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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:
Prevalence of Salmonella infecting bacteriophages associated with Ontario pig farms and the holding area of a high capacity pork processing facility
Posted in: Ontario Pork, Pork Insight Articles by admin on April 27, 2010 | No Comments
There is interest in applying bacteriophages to control Salmonella in pig production and pork processing. The following reports on the prevalence of Salmonella infecting bacteriophages within Ontario pig farms and associated with the holding area of a pork slaughterhouse. Salmonella infecting bacteriophages were present in 30 and 28 of the effluent manure samples collected from 36 farms using S. Typhimurium DT104 or S. Heidelberg as host cell respectively. Bacteriophages were recovered in 95–100% of the 48 samples taken from holding pens within a high capacity slaughterhouse over a 12 month period. Bacteriophages isolated from farms exhibited similar host ranges which differed to that of slaughterhouse isolates. Salmonella (n = 21) from the slaughterhousewere susceptible to the endogenous bacteriophages. Despite being susceptible to the resident phages, the Salmonella populations were found to be genetically stable with the same genotypes being recovered over successive visits. Salmonella isolated from the farms were frequently resistant to the endogenous phages. Bacteriophages are prevalent in the pig slaughterhouse environment although they do not have a significant impact on the genetic structure of Salmonella populations. However, there was evidence that the Salmonella population structure on farms is influenced by the presence of infecting phages.
Effect of plasmid pTENT2 on severity of porcine post-weaning diarrhoea induced by an O149 enterotoxigenic Escherichia coli
Posted in: Ontario Pork, Pork Insight Articles, Welfare by admin on April 10, 2010 | No Comments
A particularly virulent O149:H10 enterotoxigenic Escherichia coli clone harbours a newly characterized plasmid pTENT2 carrying the tetracycline-resistance tetA and the virulence genes estA, paa, and sepA that were not present in less virulent clones. The objectives of this study were to assess whether the additional genes on pTENT2 played a role in the increased severity of post-weaning diarrhoea and if they provided any potential advantage for the emergence of the highly virulent clone. Groups of pigs were dosed orally with isogenic pTENT2-positive and pTENT2-negative ETEC strains, and the clinical and pathological changes were compared between the groups. Two additional groups were given the pTENT2-positive strains and maintained on feed with or without chlortetracycline to assess the effect of subtherapeutic levels of tetracycline on the short-term persistence of the ETEC O149:H10 clone. The severity of diarrhoea within the first few hours post-inoculation was significantly increased ( p = 0.0408) in animals receiving pTENT2-positive strains as compared to animals receiving pTENT2-negative strains. There were no consistent or significant histopathological differences between any of the groups and no significant difference in the persistence of ETEC between groups.
Determining sow performance and mineral digestibility with phytase supplementation of the lactating sow ration
Posted in: Ontario Pork, Pork Insight Articles by admin on March 9, 2010 | No Comments
One potential way for producers to save on feed costs is to introduce phytase into the pigs diets. Phytase binds up phosphorus making it poorly available so it doesn’t negatively impact land, it also renders calcium, iron, zinc, manganese and copper poorly available. Tests have shown that 0.1 % reduction in calcium and phosphorus have no impact on carcass traits or meat quality. In lactating sows, no work has been done concerning the response due to phytase supplementation with respect to: 1) digestibility of trace minerals, 2) response of milk production and quality, and 3) piglet performance. These things are important to understand before farmers begin introducing phytase into diets. To test phytase use on sows a group of 36 sows were assigned one of four mineral phytase treatments when they were in farrowing crates. The four treatments were:1) phytase and a trace mineral premix, 2) no phytase and a trace mineral premix, 3) only phytase and no trace mineral premix, and 4) neither phytase or a trace mineral premix. Farrowing data was recorded as well as blood, feces and milk samples were taken for analysis. Also sow feed and water intake was recorded along with weaning data. Results showed that in the short term sows did not need typical levels of calcium and phosphorus and any trace mineral supplementation they receive. No production parameters were found to be impacted by the treatments. Phytase supplementation did not improve digestibility of phosphorus, calcium or the trace
minerals, as it has in other studies. It is unclear at this point why that was the case but there is at least one significant confounding factor, being dry matter intake. For some reason, the sows consuming treatments that received reduced calcium and phosphorus and no trace mineral supplementation tended to consume more feed than those that received normal mineral
supplementation. To learn why this is more studies will need to be done on a larger group of sows.
Epidermal Growth Factor-Expressing Lactococcus lactis Enhances Intestinal Development of Early-Weaned Pigs
Posted in: Nutrition, Ontario Pork, Pork Insight Articles by admin on February 10, 2010 | No Comments
Stress and incomplete gastrointestinal development in early-weaned piglets represent significant challenges in commercial swine farming. Orally ingested recombinant epidermal growth factor (EGF) has been shown to remain biologically active in the gastrointestinal tract as well as stimulate intestinal development, reducing the incidence of pathogen infection and diarrhea. We have previously shown that the food-grade bacterium Lactococcus lactis can be genetically altered to express biologically active EGF when fed to early-weaned mice. In this study, we assigned 8 pigs to
each of 4 groups that were given EGF-expressing L. lactis (EGF-LL), empty vector-expressing L. lactis (EV-LL), recombinant human EGF, or unsupplemented bacterial media, all of which were delivered as 50-mL i.g. doses twice per
day. All pigs were killed after 14 d to examine intestinal morphology. Pigs in the EGF-LL group had greater jejunal and duodenal villus heights (P,0.0001) and intestinal length (P = 0.049) than pigs in the control group. Immunohistochemistry with antibodies against proliferating cell nuclear antigen (PCNA) revealed that the proliferation of intestinal cells was significantly greater in the EGF-LL group than in the control group. PCNA expression and intestinal length also were greater in the EV-LL group, which received L. lactis that did not express EGF, than in the control group (P = 0.049), further supporting the use of naturally occurring intestinal microbes as desirable vectors for recombinant protein delivery. Our data demonstrates the feasibility of delivering a growth factor using common probiotic bacteria to farm animals for commercial practice.
Review of advances in metabolic bioavailability of amino acids
Posted in: Ontario Pork, Pork Insight Articles by admin on January 1, 2010 | No Comments
The animal’s amino acid requirement and the potential of feedstuffs to supply those amino acids in metabolically available form (amino acid bioavailability) are intertwined. Although standardized ileal amino acid digestibility is currently most widely used as an estimate of dietary protein quality, numerous factors influence these estimates. Slope ratio assays are considered the standard against which other methods of amino acid availability are judged because they measure the effect of protein quality on the entire metabolism of the animal. However, practical use of slope ratio growth assays is limited. Recently, the slope ratio assay utilizing the indicator amino acid oxidation technique has been developed to determine the
metabolic availability (MA) of amino acids in pigs and humans This review will discuss how the indicator amino acid oxidation (IAAO) technique can: 1) address some of the problems associated with the slope ratio assay; 2) be used to determine the metabolic availability (MA) of amino acids in animal feedstuffs; 3) become a valuable measure of amino acid bioavailability; and 4) be applied in practical swine nutrition.
A clinical field trial to evaluate the efficacy of vaccination in controlling Salmonella infection and the association of Salmonella-shedding and weight gain in pigs
Posted in: Ontario Pork, Pork Insight Articles, Welfare by admin on November 23, 2009 | No Comments
A clinical field trial was performed to determine the effectiveness of an autogenous Salmonella Typhimurium bacterin compared with a commercial live S. Choleraesuis vaccine in pigs. The association between Salmonella shedding and weight gain was also investigated. Nine cohorts of weaned pigs, (330 to 350 pigs per cohort), were randomly assigned to 1 of 3 treatment groups (injection with S. Typhimurium bacterin, vaccination via water with S. Choleraesuis vaccine, or a control group receiving no vaccine). In each cohort, the average daily gain was calculated for a selected pen throughout the production stage. Pen (pooled) fecal samples were collected bi-weekly and cultured. The odds of Salmonella shedding in both vaccinated groups was higher than in the control group (P , 0.05). The prevalence of Salmonella shedding declined overall as pigs aged (P 5 0.04). However, the control pigs showed the smallest decrease in Salmonella shedding over the entire production stage, while prevalence of Salmonella shedding in the vaccinated groups decreased twice as much as the control group over the entire production stage. Salmonella Typhimurium var. Copenhagen DT104, S. Cerro, and S. Agona, which had been isolated on the study farm previously, were recovered from pigs in this study. Shedding of S. Typhimurium var. Copenhagen decreased over time in both vaccine treatment groups. On the other hand, S. Cerro shedding rate was lower in the control pigs compared with vaccinated pigs and S. Agona could be recovered only from the samples collected from S. Choleraesuis vaccinated pigs. The pigs from pens with a higher Salmonella recovery rate experienced slower growth compared with pigs from pens where Salmonella was not isolated. This latter finding indicates that there might be an economic incentive for producers to try to control endemic salmonellosis if effective programs could be developed.
Evaluation of the Risk Factors for Shedding Salmonella with or without Antimicrobial Resistance in Swine Using Multinomial Regression Method
Posted in: Environment, Ontario Pork, Pork Insight Articles by admin on November 11, 2009 | No Comments
A multinomial logistic regression method was used to investigate the risk factors for antimicrobial resistance (AMR) in Salmonella isolated from faecal samples collected on 80 Ontario swine farms in Canada. The samples were classified into three groups including Salmonella-negative samples (S)), Salmonella-positive samples without AMR (S+AMR)) and Salmonella-positive samples with AMR (S+AMR+). The samples collected directly from pigs had a greater chance to be positive for Salmonella with AMR compared to those samples collected from the pen floor. The odds of culturing Salmonella with or without AMR was higher if pelleted feed was used compared with mash or liquid feed (P < 0.001). The faecal samples collected on farrow-to-finish farms had a significant lower chance of testing positive for Salmonella with multidrug resistance than the samples from grow-finisher farms (P = 0.004). The chance of culturing Salmonella without AMR on farms with a continuous system was higher than on farms with an all-in/all-out system (P = 0.009). However, there was no significant association between the flow system and recovery of Salmonella with AMR. The larger farms were more likely to be in S+AMR+ group than in S) group (P < 0.001) whereas herd size did not appear as a risk factor for being in S+AMR) group compared with S) group. These findings indicate that although on-farm antimicrobial use is one component of resistance, there might be other farm management factors that also affect the development of emerging resistant bacterial foodborne pathogens on swine farms. Finding different risk factors for shedding Salmonella with or without antimicrobial resistance would help to take the appropriate approach to each group if a control programme were to be implemented or an intervention applied.
Prevalence of Yersinia enterocolitica shedding and bioserotype distribution in Ontario finisher pig herds in 2001, 2002, and 2004
Posted in: Environment, Ontario Pork, Pork Insight Articles, Welfare by admin on October 10, 2009 | No Comments
We investigated characteristics of Yersinia enterocolitica infection in Ontario finisher pig herds. Our specific objectives were to estimate or test: prevalence of Y. enterocolitica shedding in finisher pigs, bioserotype distribution, agreement between the herd-level tests based on sampling pig and pooled fecal samples, whether bioserotypes cluster by farms, and whether Y. enterocolitica-positive herds cluster spatially. In total, 3747 fecal samples were collected from 100 farms over the years 2001, 2002, and 2004 (250 total herd visits). Fecal samples were tested by culture and positive isolates were biotyped and serotyped. Apparent pig-level prevalence of Y. enterocolitica was 1.8%, 3.2%, and 12.5% in 2001, 2002, and 2004, respectively. Estimated true pig-level prevalence of Y. enterocolitica was 5.1%, 9.1%, and 35.1% in 2001, 2002, and 2004, respectively. Herd-level prevalence was 16.3%, 17.9%, and 37.5% in 2001, 2002, and 2004, respectively. In all years, the most common bioserotype was 4, O:3, followed by bioserotype 2, O:5,27. Kappa between herdlevel status based on pig and pooled samples ranged between 0.51 and 0.68 for biotype 1A and bioserotype 4, O:3, respectively. For 4, O:3, a significant bias in discordant pairs was detected, indicating that pig samples were more sensitive than pooled samples in declaring a herd as positive. Farms tended to be repeatedly positive with the same bioserotype, but positive study farms did not cluster spatially (suggesting lack of between herd transmission and lack of a common geographic risk factor).
Making Fusarium-Resistant Plants from Pollen
Posted in: Ontario Pork, Pork Insight Articles by admin on October 1, 2009 | No Comments
Researchers at the University of Guelph are finding new ways to produce fusarium-resistant corn plants from pollen. The process involves extracting pollen from mature plants and holding it in a dish where it can be exposed to screenings. The millions of pollen grains being held are exposed to acids found in fusarium that help the disease break down plants to help penetrate it and to UV lights which kills most of the pollen grains but some are mutated and remain. The researchers then select the pollen grains that are able to survive the screening and have the desired traits they are after. The surviving embryos are then grown to maturity in a lab and put through test to see how resistant they are. This process allows for creating disease resistant plants while not altering the genes, meaning they are not transgenic. Not being transgenic allows the plants to avoid the regulations and scrutiny that comes with other mutated plants.
Angiogenic DC-SIGN+ cells are present at the attachment sites of epitheliochorial placentae
Posted in: Ontario Pork, Pork Insight Articles, Production by admin on September 15, 2009 | No Comments
Spontaneous early and mid-gestation fetal losses occur in swine. At both stages, endometrial lymphocytes associated with smaller, paler conceptuses have fewer pro-angiogenic and more pro-inflammatory cytokine transcripts compared with robust conceptuses. We hypothesized that similar differences occur in conceptus-associated dendritic cells (DCs). Using laser capturemicrodissection, dendritic cell-specific intercellular adhesion molecule-grabbing non-integrin (DC-SIGN)+ cells were isolated from attachment sites of healthy and arresting conceptuses at gestation day (gd)20 and 50. DC-SIGN+ cells were screened using real-time PCR for vascular endothelial cell growth factor (Vegf), its receptors, semaphorins (Sema) and plexins (Plxn), and for toll-like receptor (Tlr) transcripts to address potential activation pathways. Homogenized endometrial and trophoblast biopsies were quantified for type 1/type 2 cytokine transcripts/proteins. DC-SIGN+ cells from healthy and arresting conceptuses had more Vegf transcripts at early than mid gestation whereas transcripts for Vegfr1 and Vegfr2 were stable. In gd20 arresting site DC-SIGN+ cells, Neuropilin-2 transcripts were elevated, whereas at gd50 arresting sites, Plxn-A2 increased and Sema3A transcripts were lost. Tlr-1, Tlr-4 and Tlr-6 transcript abundance was independent of conceptus health. At gd20, type 1 cytokines were prevalent, whereas at gd50 type 2 cytokines predominated in endometrium and trophoblast. Thus, gestational features, characteristic of haemochorial placentation, are present in species with distinctly different placentation.