Effect of Feed-Borne Fusarium Mycotoxins on Equine Gastric Ulcer Syndrome

131 Pages·2013·3.01 MB·English

by  Melissa Mortson

Effect of Feed-Borne Fusarium Mycotoxins on
Equine Gastric Ulcer Syndrome

By

Melissa Mortson

A Thesis
Presented to
The University of Guelph

In partial fulfillment of requirements
for the degree of
Master of Science
in
Animal and Poultry Science and Toxicology

Guelph, Ontario, Canada

© Melissa Mortson, December, 2012
ABSTRACT

EFFECTS OF FEED-BORNE FUSARIUM MYCOTOXINS ON
EQUINE GASTRIC ULCER SYNDROME

Melissa Mortson Advisor:
University of Guelph, 2012 Trevor K. Smith

Consumption of feedstuffs contaminated by Fusarium mycotoxins and the
development of equine gastric ulcer syndrome (EGUS) affect the overall health of horses.
A study was conducted to determine if feed-borne mycotoxins have an effect on EGUS,
and the efficacy of a glucomannan mycotoxin adsorbent (GMA) was determined. Feed
intake was decreased with the GMA diet compared to control horses. Body weight, ulcer
score and gastrin concentration were unaffected by diet. Some significant changes in
blood parameters potentially indicate liver damage and inhibition of protein synthesis.
Histological evaluation showed an increase in mononuclear cells in the glandular region
of the contaminated group likely indicating signs of gastritis. The incorporation of the
GMA may reduce these negative effects on the horse based on our findings. It can be
concluded that horses are susceptible to Fusarium mycotoxins with a possible effect on
EGUS, as seen in the cells of the gastric glandular mucosa.
In dedication to my papa, Mervyn Mortson

  iii
Acknowledgements
I would like to begin by thanking my advisor Dr. Trevor Smith for his continued
guidance and support throughout my studies. Thank you for believing in me and for
giving me the opportunity to do this research. I would also like to thank my advisory
committee, Dr. Laurent Viel and Dr. Niel Karrow, for their interest in this project and for
supporting and guiding me throughout.
I would like to thank the staff at the Arkell Equine Research Station as this
research would not have been possible without their help. With special thanks to Heidi
Naumann and Nancy Wedel for helping me with the horses during the busy sample
collection days and to Dave Vandenberg and Brad Rogers for allowing me to use the
facility and for getting me the horses for the project. I would also like to thank the
veterinary technicians, veterinarians and agricultural assistants at the OVC Large Animal
Clinic for their help organizing and coordinating this project. With special thanks to
Michelle Morin and Ingrid Alexy-Ferrede for their assistance and support during the
gastroscopies and sample collection periods. I would again like to thank Dr. Viel and his
team, Aitor Gallastegui and Andres Diaz as well as Dr. Henri Staempfli for their help
with the gastroscopies and sample collection. I could not have completed this project if it
wasn't for all of you. I want to thank Rob Leighton and the agricultural assistants Rick
and Mike for their help with coordinating and organizing the trailering of my research
horses to and from the research station, your assistance was invaluable and I appreciate
all that you did for me.
I would also like to thank the staff at the Animal Health Laboratory for the blood
sample analysis as well as for the preparation of the tissue biopsies. With special thanks
to Josepha DeLay for her work on the histological evaluation of our biopsy samples. I
would also like to thank the staff at the University of Guelph Laboratory Services
division and the Agri-Food Laboratories for their analysis of our feed samples. I would
like to extend my sincere thanks to Dr. Mohammed Abo-Ismail for his continued
guidance, support and expertise on our statistical analysis. I could not have done it
without your help, thank you for your patience and for teaching me how to use the SAS
program.
To my friends and labmates, Maureen Crump, George Girgis, Brandon Walters
and Si-Trung Tran, I could not have completed this project without all of your help. To
Maureen, without your help I may not have pulled this project off, I thank you from the
bottom of my heart for all you have helped me with during this project. As well as to
George, thank you for guiding me through the process of sample collection and analysis.
I could not have done it without your knowledge and support. I would like to thank my
family and friends for supporting me throughout my degree. To my mom and dad, thank
you for believing in me. Thank you to Ally for supporting me and taking care of
Maxwell for me. To Dave, I could not have done it without your love and support.
Thank you for always being there, it means the world to me.
My research would not have been possible without the generous financial support
of OMAFRA and Alltech Inc. Nicholasville, Kentucky, United States of America.

  iv
TABLE OF CONTENTS
CHAPTER 1
Review of Literature……………………………………………………………………1

1.1. Introduction………………………………………………………………………….1
1.2. Equine Gastric Ulcer Syndrome…………………………………………………….3
1.2.1. Prevalence…………………………………………………………………4
1.2.2. Risk Factors……………………………………………………………….5
1.2.3. Signs………………………………………………………………………8
1.2.4. Diagnosis………………………………………………………………….9
1.2.5. Prevention/Treatment……………………………………………………..10
1.3. Fusarium Mycotoxins……………………………………………………………….11
1.3.1. Equine Fusarium Mycotoxicosis………………………………………….13
1.3.2. Fusarium Mycotoxins and GIT Damage………………………………….16
1.4. Mycotoxin Adsorbents………………………………………………………………18

CHAPTER 2
Experimental Rationale, Hypotheses and Objectives………………………………..21

2.1. Experimental Rationale……………………………………………………………..21
2.2. Experimental Hypotheses…………………………………………………………...22
2.3. Objectives…………………………………………………………………………...23
2.3.1. Pilot Trial………………………………………………………………….23
2.3.2. Main Trial…………………………………………………………………23

CHAPTER 3
The Effect of Feed-Borne Fusarium Mycotoxins On The Development of Equine
Gastric Ulcer Syndrome: A Pilot Trial………………………………………………..25

3.1. Abstract……………………………………………………………………………...25
3.2. Introduction………………………………………………………………………….26
3.3. Materials and Methods………………………………………………………………28
3.3.1. Experimental Animals and Diets………………………………………….28
3.3.2. Experimental Design and Housing………………………………………..29
3.3.2. Approval of Experimental Protocol……………………………………….30
3.3.3. Analysis of Dietary Mycotoxins…………………………………………..30
3.3.4. Experimental Parameters Studied…………………………………………31
3.3.4.1. Feed Intake and Body Weight…………………………………...31
3.3.4.2. Hematology and Serum Biochemistry…………………………..31
3.3.4.3. Gastroscopy and Ulcer Scoring of Gastric Mucosa……………..33
3.4. Results……………………………………………………………………………….34
3.4.1. Dietary Mycotoxin Concentrations………………………………………..34
3.4.2. Feed Intake and Body Weights……………………………………………34
3.4.3. Hematology and Serum Biochemistry…………………………………….35
3.4.4. Ulcer Scoring……………………………………………………………...35
3.5. Discussion…………………………………………………………………………...36
  v
3.5.1. Dietary Mycotoxin Concentrations………………………………………..36
3.5.2. Feed Intake and Body Weight..……………………………………………37
3.5.3. Hematology and Serum Biochemistry…………………………………….38
3.5.4. Ulcer Scoring……………………………………………………………...39

CHAPTER 4
The Effect of Feed-Borne Fusarium Mycotoxins On Equine Gastric Ulcer Syndrome
And The Efficacy Of A Glucomannan Mycotoxin Adsorbent……………………….51

4.1. Abstract……………………………………………………………………………...51
4.2. Introduction………………………………………………………………………….52
4.3. Materials and Methods………………………………………………………………55
4.3.1. Experimental Animals and Diets………………………………………….55
4.3.2. Experimental Design and Housing………………………………………..56
4.3.3. Approval of Experimental Protocol……………………………………….57
4.3.4. Analysis of Dietary Mycotoxins…………………………………………..57
4.3.5. Experimental Parameters Studied…………………………………………58
4.3.5.1. Feed Intake and Body Weight…………………………………...58
4.3.5.2. Hematology and Serum Biochemistry…………………………..58
4.3.5.3. Gastrin Analysis…………………………………………………59
4.3.5.4. Gastroscopy and Ulcer Scoring of Gastric Mucosa……………..60
4.3.5.5. Histological Evaluation of Tissue Biopsies……………………..61
4.3.6. Statistical Analysis………………………………………………………...62
4.4. Results……………………………………………………………………………….63
4.4.1. Dietary Mycotoxin Analysis………………………………………………63
4.4.2. Feed Intake and Body Weight……………………………………………..63
4.4.3. Serum Hematological and Biochemical Parameters………………………64
4.4.4. Serum Gastrin Analysis…………………………………………………...66
4.4.5. Ulcer Scoring and Histological Evaluation of Tissue Biopsies…………...67
4.5. Discussion…………………………………………………………………………...68
4.5.1. Dietary Mycotoxin Analysis………………………………………………68
4.5.2. Feed Intake and Body Weight……………………………………………..70
4.5.3. Serum Hematological and Biochemical Parameters………………………72
4.5.4. Serum Gastrin Analysis and Ulcer Score………………………………….79
4.5.5. Histological Evaluation of Tissue Biopsies……………………………….81
4.5.6. Efficacy of a Glucomannan Mycotoxin Adsorbent……………………….83

CHAPTER 5
Overall Conclusions…………………………………………………………………...102

REFERENCES………………………………………………………………………...105

  vi
LIST OF TABLES
Table Page

3.1. Composition of Dietary Equine Concentrates over the 28 Day Experimental Period,
Dry Matter Basis……………………................................................................................41
3.2. Equine Gastric Mucosal Ulcer Scoring System……………………………………..41
3.3. Dietary Mycotoxin Content of Equine Concentrates, As Fed Basis..……………….42
3.4. The Effect of Diet on Serum Biochemistry I………………………………………..43
3.5. The Effect of Diet on Serum Biochemistry II……………………………………….44
3.6. The Effect of Diet on Serum Biochemistry III……………………………………...45
3.7. The Effect of Diet on Serum Biochemistry IV……………………………………...46
3.8. The Effect of Diet on Serum Hematology I…………………………………………46
3.9. The Effect of Diet on Serum Hematology II………………………………………..47
4.1. Composition of Dietary Concentrates, Dry Matter Basis…………………………...86
4.2. Dietary Mycotoxin Content of Equine Concentrates, As Fed Basis………………...86
4.3. The Effect of Diet on Feed Intake and Body Weight in the Horse over the 28 Day
Experimental Period…………………………………….……………………………….87
4.4. The Effect of Diet on Serum Biochemistry I………………………………………..88
4.5. The Effect of Diet on Serum Biochemistry II……………………………………….89
4.6. The Effect of Diet on Serum Biochemistry III……………………………………...90
4.7. The Effect of Diet on Serum Biochemistry IV……………………………………...91
4.8. The Effect of Diet on Serum Biochemistry V………………………………………92
4.9. The Effect of Diet on Serum Biochemistry VI……………………………………...93
4.10. The Effect of Diet on Serum Biochemistry VII…………………………………...94
4.11. The Effect of Diet on Serum Hematology I………………………………………..95
  vii
4.12. The Effect of Diet on Serum Hematology II……………………………………….96
4.13. The Effect of Diet on Serum Hematology III……………………………………...97
4.14. The Effect of Diet on Serum Hematology IV……………………………………...98
4.15. The Effect of Diet on Ulcer Score and Serum Gastrin Concentration in the Horse
over the 28 Day Experimental Period…………………………………….……………...99

  viii
LIST OF FIGURES
Figure Page
3.1. Effect of Diet on Serum Alkaline Phosphatase Activity…………………………….48
3.2. Effect of Diet on Serum Calcium Concentrations…………………………………..48
3.3. Gastric Mucosal Changes…………………………………………………………...49
a) Day 5/6 Control Group………………………………………………………..49
b) Day 5/6 Contaminated Group…………………………………………………49
c) Day 12/13 Control Group……………………………………………………..49
d) Day 12/13 Contaminated Group………………………………………………49
e) Day 20/21 Control Group……………………………………………………..50
f) Day 20/21 Contaminated Group………………………………………………50
g) Day 27/28 Control Group……………………………………………………..50
h) Day 27/28 Contaminated Group………………………………………………50
4.1. The Effect of Dietary Treatment on Feed Intake…………………………………..100
4.2. The Effect of Dietary Treatment on Serum Total Protein…………………………100
4.3. The Effect of Dietary Treatment on Serum Total Bilirubin…………………….….101
4.4. The Effect of Dietary Treatment on Serum Free Bilirubin………………………...101

  ix
LIST OF ABBREVIATIONS
3-acetylDON 3-Acetyl-deoxynivalenol
15-acetylDON 15-Acetyl-deoxynivalenol
AFLA Aflatoxin
ANCOVA Analysis of Covariance
ANOVA Analysis of Variance
AST Aspartate Amino Transferase
CHO Carbohydrates
CK Creatine Kinase
DON Deoxynivalenol, Vomitoxin
EDTA Ethylenediaminetetraacetic acid
EGUS Equine Gastric Ulcer Syndrome
ELEM Equine Leukoencephalomalacia
FUMON Fumonisin
GGT Gamma Glutamyltransferase
GIT Gastrointestinal Tract
GLDH Glutamate Dehydrogenase
GMA Glucomannan Mycotoxin Adsorbent
Hb Hemoglobin
HCl Hydrochloric Acid
HCT Hematocrit
HPLC High Performance Liquid Chromatography
H. pylori Helicobacter Pylori
  x