Short-term and long-term PQ, QT and R-R intervals' variability at the resting condition and after exercise testing in healthy Anglo-Arabian horses

The duration of electrocardiographic (ECG) parameters: PQ, QT and R-R intervals change during long-term and short-term observation as the consequence of the fluctuations in autonomic nervous system activity among others dependent on the exercise and resting. There is no data of horse breed influence on these parameters. The aim of the study was to assess the duration and the variability of the PQ, QT and R-R intervals in the resting conditions and after exercise testing in Anglo-Arabian horses. Material and Methods: 27 healthy Anglo-Arabian horses aged 3.4 +/- 1.0 years (15 male, 12 female) had ECG examination in the standing position using Einthoven system of leads. The longest and the shortest PQ, QT and R-R intervals were measured after night rest and after exercise testing and the means were calculated. Conclusions: 1) In Anglo-Arabian horses the difference between the longest and the shortest PQ interval at rest vs. after exercise is 0.06 +/- 0.05 vs. 0.03 +/- 0.02, QT interval is 0.04 +/- 0.03 vs. 0.04 +/- 0.04, R-R interval 0.19 +/- 0.15 vs. 0.08 +/- 0.11. 2) The PQ and R-R intervals reveal high short-term variability either at the resting conditions or after exercise testing. 3) After exercise testing PQ, QT and R-R intervals are shorter than at the resting conditions. The delta PQ and R-R are 2 times smaller in contrast to delta QT which is constant. 4) The PQ and R-R interval variability was greater at the baseline condition than after exercise testing. The QT variability was similar at baseline condition to that after exercise testing.     

Contributions to an animal trait ontology

Improved understanding of the biology of traits of livestock species necessitates the use and combination of information that is stored in a variety of different sources such as databases and literature. The ability to effectively combine information from different sources, however, depends on a high level of standardization within and between various resources, at least with respect to the used terminology. Ontologies represent a set of concepts that facilitate standardization of terminology within specific domains of interest. The biological mechanisms underlying quantitative traits of farm animal species related to reproduction and host pathogen interactions are complex and not well understood. This knowledge could be improved through the availability of domain-specific ontologies that provide enhanced possibilities for data annotation, data retrieval, data integration, data exchange, data analysis, and ontology-based searches. Here we describe a framework for domain-specific ontologies and the development of 2 first-generation ontologies: Reproductive Trait and Phenotype Ontology (REPO) and Host Pathogen Interactions Ontology . In these first-generation ontologies, we focused on "female fertility in cattle" and "interactions between pigs and Salmonella". Through this, we contribute to the global initiative toward the development of an Animal Trait Ontology for livestock species. To demonstrate its usefulness, we show how REPO can be used to select candidate genes for fertility.     

Messenger ribonucleic acid expression of the MyoD gene family in muscle tissue at slaughter in relation to selection for porcine growth rate

Livestock meat production capacity is related to muscle fiber numbers and growth. Muscle fibers develop during early embryonic development from proliferating and differentiating myoblasts. Post-natal muscle growth requires satellite cell proliferation and differentiation. Myoblast and satellite cell proliferation and differentiation is regulated by the genes of the MyoD gene family (myogenin, myf-5, myf-6, and MyoD1). Our aim was to study the mRNA expression of these genes in postnatal muscle tissue in relation to porcine selection for growth rate or leanness. Five boars from a line selected for fast growth (F-line) and five boars from a line selected against backfat thickness (L-line) were slaughtered, and biopsies were taken from 12 muscles. Between-line effects, within-line effects in relation to the performance of the pigs, and muscle-specific effects were studied. Comparing the F-line with the L-line revealed significantly greater myogenin, myf-5, and MyoD1 mRNA expression in some muscles of the F-line. The expression of myf-6 showed a tendency for the opposite effect in some muscles. Muscles were ordered by their muscle-specific growth rate (b-value). Within-line evaluation of the data revealed a systematic muscle effect for the myf-6 expression level in the F-line because higher b-values correlated with increased myf-6 expression level. Backfat thickness was negatively related to myogenin expression in the F-line. A relationship was found between myogenin:MyoD1 mRNA expression ratio and meat color/muscle fiber type composition in the L-line. Furthermore, the myogenin:MyoD1 ratio was greater in muscles from F-line boars than in muscles from L-line boars, which relates to the difference between the lines in muscle fiber type. We conclude that the mRNA levels of the MyoD genes in porcine muscle tissue at slaughter showed different relationships to selection for growth rate when evaluated between selection lines and within selection lines.     

Rate of bentazone transformation in four layers of a humic sandy soil profile with fluctuating water table

The rate of transformation of a pesticide as a function of the depth in the soil is needed as an input into computations on the risk of residues leaching to groundwater. The herbicide bentazone was incubated at 15 °C in soil materials derived from four layers at depths of up to 2.5 m in a humic sandy soil profile with a fluctuating water table (0.8 to 1.4 m), while simulating the redox conditions existing in the field. Gamma‐irradiation experiments indicated that bentazone is mainly transformed by microbial activity in the soil. The rate constant for transformation was highest in the humic sandy top layer; it decreased with depth in the sandy vadose subsoil. However, material from the top of the phreatic aquifer had a higher rate constant than that from the layers just above. The presence of fossil organic material in the fluviatile water‐saturated sediment probably stimulated microbial activity and bentazone transformation. The changes in the transformation rate constant with depth showed the same trend as those in some soil factors, viz organic carbon content, water‐extractable phosphorus and microbial density as measured by fluorescence counts. However, the (low) concentration of dissolved organic carbon (DOC) in the top of the aquifer did not fit the trend. The rate constant for bentazone transformation in the layers was higher at lower initial contents of the herbicide. © 2001 Society of Chemical Industry     

Evaluation of vaccination strategies against infection with feline immunodeficiency virus (FIV) based on recombinant viral vectors expressing FIV Rev and OrfA

In recent years it has become clear that cell-mediated immunity is playing a role in the control of lentivirus infections. In particular, cytotoxic T lymphocyte responses have been associated with improved outcome of infection, especially those directed against the regulatory proteins like Rev and Tat, which are expressed early after infection. Therefore, there is considerable interest in lentiviral vaccine candidates that can induce these types of immune responses. In the present study, we describe the construction and characterisation of expression vectors based on recombinant Semliki Forest virus system and modified vaccinia virus Ankara for the expression of feline immunodeficiency virus (FIV) accessory proteins Rev and OrfA. These recombinant viral vectors were used to immunize cats using a prime-boost regimen and the protective efficacy of this vaccination strategy was assessed after challenge infection of immunized cats with FIV.     

Influences of myogenin genotypes on birth weight, growth rate, carcass weight, backfat thickness, and lean weight of pigs.

Lean weight is related to muscle fiber number. Muscle fiber formation (myogenesis) occurs only during embryonic development when it is under the control of the MyoD gene family consisting of myogenin, MyoD1, myf-5, and myf-6. Myogenin has a central position within the MyoD gene family because myogenin expression abrogates myoblast proliferation potential and regulates the differentiation of single nucleated myoblasts into multinucleated myofibers. Thus, myogenin genotype could be related to variation in the number of muscle fibers formed, leading to variation in muscle mass and, thus, lean weight. A polymorphism at the porcine myogenin locus was associated with birth weight, growth rate, lean weight at 200 d, and backfat thickness. Yorkshire pigs from two commercial lines were genotyped, and crosses between heterozygous pigs and heterozygous and homozygous pigs were made. Resulting litters were genotyped, and phenotypic data were collected. Significant differences were found between the two homozygous myogenin genotypes for birth weight, growth rate, and lean weight, but not for backfat thickness. Variation at the myogenin locus explained 4% of the total phenotypic variation in birth weight, growth rate, and carcass weight, and 5.8% of the total variation in lean weight. We conclude that myogenin genotype influences porcine growth rate and muscle mass.     

Effect of genetic variants of the heart fatty acid-binding protein gene on intramuscular fat and performance traits in pigs.

In order to find genetic markers to improve the meat quality of pigs by breeding we studied the relationship between variation in the heart fatty acid-binding protein (H-FABP) gene (FABP3) and intramuscular fat (IMF) content. To estimate the effect of H-FABP, pigs from two Duroc populations were selectively mated in such a way that at least two genotypes were present in each litter. In total, data from 983 pigs and pedigree information from three preceding generations were analyzed. Offspring were tested for IMF content as well as backfat thickness (BFT), BW, and drip loss of the meat (DRIP). All pigs were assigned to H-FABP RFLP genotype classes either by the assessed genotype (75%) or based on a probability score determined according to genotypic information of their relatives (25%). Contrasts were detected between homozygous H-FABP RFLP genotype classes for IMF content (.4%, P < .05), BFT (.6 mm, P < .01), and BW (2.4 kg, P < .10). No significant contrasts were detected for DRIP. Results for IMF content, BFT, and BW were confirmed when only genotyped animals were analyzed. Variation in BFT partially explained the effect on IMF content. Although other closely linked genes on porcine chromosome 6 might be responsible for the observed effect, interference of the halothane gene was excluded because all parental animals were noncarriers. In conclusion, H-FABP RFLP can be used as markers to select for increased IMF content and growth in breeding programs.     

The immunohistochemical evaluation of selected markers in the left atrium of dogs with end-stage dilated cardiomyopathy and myxomatous mitral valve disease – a preliminary study

Background

Dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD) are the most common diseases noted in dogs. Although their pathogenesis varies, both include a significant enlargement of the left atrium.The study was carried out on left atrial specimens obtained from 56 dogs, including those from 34 dogs with clinically diagnosed MMVD, 15 dogs with DCM and 7 dogs without heart disease (control group). Dogs in the MMVD and the DCM groups presented with left atrial enlargement and stage D heart failure. The specimens underwent immunohistochemical examination using desmin, vimentin, periostin and caspase-3 antibodies.

Results

There were alterations in the expression of the studied proteins in the study groups compared to the control group. The changes included: irregularity of desmin cross-striation and desmosomes, a higher amount of vimentin-positive cells, a change in the periostin expression pattern from cytoplasmic to extracellular, and a lower expression of caspase-3. The alterations were more pronounced in the DCM group than in the MMVD group.

Conclusions

During heart failure, the pattern of desmin, vimentin, periostin and caspase-3 expression alters in the left atrium, regardless of the cause. The changes are more pronounced in dogs with DCM than in dogs with MMVD and similar left atrial enlargement, suggesting that volume overload may not be the only cause of myocardial changes in DCM.

     

Metronidazole pharmacokinetics during rapid growth in turkeys – relation to changes in haemodynamics and drug metabolism

Whereas interspecies variation in pharmacokinetics is a commonly investigated issue, variations in drug kinetics within a species are less documented. The aim of the study was to assess the influence of age‐related changes in haemodynamics on the pharmacokinetics of metronidazole (MTZ) and its hydroxy metabolite (MTZ‐OH) in turkeys. MTZ was administered intravenously and orally at a dose of 25 mg/kg. Plasma drug and metabolite concentrations were assessed by high‐performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. Haemodynamic parameters (heart rate, stroke volume, cardiac output) were assessed by echocardiography and extraction ratio for MTZ was calculated based on total body clearance (Cl_B). Between the 5th and 15th week of age, Cl_B of MTZ decreased from 3.6 to 1.2 mL/min/kg causing a twofold increase in the mean residence time (MRT) and elimination half‐life (T_1/2el). The MTZ‐OH production decreased threefold and its MRT and T_1/2el increased. Although heart rate significantly decreased with age, cardiac output increased. Extraction ratio was low in all age groups. It is concluded that significant age‐dependent decrease in Cl_B of MTZ in turkeys resulted from decreased perfusion of the clearing organs and their reduced metabolic capacity. This phenomenon is probably species specific and may apply to other therapeutic agents.