Gastric acid secretion in conscious miniature pigs

Summary Gastric acid secretion was studied in 5 miniature pigs provided with a chronic gastric fistula. Basal secretion did not change during the growth of the animals. Histamine, carbachol, and pentagastrin produced a dose-dependent volume and acid response. The highest peak acid output (PAO) was achieved with histamine. The maximal peak volume output after histamine was only exceeded by carbachol which was due to an excessive salivation. The maximal PAO after carbachol and pentagastrin as well as the maximal peak volume output after pentagastrin were very low. The poor secretory responses to carbachol and pentagastrin are discussed in the light of possible inhibitory mechanisms or of drug-receptor-interactions.Supported by a grant from the Deutsche Forschungsgemeinschaft.     

Studies with activated charcoal in the treatment of drug overdosage using the pig as an animal model

Pigs were given large oral doses of paracetamol, amylobarbitone and amitriptyline. The effect of administering activated charcoal at varying intervals after dosing on the blood drug-level profiles of paracetamol and amylobarbitone was assessed by comparison with the profiles obtained when charcoal therapy was withheld. An appreciable effect on paracetamol absorption was demonstrated when charcoal was given up to l h after dosing. The amylobarbitone-dosed pigs exhibited delayed gastro-intestinal absorption of drug and this was substantially reduced by activated charcoal given 4 hrs after dosing. The pigs metabolised amitriptyline at too high a rate for meaningful studies to be undertaken with this drug.     

Water-jet dissection in renal surgery: experimental study of a new device in the pig

The pig model was used for experiments with a new type of water-jet dissector, which produces high-pressure water by application of a gas and maintains the water fully sterile in a single-use delivery apparatus. The experiment was conducted ex vivo (14 kidneys) and in vivo to compare electric cautery section with water-jet dissection (5 vs 11 partial nephrectomies). Ex vivo study confirmed sparing of blood vessels and pelvicaliceal system. In vivo study did not show significant differences in blood loss but, the water-jet allowed precise dissection and tight closure of the excretory system. More frequent haemorrages were noted on histological examination of the WJ group, but no coagulation necrosis. These are preliminary findings and further studies of long-term results may confirm the benefits of the absence of parenchymal necrosis and the definite advantage of precise closure of the pelvicaliceal system, as morbidity of partial nephrectomy is often related to secondary haemorrages and urinary fistulae.     

Intracranial Pressure Response to Non-Penetrating Ballistic Impact: An Experimental Study Using a Pig Physical Head Model and Live Pigs

This study was conducted to characterize the intracranial pressure response to non-penetrating ballistic impact using a "scalp-skull-brain" pig physical head model and live pigs. Forty-eight ballistic tests targeting the physical head model and anesthetized pigs protected by aramid plates were conducted with standard 9 mm bullets at low (279-297 m/s), moderate (350-372 m/s), and high (409-436 m/s) velocities. Intracranial pressure responses were recorded with pressure sensors embedded in similar brain locations in the physical head model and the anesthetized pigs. Three parameters of intracranial pressure were determined from the measured data: intracranial maximum pressure (P_max), intracranial maximum pressure impulse (PI_max), and the duration of the first positive phase (PPD). The intracranial pressure waves exhibited blast-like characteristics for both the physical model and l live pigs. Of all three parameters, P_max is most sensitive to impact velocity, with means of 126 kPa (219 kPa), 178 kPa (474 kPa), and 241 kPa (751 kPa) for the physical model (live pigs) for low, moderate, and high impact velocities, respectively. The mean PPD becomes increasingly short as the impact velocity increases, whereas PI_max shows the opposite trend. Although the pressure parameters of the physical model were much lower than those of the live pigs, good correlations between the physical model and the live pigs for the three pressure parameters, especially P_max, were found using linear regression. This investigation suggests that P_max is a preferred parameter for predicting the severity of the brain injury resulting from behind armor blunt trauma (BABT).     

A multiple SYBR Green I-based real-time PCR system for the simultaneous detection of porcine circovirus type 2, porcine parvovirus, pseudorabies virus and Torque teno sus virus 1 and 2 in pigs

Multiple viral infections are common in pigs under intensive production conditions. All five of the viruses included in this study are associated with multifactorial diseases that cause significant economic losses in swine farming worldwide. The development is described of a novel multiple real-time PCR system based on the use of SYBR Green I that allows the simultaneous detection and differentiation of porcine circovirus 2 (PCV-2), porcine parvovirus (PPV), pseudorabies virus (PRV) and Torque teno sus virus species 1 and 2 (TTSuV1 and TTSuV2) in pigs. The method was able to distinguish between all five viral agents, and tests of other DNA viruses proved the specificity of the system. The multiple real-time PCR system was sensitive, as the limits of detection ranged from 3.65 × 10³ to 5.04 × 10³ copies of DNA template per reaction. The coefficients of variation were low for both intra-assay and inter-assay variability. In addition, the results of the multiple real-time PCR system tests were 100% consistent with previous results based on specific PCR assay testing of field samples. This method could be a useful tool for epidemiological studies and disease management.     

Experimental high-volume hemofiltration with predilutional tris-hydroxymethylaminomethane for correction of low tidal volume ventilation-induced acidosis

The most common method of controlling acidemia during lung‐protective ventilation is CO₂ removal with an extracorporeal lung assist (ECLA) system. Another possibility to prevent acidemia is based on intravenous (i.v.) application of tris‐hydroxymethyl‐aminomethane (3 mol/L, THAM) buffer, which can bind hydrogen protons and which can be removed from the body via renal replacement therapy (RRT). We investigated whether RRT combined with predilutional (prefilter) THAM‐application provides an alternative to ECLA for a rescue situation. For this, anesthetized pigs, 40 kg of body weight, six animals per group, underwent 5 h of acidemia (pH 7.19–7.24) induced by acid infusion and permissive hypercapnia (low tidal volume ventilation, PaCO₂ 80–90 mm Hg). Isovolemic, high‐volume hemofiltration (HVHF) was operated with predilutional THAM‐infusion for treatment. To evaluate adverse effects of this approach, we set up further groups: HVHF with postdilutional (post‐filter) THAM‐application; i.v.‐THAM without HVHF; normal pH homeostasis with HVHF. Acid‐base parameters, hemodynamics, renal function, and lung morphology were investigated. HVHF with predilutional THAM‐infusion of 8 mmol/kg/h allowed fast pH normalization, significant reduction in PaCO₂ to 56 mm Hg and tolerable hemodynamics. HVHF alone or lower dose i.v. THAM (2 mmol/kg/h) failed to produce a comparable result. A postdilutional THAM infusion reduced hemodynamic tolerability and increased lung edema formation. HVHF in pigs with normal acid‐base status resulted in a decreased base excess and urine acidification. In conclusion, predilutional THAM‐application and HVHF corrected the acid‐base disorder and improved pulmonary hemodynamics. Further studies are necessary to optimize the protocol including the dosage.     

The mycotoxin T-2 inhibits hepatic cytochrome P4503A activity in pigs

Mycotoxins are toxic metabolites produced by fungi that readily colonize crops. After ingestion, these mycotoxins can compromise intestinal health, and once entering the blood stream, even affect the liver and its metabolizing enzymes. It was therefore the aim of the present study to investigate the effect of T-2 toxin, an emerging and potent Fusarium mycotoxin, on the enzymatic activity of cytochrome P4503A (CYP3A) metabolizing enzymes in the liver of pigs. In addition, a yeast-derived feed additive that claims to bind T-2 toxin was included in the study to evaluate its efficacy. Our results demonstrated that a 14-days intake of T-2 toxin contaminated feed at a dose of 903 μg/kg feed, whether or not combined with the mycotoxin binder, results in a substantial inhibition of the CYP3A activity in the liver of pigs. This result may be of importance for animal health, the pharmacokinetics and the withdrawal time of drugs that are substrate of CYP3A enzymes, and consequently can be a threat for public health with respect to tissue residues of these drugs.     

Bayesian Analysis of Genetic Associations of Skin Lesions and Behavioural Traits to Identify Genetic Components of Individual Aggressiveness in Pigs

There is increasing interest in genetic selection against behavioural traits that impact negatively on welfare and productivity in commercial livestock production. Post-mixing aggressiveness in pigs shows wide phenotypic variation, affects health, welfare and growth performance and is a routine feature of production. A Bayesian approach was used to estimate the heritability of three traits associated with aggressiveness in pigs during the 24 h post-mixing; duration in reciprocal aggression, and in receipt of, or delivery of non-reciprocal aggression (NRA). For the purposes of genetic selection, recording aggressive behaviour is excessively labour intensive. The genetic correlations were quantified between the behavioural traits and an easily measurable indicator trait; the number of skin lesions following mixing (lesion score, LS). The heritabilities for the three behavioural traits ranged from 0.17 to 0.46 (receipt of NRA and reciprocal aggression respectively). The duration in reciprocal aggression and in delivery of NRA showed a strong genetic correlation (r _g = 0.79 with 95% Bayesian credibility interval of 0.62–0.94). The genetic correlation between LS and these two behaviours indicated that selection on breeding values of LS could be used to reduce aggressiveness. The duration in receipt of NRA appeared to be regulated by different genes or genomic effects compared with the other behavioural traits and LS. Although duration in receipt of NRA was not genetically associated with LS, it was lowly but significantly environmentally associated with the residuals of central and caudal LS (r _e = 0.28–0.32), indicating that pigs that received NRA also received bites on the central and caudal third of the body. The pen that the animals were mixed into was found to be a very important factor for the analysed traits, in particular those representing behavioural characteristics. Based on the estimated genetic parameters, it is concluded that selection on breeding values for reduced LS (especially central LS) is expected to reduce reciprocal aggression and the delivery of NRA but will not change the receipt of NRA directly. Edited by Stephen Maxson.     

Swine adipose stromal cells loaded with recombinant bovine herpesvirus 4 virions expressing a foreign antigen induce potent humoral immune responses in pigs

Increasingly effective vaccination strategies are needed to counteract the high incidence of contagious diseases associated with intensive swine breeding. Recombinant viral vaccines are a promising new avenue in this direction. Key features of viral vectors suitable for immunoprophylaxis are safety, ease of manipulation and the ability to replicate in a variety of hosts. Most of the above requirements are met by bovine herpesvirus 4 (BoHV-4), a non-pathogenic dsDNA virus capable of infecting a broad range of cell types in vitro. Here we report the results of an exploratory study using an engineered BoHV-4 virus (eBoHV-4) expressing two unrelated glycoprotein antigens from bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1), to assess the potential of recombinant BoHV-4 as a self-adjuvanted immunogen in pigs. Free eBoHV-4 virions and virions preloaded into homologous swine adipose-derived stromal cells (SADSC) were tested. Neither virus formulation elicited neutralizing anti-BoHV-4 antibodies, nor any disease symptom, yet both induced specific immune responses against the heterologous antigens. However, a much earlier (18 vs 28 days post-infection) and more robust neutralizing response against BVDV and BoHV-1 viruses was elicited by eBoHV-4-preinfected SADSCs compared to free virions. The data validate BoHV-4 as a safe and effective heterologous antigen carrier/producer and identify SADSCs as helpful tools for the formulation of increasingly efficacious recombinant immunogens for pig vaccination.     

Diatom extraction with HCl from animal tissues: a technical note

Identification of diatoms from human or animal tissue may be affected by factors concerning techniques of extraction and analysis which cause fragmentation or loss of diatoms. In this brief technical note a novel efficient method of extraction of diatoms from animal tissues is presented. The authors have tested an H₂O₂ plus HCl and HCl method to detect diatoms in several tissues from pig immersed in water rich in diatoms; they have also compared this method to other methods of extraction including enzymatic ones. The experiment showed that all siliceous frustules of fresh water diatoms are resistant to the treatment proposed and are still recognizable after the digestion.Among the different tests, treatment by 20% HCl (T1) proved to be more simple and time-saving, and seems to be a valuable diagnostic tool for routine forensic procedures in the extraction and detection of diatoms.The positive results obtained in all cases should lead to further studies in order to evaluate the reliability of the proposed methods also from a quantitative point of view.