and 90 g/kg lipid) were formulated to contain 0 (control), 250, 500, 1,000 or 2,000 mg/kg SB. Triplicate groups of 40 fish (BW = 1.26 ± 0.01 g) per tank (300-L cylindrical fiberglass tanks) for each diet were fed to apparent satiation twice daily. Stomach, hepatopancreas and intestine samples were obtained for digestive enzymes activities analyses. A real-time quantitative PCR analysis was performed to determine the relative expression of target of rapamycin (TOR) and lipoprotein lipase (LPL) in the hepatopancreas and intestine. Fish fed the diets supplemented with SB at 500 and 1,000 mg/kg showed significantly higher specific growth rate and significantly lower feed conversion ratio compared to the control (P < 0.05). Dietary SB inclusion did not alter activities of intestinal amylase, creatine kinase and sodium–potassium adenosine triphosphatase (Na⁺/K⁺-ATPase), but increased activities of hepatic trypsin, stomachic lipase, intestinal lipase, alkaline phosphatase and γ-glutamyl transpeptidase for fish fed 1,000 mg/kg SB compared to the control (P < 0.05). Intestine length index, intestine somatic index, fold height and muscular thickness of distal intestine were significantly higher in 1,000 mg/kg SB groups compared to the control (P < 0.05). Significantly higher levels of whole-body crude protein, ash, calcium, phosphorus, nutrition retention and relative mRNA of intestinal TOR were observed in 1,000 mg/kg SB group (P < 0.05). Whole-body lipid content and hepatopancreas LPL mRNA expression in 2,000 mg/kg SB group were significantly higher than the control (P < 0.05). Relative mRNA levels of intestinal LPL and hepatopancreas TOR were significantly higher in the 500 mg/kg SB group compared to those in other groups (P < 0.05). The increased growth performance, digestive enzymes and nutrient retention in fish fed the diets supplemented with SB at 500 and 1,000 mg/kg suggests that SB can be a desirable growth promoter as an antibiotic alternative in diets.     

Dietary nano-selenium alleviated intestinal damage of juvenile grass carp(Ctenopharyngodon idella)induced by high-fat diet:Insight from intestinal morphology,tight junction,inflammation,anti-oxidization and intestinal microbiota

In recent years,high-fat diet(HFD)has been widely applied in aquaculture,which reduces the intestinal health of cultured fish.The current study evaluated the protective effects of nano-selenium(nano-Se)on intestinal health of juvenile grass carp(Ctenopharyngodon idella)fed with HFD.A total of 135 experimental fish were fed with a regular diet(Con),a HFD(HFD)and a HFD containing nano-Se at 0.6 mg/kg(HSe)for 10 weeks.The results showed that dietary nano-Se significantly improved the survival rate and feed efficiency which were reduced by HFD in juvenile grass carp(P<0.05).Also,nano-Se(0.6 mg/kg)supplement alleviated intestinal damage caused by the HFD,thus maintaining the integrity of the intestine.Moreover,it significantly up-regulated the expression of genes related to tight junction(ZO-1,claudin-3 and occludin),anti-oxidization(GPx4a and GPx4b),and the protein of ZO-1 in the intestine of juvenile grass carp,which were depressed by the HFD(P<0.05).Furthermore,nano-Se supplementation significantly suppressed the expressions of genes related to the inflammation,including inflammatory cytokines(IL-8,IL-1β,IFN-γ,TNF-αand IL-6),signaling molecules(TLR4,p38 MAPK and NF-kB p65),and protein expression of NF-kB p65 and TNF-αin the intestine of juvenile grass carp which were induced by the HFD(P<0.05).Besides,dietary nano-Se normalized the intestinal microbiota imbalance of juvenile grass carp caused by the HFD through increasing the abundance of the beneficial bacteria,e.g.,Fusobacteria.Finally,dietary nano-Se increased the production of short chain fatty acids(SCFA)in the intestine,especially for butyric acid and caproic acid,which were negatively related to the increase of intestinal permeability and inflammation.In summary,supply of nano-Se(0.6 mg/kg)in HFD could effectively alleviate intestinal injury of juvenile grass carp by improving intestinal barrier function and reducing intestinal inflammation and oxidative stress.These positive effects may be due to the regulation of nano-Se on intestinal microbiota and the subsequently increased beneficial SCFA levels.     

Prolonged expression of senescence markers in mice exposed to gamma-irradiation

Although ionizing radiation is known to induce cellular senescence in vitro and in vivo, its long-term in vivo effects are not well defined. In this study, we examined the prolonged expression of senescence markers in mice irradiated with single or fractionated doses. C57BL/6 female mice were exposed to 5 Gy of γ-rays in single or 5, 10, 25 fractions. At 2, 4, and 6 months after irradiation, senescence markers including mitochondrial DNA (mtDNA) common deletion, p21, and senescence-associated β-galactosidase (SA β-gal) were monitored in the lung, liver, and kidney. Increases of mtDNA deletion were detected in the lung, liver, and kidney of irradiated groups. p21 expression and SA β-gal staining were also increased in the irradiated groups compared to the non-irradiated control group. Increases of senescence markers persisted up to 6 months after irradiation. Additionally, the extent of mtDNA deletion and the numbers of SA β-gal positive cells were greater as the number of radiation fractions increased. In conclusion, our results showed that ionizing radiation, especially that delivered in fractions, can cause the persistent upregulation of senescence marker expression in vivo. This should be considered when dealing with chronic normal tissue injuries caused by radiation therapy or radiation accidents.     

Alpha basic crystallin expression in canine mammary tumors

The aim of this study was to evaluate prognostic and/or diagnostic factors of canine mammary tumors by immunohistochemically analyzing the expression of alpha basic crystallin (αB-c). For this, formalin-fixed, paraffin-embedded blocks of 51 naturally-occurring canine mammary tumors (11 benign and 40 malignant) were used. Tissue from eight normal canine mammary glands were served as a control. Immunohistochemically, in the control mammary tissues, a few luminal epithelial cells were αB-c positive but myoepithelial cells were negative. In benign or simple type malignant tumors, αB-c expression was observed in luminal epithelial cells while the myoepithelial basal cells were negative. In benign or complex type malign tumors, positive staining was predominantly found in the cytoplasm of epithelial cells. Immunoreactivity of αB-c was also observed in neoplastic myoepithelial cells. Statistically, the number of cells immunolabeled with αB-c was found to be significantly different among tissues from normal canine mammary glands, benign lesions, and malignant tumors (p < 0.05). αB-c immunoreactivity was higher in malignant tumors than the control mammary tissues (p < 0.001). Data obtained in the current study revealed a strong association between high expression levels of αB-c and primary mammary gland tumors in canines.     

Impact of combined α-galactosidase and xylanase enzymes on growth performance,nutrients digestibility,chyme viscosity,and enzymes activity of broilers fed corn–soybean diets

Two experiments were conducted to investigate the effects of a combined α-galactosidase and xylanase preparation on nutrients digestibility and growth performance in broiler chickens. Experiment 1 had 240 broilers allocated to 3 treatments with the dietary supplementation of 0, 300, and 500 g/t of the enzyme combination. Diet and amino acid (AA) digestibility were assessed. Experiment 2 was a 2 × 3 (enzyme × diet) factorial arrangement with 10 replicates of 12 male broilers per replicate. Diets were based on corn–soybean meal (SBM) diet and had 3 nutritional levels (normal, 2% apparent metabolizable energy (AME) and crude protein (CP) reduction, and 4% AME and CP reduction). Each of these diets was fed with or without enzyme supplementation. Growth performance, chyme viscosity, nutrients digestibility, and endogenous enzymes activity were assessed. In experiment 1, enzyme supplementation improved the digestibility of Ca (P = 0.025) and ileal digestibility of total AA, Pro, Alu, Ile, Lys, His, Thr, Glu, Val, Leu, Tyr, and Phe (P < 0.05), and also tended to increase the AME of diets (P < 0.10). In experiment 2, broilers fed the corn–SBM diet with 4% nutrient reduction had better growth performance (P < 0.05), jejunal digesta viscosity at 42 d (P < 0.01), and lower digestibility of gross energy (GE; P < 0.05) when compared with those fed the normal nutrient diet. Enzyme inclusion increased digestibility of CP (P = 0.044), GE (P = 0.009), raffinose (P < 0.001) and stachyose (P < 0.001), improved average daily gain (P = 0.031), and reduced jejunal digesta viscosity at 42 d (P = 0.011). Besides, similar improvements trend in amylase, trypsin, sucrase, and maltase activity with enzyme inclusion were observed as with energy. These data support that the enzyme supplementation increased nutrients and ileal AA digestibility, improved performance and endogenous enzymes activity.