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Evaluation of the Risk Factors for Shedding Salmonella with or without Antimicrobial Resistance in Swine Using Multinomial Regression Method

Posted in: Uncategorized by admin on August 13, 2010 | No Comments

A multinomial logistic regression method was used to investigate the risk factorsfor 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 samplescollected from the pen floor. The odds of culturing Salmonella with or without AMR was higher if pelleted feed was used compared with mash orliquid 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.

Results Pages

Posted in: Uncategorized by admin on July 29, 2010 | No Comments

RESULTS PAGES

Precision feeding can significantly reduce feeding cost and nutrient excretion in growing animals

Posted in: Uncategorized by admin on June 25, 2010 | No Comments

Precision feeding is a concept in pig production that attempts to give specific tailored diets to individual pigs as needed. Traditionally pigs that are fed more than there daily requirements of nitrogen and phosphorous experience optimal growth but only use the nutrients they require and the rest of the nutrients are excreted in urine and feces. N and P are costly ingredients in a feed composition therefore more efficient use of these nutrients can improve feeding costs and avoid environmental harm caused by there disposal. This study used data from a previous study where individual pigs were tracked to characterize feed intake, body weight gain and nutrient requirement patterns. The herd consisted of 68 pigs tracked over 83 days. The InraPorc model was slightly modified to simulate growth rates of individual pigs. The pigs were weighted four time in the data, a quadratic equation was used with time to estimate body weight. Other mathematical models were used to predict lysine requirements, and transformation of protein and lipids. The estimated results of precision feeding were compared to a commonly used three phase diet. Results showed that ADFI, ADG and feed conversion were the same for both methods, while feed cost, N and P intake, and N and P excretion were all lower for precision feeding.

A note on genetic parameters of gilt responses to humans

Posted in: Uncategorized by admin on December 16, 2009 | No Comments

In this study, a response test towards a stockperson was evaluated for improved maternal behaviour and increased piglet survival. Records were available from 638 German Landrace gilts with 860 observations tested for the response to an observer in the familiar environment of the mating centre. The degree of response was scored in five ordered categories. Fertility information (number of piglets born alive and stillborn) was available from 293 sows. The figures for survival rate and crushing by the sow were used from 2408 piglets. The estimated heritability in the human response test was h² = 0.09. Gilts which displayed only low response to humans showed fewer stillborn or crushed piglets in their first litter.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Attenuation of allergy to ovomucoid in pigs by neonatal treatment with heat-killed Escherichia coli or E. coli producing porcine IFN-g

Posted in: Uncategorized by admin on September 19, 2009 | No Comments

Food allergy is epidemic and prompts investigation to reduce allergic predisposition. It was hypothesized that heat-killed Escherichia coli injected intramuscularly (im) with or without interferon gamma (IFN-g), reduces neonatal susceptibility to experimental egg allergy. Two litters of Yorkshire pigs were assigned to three intramuscular treatment
groups (four/group): control (PBS), heat-killed E. coli with or without IFN-g-expressing plasmid. Pigs were sensitized to ovomucoid (Ovm) by intraperitoneal injection with cholera toxin. To assess induction of allergy, pigs were fed egg white in yoghurt and assigned scores for allergic signs. Significantly fewer pigs developed allergy and passive cutaneous anaphylaxis in E. coli and E. coli + IFN-g vs control groups. E. coli-treated pigs also had significantly lower frequency of mean clinical scores. E. coli and E. coli + IFN-g groups did not differ. Serum antibody associated with IgG (H & L), IgG1, IgG2 or IgE all correlated but did not differ by treatment groups. Thus, treatment of neonatal pigs with heat-killed E. coli by im injection reduced susceptibility to allergic sensitization with Ovm. Inclusion of the type-1 cytokine, IFN-g, had no additional effect. Results indicate a method for prophylaxis of allergy and suggest support for the ‘‘hygiene hypothesis’’.

Factors associated with in-transit losses of market hogs in Ontario in 2001

Posted in: Uncategorized by admin on August 13, 2008 | No Comments

In-transit losses and stage of transport when deaths occurred were determined for 4 760 213 market-weight pigs produced in
2001 by 4159 Ontario producers. These pigs were marketed through 117 transport companies to 33 packers located in Canada (96%) and the United States. Approximately 73% and 21% of producers marketed , 2000 pigs and , 500 pigs, respectively. In-transit loss was 0.017%, with 75% of producers losing # 5 pigs annually. Approximately half of in-transit losses occurred on the truck, with 14% of the other deaths occurring at the assembly yards, 4% on the producers’ trucks, and 24% at the abattoir. Fifteen percent of in-transit deaths, representing 1212 pigs, occurred in pigs that were previously identified as abnormal by the transporter or personnel working at the assembly yard or abattoir. Average losses were higher for producers marketing , 2000 pigs, and in-transit loss ratio (ITLR) was highest among those marketing , 100 pigs. Pigs from small farms traveled greater distances than those from larger operations. In-transit losses increased sharply between 590 and 720 km traveled, and decreased at distances. 980 km. Environmental temperatures reached $ 31°C for 4.2% of pigs shipped in June, July, and August, with median and mean temperatures of 20.6°C and 20.3°C, respectively, for these months. Twenty percent of all in-transit losses (1617 pigs) occurred in August.

Molecular epidemiology and antimicrobial resistance of Salmonella Typhimurium DT104 on Ontario swine farms

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This study was conducted to examine antimicrobial resistances, plasmid profiles, and pulsed-field gel electrophoresis patterns of 80 Salmonella Typhimurium DT104 strains (including DT104a and DT104b) recovered from pig and environmental fecal samples on 17 swine farms in Ontario. No resistance was observed to amoxicillin/clavulanic acid, apramycin, carbadox, cephalothin, ceftriaxone, ceftiofur, cefoxitin, ciprofloxacin, nalidixic acid, trimethoprim, and tobramycin.

However, the isolates exhibited resistance against 4 to 10 antimicrobials with the most frequent resistance being to sulfonamides (Su), ampicillin (A), streptomycin (S), spectinomycin (Sp), chloramphenicol (C), tetracycline (T), and florfenicol (F). It was found that 88% of isolates shared thetypical R-type “ACSSuT,” which has been frequently reported in association with DT104 isolates from different sources in Canada and other countries. Resistances to “ACT,” “ACNT,” and “ACNSSuTm” were the most common patterns that occurred among DT104 isolates recovered from healthy pigs in the slaughterhouses receiving animals from Quebec, Ontario, Manitoba, Saskatchewan, and British Columbia.

The isolates were classified into 23 distinct genotypes by PFGE-SpeI 1 BlnI when difference in at least one fragment was defined as a distinct genotype. In total, 39 distinct “types” were observed when defining a “type” based on the combination of antimicrobial resistance, plasmid pattern, and PFGE-SpeI 1 BlnI for each isolate. The highest diversity was 0.96 (95% CI: 0.92, 0.96) for the “type” described above followed by 0.92 (95% CI: 0.88, 0.93) for PFGE-SpeI 1 BlnI. The diversity of DT104 isolates indicates there might be multiple sources for this microorganism on swine farms. This knowledge might be used to track these sources, as well as to study the extent of human salmonellosis attributed to pork compared to food products derived from other food-producing animals

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.

The Welfare of Pigs: Review of Recent Literature

Posted in: Pork Insight Articles, Uncategorized, Welfare by admin on February 7, 2008 | No Comments

Animal welfare issues pertaining to pig farming are diverse, and scientific efforts to address these issues have resulted in a plethora of new literature. This review consolidates and summarizes this literature in an effort to provide a better understanding of pig welfare. Considerable attention has been given to housing design, husbandry and transportation of pigs.

Differential Gene Expression in Endometrium, Endometrial Lymphocytes, and Trophoblasts during Successful and Abortive Embryo Implantation

Posted in: Uncategorized by admin on August 8, 2006 | No Comments

Prenatal mortality reaching 30% occurs during the first weeks of gestation in commercial swine. Mechanisms for this are unknown although poor uterine blood supply has been postulated. In other species, vascular endothelial growth factor, hypoxia-inducible factor 1-, and IFN- regulate gestational endometrial angiogenesis. Vascular endothelial growth factor and hypoxia-inducible factor 1- are also important for placental angiogenesis while trophoblastic expression of Fas ligand is thought to protect conceptuses against immune-mediated pregnancy loss. In this study, we document dynamic, peri-implantation differences in transcription of genes for angiogenesis, cytokine production, and apoptosis regulation in the endometrium, and laser capture microdissected endometrial lymphocytes and trophoblasts associated with healthy or viable but arresting porcine fetuses. In healthy implantation sites, endometrial gene expression levels differed between anatomic subregions and endometrial lymphocytes showed much greater transcription of angiogenic genes than trophoblasts. In arresting fetal sites, uterine lymphocytes had no angiogenic gene transcription and showed rapid elevation in transcription of proinflammatory cytokines Fas and Fas ligand while trophoblasts showed elevated transcription of IFN- and Fas. This model of experimentally accessible spontaneous fetal loss, involving blocked maternal angiogenesis, should prove valuable for further investigations of peri-implantation failure of normally conceived and surgically transferred embryos in many species, including the human

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