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Prairie Swine Centre is an affiliate of the University of Saskatchewan
Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.
Financial support for the Enterprise Model Project and Pork Insight has been provided by:
Association between in-transit loss, internal trailer temperature, and distance traveled by Ontario market hogs
Posted in: Ontario Pork, Pork Insight Articles by admin on August 13, 2008 | No Comments
This observational study investigated market pig deaths during transport from the farms to the abattoirs in Ontario. Three trucking companies were studied with respect to temperature, relative humidity, and global positioning data for 104 trips that delivered 21 834 pigs from 371 producers to Ontario abattoirs. 94% of producers investigated in this study experienced no in-transit pig losses but the overall average in-transit loss was 0.12%. As trailer temperature increased, pig losses increased. This study was conducted in the summer months of July to October 2004 to gain valuable knowledge on the effect of transport temperatures on animal welfare and health. It was concluded that temperature and humidity monitors were less expensive than pig losses during transport and that sprinklers or fans in transport trailers would be efficient at reducing in-transit market pig losses.
Molecular epidemiology and antimicrobial resistance of Salmonella Typhimurium DT104 on Ontario swine farms
Posted in: Ontario Pork, Pork Insight Articles by admin on | No Comments
This study investigated antimicrobial resistance of 80 Salmonella Typhimurium DT104 strains on 17 commercial swine farms in Ontario. Of the 24 antimicrobials tested, the isolates showed resistance to 4 to 10 of them. Most frequently, the isolates showed resistance to sulfonamides (Su), ampicillin (A), streptomycin (S), spectinomycin (Sp), chloramphenicol (C), tetracycline (T), and florfenicol (F). Thirteen resistance patterns were observed with 88% of the isolates presenting with the resistance pattern “ACSpSSuT.” Plasmid profiles were investigated and the isolates were classified into 23 distinct genotypes by PFGE-SpeI 1 BlnI. In total, 39 distinct “types” were observed when a “type” was based on antimicrobial resistance, plasmid pattern, and PFGE-SpeI 1 BlnI for each isolate. In conclusion, the diversity of isolates discovered suggessts the Salmonella Typhimurium DT104 strains come from multiple sites on the swine farms. These findings can be used to determined the exact source of contamination as well as to trace Salmonella Typhimurium DT104 infections in humans back to the source either swine-related or from other food-producing animals.
Fractional Protein Synthesis Rates Are Similar When Measured by Intraperitoneal or Intravenous Flooding Doses of L-[ring-2H5]Phenylalanine in Combination with a Rapid Regimen of Sampling in Piglets
Posted in: Nutrition, Ontario Pork, Pork Insight Articles by admin on July 24, 2008 | No Comments
Fractional protein synthesis rates (FSR) are widely measured by the flooding dose technique via either an i.g. or an i.v. route. This study was conducted to compare differences in tracer incorporation and FSR in organs and tissues of fed piglets. The piglets were surgically implanted with catheters and randomly assigned to receive a flooding dose of Phe (1.5 mmol/kg body weight, 40 percent molar enrichment with [2H5]Phe) in saline administered via an i.p. or an i.v. route. [2H5] Phe free-pool enrichment in plasma increased logarithmically (P , 0.05) from 0 to 25% in the i.p. group, whereas it
rose to a peak level within 3 min of the tracer injection and then decreased linearly (P , 0.05) in the i.v. group. Intracellular free-pool tracer enrichments in organs and tissues were within the range of the values measured for the plasma-free pool (25–27%), reaching the flooding status. Administration of the tracer via the i.p. and i.v. routes induced a logarithmical pattern (P , 0.05) of a surge in plasma cortisol concentrations within 30 min. Measurements of FSR in plasma, cardiac muscle, and skeletal muscles were lower (P , 0.05) in the i.p. than in the i.v. group due to the adverse effect of cortisol surge being more dramatic (P , 0.05) in the i.p. than in the i.v. group at 30 min of the post-tracer administration. We conclude that FSR may be measured by the flooding dose through an i.p. or an i.v. route and the i.p. route may underestimate FSR by the flooding dose for plasma, cardiac muscle, and skeletal muscles. This concern may be addressed by a fast regimen of sampling to be completed within 12–20 min after an i.p. route of tracer injection.
Porcine IgE in the context of experimental food allergy: Purification and isotype-specific antibodies
Posted in: Ontario Pork, Pork Insight Articles by admin on May 30, 2008 | No Comments
Measurement of allergen-specific immunoglobulin E (IgE) is a common practice in the investigation of allergy. It has not been possible to measure porcine IgE due to unavailability of anti-porcine IgE. This study was undertaken to purify and characterize porcine IgE from sera of allergic pigs, identify heterologous anti-IgE reactive with pig IgE and to use purified heavy (H) chain of porcine IgE to generate rabbit anti-IgE. A four-step process for the purification of porcine IgE is reported using ammonium sulphate precipitation, Protein G affinity chromatography, DEAE cellulose anion-exchange chromatography and sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) to obtain IgE H chain. The resultant IgE was evaluated for purity using SDSPAGE and immunoreactivity was detected by Prausnitz–Ku¨stner (PK) tests and passive cutaneous anaphylaxis with the allergen,crude peanut extract, used to induce experimental allergy. Cross-reactivity with anti-mouse and anti-human IgE antibodies were confirmed in western blot and enzyme-linked immunosorbent assays (ELISA). The H chain of IgE was excised from SDS-PAGE gels and used to develop rabbit anti-porcine IgE antisera. Antiserum obtained from rabbits immunized with porcine IgE, as well as heterologous murine and human-specific anti-IgE, induced reverse cutaneous anaphylaxis in pig skin and detected allergen-specific IgE in ELISA but did not react with IgG H chain in western blots. These results confirm allergy-associated bioactivity of porcine IgE and describe both homologous and heterologous anti-pig IgE suitable for use in allergen-specific and other assays. This will enhance utility of pig allergy models and provide an additional measure of type-2 immune response in pigs.
Possibilities for Anaerobic Digestion On Ontario Swine Farms
Posted in: Ontario Pork, Pork Insight Articles by admin on May 14, 2008 | No Comments
Liquid swine manure can have negative effects on the environment such as soil leaching with P and N, pathogens in digesters, and emissions of green house gases. Some of these effects can be alleviated with the manure being put into an anaerobic digesters which can also reduce the odor and create energy. To test the usefulness of anaerobic digesters researchers tested different combinations of manure and organic materials, the test treatments were liquid swine manure, liquid swine manure mixed with corn silage and liquid swine manure mixed with shredded sugar beets. The main objectives of this study were to test liquid swine manure by itself and with typical organic additives, and measure biogas production and digestate quality, to recorded logistical considerations for each manure additive, and to find gas yields from the manure combinations used and the costs of producing electrical power from each combination. When liquid swine manure was put by itself into the digester the total amount was 11 700L about 244L per day, this produced 264 m3 of boigas that was an average of 68% methane. For liquid swine manure mixed with corn silage the digester had some problems handling the solid material, as it designed for liquid only. A chopping pump was implemented to make the straw more liquid like. 227kg of corn silage was added to the digester along with 4681 L of swine manure. This was an average of 5.82 kg of corn silage per day and 120 L of liquid swine manure. This produced 214 m3 of biogas that averaged 55.8% methane – resulting in the production of 119 m3 of methane. The average biogas production was 5.5 m3 per day. The sugar beet additive was the last test recipe, it involved 99 kg of sugar beets, along with 560 liters of swine manure. This was an average of 5.5 kg of sugar beets per day and 31.1 L of liquid swine manure. This produced 13.6 m3 of biogas that averaged 54.7% methane, yielding 7.44 m3 of methane. The average daily biogas production was 0.756 m3 per day. After comparing the data recovered, some observations that were made include liquid swine manure produced the most methane per kg of additive. The sugar beat recipe was the last for methane produced per kg of organic matter but the researchers believe this is underestimated because of complications with the equipment.
Enhanced Resistance to Bacterial Infection in Protegrin-1 Transgenic Mice
Posted in: Environment, Nutrition, Ontario Pork, Pork Insight Articles by admin on April 29, 2008 | No Comments
Antibiotic-resistant bacteria have become a public health concern. It was suggested that one source of resistant pathogens may be food-producing animals. Alternative approaches are therefore needed to enhance the resistance of farm animals to bacterial infection. Protegrin-1 (PG-1) is a neutrophil-derived antimicrobial peptide that possesses activity against a wide range of bacteria and enveloped viruses. Here we report on the production of transgenic mice that ectopically expressed PG-1 and compare their susceptibilities to Actinobacillus suis infection with those of their wild-type (WT) littermates. Of the 126 mice that were challenged with A. suis, 87% of the transgenic mice survived, whereas 31% of their WT littermates survived. The PG-1 transgenic mice had significantly lower bacterial loads in their lungs and reduced numbers of pulmonary pathological lesions. The antimicrobial function of PG-1 was confirmed in vitro by using fibroblast cells isolated from the transgenic mice but not the WT mice. Moreover, differential blood cell counts in bronchoalveolar lavage fluid indicated greater number of neutrophils in PG-1 transgenic mice than in their WT
littermates after bacterial challenge. Our data suggest that the ectopic expression of PG-1 in mice confers enhanced resistance to bacterial infection, laying the foundation for the development of livestock with improved resistance to infection.
The mammalian target of rapamycin-signaling pathway in regulating metabolism and growth
Posted in: Ontario Pork, Pork Insight Articles, Uncategorized by admin on April 21, 2008 | No Comments
The mammalian target of rapamycin (mTOR) plays key roles in cellular metabolism and hypertrophic- hyperplasic growth, and it acts as a central regulator of protein synthesis and ribosome biogenesis at the transcriptional and translational levels by sensing and integrating signals from mitogens and nutrients. Hormonal and stress factors can affect the mTORsignaling
pathway via their receptors and signal transduction pathways. Nutritional regulation of the mTORsignaling pathway is mediated by their corresponding plasma membrane transporters, other unknown mechanisms, or both. Adenine monophosphate-activated protein kinase, an important cellular energy sensor, can interact with the mTOR-signaling pathway to maintain cellular energy homeostasis. Interactions ofmTORwith regulatory-associated protein of TOR or rapamycin-insensitive companion of mTOR result in 2 mTOR complexes, with the former (mTOR complex-1) being the primary controller of cell growth and the latter (mTOR complex-2) mediating effects that are insensitive to rapamycin, such as cytoskeletal organization. Upstream elements of the mTOR-signaling pathway include Rashomolog enriched in brain, and tuberous sclerosis complex 1 and 2, with tuberous sclerosis complex 2 as the linker between phosphatidylinositol 3-kinase/protein kinase B or Ras-Raf-mitogen-activated protein kinaseextracellular signal-regulated protein kinase pathways and the mTOR pathway. Ribosomal protein S6 protein kinase 1 and eukaryotic initiation factor 4E binding protein 1 are currently the 2 best-known downstream effectors of mTOR signaling. Hormonal factors, stressors, and nutrients can differentially mediate cellular metabolism and growth via the mTOR pathway with
effectors specific to the organ or tissue types involved.
Adverse effects induced by short hairpin RNA expression in porcine fetal fibroblasts
Posted in: Ontario Pork, Pork Insight Articles by admin on March 20, 2008 | No Comments
RNA interference is a recent, gene silencing technique that could be extremely valuable in studying gene function, treating diseases, and developing novel animal models for human diseases. Here, we investigated the feasibility of applying shRNA-mediated RNA interference in fetal fibroblasts for silencing of the myostatin gene and investigate adverse effects of RNAi. We report that up to 97% silencing of myostatin mRNA was achieved using shRNA constructs in transiently and stably transfected fetal fibroblasts (p < 0.05). At the same time we also demonstrate that high level of shRNA expression resulted in 10- to 1000-fold induction of interferon responsive genes (OAS1, IFN-b) (p < 0.05). In addition we also report novel adverse effect of shRNA expression in stably transfected cells—interference with microRNA processing/ transport which led to 500-fold increase in the level of miR21 precursors (p < 0.05). Reduction of these side effects will be essential to obtain long term stable RNAi silencing.
Dietary means to enhance gut health, growth performance and well-being of newly weaned pigs
Posted in: Ontario Pork, Pork Insight Articles by admin on March 10, 2008 | No Comments
Poor gut health has always been a problem for pork producers. Traditionally anti-biotics were used to improve gut health but the use of anti-biotics has recently come under scrutiny so alternative methods to improve gut health have come into demand. This study looks for some alternative methods to improve gut health. The first trail involved a diet enhanced with zinc and copper and a control diet, this test consisted of 180 piglets, and they were analyzed for growth performance, circulating cytokines levels and gut microbiota. There was no difference found in growth performance between the two groups, there was no difference in circulating cytokine levels other than cortisol being higher in pigs in the test diet. Enhanced growth performance of the newly weaned piglets fed high dietary Zn and Cu during the first two weeks post-weaning appears mediated via changes in gut microbiota as well as a reduced cortisol response following an immune challenge. The second study involved feeding 129 piglets a diet of galactomannan oligosaccharides (GMOS) or a control diet and then they were tested on growth performance, immune response and intestinal microbiota.Results showed that inclusion of GMOS at 0.3% appeared to alter the compositions of both ileal and colonic microbiota. These results suggest that dietary GMOS was able to increase humoral immunity and alter the compositions of microbiota of newly-weaned pigs, while reducing feed intake and growth performance during the first week post-weaning.
A Neonatal Swine Model of Allergy Induced by the Major Food Allergen Chicken Ovomucoid (Gal d 1)
Posted in: Ontario Pork, Pork Insight Articles by admin on December 14, 2007 | No Comments
Food allergy is a serious health problem for which a validated outbred large animal model would be useful in comparative investigations of immunopathogenesis and treatment and in testing hypotheses relevant to complex
host-environmental interactions in predisposition to and expression of food allergy. Objective: To establish a neonatal
swine model of IgE-mediated allergy to the egg protein ovomucoid (Ovm) that may mimic human allergy. In order to induce Ovm sensitivity, piglets at days 14, 21 and 35 of age were sensitized by intraperitoneal injection of 100 g of crude Ovm and cholera toxin (50, 25 or 10 g). Controls received 50 g of cholera toxin in phosphate-buffered saline. The animals were challenged orally on day 46 with a mixture of egg white and yoghurt. Outcomes were reported as direct skin tests, clinical signs, IgG-related antibody and passive cutaneous anaphylaxis. Results: Sensitized pigs developed immediate wheal and flare reactions, and after oral challenge, sensitized but not control animals displayed signs of allergic hypersensitivity. Serum IgG-related, Ovm-specific antibodies were detected only in the sensitized pigs and IgE-mediated antibody response to Ovm was confirmed by positive passive cutaneous anaphylaxis reactions induced by sera of sensitized but not by heat-treat-ed sera from Ovm-sensitized pigs or sera of unsensitized control pigs. The present results confirm induction of Ovm-specific allergy in pigs and provide opportunity to investigate allergic predisposition and immunopathogenesis of IgE-induced Ovm allergy using outbred neonatal swine. This may better simulate allergic disease in humans and allow investigation of candidate prophylactic and therapeutic approaches.