Single‐ and multiple dose pharmacokinetics and multiple dose pharmacodynamics of oral ABT‐116 (a TRPV1 antagonist) in dogs

Six dogs were used to determine single and multiple oral dose pharmacokinetics of ABT‐116. Blood was collected for subsequent analysis prior to and at 15, 30 min and 1, 2, 4, 6, 12, 18, and 24 h after administration of a single 30 mg/kg dose of ABT‐116. Results showed a half‐life of 6.9 h, k_el of 0.1/h, AUC of 56.5 μg·h/mL, T_max of 3.7 h, and C_max of 3.8 μg/mL. Based on data from this initial phase, a dose of 10 mg/kg of ABT‐116 (no placebo control) was selected and administered to the same six dogs once daily for five consecutive days. Behavioral observations, heart rate, respiratory rate, temperature, thermal and mechanical (proximal and distal limb) nociceptive thresholds, and blood collection were performed prior to and 4, 8, and 16 h after drug administration each day. The majority of plasma concentrations were above the efficacious concentration (0.23 μg/mL previously determined for rodents) for analgesia during the 24‐h sampling period. Thermal and distal limb mechanical thresholds were increased at 4 and 8 h, and at 4, 8, and 16 h respectively, postdosing. Body temperature increased on the first day of dosing. Results suggest adequate exposure and antinociceptive effects of 10 mg/kg ABT‐116 following oral delivery in dogs.     

B‐Mode and Doppler Sonography of the Mammary Glands in Dairy Goats for Mastitis Diagnosis

This study aimed to evaluate the sonographic characteristics of the udder and teats and to determine the Doppler indexes of mammary artery in healthy and undergoing subclinical and clinical mastitis goats. Thirty animals among Saanen and Alpine Brown goats were arranged in three groups, healthy goats (HG), goats with subclinical mastitis (SMG) and goats with clinical mastitis (CMG). Using the B‐mode, the sonographic characteristics (echotexture and echogenicity) and biometry (diameter and area of the udder cistern, diameter and area of the teat cistern and thickness of the teat wall) were evaluated. Using Doppler ultrasonography, the vascular indexes of the mammary artery were obtained. It was observed hyperechogenicity with solid component in the gland cistern when comparing animals with clinical mastitis and healthy mammary tissue. Regarding the echotexture of the breast tissue, there was heterogeneity in the mammary parenchyma on the three groups, for the milk, it was observed homogeneity for animals on HG and SMG and heterogeneity for animals on CMG. Grey‐scale quantitative assessment revealed increase in echogenicity (mean value) for all the structures when comparing the three groups. Biometry did not reveal statistical difference between groups, for none of the evaluated structures. Doppler examination of the mammary artery showed the decrease of end diastolic velocity and raise of pulsatility index between groups. The association of B‐mode and Doppler ultrasonography is useful for the evaluation of the udder of dairy goats with mastitis. It is a sensitive and specific method for the study of this disease. Doppler mode was unable to establish reliable criteria for diagnosis of subclinical mastitis. Moreover, the quantification of echogenicity is a useful technique for the evaluation of the milk in animals with mastitis; therefore, it is suggested that it can be used as complementary technique for the diagnosis of mastitis in goats.     

Genetic association between different criteria to define sexual precocious heifers with growth,carcass, reproductive and feed efficiency indicator traits in Nellore cattle using genomic information

The aim of this study was to estimate genetic parameters for different precocious calving criteria and their relationship with reproductive, growth, carcass and feed efficiency in Nellore cattle using the single‐step genomic BLUP. The reproductive traits used were probability of precocious calving (PPC) at 24 (PPC24), 26 (PPC26), 28 (PPC28) and 30 (PPC30) months of age, stayability (STAY) and scrotal circumference at 455 days of age (SC455). Growth traits such as weights at 240 (W240) and 455 (W455) days of age and adult weight (AW) were used. Rib eye area (REA), subcutaneous fat thickness (SFT), rump fat thickness (RFT) and residual feed intake (RFI) were included in the analyses. The estimation of genetic parameters was performed using a bi‐trait threshold model including genomic information in a single‐step approach. Heritability for PPC traits was moderate to high (0.29–0.56) with highest estimates for PPC24 (0.56) and PPC26 (0.50). Genetic correlation estimates between PPC and STAY weakened as a function of calving age. Correlation with SC455, growth and carcass traits were low (0.25–0.31; ?0.22 to 0.04; ?0.09 to 0.18, respectively), the same occurs with RFI (?0.09 to 0.08), this suggests independence between female sexual precocity and feed efficiency traits. The results of this study encourage the use of PPC traits in Nellore cattle because the selection for such trait would not have a negative impact on reproductive, growth, carcass and feed efficiency indicator traits. Stayability for sexual precocious heifers (PPC24 and PPC26) must be redefined to avoid incorrectly phenotype assignment.     

Low‐density lipoproteins and milk serum proteins improve the quality of stallion sperm after vitrification in straws

Lipids and proteins can be used for sperm vitrification to preserve the integrity of sperm membranes or to increase the viscosity of the medium. This study evaluated the effect of low‐density lipoproteins (LDL) and milk serum proteins (Pronexcell) for stallion sperm vitrification. Hippex extender (Barex Biochemical Products, The Netherlands), plus 1% of bovine serum albumin and 100 mM of trehalose, was used as control for sperm vitrification. In experiment 1, different concentrations of LDL (L1 = 0.25, L2 = 0.5, L3 = 1%) and in experiment 2 of Pronexcell (P1 = 1, P2 = 5, P3 = 10%) were added to control extender. Vitrification was performed in 0.25‐ml straws directly plunged into liquid nitrogen. Total motility (TM, %) and progressive motility (PM, %) were analysed by CASA, and plasma membrane (IMS, %) and acrosome membrane integrity (AIS, %) were assessed under epifluorescence microscopy. Post‐warmed sperm parameters were compared between treatments by ANOVA. Results were expressed as mean ± SEM. In both experiments, the minimum concentration of LDL and Pronexcell obtained significantly higher values (p < 0.01) than the control extender for TM (L1 = 52.95 ± 4.4; P1 = 58.99 ± 4.6; C = 30.88 ± 3.0), PM (L1 = 36.79 ± 5.5; P1 = 47.25 ± 4.3; C = 19.20 ± 2.4), IMS (L1 = 68.88 ± 3.6; P1 = 47.25 ± 4.3; C = 52.81 ± 2.6) and AIS (L1 = 45.88 ± 3.6; P1 = 47.25 ± 4.3; C = 26.00 ± 2.1). No differences in sperm parameters were found among different concentrations of LDL or Pronexcell. In conclusion, the addition of 0.25% LDL and 1% Pronexcell to the vitrification extender is recommended to improve the quality of stallion sperm after vitrification.     

Microarray-based detection of viruses causing vesicular or vesicular-like lesions in livestock animals

Definitive diagnosis of vesicular or vesicular-like lesions in livestock animals presents challenges both for veterinary clinicians and diagnostic laboratories. It is often impossible to diagnose the causative disease agent on a clinical basis alone and difficult to collect ample vesicular epithelium samples. Due to restrictions of time and sample size, once laboratory tests have ruled out foot-and-mouth disease, vesicular stomatitis and swine vesicular disease a definitive diagnosis may remain elusive. With the ability to test a small quantity of sample for a large number of pathogens simultaneously, DNA microarrays represent a potential solution to this problem. This study describes the application of a long oligonucleotide microarray assay to the identification of viruses known to cause vesicular or vesicular-like lesions in livestock animals. Eighteen virus isolates from cell culture were successfully identified to genus level, including representatives of each foot-and-mouth disease virus serotype, two species of vesicular stomatitis virus (VSV), swine vesicular disease virus, vesicular exanthema of swine virus (VESV), bovine herpesvirus 1, orf virus, pseudocowpox virus, bluetongue virus serotype 1 and bovine viral diarrhoea virus 1. VSV and VESV were also identified in vesicular epithelium samples, with varying levels of sensitivity. The results indicate that with further development this microarray assay could be a valuable tool for the diagnosis of vesicular and vesicular-like diseases.     

Genetic immunization with the immunodominant antigen P48 of Mycoplasma agalactiae stimulates a mixed adaptive immune response in BALBc mice

A DNA vaccine against contagious agalactia was developed for the first time, encoding the P48 of Mycoplasma agalactiae. Specific immune responses elicited in BALB/c mice were evaluated. Both total IgG and IgG1 were detected in mice vaccinated with pVAX1/P48. Proliferation of mononuclear cells of the spleen, levels of gamma interferon, interleukin-12, and interleukin-2 mRNAs were enhanced in immunized animals. Results indicate that pVAX1/P48 vaccination induced both T_h1 and T_h2 immune responses. Nucleic acid immunization could be a new strategy against M. agalactiae infections and may be potentially used to develop vaccines for other Mycoplasma diseases.     

Effects of the opioid remifentanil on the arrhythmogenicity of epinephrine in halothane-anesthetized dogs

Opioids may exert a protective effect against ventricular arrhythmias via a vagally mediated mechanism. This study evaluated the effects of the opioid remifentanil on arrhythmogenicity of epinephrine during halothane anesthesia. Eight dogs were assigned to 2 treatments in a randomized crossover design, with 1-week intervals between treatments. Anesthesia was maintained with 1.3% end-tidal halothane in oxygen and mechanical ventilation to maintain eucapnia. A constant rate infusion of remifentanil (0.72 microg/kg/min) was administered throughout the study in the experimental treatment, while control animals received physiologic saline as placebo. The arrhythmogenic dose of epinephrine (ADE), defined as 4 premature ventricular complexes (PVCs) within 15 s, was determined by administering progressively increasing infusion rates of epinephrine (2.5, 5.0, and 10 microg/kg/min), allowing 20 min intervals between each infusion rate. In both treatments, epinephrine infusions induced bradyarrhythmias and atrioventricular conduction disturbances, which were followed by escape beats and PVCs. In the remifentanil treatment, mean +/- s ADE values (11.3 +/- 4.9 microg/kg) did not differ from values observed in control animals (9.9 +/- 6.1 microg/kg). On the basis of the ADE model for assessing the arrhythmogenity of drugs during halothane anesthesia, the present study did not demonstrate a protective effect of remifentanil (0.72 microg/kg/min) against ventricular arrhythmias in dogs.     

Effects of epidurally administered morphine or buprenorphine on the thermal threshold in cats

Objective: To determine the antinociceptive effects of epidural administration of morphine or buprenorphine in cats by use of a thermal threshold model. ANIMALS: 6 healthy adult cats. PROCEDURES: Baseline thermal threshold was determined in duplicate. Cats were anesthetized with isoflurane in oxygen. Morphine (100 microg/kg diluted with saline [0.9% NaCl] solution to a total volume of 0.3 mL/kg), buprenorphine (12.5 microg/kg diluted with saline solution to a total volume of 0.3 mL/kg), or saline solution (0.3 mL/kg) was administered into the epidural space according to a Latin square design. Thermal threshold was determined at various times up to 24 hours after epidural injection. RESULTS: Epidural administration of saline solution did not affect thermal threshold. Thermal threshold was significantly higher after epidural administration of morphine and buprenorphine, compared with the effect of saline solution, from 1 to 16 hours and 1 to 10 hours, respectively. Maximum (cutout) temperature was reached without the cat reacting in 0, 74, and 11 occasions in the saline solution, morphine, and buprenorphine groups, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of morphine and buprenorphine induced thermal antinociception in cats. At the doses used in this study, the effect of morphine lasted longer and was more intense than that of buprenorphine.     

Salmonella enterica serovar Choleraesuis derivatives harbouring deletions in rpoS and phoP regulatory genes are attenuated in pigs, and survive and multiply in porcine intestinal macrophages and fibroblasts, respectively

Live attenuated Salmonella enterica strains have been extensively studied as potential vectors for the oral delivery of heterologous antigens. Due to its ability to target immune cells, its specific mechanism for crossing the intestinal barrier, and its swine-restricted tropism, S. enterica subspecies enterica serovar Choleraesuis (S. Choleraesuis) has attracted a great deal of interest for the production of bacterial-based oral carriers specifically adapted to swine. In this study, two mutants of S. Choleraesuis were constructed and their attenuation and intracellular fate analysed with the purpose of engineering new attenuated live strains with improved properties as oral vaccine carriers. Those strains harboured a specific deletion either within the phoP or rpoS genes, which encode virulence-related regulators in S. Typhimurium. In comparison to the wild-type parental S. Choleraesuis, the mutant strains, especially DeltaphoP, were extremely low in virulence in the murine model and in the natural host, the pig. Moreover, when compared with a commercial live vaccine strain, SC-54, the two mutants showed a higher level of attenuation in mice and DeltaphoP also in pigs. In addition, DeltarpoS and DeltaphoP presented a proliferation and survival phenotype within swine intestinal primary fibroblast and macrophage cell cultures, respectively. Collectively, the present results indicate that the DeltarpoS and DeltaphoP strains of S. Choleraesuis gather adequate features to be potential candidates for vaccine vectors for the specific delivery of heterologous antigens adapted to pigs.