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United States Department of Agriculture

Agricultural Research Service


Location: Livestock Behavior Research

2013 Annual Report

1a. Objectives (from AD-416):
Objective 1: Identify physiological, immunological, endocrinological and gastrointestinal-microbiological alterations which occur in infected livestock when subjected to common managerial stressors. Objective 2: Understand how handling and transportation stress influence livestock pathogens, such as, Salmonella and Campylobacter, which have the potential to detrimentally affect human health.

1b. Approach (from AD-416):
We will subject livestock to both mixing and transportation and collect behavioral, physiologic, immunologic, endocrine, and bacterial data. The behavior data will include: agonistic encounters, loss of balance, vomiting, standing, lying, stereotypic behavior, and any other abnormal behaviors (i.e. shaking, jumping, etc). The physiologic, immunologic, and endocrine data will include: heart rate, body temperature, cortisol, epinephrine, norepinephrine, dopamine, immune cell populations, interferon-gamma, interleukin-1, interleukin-12, haptoglobin, alpha 1-acid glycoprotien, and immunoglobulins. The bacterial data will include: DGGE pattern, total aerobes, anaerobes, Enterobacteriaceae counts, and the proportion of antimicrobial resistant Enterobacteriaceae in different compartments of the gastrointestinal tract and in mesenteric lymph nodes. Analysis of these collective data will allow for identification of key processes that create high pathogen loads at slaughter plants. Our approach is a strategy that will 1) use a novel technique to monitor the progression of infection of stressed swine, 2) study the influence of mammalian stress hormones on bacteria, and 3) determine physiologically how a dietary supplement can impair bacterial infection. All three of these approaches will provide novel information on how stress influences bacterial pathogens.

3. Progress Report:
This FY three studies were completed: 1 ) determination of cranberry products effect on microbial populations and immune development, 2) effects of copper sulfate and zinc oxide on microbial communities, and 3) effect of essential oils antimicrobial activity. For the cranberry study, pigs were fed either dried cranberry or liquid cranberry, fecal samples were taken to access the level of pathogenic bacteria in their system. Results are presented in the Accomplishments below. The second study fed either copper sulfate or zinc oxide to pig and bacteria was cultured from the feces to determine their effects. The third study fed various essential oils, such as thyme and cinnamon, dependent on the concentrations of the oils bacteria were either reduced or enhanced. The cranberry study data were presented at the Midwest ADSA/ASAS meetings in March, 2013. The studies of zinc and copper and essential oils were presented at the national ADSA/ASAS meeting in July, 2013.

4. Accomplishments
1. Cranberry supplementation to piglets. Neonatal pigs (1 to 28 days of age) are vulnerable to infection by pathogenic bacteria resulting in decreased growth rates and increased mortality. Cranberry products have shown potential to reduce colonization by pathogens without harming the microbial populations necessary for digestive processes. ARS researchers at West Lafayette, IN, found that cranberry products (cranberry juice, whole cranberry powder, and cranberry fiber) helped the piglets to resist Salmonella allowing a quicker recovery from a Salmonella challenge. This suggests that the whole cranberry powder may provide protection from some enteric pathogens in weaned pigs. This protection will help the pigs combat diseases and increase their growth.

2. Essential oils are antimicrobial. Increased pressure to move away from antibiotic use in swine makes it imperative that alternatives which promote health be discovered. Essential oils are being used as feed additives to promote health and growth in swine and poultry production. ARS researchers at West Lafayette, IN discovered that essential oils of oregano, tea, cinnamon, and thyme had antimicrobial effects in vitro against against a range of disease causing bacteria including Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis, suggesting a broad spectrum protection against a range of disease causing bacteria. Essential oil of thyme had the greatest effect, followed by oregano, cassia, and tea oils. This study demonstrated the potential of essential oils to reduce pathogen loads and has led to investigation of cross-resistance to antibiotics through exposure to sub-lethal concentrations of the essential oils. Successful use of essential oils will allow swine to maintain their health when challenged with disease.

3. Copper sulfate and zinc oxide differ in induction of cross-resistance of bacteria. Increased pressure to move away from antibiotic use in swine makes it imperative that alternatives which promote health be discovered. Copper sulfate and zinc oxide have been extensively used as alternatives to antibiotics for health and growth promotion in animal production. However, concerns regarding bacterial cross-resistance between these compounds and antibiotics are emerging. ARS researchers at West Lafayette, IN, discovered that copper sulfate and zinc oxide differed in their ability to induce antibiotic resistance. Zinc did not affect bacterial responses to antibiotics, however copper sulfate had varied effects, depending on the targeted bacterial strain. Thus zinc supplementation will not affect antibiotic use in pigs whereas supplementation with copper can allow for bacteria to become resistant to antibiotics and thus allow pigs to succumb to disease.

Last Modified: 05/27/2017
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